NHS Choices

Nitrate-rich leafy greens 'good for the heart'

NHS Choices - Behind the Headlines - Thu, 04/12/2014 - 11:30

“Leafy vegetables contain chemical nitrate that improves heart health,” the Mail Online reports. In a recent study, researchers looked at the effects of a nitrate-rich diet on rats.

Nitrate is a chemical that can react to a number of different substances in a range of ways. For example, it can be used as a fertiliser or as the active ingredient in a bomb. Some nitrates are used as medication for angina, as they dilate the blood vessels.

This study found that rats given nitrate had lower levels of red blood cells (which carry oxygen) compared to a control group. This was associated with a reduction in the hormone erythropoietin (EPO), which regulates red blood cells.

Excessive amounts of red blood cells (polycythaemia) can sometimes trigger blood clots.

Blood clots can sometimes lead to serious complications, such as a stroke.

This study found that increasing nitrate in your diet stops low oxygen levels causing the over-production of EPO. The increased nitrate optimises the production of EPO from the liver and kidneys, which in turn reduces the blood’s thickness, but without compromising oxygen supply.

While the study involved rats not people, it’s always a good idea to eat up your greens. They contain a number of nutrients thought to help prevent cancer and heart disease.

 

Where did the story come from?

The study was carried out by researchers from the Universities of Cambridge and Southampton. It was funded by the British Heart Foundation, the Research Councils UK, the WYNG Foundation of Hong Kong, the European Union Framework 7 Inheritance project, the Wellcome Trust and the University of Southampton.

The study was published in the peer-reviewed Journal of the Federation of American Societies for Experimental Biology.

The reporting in the Mail Online and the Daily Express appears to be based on a press release that combined the findings of three related studies on nitrates:

  • The study we are analysing today (we chose this, as it is the most recent research).
  • study on the effects that nitrates have on how efficient the heart is in pumping blood around the body.
  • study into whether nitrates could have a protective effect against obesity and type 2 diabetes.

The reports in both the Express and the Mail overstate the results of all the studies, including the one we are discussing today. Neither paper mentioned that these were laboratory studies carried out in rats. Perhaps this is not surprising, given that the accompanying press release – and the authors quoted by it – did not mention it either.

 

What kind of research was this?

This was a laboratory study, which looked at the effect of nitrate supplementation on the red blood cells of rats.

EPO is responsible for regulating red blood cells in mammals, to meet the need for oxygen. In conditions of severe oxygen shortage, such as during critical illness and at high altitude, EPO increases, stimulating the production of more oxygen-carrying red blood cells.

While red blood cells are needed to supply enough oxygen, they can also lead to an increase in the blood’s “viscosity” or thickness, which may impair blood flow, as happens in chronic obstructive pulmonary disease, preventing it from flowing through small blood vessels in the lungs.

There is also the risk of a blood clot developing, which can lead to serious complications, such as a heart attack, stroke or pulmonary embolism.

A balance therefore needs to be met to get the optimum number of red blood cells and oxygen around the body.

Nitrate has already been shown to have beneficial effects on the heart and circulation. Here, the researchers wanted to test the theory that dietary nitrate might limit rises in the red blood cells needed for oxygen delivery by improving the efficiency of the body’s use of oxygen.

 

What did the research involve?

Two rat studies were performed to assess the effect of dietary supplementation with nitrates.

The first involved 40 rats. Half of them had nitrate added to their drinking water, while the other half acted as a control group with no supplementation. After four days, both groups were put in a chamber of low oxygen (12% rather than normal air, which is 21%). They continued to have either nitrate supplement or no supplement for 14 days.

The researchers compared their food and water intake, any change in body weight and plasma nitrate and haemoglobin (oxygen carrying component of red blood cells) levels in normal air and in low oxygen.

The second study aimed to see how fast and at what concentration the nitrate made changes to the haemoglobin levels. 24 rats were kept in normal oxygen conditions. After 12 days, half the group had their water supplemented with 0.7mm of nitrate. They measured the haemoglobin level in the blood after 0, 2, 4, 6, 9 and 12 days.

 

What were the basic results?

The researchers report that in both experiments rats given nitrate had lower concentrations of red blood cells in normal and low oxygen conditions compared with control groups.

They found that these rats also had lower levels of EPO. They say this suggests that the effects of nitrate were mediated via changes in EPO production.

The researchers found that nitrates reduced the amount of EPO released by the liver, but increased the amount released by the kidneys. They report that this balance meant that the nitrates were able to help the body produce the optimum minimum amount of haemoglobin that they required.

Nitrate supplementation did not alter the amount of food or water intake of the rats, or on their weight or growth.

 

How did the researchers interpret the results?

They conclude that nitrate acts to suppress the production of EPO by the liver, thereby lowering circulating red blood cells. Nitrate prevented an expected rise in circulating red blood cells in rats deprived of oxygen and also decreased red blood cells in rats with a normal oxygen supply.

They point out that nitrate levels used are readily achievable in humans via the diet, through eating green leafy vegetables.

In an accompanying press release, co-author Professor Martin Feelisch, from the University of Southampton, said: "These findings suggest simple dietary changes may offer treatments for people suffering from heart and blood vessel diseases that cause too many red blood cells to be produced. It is also exciting as it may have broader implications in sport science, and could aid recovery of patients in intensive care by helping us understand how oxygen can be delivered to our cells more efficiently."

 

Conclusion

It’s always a good idea to eat up your greens. This research suggests that one possible benefit is through the mechanism of nitrate “thinning” the blood and protecting against heart disease.  While the research is interesting, it’s a pity that no one thought to mention that this was a laboratory study on rats. It is important to remember that high levels of nitrates can be toxic, which is why there are safety limits for the level of nitrates in drinking water. High nitrate levels are especially harmful for infants.

A healthy diet – including plenty of vegetables – and regular exercise are important for a healthy heart and weight.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Now there's no excuse not to eat your greens: Leafy vegetables contain chemical nitrate that improves heart health and combats diabetes. Mail Online, November 4 2014

Eat up your greens and slash the risk of diabetes and obesity. Daily Express, November 4 2014

Links To Science

Ashmore T, Fernandez BO, Evans CE, et al. Suppression of erythropoiesis by dietary nitrate. The FASEB Journal. Published online November 24 2014

Categories: NHS Choices

Do time-restricted eating habits reduce obesity?

NHS Choices - Behind the Headlines - Thu, 04/12/2014 - 09:00

“Want to lose weight? Eat all your food in an eight-hour time frame – and never snack at night,” reports the Mail Online. However, these tips are based on a mouse study – no humans were involved.

Nearly 400 mice were studied in a series of experiments for up to 26 weeks. Sets of mice were given unrestricted 24-hour access to high-fat food, high-fat and high-sugar food or low-fat, high-fruit sugar foods. Their weight gain was compared to mice given the same types of food, but restricted to 9, 12, or 15 hours per day.

Mice ate the same number of calories per day irrespective of the number of hours they had access. All mice on high-fat or high-fat and high-sugar diets gained a large amount of weight regardless of access timescales. However, those with time-restricted access gained less weight.

The current stage of this research has limited application for people. We already know that high-fat and high-sugar diets cause weight gain, as was found here. It may be that future randomised controlled trials in humans will show that the amount of weight gain is more if the calories are consumed at times which do not make the most of our natural metabolic rhythm. However, despite the continued quest to “have your cake and eat it”, at present the best advice to combat obesity is to eat a balanced diet and to take regular exercise.

 

Where did the story come from?

The study was carried out by researchers from the Salk Institute for Biological Studies in La Jolla and the University of California. It was funded by the US National Institutes for Health, grants from the American Federation for Aging Research, Leona M and Harry B Helmsley Charitable Trust, the Glenn Center for Aging, the American Diabetes Association, the Philippe Foundation and the American Association for the Study of Liver Diseases.

The study was published in the peer-reviewed medical journal Cell Metabolism.

BBC News reported the story accurately; however, the Mail Online’s report was misleading. Its headline implies this study was conducted on humans, when it was only on mice. It also says that people should stop “eating after 4pm”. The restricted feeding times used in this study were for mice with nocturnal eating habits. There is no evidence from this study that weight gain would be avoided in people if we stopped eating at 4pm.

 

What kind of research was this?

This was a piece of animal research that aimed to look at whether restricting the timing of feeding could prevent weight gain or cause weight reduction in obese mice.

Obesity rates are increasing at an alarming rate and traditional methods of weight control – such as calorie restriction, change in diet and increase in exercise – are hard for many people to adhere to.

A person’s metabolic rhythm changes over the course of the day. Previous research has shown that this rhythm is heavily dependent on eating at the same time each day. Therefore, the researchers wanted to see if sticking to the optimal time of eating within this rhythm would prevent weight gain. They called this time-restricted feeding (TRF). As this study was conducted on mice, the optimal nine-hour feeding time was chosen to be during the night.

Research such as this is a good starting point for understanding the biological processes within an animal’s body, and seeing what can influence this, but we don’t know that the results will be directly applicable to people.

As the researchers conclude, a randomised controlled trial in people would be required.

 

What did the research involve?

The researchers used 392 male wild-type mice aged 12 weeks for a series of experiments lasting up to 26 weeks.

The mice were given free access to food 24 hours a day or TRF for either 9, 12 or 15 hours overnight. Some mice were switched from one type of access to the other.

The mice were given one of the following types of diets:

  • high-fat (32%), high-sucrose (25% table sugar) diet
  • high-fat (62%) diet
  • low-fat (13%) and fructose (60% fruit sugar) diet
  • normal chow diet

The weights of the mice on each regime and diet were compared. Further studies looked at the effect of obese mice switching to TRF regimes.

 

What were the basic results?

Mice fed a high-fat, high-sucrose diet for 12 weeks gained at least a fifth of their body weight. Weight gain doubled if they could eat at any time, despite eating the same number of calories:

  • 9 hours of access caused 21% weight gain
  • 24-hour access caused 42% weight gain

Mice fed a high-fat diet had higher weight gain with longer periods of food accessibility, despite consuming the same number of calories:

  • 9-hour access caused 26% weight gain
  • 15-hour access caused 43% weight gain
  • 24-hour access caused 65% weight gain

To measure whether a “lapse” in TRF had any effect, mice were fed a high-fat diet for five days using TRF and two days of unrestricted feeding (to mimic the two-day weekend). They gained 29% body weight over 12 weeks, similar to the weight gain without the lapse.

Mice fed a low-fat, high-fructose diet had a 6% weight gain in both feeding situations over 12 weeks, which was similar to control mice fed a normal chow diet.

Mice fed a high-fat diet for 13 weeks using TRF and then given 24-hour access for 12 weeks, rapidly gained weight after switching so that they gained the same amount of weight as mice with unrestricted access for the whole 15 weeks (111% to 112% body weight). A control set who had TRF for the 25 weeks gained 51% body weight.

In mice with pre-existing dietary-induced obesity from having 24-hour access to a high-fat diet, switching to TRF caused them to consume the same number of calories within a few days. However, they lost weight:

  • switching from 13 weeks of unrestricted access to 12 weeks TRF caused a drop in weight from 40g to 38g (5% body weight loss)
  • switching from 26 weeks of unrestricted access to 12 weeks TRF caused a drop in weight from 53.7g to 47.5g (12% body weight loss)

MRI images showed that the difference in body weight for all of these experiments was due to fat mass rather than lean body mass. There were also inflammatory markers in the fatty tissue of mice with round the clock access compared to no inflammatory markers in TRF mice.

 

How did the researchers interpret the results?

The researchers concluded that these “results highlight the great potential for TRF (time-restricted feeding) in counteracting human obesity and its associated metabolic disorders”. They believe “it is worth investigating whether the physiological observations found in mice apply to humans” and say that “a large-scale randomised control trial investigating the role of TRF would show whether it is applicable to humans”.

 

Conclusion

Time-restricted feeding caused less weight gain than all-hour access for mice eating a high-fat, high-sugar diet over 12 to 26 weeks. It also led to weight loss of up to 12% when applied to mice that were already obese. TRF does not appear to have an influence on weight gain for mice eating a healthy or normal diet.

The current stage of this research means it has limited application for humans. We already know that high-fat and high-sugar diets cause weight gain, as was found here. It may be that future randomised controlled trials in humans will show that the amount of weight gain is more if the calories are consumed at times that do not make the most of our natural metabolic rhythm.

Even if the timing of eating patterns do have an effect on weight gain, we suspect that any beneficial effects would be modest. If you regularly consume high-fat and high-sugar foods, and do not exercise, you will put on weight regardless of any time-restricted eating habits. Sadly, there is no quick fix to weight loss.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Why late night dining may encourage weight gain. BBC News, December 2 2014

Eat within 12-hour window to lose weight, say scientists. The Daily Telegraph, December 2 2014

Want to lose weight? Eat all your food in an eight-hour time frame - and NEVER snack at night. Mail Online, December 3 2014

Links To Science

Chaix A, Zarrinpar A, Mu P, et al. Time-Restricted Feeding Is a Preventative and Therapeutic Intervention against Diverse Nutritional Challenges. Cell Metabolism. Published online December 2 2014

Categories: NHS Choices

NICE recommends home births for some mums

NHS Choices - Behind the Headlines - Wed, 03/12/2014 - 11:00

Home births have dominated the UK media today, following the publication of guidance by the National Institute for Health and Care Excellence (NICE) on the care of healthy women and their babies during childbirth. The main talking point was the recommendation that women thought to have a low risk of pregnancy complications would be better served by giving birth at home or at a midwife-led unit, rather than at hospital.

NICE has reviewed the evidence for the vast majority of pregnant women in England and Wales who have healthy, uncomplicated pregnancies. The rate of interventions, such as the use of forceps or a caesarean section, in these low-risk women are generally slightly lower in the home or midwife-led units, compared with hospital-based maternity wards.

For women having their second or subsequent baby, a birth in either the home or a midwife-led unit are equally safe options. However, for low-risk first-time mothers, the midwife-led unit may be the best choice.

No woman will be “forced” to give birth at home or a midwife-led unit. NICE advises that all low-risk women should be free to choose their birth setting, and be supported in this choice.  

 

Who does the new guidance cover?

This new guidance focuses on the care of healthy women with uncomplicated pregnancies and low risk of complications. This represents the majority of pregnant women and childbirth in this country.

According to NICE, about 700,000 women give birth in England and Wales each year, around 40% of whom are having their first baby. The majority of these women will have a straightforward pregnancy and birth – around 90% giving birth at full term (over 37 weeks of pregnancy) to a single baby who is presenting head first. Around two-thirds of women will also go into labour spontaneously (without needing to be induced).

 

What was the media reaction to the guidelines?

Media reaction to the guidelines has been mixed. Some news organisations, such as The Guardian, have been broadly supportive, emphasising the benefits of home or midwife-led unit births, such as a lower risk of interventions, which include caesarean sections. Others, such as the Daily Mirror, have taken a more negative tone, implying that the guidelines have been influenced by concerns that some hospitals are under-resourced or are unsafe to handle cases of labour.

Claims by the Mail Online that “new rules” have been introduced are also misleading. As mentioned, all women will have the choice of where they want to give birth.

 

What do NICE say about the safety of home compared to hospital births?

NICE has compared the outcomes for “low-risk” women giving birth in four different settings: the standard hospital maternity (obstetric) unit, alongside midwifery units (separate midwife-led units alongside an obstetric unit), a freestanding midwifery unit and birth at home.

When looking at rates per 1,000 women, they found that most outcomes were generally similar or slightly better in the home, compared to the hospital setting. Results included the following:

  • Rates of spontaneous (not induced) vaginal birth were broadly the same in all settings, though slightly higher at home and in freestanding units. For multiparous mothers (i.e. women who have already had at least one baby) rates were 984 per 1,000 at home, 980 at a freestanding midwifery unit (FMU), 967 at an alongside midwifery unit (AMU) and 927 in a hospital obstetric unit. For first-time mothers, rates were 794 at home, 813 FMU, 765 AMU and 688 at hospital.
  • Use of epidural or spinal anaesthesia for pain relief was lower at home compared to other settings: for multiparous mothers, 28 per 1,000 at home, 40 at FMU, 60 at AMU and 121 in hospital. For first-time mothers, 218 at home, 200 FMU, 240 AMU and 349 at hospital.
  • Instrumental delivery rates (i.e. use of forceps or ventouse): for multiparous mothers, 9 per 1,000 at home, compared with 12 in FMU, 23 in AMU and 38 in hospital. For first-time mothers, 126 at home, 118 FMU, 159 AMU and 191 at hospital.
  • Rates of caesarean: for multiparous mothers, 7 per 1000 with planned home birth, 8 for FMU, 10 for AMU and 35 for planned hospital births. For first-time mothers, 80 for planned home birth, 69 at FMU, 76 at AMU and 121 for planned hospital births. 

When looking at outcomes for the baby, there was no difference in rates of complications between birth settings for babies born to multiparous women:

  • Babies born without serious medical problems: 997 per 1,000 babies of planned home birth, 997 for FMU, 998 for AMU and 997 for planned hospital births.
  • Babies born with serious medical problems (e.g. breathing in meconium, or brain problems): 3 per 1,000 babies of planned home birth, 3 for FMU, 2 for AMU and 3 for planned hospital births.

For babies born to first-time mothers, there were four extra babies born with serious medical problems:

  • Babies born without serious medical problems: 991 per 1,000 babies of planned home birth, 995 per 1,000 babies for all other settings.
  • Babies born with serious medical problems: nine per 1,000 babies of planned home birth, five per 1,000 babies for all other settings.

Therefore, birth in a hospital obstetric unit is generally associated with slightly higher rates of interventions and lower rates of spontaneous vaginal birth, compared to the other settings. While a number of possible reasons for the slightly higher rate of interventions in hospital have been discussed (such as women finding the hospital setting more stressful), none have been proven. Further research is therefore required.

For multiparous women, either at home or a in midwife-led unit are equally safe. However, for low-risk first-time mothers, the finding that four extra babies per 1,000 are born with serious medical problems with home births compared to other settings suggests that the midwife-led unit may be the best option for them.

 

What does NICE recommend?

A summary of the main guideline recommendations in terms of patient care, on place of birth, are as follows:

  • Explain to both multiparous and first-time mothers that they may choose any birth setting (home, FMU, AMU or hospital obstetric unit), and support them in their choice of setting wherever they choose to give birth.
  • Advise low-risk multiparous women that planning to give birth at home or in a midwifery-led unit is particularly suitable for them, because the rate of interventions is lower and the outcome for the baby is no different compared with an obstetric unit.
  • Advise low-risk first-time mothers that planning to give birth in a midwifery-led unit is particularly suitable for them, because the rate of interventions is lower and the outcome for the baby is no different compared with an obstetric unit.
  • Explain that if they plan their birth at home, there is a small increase in the risk of an adverse outcome for the baby.

 

Conclusion

NICE concludes that for low-risk women, whether having their first or subsequent baby, birth is generally very safe for both mother and baby, and they should be free to choose any of the four birth settings and be supported in their choice.

As their findings suggest, it is important that the woman is able to make a fully informed decision, by being given all the relevant information about birth in the different settings – including, as Professor Mark Baker of NICE states: “Where and how a woman gives birth to her baby can be hugely important to her. Although women with complicated pregnancies will still need a doctor, there is no reason why women at low risk of complications during labour should not have their baby in an environment in which they feel most comfortable.” He suggests that the new guidance “will encourage greater choice in these decisions and ensure the best outcomes for both mother and baby”.

As Susan Bewley, Professor of Complex Obstetrics at King’s College London, importantly highlights, women should not feel pressured into giving birth outside of a hospital if this is not their preference: “If a woman would prefer to have her baby in a hospital because it makes her feel ‘safer’, that is also her right. Giving birth is a highly personal experience and there is no ‘one size fits all’ model that suits all women.

“What’s important is that women and their families are given the most up-to-date information based on the best available evidence, so that they can make an informed decision about where the mother gives birth to her child.”

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

Home births are 'best for many mothers'. BBC News, December 3 2014

New NHS guidance could mean thousands more home births. The Independent, December 3 2014

Doctors are not needed at births, says NHS. The Daily Telegraph, December 3 2014

Home safer than hospital for birth, mothers told. The Times, December 3 2014

More mothers 'should be having their baby at home': New rules say half of women who give birth are at such low risk of problems they don't need to visit labour ward. Daily Mail, December 3 2014

Low-risk pregnant women urged to avoid hospital births. The Guardian, December 3 2014

Mums-to-be warned 'have your baby at home - it's SAFER' by health chiefs. Daily Mirror, December 3 2014

Women should give birth at home or in midwife-led centres advises NHS. Daily Express, December 3 2014

Categories: NHS Choices

Weight loss surgery 'not a quick fix' for good health

NHS Choices - Behind the Headlines - Tue, 02/12/2014 - 15:43

"Weight loss surgery isn't just a quick fix to becoming healthy – you have to exercise too," the Mail Online reports.

Weight loss surgery, such as fitting a gastric band, usually results in significant weight loss.

But this weight loss doesn't automatically lead to improvements in important markers for metabolic health, such as insulin sensitivity. A low level of insulin sensitivity is a major risk factor for type 2 diabetes.

In a new study, 128 adults were randomised into two groups. One group received a six-month moderate exercise programme, while the other received a six-month health education programme.

After six months, those that followed the exercise programme had better insulin sensitivity than those following the educational programme.

But the picture was not completely clear. Quite a few people dropped out of the study or did not adhere to the six-month exercise programme fully.

This could mean the programme as a whole would not yield any significantly better improvements at a population level. This balance of cost and benefit influences whether a supervised exercise plan would (or should) be funded on the NHS.

 

Where did the story come from?

The study was carried out by researchers from the University of Pittsburgh, East Carolina University and Florida Hospital in the US.

It was funded by the US National Institutes of Health.

The study was published in The Journal of Clinical Investigation, a peer-reviewed medical journal, on an open access basis, so it is free to read online or download as a PDF.

The Mail Online's coverage of the science was generally accurate, although they did not discuss the issues around compliance to the exercise programme. 

 

What kind of research was this?

This was a single-blinded, prospective, randomised clinical trial (RCT) to find out whether, after weight loss surgery, an exercise programme improved insulin sensitivity, compared with a health education programme.

A single-blinded RCT means the researchers analysing the data at the end of the trial did not know what programme each individual was assigned to.

The study reports weight loss surgery can result in dramatic weight loss and helps partially cure type 2 diabetes in a large percentage of obese patients.

However, it seems their insulin sensitivity does not return to healthy levels, despite significant weight loss.

Insulin helps lower blood glucose levels. How sensitive the body is to insulin (insulin sensitivity) varies from person to person.

People with type 2 diabetes are not very sensitive to insulin (insulin resistant), meaning they need more insulin to lower their blood sugar levels than someone who is more insulin sensitive.

Insulin sensitivity is often used as an indicator of how well the body is regulating blood glucose levels and can be a sign of diabetes.

The researchers thought exercise might help insulin sensitivity in patients after weight loss surgery, so they designed the trial to test this theory.

 

What did the research involve?

The researchers randomised 128 mainly female adult volunteers who had recently undergone weight loss surgery into two groups.

One group was assigned a six-month semi-supervised moderate exercise programme (66 people), while the other group was assigned a health education programme over a similar period to act as a control group (62 people).

After six months, the researchers compared the two groups for insulin sensitivity, fitness and body composition.

All participants had a Roux-en-Y gastric bypass within one to three months of the study's start date. This procedure involves creating a small pouch at the top of the stomach.

This pouch is then connected directly to a section of the small intestine, bypassing the rest of the stomach and bowel, so it takes less food for a person to feel full.

The Roux-en-Y gastric bypass was described in the research as the most commonly performed weight loss surgery in the US.

Participants had to be aged between 21 and 60 to be included in the study. They were excluded if they had a diagnosis of diabetes, hypertension, anaemia, hypothyroidism, elevated liver enzymes, current malignancy or a history of cancer within the past five years.

They were also excluded if they had had a stent placement within the past three years, or if they had a history of myocardial infarction, angioplasty, angina, liver disease or neuromuscular disease.

The exercise intervention was three to five exercise sessions per week, with at least one directly supervised session a week to ensure that target exercise intensity and duration was achieved.

Participants used a heart rate monitor and recorded detailed logs of their exercise sessions, including the type of exercise, duration and average heart rate.

Exercise was built up gradually, but they were aiming to achieve a minimum of 120 minutes of exercise a week for the last three months of the intervention.

The health education control group was asked to attend six health education sessions. The sessions were held once a month, and involved lectures, discussions and demonstrations providing up-to-date information on topics such as medication use, nutrition and upper body stretching.

The participants in the exercise group also received the same health education sessions, including advice on nutrition (six sessions, one every month).

As well as insulin sensitivity, the team measured glucose effectiveness, which was worked out from an intravenous glucose tolerance test.

Data was analysed to assess whether the exercise programme worked better than the education programme for:

  • all participants using intention-to-treat (ITT) calculations
  • participants who completed the exercise and education interventions using a per protocol (PP) approach

 

What were the basic results?

A total of 128 participants were randomised at the start of the trial, and 100 completed the six-month interventions as planned, giving an overall completion rate of 78%.

This breaks down into 67% completing the exercise intervention and 90% completing the educational intervention.

There was a similar and significant decrease in body weight, waist circumference and fat mass for both groups following surgery and the interventions. Insulin sensitivity also significantly improved in both groups post-surgery.

The main finding was that exercise intervention led to a greater improvement in insulin sensitivity than the education intervention.

But this was only true (statistically significant) using the per protocol data. This means the people who completed the exercise intervention from start to finish benefited more than the education group.

However, not everyone assigned to the exercise intervention completed it. When these "non-completers" were included in the analysis (ITT analysis), the improvement for each group was the same.

The fact that a relatively large minority dropped out of the exercise programme has wider implications when considering whether such a programme would be effective and efficient if it was rolled out to larger populations. 

Additional ITT analysis showed exercise improved cardiorespiratory fitness compared with the education group.

 

How did the researchers interpret the results?

The authors interpreted their results as meaning that, "Moderate exercise following RYGB [Roux-en-Y gastric bypass] surgery provides additional improvements in SI, SG, [insulin sensitivity and blood glucose control] and cardiorespiratory fitness compared with a sedentary [non-active] lifestyle during similar weight loss."

 

Conclusion

This study provides some tentative evidence that adding a six-month exercise programme shortly after people have weight loss surgery might lead to more improvements in insulin sensitivity compared with a six-month-long educational programme.

However, the picture is muddied by the fact quite a few people dropped out or did not adhere to the exercise programme fully. It seemed that if people were able to stick to the exercise programme, it was more beneficial than no exercise.

This might seem obvious, but if this programme was introduced more widely, you might expect a similar proportion of people not to complete it. This could mean the programme as a whole would not yield any significant improvements at a population level.

Indeed, when all participants in each group were included in the analyses, there was little difference between the groups.

The authors reported high completion rates for both exercise and educational interventions – both over 90%. However, our calculations put this at a significantly lower 67% and 90% respectively.

Irrespective of the exact figures, those that did not complete the intervention did influence the results. This suggests the exercise intervention may be more effective than an education-only programme, but there is an important group who failed to adhere to it.

If the reasons for this non-compliance are not explored, they have the potential to widen health inequalities.

The study also mostly recruited adult women who were free from many additional diseases, such as cancer. This group might not be representative of the wider UK population undergoing weight loss surgery. Further trials involving more representative groups would give more generally applicable results.

In sum, for those who completed the trial as planned, exercise improved their insulin sensitivity, but there were adherence issues that call into question whether it would be effective at a population level.

If you want to gain the maximum benefit from weight loss surgery, it is important to adhere to any post-surgical advice, such as recommendations on diet and exercise.

Failure to do so could lead to a worsening of your health and possibly regaining some of the weight you previously lost.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Weight loss surgery isn't just a quick fix to becoming healthy - you have to exercise too, doctors warn. Mail Online, December 1 2014

Links To Science

Coen PM, Tanner CJ, Helbling NL, et al. Clinical trial demonstrates exercise following bariatric surgery improves insulin sensitivity. The Journal of Clinical Investigation. Published online December 1 2014

Categories: NHS Choices

HIV evolving into less deadly form

NHS Choices - Behind the Headlines - Tue, 02/12/2014 - 10:29

“HIV is evolving to become less deadly and less infectious,” BBC News reports.

A new study showed that HIV adapts to a person’s immune system, and that some of these adaptations may reduce the virulence of the virus.

The research team looked specifically at HIV in Botswana and South Africa. It found that over time, human immune system proteins, in addition to the use of HIV drugs, may have forced the virus to change into less virulent forms.

This is consistent with the theory that viruses get less virulent over time. The optimal evolutionary strategy for a virus is to be infectious (so it creates more copies of itself) but non-lethal (so its host population doesn’t die out). The "poster boy" for successful long-living viruses is, arguably, the family of viruses that cause the common cold, which has existed for thousands of years.

The authors warn that HIV, even at the reduced virulence, can still trigger the onset of AIDS.

Similarly, this study does not show that HIV virulence in the UK is decreasing, and that the virus remains life-threatening.

The simplest way to protect yourself against HIV infection in the UK is to use a condom during sex and never share needles if you are an injecting drug user.

Where did the story come from?

The study was led by researchers from Oxford and several institutes in Canada, the US, South Africa, Botswana and Japan. It was funded by grants from the National Institutes of Health (US), the Wellcome Trust (UK), the Medical Research Council UK and the Canadian Institutes of Health.

The study was published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS), a peer-reviewed science journal. It is an open-access study, meaning that anyone can read it online or download it for free.

The UK media reported the story accurately. It was important that they included a warning that, despite a small decrease in the virus’ potency in some areas of Africa, HIV still causes AIDS. This can significantly shorten life, due to impairment of the immune system if the correct treatment is not followed and made available soon after infection.

 

What kind of research was this?

This was a laboratory study investigating whether HIV virulence has changed over time, and what might be influencing it.

The term virulence means the ability of the virus to cause disease. This is generally described in terms of:

  • how likely the virus is to be passed on to a different person (transmissibility)
  • how much of the virus the person carries in their bloodstream (viral load)
  • how quickly the virus replicates itself (viral replicative capacity)

Individuals can have slightly different immune responses to HIV infection. This (and other factors) can affect how virulent HIV is in the person’s body and how long it takes HIV infection to cause AIDS. Understanding this variation is important in the effort to minimise the suffering and deaths from the disease.

After HIV infection, some people develop AIDS quicker than others. This natural variation is partly caused by changes in human leukocyte antigen (HLA) genes, a group of genes that encode HLA proteins involved in the immune response. This study wanted to find out how HIV evolution has been shaped by specific HLA proteins that are known to protect against disease progression. They also wanted to know whether HIV drugs (antiretroviral therapy) had influenced the evolution of the virus.

 

What did the research involve?

This study looked at the genetics and virulence of HIV from epidemic regions in Botswana and South Africa, two countries severely affected by HIV infection. They compared many measures of virulence in the two areas and looked at whether HIV genetics had adapted to HLA proteins known to be protective against disease progression.

In characterising virulence they looked at:

  • prevalence of the virus in adults in the two countries
  • how much virus people carried in their bloodstream (viral load)
  • how quickly the virus replicated itself (viral replicative capacity)
  • CD4 count (CD4 cells are key to a person’s immune system, but HIV infects and destroys them; once CD4 cell level falls below a certain point, the person has AIDS)

The study also contained data from Japan, where HIV prevalence has remained low, and never exceeded 0.1% of the adult population.

 

What were the basic results?

The epidemic in Botswana started earlier than in South Africa. As such, the adult prevalence of HIV infection in Botswana was consistently and significantly higher than South Africa over the last 20 years. So too was the use of antiretroviral therapy to prevent disease progress to AIDS.

Despite the higher prevalence, viral load and viral replicative capacity of HIV in Botswana was significantly lower than HIV in South Africa. This meant that the virus was slightly less virulent. This appeared to be due to both an adaptation to different HLA proteins that forced the virus into a less virulent form and the use of antiretroviral therapy.

 

How did the researchers interpret the results?

The research team concluded that “HIV evolution is progressing rapidly” and that “The contrasts between Botswana and South Africa, in the degree of adaptation of HIV to prevailing HLA molecules in the populations and in the protective impact of protective alleles such as HLA-B*57 and HLA-B*58:01, coincide with the substantial differences in duration and magnitude of the epidemic in these two localities”.

 

Conclusion

This study shows that HIV adapts to a person’s immune system, and that some of these adaptations may reduce the virulence of the virus. It appears that over time, the virulence of HIV in Botswana has decreased compared with HIV in South Africa, because of such adaptations and the use of HIV drugs. Specific HLA proteins present in adults in Botswana have, over time, forced the virus to change into less virulent forms, allowing it to survive, replicate and spread.

This is consistent with a broader theory that epidemic viruses get less virulent over time, due to natural selection. The most severe viruses kill their hosts too early to be passed on. Hence, eventually, the very severe strains die out or mutate into milder forms.

This study furthers our understanding of the evolution of HIV in Botswana and South Africa. However, we cannot be complacent. HIV, even at the reduced virulence in Botswana, does cause pain, suffering and death. While HIV can be managed over the long term to push back the development of AIDS, this is dependent on quick and appropriate access to HIV drugs. This may not be the case for everyone.

Similarly, this study does not show that HIV virulence in the UK has decreased or is decreasing, so it is important not to be complacent or to diminish the serious and life-threatening risk of HIV infection.

The simplest way to protect yourself against HIV infection is to use a condom during sex; 95% of cases in the UK in 2011 were as a result of unprotected sexual contact. You should also never share needles if you are an injecting drug user. Some NHS trusts and local authorities run needle exchange programmes – this link can provide information about drug support services in your local area.

Read more about HIV prevention.

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

HIV evolving 'into milder form'. BBC News, December 1 2014

HIV is evolving to become less deadly. Metro, December 2 2014

HIV evolves into less deadly form. New Scientist, December 1 2014

Links To Science

Payne R, Muenchoff M, Mann J, et al. Impact of HLA-driven HIV adaptation on virulence in populations of high HIV seroprevalence. PNAS. Published online December 1 2014

Categories: NHS Choices

Can a pill cure binge drinking and dementia?

NHS Choices - Behind the Headlines - Mon, 01/12/2014 - 12:00

"'Wonder' drug could cure binge drinking, Alzheimer's and dementia," the Mail Online reports. But before you raise a glass or two, these are premature claims based on research in rats that has not yet been proven, or even tested, in people.

Researchers gave rats alcohol to mimic the habits of human binge drinking. After three weeks of binging, the rats had signs of damage to their brain and performed worse at tasks that involved running through mazes.

When the scientists gave some of the mice a compound called ethane-β-sultam, it significantly reduced the alcohol-associated brain damage and inflammation, and resulted in improved performance in the maze tests.

This research suggests there may be a way to reduce the effects of excessive alcohol consumption on brain cells. But this is not a "cure" for binge drinking. Researchers only looked at short-term effects in rats, so the effects in humans remain unknown.

Also, the study only focused on the potential protective effects of the drug on the brain. Excessive alcohol consumption can also damage the liver. But the drug was not designed to work in this way and this was not looked at as part of the study.

Claims the compound could also be used to treat dementia are also pure speculation at the moment, as this was not tested.

 

Where did the story come from?

The study was carried out by researchers from universities in Italy, Belgium and the UK, and was funded by the European Foundation for Alcohol Research and the European Cooperation in Science and Technology (COST).

It was published in the peer-reviewed journal Alcoholism and Drug Dependence on an open access basis, so it is free to read online.

The science was covered by the Mail Online, which exaggerated the findings by implying the rat results also applied to humans and binge drinking, as well as Alzheimer's and other "brain diseases".

This may be the case, but it is too early to say with any confidence or assurance. The study did not test the effects of the drug, even in animal models of Alzheimer's or non-alcohol-related brain diseases.

Describing the drug as "curing" binge drinking is also misleading. While the drug showed some protective effect on brain cells and function, there was no assessment on damage to the liver, which is a significant cause of alcohol-related disease and death.

However, the Mail's coverage may have been influenced by a rather overexcited press release issued by the University of Huddersfield, which claimed that, "Huddersfield scientists develop breakthrough compound, reducing harmful side effects of 'binge drinking', and offering potential new ways to treat Alzheimer's and other neurological diseases that damage the brain".

 

What kind of research was this?

This was an animal study using rats to study the potential protective effects of the chemical ethane-β-sultam on the brain against the effects of binge drinking.

Intermittent excessive alcohol consumption – euphemistically termed "binge drinking" – is defined as drinking more than the maximum daily recommended units in a single session. This is often followed by a period of abstinence.

The research team says binge drinking harms brain cells, causes inflammation in the brain, and worsens learning and memory.

This research sought to use rats to better understand the underlying biology of the effects of binge drinking on the brain, and investigate whether a drug could be used to protect against some of the harms.

Researchers often use mice or rats for research purposes because, as mammals, they share similar biology to humans. This means research in rats can tell us what might happen in humans without directly experimenting on people in ways that would not be feasible or ethical.

However, there is no guarantee results in rats will be replicated in humans because, while we are similar, our biology is far from identical and these differences can be crucial. Often, direct study on humans is the only way to get the right results.

 

What did the research involve?

The research took a group of rats and gave them alcohol to mimic various scenarios of human binge drinking. Some of the mice were also given a drug called ethane-β-sultam to see if it was protective against harm from alcohol.

After different binge drinking simulations, the rats underwent tests assessing the levels of cellular degeneration and inflammation in their brains, as well as a test of their spatial memory involving escape from a maze.

Ultimately, the researchers were looking for differences between mice given ethane-β-sultam and those that were not.

The team tested two binge drinking levels: 1g/kg and 2g/kg. The human equivalent for a person of average weight would be eight units of alcohol for the first level (around two-and-a-half pints of strong lager) and 16 units for the second level (around one-and-a-half bottles of wine).

The rats had at least two different binge drinking sessions followed by a period of no drinking. 

Ethanol (alcohol) doses (20%) were administered three times per day with three-hour intervals on two consecutive days, followed by five days of abstinence. This was repeated for a total of three weeks.

Those allocated to receive ethane-β-sultam were given it every day of the three-week experiment and one week prior to starting the binge drinking simulation.

The rats underwent brain surgery at day five and after three weeks to see how alcohol was affecting their brains.

 

What were the basic results?

The main results showed the rats on the binge drinking regime had brain cell loss in a specific area of their brains called the hippocampus, and this was also associated with inflammation in those areas.

Daily supplementation of ethane-β-sultam suppressed much of the inflammation and reduced the loss of brain cells, particularly in rats given the lower of the two alcohol doses (1g/kg).

Binge-drinking rats administered 1g/kg ethanol took longer to solve a spatial navigation test compared with rats not consuming alcohol.

However, test results were almost normal for the group of rats receiving the same 1g/kg binge drinking regimen but also supplemented with daily ethane-β-sultam.

 

How did the researchers interpret the results?

The team said that, "Such results confirm that the administration of ethane-β-sultam to binge drinking rats reduces neuroinflammation in both the periphery and the brain, suppresses neuronal loss, and improved working memory of rats in a water maze study."

 

Conclusion

This research shows there may be a way to reduce the harmful effects of excessive alcohol consumption on brain cells, and potentially protect against associated deterioration in brain function.

However, none of this was conclusively proven in rats or humans, so the headlines suggesting a "cure for binge drinking" in people are premature.

While the results are promising, they represent a very early step on the road towards treatment in people. For example, the study looked at the effects of the drug in rats. While biologically similar to humans, they are not identical, and sometimes the differences are crucial.

As a result, the effects in humans could be different in many important ways. At this stage, there have been no experiments using people.

This is the first test of its kind, so ideally it will be repeated in other groups of rats to ensure the results are reliable and repeatable. If these do well, tests in humans may well begin.

It is likely to be unethical to force people to binge drink for the purposes of research, so it may be tricky to replicate these studies in humans.

Researchers will also need to know whether the drug has any effect if given after binge drinking, rather than at the same time as the alcohol. The drug will not be able to reverse brain cell loss that has already happened.

This study only focused on the potential protective effects of the drug on the brain. But some of the most serious consequences of excessive alcohol consumption affect the liver, and can ultimately lead to liver scarring and potentially death. The drug was not designed to stop any of these liver-related harms, and may not do so.

Some of the news coverage mentioned the potential for this drug to be used in other diseases associated with inflammation and deterioration in the brain, such as Alzheimer's disease.

Inflammation of the brain is also a problem in these conditions, so it is biologically plausible theoretically, but this was not tested in this study.

The issues around developing a drug to treat what some people perceive as a lifestyle choice and others an addiction may also attract some ethical debate.

On this point, lead author Professor Page was quoted in the Mail Online as saying: "If you accept that alcohol abuse is going to continue, then it might be sensible for society to try and treat it in some way."

Ethical considerations aside, if this drug works in people, it may be a pragmatic way of minimising some of the brain-related harms associated with binge drinking, and potentially other types of harmful drinking.

As we have said, though, it will do nothing to combat harms to other body organs, such as the liver, which are serious. 

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

'Wonder' drug could cure binge drinking, Alzheimer's AND dementia, scientists claim. Mail Online, November 28 2014

New Drug Created To Reduce Harmful Effects Of Binge-Drinking. Huffington Post, November 28 2014

Links To Science

Stefanini C, Colivicchi MA, Della Corte L, et al. Ethane-β-Sultam Modifies the Activation of the Innate Immune System Induced by Intermittent Ethanol Administration in Female Adolescent Rats. Journal of Alcoholism and Drug Dependence. Published online February 20 2014

Categories: NHS Choices

HIV drug may slow the spread of prostate cancer

NHS Choices - Behind the Headlines - Mon, 01/12/2014 - 11:40

“A drug used to treat HIV infection can slow the spread of prostate cancer, research has shown,” The Independent reports.

The news centres on the drug maraviroc (Celsentri), which researchers have found may slow the spread of prostate cancer into the bone and brain in early tests in mice.

Each man’s prostate cancer can progress in different ways. Many cases grow slowly, and the cancer remains within the prostate. A minority of cases are highly aggressive and can spread into other areas of the body, such as bones and the brain – a process known as metastasis.

In this research, scientists found a way to prompt mouse prostate cells to take on the characteristics of metastatic cancer cells, and then studied what proteins played a role in this change.

A protein called CCR5 was found to be implicated. Luckily maraviroc, a drug licensed for treating people with HIV, is already known to inhibit this protein. Giving maraviroc to mice that had been injected with the prostate cancer-like cells reduced the spread of the cancer to brain and bone by more than 60%.

This is still very early-stage research, and we will need to see the results of human trials before we know whether this drug is effective for preventing or treating prostate cancer metastases in humans.

 

Where did the story come from?

The study was carried out by researchers from Thomas Jefferson University in the US and other universities in the US, Italy and Mexico. It was funded by the US National Institutes of Health, the Dr. Ralph and Marian C. Falk Medical Research Trust, the Margaret Q. Landenberger Research Foundation, the Pennsylvania Department of Health, The National Autonomous University of Mexico and Thomas Jefferson University.

One of the authors is the founder of a company called ProstaGene, LLC and AAA Phoenix, Inc., and owns patents relating to prostate cancer cell lines and uses for these.

The study was published in the peer-reviewed medical journal Cancer Research on an open access basis, so it's free to read online.

The Independent covered this study accurately, if briefly, stating that the research was at an early stage and carried out on mice. The Daily Express also provides an accurate summary of the study, along with some useful background information about prostate cancer.

 

What kind of research was this?

This was animal research looking at how prostate cancer cells spread (metastasise) to bone, and how this might be stopped.

When prostate cancer spreads in the body, it often spreads to bone. Researchers would like to know why this is and how to stop it. None of the existing mouse models of prostate cancer reliably develop bone metastases, and this makes it difficult to study. The researchers wanted to develop a mouse model of prostate cancer, which would develop bone metastases, and use it to study this condition.

Animal studies are often used to get a better understanding of the biology of human disease and how it might be treated. The biology of animals such as mice has a lot of similarities to humans, but there are also differences. This means that results seen in mice won’t always be seen in humans, so human studies are needed to confirm initial findings in mice.

 

What did the research involve?

The researchers obtained cells from mouse prostate tissue and used genetic engineering to get them to produce an abnormally active form of a protein called Src, which encourages cells to become cancerous. They then looked at whether the cells divided and moved more in the lab, allowing them to “invade” a gel substance that resembles body tissue. These characteristics indicate whether the cells are behaving more like cancer cells spreading in the body. They also looked at what happened if they injected these cells under the skin or into the bloodstream of mice.

The researchers then compared which genes were active in normal mouse prostate cells, in the genetically engineered prostate cancer-like cells grown in the lab and those injected into the mice. Genes that are more active in the cancer-like cells could be contributing to their growth and spread. After this, the researchers looked at whether any of these genes were also more active in human prostate cancer tissue, using a bank of existing data on gene activity in human tissues.

Once they identified a gene that could be playing a role in prostate cancer, they carried out a range of experiments to further look at its effects. These included tests looking at whether stopping the protein produced by this gene from working may stop the spread of the genetically engineered prostate cancer tumours in the mice.

 

What were the basic results?

Prostate cells producing the abnormally active Src protein divided and moved more, and were more invasive in the lab. They grew into tumours if injected under the skin of mice, and if injected into the bloodstream, they spread to various organs, including the bone and brain. The tumours in the bone still had the appearance of prostate cancer tissue.

Genes playing a part in a particular pathway called the CCR5 signalling pathway were more active in these prostate cancer-like cells than in normal mouse prostate cells. The CCR5 gene was also found to be more active in human prostate cancer, particularly metastatic cancers. This and previous research suggests this gene could be contributing to the spread of the prostate cancer cells.

An HIV drug called maraviroc stops the protein produced by the CCR5 gene from working as effectively, so the researchers tested whether it could prevent the cells from spreading. They found maraviroc stopped the mouse prostate cancer-like cells from being invasive in the lab.

The researchers also found that giving maraviroc to mice injected with mouse prostate cancer-like cells also reduced metastases by more than 60%.

 

How did the researchers interpret the results?

The researchers concluded that they had developed a new mouse model of human prostate cancer, which may be a useful addition to the existing models of this disease. The protein CCR5 appears to be more active in metastatic prostate cancer cells. The spread of these cells in mice is reduced by the oral CCR5 inhibiting drug maraviroc, which is already approved as a treatment for HIV. The results suggest that clinical trials might be warranted for maraviroc or similar CCR5 inhibiting drugs in men with prostate cancers found to have high levels of CCR5 activity.

 

Conclusion

This animal research has identified the protein CCR5 as potentially playing a role in how prostate cancer cells spread (metastasise) through the body. The study has also shown that a drug already on the market for treating HIV, called maraviroc (brand name "Celsentri") can reduce prostate cancer-like metastases in mice.

As the drug maraviroc has already obtained a license for HIV use, there is already evidence suggesting that it is safe enough for use in humans. This could mean that clinical trials of this drug for prostate cancer could take less time to happen than if this was a new chemical compound whose safety had not been previously tested in humans.

However, it’s worth bearing in mind that this is still very early-stage research. Researchers are likely to want to carry out more studies on human prostate cancer tissue and cells in the lab, and in animals, to confirm that CCR5 is playing a role in the spread of prostate cancer. We will need to see what the results of human trials are before we know whether this drug is effective for preventing or treating prostate cancer metastases in humans.

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

HIV drug maraviroc may slow prostate cancer. The Independent, November 30 2014

HIV drug 'dramatically SLOWS' spread of prostate cancer. Daily Express, December 1 2014

Links To Science

Sicoli D, Jiao X, Ju X, et al. CCR5 Receptor Antagonists Block Metastasis to Bone of v-Src Oncogene–Transformed Metastatic Prostate Cancer Cell Lines. Cancer Research. Published online December 1 2014

Categories: NHS Choices

Majority of supermarket chickens carry food bug

NHS Choices - Behind the Headlines - Fri, 28/11/2014 - 12:00

“More than 70% of fresh chickens being sold in the UK are contaminated,” BBC News reports.

A Food Standards Agency (FSA) investigation found worryingly high levels of contamination with the campylobacter bug, which can cause food poisoning, on chickens being sold across the country. The Guardian reported a food scientist, Professor Tim Lang, calling for a “boycott of supermarket chicken because of 'scandalous' levels of contamination”.

Campylobacter is a type of bacteria thought to be the leading cause of food poisoning in the UK. Eating food contaminated with campylobacter can trigger symptoms such as nausea, vomiting, diarrhoea and stomach cramps.

Who produced the report?

The FSA released the latest figures from its testing of raw chickens in the first half of 2014. The agency has a key role in preventing foodborne illnesses. Reducing campylobacter in chickens is one of its main priorities because more than 280,000 people are infected with it each year in the UK.

The European Food Standard Authority (EFSA) has reported that up to 80% of campylobacter cases are due to raw poultry. It has estimated that the number of cases could be cut by between 50% and 90% if the levels of campylobacter in poultry across Europe was reduced to a tenth of the current levels.

 

What did the survey involve?

The FSA tested 1,995 fresh whole raw chickens and their outer packaging for the presence of campylobacter from February 2014 to August 2014. The chickens came from a wide range of UK supermarkets, small independent stores and butchers. The chickens were UK-produced standard, free range or organic, and not frozen, stuffed or marinated.

The FSA recorded the level of campylobacter on the chicken skin and outer packaging, and also reported whether the level on the skin was greater than the level at which the bug is thought to be most likely to infect humans (1,000 colony forming units per gram (cfu/g)).

 

What are the findings of the report?

Overall, 70% of raw chickens contained campylobacter on the skin:

  • 18% were over the threshold where human infection is most likely (1,000cfu/g)
  • 31% had moderate levels (between 100 and 1000cfu/g)
  • 21% had low levels (between 10 and 99cfu/g)

Outer packaging was contaminated in 6% of chickens:

  • One chicken’s outer packaging had levels over the 1,000cfu/g threshold
  • 1% had moderate levels (100 to 1000cfu/g)
  • 5% had low levels (10 to 99cfu/g)

The rates of campylobacter in chickens from different supermarkets or shops varied between 64% and 69%.

Some supermarkets had slightly better results than others, but all needed to improve.

The results grouped of all of the independent retailers and butchers together, so were unable to provide figures for these different types of chicken sellers. The assessment was not specifically designed to give a robust comparison between different supermarkets or shops. The FSA was unable to analyse the data to determine if there was a difference between the types of chicken tested – housed, organic or free range.

 

What are the potential health risks associated with chicken containing campylobacter?

Eating food contaminated with campylobacter – such as raw poultry, undercooked chicken liver pate and unpasteurised milk – can cause food poisoning. The symptoms usually start within two to five days, but can take up to 10 days to begin.

Campylobacter is the most common cause of diarrhoea in the world. Other symptoms can include abdominal pain, fever, headache, nausea and vomiting. It is usually a mild infection, lasting from three to six days, but can be fatal for very young children, the elderly and people whose immune system is not working well.

Cooking chicken will kill off campylobacter. The concern is that someone may handle raw contaminated chicken and then touch their mouth, which could lead to infection. Also, incorrect storage of chicken (see below) could lead to the cross-contamination of other foods.

Seeking medical advice for treating campylobacter-related food poisoning is usually not necessary, as it should clear up by itself, but it is essential to drink lots of water to replace the extra fluid lost by the diarrhoea, to prevent dehydration. Some more severe cases may require giving salts and other substances to maintain the balance of these in the body, and the use of antibiotics.

 

What advice has been given to protect against food
poisoning?

The FSA want campylobacter levels to be as low as possible when chicken reaches consumers, but even if it is present, chicken is safe to eat if you stick to the following measures.

Cover and chill raw chicken:
  • Cover raw chicken and store at the bottom of the fridge so juices cannot drip on to other foods and contaminate them with bacteria that can cause food poisoning such as campylobacter.
Don’t wash raw chicken:
  • Do not wash raw chicken before cooking as this can spread germs by splashing onto other surfaces. There is no need to wash the chicken as cooking will kill any bacteria present.
Wash used utensils:
  • Thoroughly wash and clean all utensils, chopping boards and surfaces used to prepare raw chicken. Wash hands thoroughly with soap and warm water after handling raw chicken. This helps to stop the spread of campylobacter between different surfaces by your hands.
Cook chicken thoroughly:
  • Cooking will kill any bacteria present, including campylobacter. Make sure chicken is steaming hot all the way through before serving. Cut in to the thickest part of the meat and check that it is steaming hot with no pink meat and that the juices run clear.

 

What happens next?

The FSA is continuing to check chickens for campylobacter to complete a year’s worth of data. It intends to have sampled 4,000 chickens by February 2015. It says this will serve as a “baseline” for assessing if there are improvements over time.

Its goal, in partnership with the chicken industry, is to reduce the number of chickens with the highest levels of campylobacter (1,000cfu/g) to less than 10% by the end of 2015. Some schemes to address the problem are already underway, and their impact may well be seen when the next batch of results is released.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Supermarket chickens: 70% affected by food bug. BBC News, November 27 2014

Dirty chicken scandal: food expert calls for boycott of chicken. The Guardian, November 27 2014

Supermarkets Named And Shamed On Chicken Bug. Sky News, November 27 2014

Asda disappointed with findings from study on campylobacter in chickens. The Guardian, November 27 2014

The chicken bug, what has caused it and how it affects you. The Daily Telegraph, November 27 2014

Chicken bug: 70 per cent of British supermarket chickens test positive for food poisoning bacteria. The Independent, November 27 2014

Named and shamed: The supermarkets where up to 78% of fresh chickens are contaminated with potentially lethal food poisoning bacteria. Mail Online, November 27 2014

Categories: NHS Choices

Could depression be the result of a brain infection?

NHS Choices - Behind the Headlines - Fri, 28/11/2014 - 11:40

"Depression should be re-defined as an infectious disease … argues one scientist," the Mail Online reports.

The news comes from an intriguing opinion piece by an American academic, which argues the symptoms of depression may be caused by infection.

But, as the author of the paper says, his hypothesis is purely "speculative". 

It's fair to say feelings of depression can follow some illnesses such as flu, but this is not the same as saying it is caused by infection. And, as this is an opinion piece, the author may have cherry-picked certain articles in support of his hypothesis.

That said, the author does provide some interesting examples of how an infection can lead to a change in mood and emotion.

Infection with the T. gondii strain of bacteria can cause rats to become fearless around cats, a natural predator for these animals.

And a study we looked at in 2012 suggested people who owned cats had a higher risk of suicide, as their pets could make them vulnerable to a Toxoplasma gondii (T. gondii) infection.

Despite the lack of any hard evidence, it is an interesting hypothesis that arguably deserves further investigation, especially given the considerable burden depression places on many people.

 

Who wrote this piece?

The article was written by Dr Turhan Canli of the department of Psychology at Stony Brook University, New York.

It was published in the peer-reviewed journal Biology of Mood and Anxiety Disorders. 

The piece has been published on an open access basis, so it is free to read online.

There is no information about external funding, though the author declared no conflicts of interest.

 

What are the main arguments?

Dr Canli argues that despite decades of research, major depressive disorder (MDD) remains among the most common mental health conditions.

He argues the illness often recurs, regardless of treatment with antidepressants, and states it is time for "an entirely different approach".

Instead of seeing MDD as an emotional disorder, it should be reconceptualised as a form of infectious disease, he says.

Canli says future research should conduct a "concerted search" for parasites, bacteria or viruses that may play a role in causing depression to develop.

The paper presents a series of arguments in favour of this theory.

Inflammatory markers
  • patients with MDD exhibit "sickness behaviour" – they experience loss of energy, have difficulty getting out of bed, and lose interest in the world around them
  • studies of inflammatory biomarkers in major depression "strongly suggest an illness-related origin" – inflammatory biomarkers are chemicals in the blood that may indicate inflammation in the body
  • these inflammatory markers may represent activation of the immune system in response to some kind of pathogen, which could be a parasite, bacterium or virus
  • the author admits there is no direct evidence that major depression is caused by such organisms, but says such a process is conceivable
Examples from nature

There are existing examples of how parasites, bacteria or viruses can affect human behaviour:

  • for example, T. gondii, which lives in cats' intestines, lays eggs that are dispersed into the environment on excretion
  • when a rat is infected with these eggs, it becomes attracted to the scent of cat urine
  • the rat's loss of fear may be caused by parasitic cysts in the rodent's brain affecting levels of various chemicals
  • one-third of the world's population are believed to be infected with T. gondii, and infection is associated with inflammatory markers similar to those found in depressed patients
  • research has identified a link between T. gondii and national suicide rates, major depression and bipolar disorder

The paper argues bacteria could be another cause of depression, with rodent studies showing a link between various bacteria and levels of emotional stress.

In humans, there is data to suggest bacteria in the gut may contribute to major depression – a controversial suggestion known as "leaky gut theory".

Viruses are the third possible cause of MDD, the author states. One meta-analysis of 28 studies, which examined the link between infectious agents and depression, found viruses that had significant links included herpes simplex, varicella zoster (which causes chickenpox and shingles), Epstein-Barr and Borna disease virus.

Genes

The author says reconceptualising major depression as being causally linked to parasites, bacteria or viruses is useful when thinking about the genetics of the illness.

Perhaps the reason the search for specific genes related to depression has "come up empty" is because scientists have been looking for the wrong organism.

Researchers have been looking for internal changes in human genes that might explain depression, but 8% of the human genome is based on external changes from retroviruses.

Dr Canli goes on to portray the human body as an ecosystem that acts as host to "numerous micro-organisms" that may be passed across generations and could be linked to the risk of depression.

He concludes by suggesting unknown pathogens play a causal role in depression by altering the immune response. He speculates there may even be a class of pathogens that share common modes of action targeting the nervous system.

Such pathogens may work together with other factors, Canli argues. For example, some people may have a latent infection, but depressive symptoms may only emerge after the pathogen is activated by a stressful life event.

Large-scale studies of depressed patients and healthy controls are needed to look at the potential role of pathogens in the development of depression. Such efforts might represent the first step towards developing a vaccination for major depression.

 

What is the evidence?

The author quotes a variety of sources to support his hypothesis. Many are rodent studies, and others are laboratory studies looking at levels of certain inflammatory biomarkers in depressed and healthy patients, for example.

But this is not a systematic review of the evidence. The author has not carefully searched all the literature on the topic, assessed its quality, and come to a conclusion. He may have cherry-picked studies that might support his hypothesis while ignoring studies that don't.

 

How accurate is the reporting?

The Mail Online gave the paper's arguments considerable prominence in an article that was accurate but uncritical. Independent expert opinion was not included to balance the argument.

The New York Times took a more discursive approach based on an interview with the author. The item was part of a longer discussion with various experts.

 

Conclusion

The paper's hypothesis is interesting, but it remains just that – a hypothesis. While it is true that some pathogens, such as the Borna disease virus mentioned in the article, have been linked with neuropsychiatric disorders, there is no proof as yet that bacteria, viruses or parasites could cause major depression.

Still, as the old truism goes: "Absence of evidence is not the same as evidence of absence". The lack of evidence could be because nobody has bothered to look for it before.

The author concludes that, "It would be worthwhile to conduct large-scale studies of carefully characterised depressed patients and healthy controls using gold-standard clinical and infectious disease-related study protocols." This seems to be a reasonable and sensible suggestion.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Could depression be an INFECTIOUS DISEASE? Condition is caused by parasites, bacteria or virus and could be prevented with a jab, expert claims. Mail Online, November 27 2014

What If We're Wrong About Depression? New York Times, November 26 2014

Links To Science

Canli T. Reconceptualizing major depressive disorder as an infectious disease. Biology of Mood and Anxiety Disorders. Published online October 21 2014

Categories: NHS Choices

Ebola vaccine shows promise in human trials

NHS Choices - Behind the Headlines - Thu, 27/11/2014 - 14:54

“Ebola vaccine trial results promising, says manufacturer,” The Guardian reports. Initial results from a trial involving 20 healthy adults found that the vaccine seems to be safe.

The trial was what is known as a phase one trial, which is designed to test if a drug or intervention is safe, rather than whether it is effective against Ebola.

There were some minor side effects – such as mild pain, fever and generally feeling under the weather – but all symptoms resolved after a few days.

Although the purpose of the study was to assess safety, the researchers also measured the antibody levels that had been produced following the vaccine, which gives an indication that it might be effective in granting immunity against infection.

Links To The Headlines

Ebola vaccine trial results promising, says manufacturer. The Guardian, November 26 2014

'Positive signs' from Ebola vaccine trial. BBC News, November 26 2014

Ebola vaccine promising in first human trials. Mail Online, November 26 2014

Ebola Vaccine Trial Shows Signs Of Success. Sky News, November 27 2014

Links To Science

Ledgerwood JE, DeZure AD, Stanley DA, et al. Chimpanzee Adenovirus Vector Ebola Vaccine — Preliminary Report. The New England Journal of Medicine. Published online November 26 2014

Categories: NHS Choices

Ten-point plan to tackle liver disease published

NHS Choices - Behind the Headlines - Thu, 27/11/2014 - 11:30

"Doctors call for tougher laws on alcohol abuse to tackle liver disease crisis," The Guardian reports. But this is just one of 10 recommendations for tackling the burden of liver disease published in a special report in The Lancet.

The report paints a grim picture of an emerging crisis in liver disease in the UK, saying it is one of the few countries in Europe where liver disease and deaths have actually increased rapidly over the last 30 years. It concludes with 10 recommendations to tackle the burden of liver disease.

The media has approached the recommendations from many different angles, with many sources only reporting on one, not all, of the recommendations.

For example, BBC News and The Daily Telegraph focused on the call for improved diagnosis in primary care: "GPs should offer liver scans to those who drink too much," reported The Telegraph.

The Guardian focused on calls for tougher regulation of the alcohol industry, such as minimum pricing for alcohol and a restriction on advertising and sponsorship by alcohol manufacturers, while the Mail's reporting focused on their core audience: "The middle class are fuelling an increase in death from liver disease".

 

What is liver disease?

There are more than 100 types of liver disease, which together affect at least 2 million people in the UK.

In the UK, the three most common types are:

All three are preventable:

 

Who wrote this report?

The report was compiled by a group of UK doctors and academics, and was published in the peer-reviewed medical journal, The Lancet.

The work was organised by The Lancet to "provide the strongest evidence base through the involvement of experts from a wide cross-section of disciplines, making firm recommendations to reduce the unacceptable premature mortality [death] and disease burden from avoidable causes, and to improve the standard of care for patients with liver disease in hospital".

The report stated that no people involved in the report were compensated for their time and no competing interests were declared.

The report involved many of the major medical and liver research councils in the UK, including the British Liver Trust, the Royal College of General Practitioners, the Children's Liver Disease Foundation, the Royal College of Physicians, the British Society of Gastroenterology, the Foundation for Liver Research, and the British Association for the Study of the Liver.

The views expressed in the report were described as those of the authors and do not necessarily represent the views of any of the organisations involved in this report.

 

What were the issues identified in the report?

The report outlined how liver disease in the UK "stands out as the one glaring exception" to the vast improvements in health and life expectancy made over the past 30 years for many diseases, such as stroke, heart disease and many cancers.

The rise in liver disease-related deaths was described as being linked to similar rises in known risk factors for liver disease, namely alcohol consumption, obesity and an increasing number of cases of viral hepatitis (especially hepatitis C).

Deficiencies in hospital and primary care of liver disease were also highlighted alongside the financial impact to the NHS.

Some of the key facts used to describe the current "crisis" in liver disease include:

  • Death rates from liver disease have increased 400% since 1970 overall, and almost 500% in those under 65.
  • Liver disease is the third most common cause of premature death in the UK, and the rate of increase in liver disease is substantially higher in the UK than other countries in Western Europe.
  • More than 1 million admissions to hospital per year are the result of alcohol-related disorders, and both the number of admissions and the increase in deaths closely parallel the rise in alcohol consumption in the UK over the past 30 years.
  • Of the 25% of the population now categorised as obese, most will have non-alcoholic fatty liver disease, and many (up to 1 in 20) will have ongoing inflammation and scarring that finally leads to cirrhosis. Of those patients with cirrhosis, 5-10% will get liver cancer.
  • This increasing burden of liver disease is added to by chronic viral hepatitis – annual deaths from hepatitis C have almost quadrupled since 1996, and about 75% of people infected are estimated to be still unrecognised. The same applies to chronic hepatitis B infection, which can progress to cirrhosis and liver cancer.
  • The cost to the UK's National Health Service is equally staggering, with estimates of £3.5 billion per year for alcohol-related health problems and £5.5 billion per year for the consequences of obesity.
  • There is an unacceptable variation in the health outcomes of people attending different specialist liver disease services across the country. This means some specialist centres are performing much worse than others.
  • Based on survey data, the care of patients acutely sick with liver disease dying in hospital was judged to be good in less than half of cases. Other unacceptable findings were the inadequate facilities and lack of expertise of those caring for patients.
  • Deficiencies exist in primary care, which has crucial opportunities for the early diagnosis and prevention of progressive disease.
  • Those affected most by the burden of liver disease and death are the poorest and most vulnerable in our society.

 

What were the suggested solutions?

The report states the recommendations made were selected on the basis that they will have the greatest effect, and that these need to be implemented urgently.

"Although the recommendations are based mostly on data from England, they have wider application to the UK as a whole, and are in accord with the present strategy for healthcare policy by the Scottish Health Boards, the Health Department of Wales, and the Department of Health and Social Services in Northern Ireland."

The report's 10 most high-impact and urgently needed recommendations are:

1. Strengthen the detection of early liver disease and its treatment by improving the level of expertise and facilities in primary care.

2. Improve support services in the community setting for screening of high-risk patients.

3. Establish liver units in district general hospitals to be linked with 30 specialist centres distributed regionally to make highly specialised investigations and treatment available.

4. A national review of liver transplantation services to ensure better access for patients in specific areas of the country, and provide sufficient capacity for the anticipated increase in the availability of donor organs.

5. Strengthen the continuity of care in transition arrangements for the increasing number of children with liver disease surviving into adult life.

6. Implement a minimum price per unit, health warnings on alcohol packaging, and the restriction of alcohol advertising and alcohol sales.

7. The promotion of healthy lifestyles to reduce obesity in the country and its results on health, governmental regulations to reduce sugar content in food and drink, and the use of new diagnostic pathways to identify people with non-alcoholic fatty liver disease.

8. Eradicate infections from chronic hepatitis C virus in the UK by 2030 using antiviral drugs, reduce the burden of hepatitis B virus, target high-risk groups for these viruses, including immigrant communities, and use a universal six-in-one hepatitis B vaccination for infants.

9. Increase provision of medical and nursing training in hepatology, and wider educational opportunities for healthcare professionals to increase the number of doctors and nurses in hospitals and primary care.

10. Increase awareness of liver disease in the general population with a national campaign led by NHS England – clinical commissioning groups (CCGs) should increase awareness in area health teams.

 

Is the report reliable?

The report was an evidence-based piece combining established trend data and research evidence with expertise from various academics and doctors involved in liver disease and research.

It stresses the need for the recommendations to be evidence-based and scientifically focused. This gives us some confidence it is broadly reliable and represents the views of clinical opinion leaders and academics in liver disease research and treatment.

But, as far as we can tell, there was no systematic attempt to search and review the literature and data to ensure all relevant material was considered, as would be the case with a systematic review.

This means it is not clear to what extent evidence was used to support an existing stance, or whether certain relevant evidence or viewpoints have been intentionally or unintentionally excluded.

This leaves open the possibility that the report may present an overly critical or sensationalist view of the current state of affairs to stimulate a sense of urgency and instigate the action the authors perceive to be necessary.

But as the report used relatively objective data sources and stressed being scientifically focused, the impact of any bias is likely to be minimal.

 

What happens next?

It is difficult to predict. Some of the recommendations, such as providing resources to make the early diagnosis of liver disease more likely, are purely clinical.

Whether or not the recommendation is taken up will probably be based on whether the resources are available and this can be justified.

But other recommendations – such as introducing minimal alcohol pricing, restricting alcohol sales to certain times of the day, and bringing in new rules regarding the advertising of alcohol – are politically controversial, and are likely to meet with fierce opposition from the alcohol industry.

It would be surprising if any party publically supported the recommendations this side of the upcoming general election.

Governments do have the power to change behaviour, which, as with the smoking ban, can prove very successful in achieving large-scale change.

But ultimately the responsibility of preventing liver disease is yours. If you moderate your alcohol consumption, try to maintain a healthy weight, and never share needles (if you are an injecting drug user), you should have a good chance of avoiding liver disease.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Doctors call for tougher laws on alcohol abuse to tackle liver disease crisis. The Guardian, November 27 2014

Early detection of liver disease by GPs 'non-existent'. BBC News, November 27 2014

GPs should offer liver scans to those who drink too much. The Daily Telegraph, November 27 2014

Middle class 'treat booze as a lifestyle choice': Excessive drinking is fuelling deaths, experts warn. Mail Online, November 27 2014

Links To Science

Williams R, Aspinall R, Bellis M, et al. Addressing liver disease in the UK: a blueprint for attaining excellence in health care and reducing premature mortality from lifestyle issues of excess consumption of alcohol, obesity, and viral hepatitis. The Lancet. Published online November 27 2014

Categories: NHS Choices

UK 'among worst' for cancer linked to obesity

NHS Choices - Behind the Headlines - Thu, 27/11/2014 - 09:30

“Britain almost the worst in the world for obesity-fuelled cancer,” reports The Daily Telegraph.

This and other headlines report on the outcome of an international study into the rate of obesity-related cancers.

The researchers estimated the proportion of cases of cancer overall, and the proportion of specific cancers already associated with obesity, that are likely to have been caused by obesity worldwide.

They based their estimates on previous research indicating the relative risk of obesity causing cancer, and using population data to calculate the number of people who are overweight or obese.

Overall, they estimated that 3.6% of cancers in adults (aged over 30) worldwide are caused by high body mass index (BMI), with the proportion attributed to obesity slightly higher in women than in men. In the UK, 4.4% of all cases of cancer per year in men and 8.2% of all cases of cancer per year in women were estimated to be attributable to obesity.

The research focused on cancers the World Cancer Research Fund (WCRF) has already established are linked to high BMI. When looking at these cancers, the UK was joint second highest in the world for the estimated proportion of these cancers that were attributed to obesity. The US had the highest rates.

Being overweight or obese is associated with an increased risk of some cancers and increases the risk of diabetes and cardiovascular disease, such as heart attack and stroke.

 

Where did the story come from?

The study was carried out by researchers from the International Agency for Research on Cancer in Lyon, and several universities around the world. It was funded by the World Cancer Research Fund International, the Marie Curie Intra-European Fellowship from the European Commission, the US National Institutes of Health, the Australian National Health and the Medical Research Council.

The study was published in the peer-reviewed medical journal the Lancet Oncology.

The media in general reported the story accurately, with particular emphasis on the UK results.

 

What kind of research was this?

This was a population study that aimed to estimate the number of global cases of cancer which could be attributable to high BMI. The researchers intended that the results be used to help inform public health policy to reduce the global burden of cancer.

High BMI of 25 or more (overweight) is associated with increased risk of a number of chronic diseases and mortality. The authors report that recent statistics show 35% of the global adult population (20 years and older) are overweight and 12% are obese (BMI of 30 or more).

According to the WCRF, there is sufficient evidence to show that high BMI is associated with an increased risk of the following cancers:

  • oesophageal (food pipe) adenocarcinoma (cancer of the mucus-producing cells)
  • colon (large bowel)
  • rectal
  • kidney
  • pancreas
  • gallbladder (in women)
  • postmenopausal breast
  • ovarian
  • endometrial (lining of the womb)

 

What did the research involve?

For each country, the researchers estimated the average adult’s BMI from 2002. To provide a substantial enough time for the obesity to have had the potential to increase the risk of cancer, they used the 2012 global figures for cancer incidence. Using previously researched relative risk estimates of how much high BMI increases the risk of each of the cancers listed above, they estimated the number of cancer cases that could be attributed to high BMI.

 

What were the basic results?

The researchers estimated that worldwide, 481,000 adults aged 30 years or older were diagnosed in 2012 (3.6% of cases) due to high BMI. The proportion of all cancer cases that were attributed to high BMI were more than twice as frequent for women: 345,000 cases (5.4%), compared to 136,000 cases for men (1.9%).

In the UK, 4.4% of all cases of cancer per year in men (7,217), and 8.2% of all cases of cancer per year in women (13,037) were estimated to be attributable to obesity. Men in the UK had the joint fourth highest proportion of cancers attributable to high BMI with Malta (4.4%), behind the Czech Republic (5.5%), Jordan (4.5%) and Argentina (4.5%).

When focusing on the above list of cancers the WCRF associated with high BMI, obesity was attributed to 20% of these cancers in men and 15% of these cancers in women. The only country with a higher proportion was the US, at 21% for men and 20% for women.

The percentage of high BMI-related cancers attributed to obesity were:

  • oesophageal cancer: 44% for men and women
  • colon 19% for men, 10% for women
  • rectum 10% for men, 5% for women
  • pancreas 13% for men, 10% for women
  • kidney 23% for men, 31% for women

For women only:

  • gallbladder 50%
  • postmenopausal breast 12%
  • womb 43%
  • ovary 6%

 

How did the researchers interpret the results?

In conclusion, the authors say “these findings emphasise the need for a global effort to abate the increasing numbers of people with high BMI. Assuming that the association between high BMI and cancer is causal, the continuation of current patterns of population weight gain will lead to continuing increases in the future burden of cancer”.

 

Conclusion

This international study has shown alarming increases in cases of cancer that can be attributed to high BMI.

Overall, they estimated that 3.6% of cancers in adults (aged over 30 years) worldwide are caused by high BMI, with the proportion attributed to obesity slightly higher in women than in men. In the UK, 4.4% of all cases of cancer per year in men and 8.2% of all cases of cancer per year in women, were estimated to be attributable to obesity.

The research focused on cancers that the WCRF has already established are linked to high BMI. When looking at these cancers, the UK was joint second highest in the world for the estimated proportion of these cancers that were attributed to obesity. The US had the highest rates.

Being overweight or obese is associated with an increased risk of some cancers, diabetes, and cardiovascular disease such as heart attack and stroke.

There are many different ways to tackle overweight and obesity, and a good start is the NHS Choices weight loss plan.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Women 'twice as likely to have cancer linked to their weight': Obesity causes 20,000 UK cases a year. Mail Online, November 26 2014

Britain almost the worst in the world for obesity-fuelled cancer. The Daily Telegraph, November 26 2014

UK lung cancer survival rates among worst in Europe. The Guardian, November 26 2014

Links To Science

Arnold M, Pandeya N, Byrnes G, et al. Global burden of cancer attributable to high body-mass index in 2012: a population-based study. The Lancet Oncology. Published online November 26 2014

Categories: NHS Choices

Uneven or large breasts can cause teen angst

NHS Choices - Behind the Headlines - Wed, 26/11/2014 - 15:43

"How your breast size affects your mental health: Having uneven or bigger boobs lowers self-esteem and causes eating disorders, study finds," reports the Mail Online.

But the second part of the headline, which mentions eating disorders, is both misleading and inaccurate.

The study in question, which took place in the US, looked at young females (aged 12 to 21) who had asymmetrical or abnormally large breasts (macromastia) and were attending breast clinics, comparing them with controls attending other hospital clinics.

Researchers found females in the former group tended to have lower reported self-esteem, but there was no evidence they developed eating disorders because of their breasts.

There were also no differences between their responses to questionnaires about general, physical and mental health after body mass index (BMI) was taken into account. Females with macromastia reported significantly worse physical problems and symptoms of pain, such as neck pain.

If very large breasts are causing you trouble, you may be eligible for breast reduction on the NHS. You will probably have to pay for breast reduction surgery if it is being performed for cosmetic reasons. The current cost of private surgery is around £5,000.

If you, or someone you know, are concerned about asymmetrical breasts, it's worth remembering many girls' breasts will take on a more symmetrical appearance once puberty has passed.

 

Where did the story come from?

The study was carried out by researchers from Boston Children's Hospital and Harvard Medical School.

It was funded by the Plastic Surgery Foundation and the authors report no conflicting financial interests.

The study was published in the peer-reviewed medical journal Plastic and Reconstructive Surgery.

The Mail Online's headline is misleading for a number of reasons:

  • A case-control study can never prove cause and effect.
  • After BMI was taken into account, there was no significant association between asymmetrical breasts or macromastia and disordered attitudes to eating.
  • None of the participants were diagnosed with an eating disorder – they just filled out a questionnaire about their eating attitudes.

 

What kind of research was this?

This was a case-control study that aimed to compare the psychological, emotional and physical impact of having asymmetrical breasts or macromastia compared with having breasts within the average range.

This type of study is appropriate to look for associations, but it cannot account for all possible factors influencing the results (confounders).

The research was described as a prospective cohort study, but this involves following participants up over a period of time and monitoring changes. This study was conducted over a period of five years, but information for each participant was only collected at one time point.

 

What did the research involve?

Adolescents and young women aged 12 to 21 with either asymmetrical breasts or macromastia and controls were recruited to the study at Boston Children's Hospital from 2008 to 2013.

The groups were compared in terms of self-esteem, quality of life, any disordered eating, and age-adjusted BMI.

Females with asymmetrical breasts were eligible if there was at least one cup size in difference, and 59 adolescents agreed to participate. Cup size difference was measured using a standard bra that fitted the larger breast, using sizing pads on the other side until the breasts looked symmetrical.

160 females with macromastia enrolled in the study. Macromastia was defined according to Schnur criteria as overgrowth in both breasts "requiring a minimum resected amount of tissue based on the patient's body surface area".  Macromastia can cause problems such as backache and neck pain.

The controls were 142 females who attended the same hospital, but did not have breast problems, an eating disorder, severe mental illness, or chronic medical or surgical problems.

They were enrolled at clinics within the Department of Plastic and Oral Surgery and the Division of Adolescent/Young Adult Medicine.

All participants completed three questionnaires:

  • the 36-Item Short-Form Health Survey, which measures health-related quality of life in several domains, each rated from 0 (low) to 100 (high)
  • the Rosenberg Self-Esteem Scale, ranging from 10 (poor) to 40 (good)
  • the Eating Attitudes Test, with scores of 20 or more indicating disordered eating (though not necessarily an eating disorder such as anorexia nervosa or bulimia) 

The control group also completed a short survey to identify if they had any concerns about their breasts their doctor was not aware of, including:

  • satisfaction with their breasts
  • if they were contemplating breast surgery to increase, decrease or make both breasts the same size (though none differed by a cup size)

 

What were the basic results?

Significantly more females with asymmetrical breasts or macromastia were overweight or obese (66.1%) compared with controls (40.1%).

After adjusting the results to take BMI into account, females with asymmetrical breasts scored significantly lower on one domain of the Short-Form 36 questionnaire: role limitations caused by emotional problems.

There were no significant differences for the rest of the domains:

  • general health
  • social functioning
  • physical function
  • physical role
  • body pain
  • vitality
  • mental health

After adjustment for BMI, females with asymmetrical breasts had lower self-esteem on the Rosenberg Self-Esteem Scale compared with controls.

Females with macromastia scored significantly lower on the following domains of the Short Form-36 than those with asymmetrical breasts after their higher average age was taken into account:

  • social functioning
  • physical function
  • physical role
  • body pain
  • vitality

There were no significant differences between females with macromastia or asymmetry for general health, emotional role, self-esteem or disordered eating attitudes.

A quarter of controls (32) were "so dissatisfied with the appearance or size of their breasts" that they would consider surgical intervention.

 

How did the researchers interpret the results?

The researchers concluded that, "Breast asymmetry may negatively impact the psychological quality of life of adolescents similar to macromastia [large breasts]."

They go on to say that, "Breast asymmetry is not just a cosmetic issue. Providers should be aware of the psychological impairments associated with asymmetry and provide proper support."

 

Conclusion

This study found young females with macromastia report lower quality of life and physical health, as well as more pain and poorer mental health than females with asymmetrical breasts or those with average breasts.

However, in this study, females with asymmetrical breasts of more than a cup size difference did report lower self-esteem.

Contrary to the media reporting, the study did not assess the impact of any treatment or surgical interventions on self-esteem, physical or mental health.

The study also did not find that females developed eating disorders because of their breasts. The researchers found women with asymmetrical breasts scored higher on a questionnaire about disordered attitudes to eating than controls, but this was no longer significant if BMI was taken into account.

In addition, none of the women with asymmetrical breasts or macromastia were reported to have an eating disorder, and the controls were not eligible for the study if they had an eating disorder.

While self-esteem was found to be lower in females with asymmetrical breasts, there were no differences between their responses to questionnaires about general, physical and mental health after BMI was taken into account. Females with macromastia reported significantly worse physical problems, pain and mental health.

A limitation of this study is the composition of the control group. They were matched to the females attending the breast clinic in terms of age, but no other features.

For example, a control group is usually matched in terms of smoking, alcohol consumption and socioeconomic status.

They were also described as "healthy" and did not have breast problems, an eating disorder, severe mental illness, or chronic medical or surgical problems, so it is not clear why they were still attending hospital outpatient clinics.

The reasons for their attendance could have a bearing on their answers to questionnaires on vitality, quality of life, and physical and mental health. In turn, this could be why very few differences were seen on these scales between females with asymmetric breasts and the controls.

If you are concerned about asymmetrical breasts of more than a cup size difference, or have symptoms such as back pain or neck pain caused by very large breasts, you can find more information on the provision of breast reduction services by the NHS.

Surgical intervention is not usually recommended for teenagers, as their breasts are still developing, so any problem with appearance or size may correct itself without the need for surgery.

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

How your breast size affects your mental health: Having uneven or bigger boobs lowers self-esteem and causes eating disorders, study finds. Mail Online, November 25 2014

Links To Science

Nuzzi L, Cerrato F, Webb M, et al. Psychological Impact of Breast Asymmetry on Adolescents: A Prospective Cohort Study. Plastic and Reconstructive Surgery. Published online November 25 2014

Categories: NHS Choices

Are silver surfers more health savvy?

NHS Choices - Behind the Headlines - Wed, 26/11/2014 - 11:30

"Older people who use the internet … may be better equipped to keep on top of their health," BBC News reports. A survey found regular internet use in older people was associated with good health literacy.

Health literacy is a term used to describe an individual's ability to find, understand and make use of health information.

The study, which involved 4,400 adults aged 52 and over, found those who regularly used the internet were less likely to experience a drop in health literacy as they got older.

Health literacy was assessed in terms of being able to understand a mocked-up medicine label at the start of the study compared with seven years later.

There was no positive link between health literacy and reading newspapers. Indeed, certain newspapers are probably the last place you want to turn to for accurate health information. There was also a positive link for people who engage in cultural activities.

The study did not assess whether the participants were healthier, and we do not know whether being able to read a medicine label gives a reliable indication of health literacy.

Still, learning to use the internet can help combat feelings of isolation. There may be an older relative or friend you know who could benefit from "silver surfing". Organisations such as Age UK offer free internet training for older people.

 

Where did the story come from?

The study was carried out by researchers from University College London. Funding was not reported.

It was published in the peer-reviewed Journal of Epidemiology and Community Health.

The UK media reported the findings of the study accurately, but have not discussed any of its limitations.

 

What kind of research was this?

This was a cohort study that aimed to assess whether regularly reading newspapers, using the internet, and being active socially could protect against age-related reduced health literacy skills.

Only a brief study abstract of the study's findings is currently available. This means it is not possible to analyse the full methods used. A more detailed report of the study, its methodology and its findings may be published later in the year or next year.

According to the World Health Organization (WHO), "health literacy" refers to the "Cognitive and social skills which determine the motivation and ability of individuals to gain access to, understand and use information in ways which promote and maintain good health.

"Health literacy means more than being able to read pamphlets and successfully make appointments. By improving people's access to health information and their capacity to use it effectively, health literacy is critical to empowerment."

In this study, one measure of health literacy was assessed: being able to read a mocked-up medicine label.

This type of research cannot prove that any of these factors improve or maintain health literacy, but it can show an association or link. 

 

What did the research involve?

Adults aged 52 or over were recruited to the study from a large ongoing study called the English Longitudinal Study of Ageing (ELSA). They were assessed at baseline in 2004-05 and followed up over the next seven years.

In this piece of research, health literacy was measured using a reading comprehension test of a fake medicine label. The 4,429 participants completed this test at the beginning of the study and again in 2010-11.

Every two years, data was also collected through interviews and questionnaires on whether the participants:

  • read the newspaper daily versus never
  • used the internet consistently or never
  • engaged in civic participation or not
  • performed leisure activities or not
  • engaged in cultural activities or not
  • engaged in social networks or were socially detached

The researchers then performed statistical analyses to look for links between reading, the internet, social engagement and maintained health literacy from the beginning to the end of the study period.

They adjusted the results to take the following confounders into account:

  • baseline age
  • ethnicity
  • education
  • cognitive function
  • cognitive decline

 

What were the basic results?

People who used the internet "consistently" compared with "never" were 25% less likely to have a decline in health literacy (odds ratio [OR] = 0.75, 95% confidence interval [CI] 0.59 to 0.95).

Engaging in "consistent" cultural activities reduced the risk by 30% (OR = 0.70, 95% CI 0.55 to 0.89).

The following were not associated with health literacy decline:

  • consistently reading a daily newspaper (OR = 1.04, 95% CI 0.84 to 1.29)
  • consistent civic participation (OR not reported)
  • leisure activities (OR not reported)
  • social networks (OR not reported)

 

How did the researchers interpret the results?

The researchers concluded that, "Internet use and cultural engagement, including attending the cinema, art galleries, museums, or the theatre, appear to help older adults to maintain health literacy skills during ageing regardless of cognitive functioning."

 

Conclusion

The authors say "consistent" use of the internet and cultural engagement helps older adults maintain health literacy skills. But their study has a number of limitations, including:

  • Only a brief abstract of this study is available. This provides fairly limited information on the study, which makes it difficult to assess the complete methods.
  • No details were provided on the average age of participants. The youngest were only 52 at the start of the study and, as they were only followed up for seven years, a major decline in the ability to read a medicine label seems unlikely.
  • Health literacy appears to only have been assessed using the ability to read and understand a medicine label. It did not include the next step advocated by WHO, which is to be able to then use the health information to make good healthcare decisions. No details have been provided on the extent of the health literacy decline in people who did not use the internet or engage in cultural activities, so it is not known whether this would be large enough to be noticeable or clinically important.
  • The researchers say engaging in these activities was linked to maintaining health literacy regardless of cognitive function. Unfortunately, because of the lack of details available about the study, it is not clear whether cognitive function was formally assessed, or whether this was repeated at different time points during the study. The researchers report adjusting for cognitive function alongside age, ethnicity and education, but, with only a brief methodology available, it is unclear whether the effects of these and other potential confounders have been fully accounted for. 
  • It is not clear what "consistent" use of each of the activities means compared with "never". The participants were divided into these all-or-nothing categories, which is unlikely to be a true reflection of normal life.
  • This process was done using a mixture of questionnaires and interviews, which can be subject to recall bias and so may not be entirely accurate. In addition, reading was only considered if it was a daily newspaper, but reading books was not included.
  • While the statistical analyses did take some potential confounders into account, many other factors weren't, such as whether the participants were still in employment.

This study does not prove that internet use and cultural activities prevent age-related decline in health literacy.

Still, we would argue that health websites such as NHS Choices can provide an invaluable resource of reliable health information, news, lifestyle advice and links to other useful relevant content.

If you are reading this online, we are obviously preaching to the converted, but you may know an older person who you think would benefit from being taught how to use the internet with confidence.

As well as charities such as Age UK, most local libraries should contain details of internet training courses.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

'Silver surfers' may be more health-aware. BBC News, November 26 2014

Silver surfing is good for your health: Regular users found to look after themselves better because they stave off mental decline. Daily Mail, November 26 2014

Internet usage boosts health of the elderly. Daily Express, November 26 2014

Links To Science

Kobayashi LC, Wardle J, von Wagner C. OP49 The influence of regular reading, internet use, and social attachment on maintaining health literacy skills during ageing in the English Longitudinal Study of Ageing. Journal of Epidemiology and Community Health. Published online September 2014

Categories: NHS Choices

No proof 5:2 diet prevents cancer

NHS Choices - Behind the Headlines - Tue, 25/11/2014 - 12:00

"Could 5:2 diet help to ward off cancer?" is the question posed by the Mail Online after the publication of a study into experimental diets.

An honest and accurate answer to the question, based on the study, would be "we don't know".

The Mail reports on a study that gives an overview of the evidence surrounding low-calorie diets and intermittent fasting, and whether they are beneficial to our health.

But this study does not provide new evidence on the 5:2 diet or whether fasting diets ward off cancer.

As the piece didn't report the methods used to find the evidence, it is unclear whether any cherry-picking took place. That is, evidence supporting the authors' opinions may have been included, but conflicting evidence may have been ignored.

The article says we need more good-quality research on issues such as whether certain types of diet can have a wider beneficial impact on health. We would certainly agree with this view.

The best way to reduce your cancer risk is to eat a balanced diet that includes plenty of fruit and vegetables, and is low in red and processed meat and salt. 

 

Where did the story come from?

The study was carried out by researchers from many different collaborating US universities, as well as one UK and one Belgian University.

It was funded by the US National Institute on Aging Intramural Research Program and the Glenn Foundation for Medical Research, the US National Institutes for Health, the European Union's Seventh Framework Programme MOPACT, Genesis Breast Cancer Prevention (UK) and the Belgian Foundation for Scientific Medical Research.

The study was published in the peer-reviewed Proceedings of the National Academy of Sciences (PNAS).

The media reporting was generally true to the facts of the research, which focused on the speculation that a fasting diet might reduce the risk of cancer. 

But neither the Mail nor The Daily Telegraph made it clear to their readers that this study was not a systematic review, which would have given more weight to its findings. Rather, it was more of an expert opinion piece.

The Telegraph did include a useful quote from Tom Stansfeld of Cancer Research UK, who said more research was needed looking into the long-term effects of intermittent fasting.

He added: "Decades of research tell us the best way to reduce the risk of cancer through nutrition is to eat a balanced diet with plenty of fruit and veg, and low in red and processed meat and salt."

 

What kind of research was this?

This was an evidence-informed "perspective" article describing the physiological responses of people and animals to controlled variation in meal size, frequency and timing of meals, and the impact on health and disease.

The study group described how research efforts have largely ignored the importance of the frequency and timing of meals, and potential benefits of periods of no or very low energy intake. Hence, they sought to describe some of the evidence around this grey area.

They argue eating three meals a day is abnormal from an evolutionary point of view. They also describe how the habit of eating three meals a day appears to have begun when humans switched from being hunter gatherers to farmers around 12,000 years ago.

The rationale is that our bodies, which have evolved incrementally over millions of years in the context of periods of fasting, may not be best suited to this relatively modern dietary switch.

Some studies suggest restricting energy intake for as little as 16 hours can have health benefits. They say the mechanisms that mediate this benefit are metabolic shifts to using fat as an energy source, and the stimulation of cellular responses that prevent and repair molecular damage.

 

What did the research involve?

It was not clear how the evidence to inform this "perspectives" piece had been searched for, selected or synthesised, as no methods were described.

As no systematic methods were described, as would be the case with a systematic review, we cannot discount the potential influence of bias on the evidence selection, sifting and synthesis. These biases have the potential to influence the content and conclusion of the article.

What we do know is the piece considered evidence on three broad experimental diets:

  • caloric restriction (CR) – where daily calorie intake is reduced by 20-40% and meal frequency is unchanged
  • intermittent energy restriction (IER) – this involves eliminating (fasting) or greatly reducing daily food and caloric beverage intake intermittently; for example, two days a week, as is used in the popular 5:2 diet
  • time-restricted feeding (TRF) – this involves limiting daily food intake and caloric beverages to a four to six-hour period

This article also reportedly incorporated information from a workshop on eating patterns and disease. Those with a particular interest in experimental diets may find the video of the workshop interesting, though we should warn you it is more than six hours long.

The Mail Online said the IER 2-Day Diet described in the article is the forerunner to the 5:2 diet. It involves two days of eating just 600 to 1,000 calories of low-carbohydrate foods. On the other five days, the dieter eats a healthy Mediterranean diet. Women usually need 2,000 calories a day, while men need 2,500.

 

What were the basic results?

There are no clear new results presented in this article, as it presents a flowing, evidence-informed description of the state of knowledge around the timing and frequency of eating and its potential influence on health. The media picked up on the description of the IER diet section around cancer.

The research said: "IER/fasting can forestall and even reverse disease processes in animal models of various cancers, cardiovascular disease, diabetes and neurodegenerative disorders", citing a single source on the molecular mechanisms of fasting.

It then goes on to describe four general biological mechanisms by which IER might protect cells against injury and disease.

It also suggests future directions for research and society-wide implications, highlighting how recommendations for healthy patterns of meal frequency and timing may emerge as more evidence gathers consensus.

 

How did the researchers interpret the results?

The researchers indicated that, "If sufficient evidence does emerge to support public health and clinical recommendations to alter meal patterning, there will be numerous forces at play in the acceptance or resistance to such recommendations."

These, they said, included the cultural tradition dictating three meals a day, the food industry's vested interest in making people eat frequently, and the ability or willingness of health systems to emphasise prevention through lifestyle modification, overtreatment and medicalisation.

 

Conclusion

This evidence-informed article presents an overview of, and perspective on, the potential mechanisms through which low calorie or intermittent fasting diets may be beneficial to the body.

The information provided by the authors is certainly interesting. But this study does not provide new or compelling evidence proving that fasting diets actually lead to a lower risk of disease or postponement of death.

This does not appear to be a systematic review, where the authors would search the global literature to identify all relevant evidence on the effects of different eating patterns on health outcomes.

As the piece reported no methods, we do not know how evidence for the article was searched for, selected or synthesised, and it therefore has the potential to be biased. 

The main contribution of this study is as a discussion starter. From the evidence included in the piece, it seems clear there is relatively little definitive evidence pointing to the best pattern or timing of meals. In this void of evidence, there may be misinformation.

For example, the researchers say that despite equivocal and even contradictory scientific evidence, breakfast is often touted as a weight-control aid, but recent evidence has suggested it may not be.

In addressing or clarifying potential misinformation, the article says we need more clarity about these still grey issues through more and better research.

The authors also say we need to ensure that the best available evidence is informing public guidelines and knowledge on these topics. It is tough to argue against this.

Intermittent fasting diets such as the 5:2 diet may not be suitable for pregnant women and people with specific health conditions, such as diabetes or a history of eating disorders.

Because it is a fairly radical approach to weight loss, it is wise to speak to your GP first if you are considering trying intermittent fasting for yourself.
 
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

The 5:2 diet helps beat cancer and Alzheimer's, study finds. The Daily Telegraph, November 24 2014

Could 5:2 diet help to ward off cancer? Scientists say having longer periods without food could be good for us. Mail Online, November 24 2014

Links To Science

Mattson MP, Allison DB, Fontana L, et al. Meal frequency and timing in health and disease. PNAS. Published online November 17 2014

Categories: NHS Choices

Can a yoghurt a day reduce diabetes risk?

NHS Choices - Behind the Headlines - Tue, 25/11/2014 - 11:20

"Eating a small portion of yoghurt every day may reduce diabetes risk," The Independent reports.

This news comes from a US study that assessed the eating habits of more than 100,000 people and then followed them up every four years, looking for new diagnoses of type 2 diabetes.

Pooling the results of this study with 14 other studies, the researchers estimated each serving of yoghurt – 244 grams (g) – a day decreased the risk of developing type 2 diabetes by around 18%.

There was no significant link between total dairy intake or intake of other specific dairy products and type 2 diabetes.

A challenge facing this and similar studies is making sure all relevant outside influencing factors (confounders) have been accounted for, which is very tricky to do in practise.

If this has not been done conclusively, yoghurt consumption may be acting as a marker of a healthier lifestyle in general and has no direct influence on diabetes risk, which may be the case here.

We also don't know what sort of yoghurt the participants consumed. For example, many low-fat yoghurts are very high in sugar, which could contribute to weight gain.

It is therefore possible yoghurt may reduce the risk of developing diabetes, but may increase the risk of other diseases.

Current advice to reduce the risk of type 2 diabetes remains the same: eat a healthy diet, maintain a healthy weight, avoid smoking, moderate alcohol consumption, and take regular exercise.

 

Where did the story come from?

The study was carried out by researchers from Harvard School of Public Health and was funded by the US National Institutes of Health.

One of the study's authors declared a competing interest as he "holds membership of Unilever North America Scientific Advisory Board".

Unilever produces a huge number of commonly eaten yoghurts. It is not clear to what extent this conflict of interest may have influenced the study design, methodology or interpretation.

The study was published in the peer-reviewed medical journal BioMed Central (BMC) Medicine. It is an open access journal, meaning that anyone can read the full research publication for free.

Generally, the media reported the study accurately. But many sources chose to suggest that, "it might be a good idea to eat yoghurt regularly" without due consideration for the potential downsides of this advice.

For example, eating low-fat, high-sugar yoghurt may contribute to weight gain and weight-related diseases other than type 2 diabetes. It could also potentially increase the risk of tooth decay, particularly in children.

It also wasn't made clear what type of yoghurt was consumed, or that the association between yoghurt and diabetes may still be influenced by other factors.

 

What kind of research was this?

This was a meta-analysis combining the results of three large prospective cohort studies.

The researchers attest that the relation between the consumption of different types of dairy and the risk of type 2 diabetes remains uncertain.

They therefore aimed to evaluate the association between total dairy and individual types of dairy consumption and incident type 2 diabetes in US adults.

Type 2 diabetes is a condition where the person can't control their blood glucose, either because the body doesn't produce enough insulin or the body's cells don't react to insulin.

The rapid rise in the number of adults in Westernised nations such as the UK developing type 2 diabetes is caused by:

  • increasing obesity levels
  • a lack of exercise
  • an increase in unhealthy diets
  • an ageing population

Read more about risk factors for type 2 diabetes.

 

What did the research involve?

The research team used existing data on 41,436 men in the Health Professionals Follow-Up Study (1986-2010), 67,138 women in the Nurses' Health Study (1980-2010), and 85,884 women in the Nurses' Health Study II (1991-2009) to look at the links between diet and type 2 diabetes.

Diet was assessed by validated food frequency questionnaires and data was updated every four years. Incident type 2 diabetes was confirmed by a validated supplementary questionnaire.

Every two years, data was gathered and updated on risk factors for chronic diseases, such as body weight, cigarette smoking, physical activity, medication use and family history of diabetes, as well as history of chronic diseases such as high blood pressure and high cholesterol.

Among participants in the two nurse studies, information on menopausal status, post-menopausal hormone use and oral contraceptive use was also gathered.

The researchers analysed their results in three phases, with each phase adjusting for more and more potentially confounding factors.

The fully adjusted analysis took account of the following potential confounders:

  • age
  • calendar time with updated information at each two-year questionnaire cycle
  • body mass index (BMI)
  • total energy intake
  • race
  • smoking
  • physical activity
  • alcohol consumption
  • menopausal status
  • menopausal hormone use (Nurses' Health Study II participants only)
  • oral contraceptive use (Nurses' Health Study II participants only)
  • family history of diabetes
  • diagnosed with high blood pressure or high cholesterol at baseline
  • trans-fat intake (a type of unsaturated fat often found in processed foods)
  • glycaemic load (eating foods known to raise blood glucose levels)

As well as intakes of:

  • red and processed meat
  • nuts
  • sugar-sweetened beverages
  • coffee
  • other types of dairy foods

The team extended their work by conducting an updated meta-analysis that combined the new results from the three large cohort studies described above with findings from previous studies.

This previous research included prospective studies with cohort, case cohort or nested case-control design investigating the association between the intake of dairy products and the risk of type 2 diabetes. Literature was searched for up until October 2013.

In studies that reported the intakes by grams (g), they used 177g as a serving size for total dairy products, and 244g as a serving size for milk and yoghurt intake to recalculate the intakes to a common scale (servings per day).

 

What were the basic results?

During 3,984,203 person years of follow-up, they documented 15,156 cases of incident type 2 diabetes.

After adjustment for age, BMI and other lifestyle and dietary risk factors, total dairy consumption was not associated with type 2 diabetes risk.

The pooled hazard ratio (HR) (95% confidence interval [CI] of type 2 diabetes for one serving per day increase in total dairy was 0.99, 95% CI 0.98 to 1.01), so the this result was not statistically significant.

Among different types of dairy products, neither low-fat nor high-fat dairy intake was appreciably associated with risk of type 2 diabetes.

However, yoghurt intake was consistently and inversely associated with type 2 diabetes risk across the three cohorts with a pooled HR of 0.83 (95% CI 0.75 to 0.92) for one serving per day increment (trend analysis).

For added validity, they conducted a meta-analysis of 14 additional prospective cohorts with 459,790 participants and 35,863 incident type 2 diabetes cases.

The pooled relative risks (RRs) (95% CIs) were 0.98 (0.96, 1.01) and 0.82 (0.70, 0.96) for one serving of total dairy per day and one serving of yoghurt per day, respectively.

 

How did the researchers interpret the results?

The researchers' main conclusion was that, "Higher intake of yoghurt is associated with a reduced risk of T2D [type 2 diabetes], whereas other dairy foods and consumption of total dairy are not appreciably associated with incidence of T2D."

They added that, "The consistent findings for yoghurt suggest that it can be incorporated into a healthy dietary pattern. However, randomised clinical trials are warranted to further examine the causal effects of yoghurt consumption, as well as probiotics on body weight and insulin resistance."

 

Conclusion

This analysis of three large cohort studies, and a meta-analysis of 14 more, came up with estimates that each serving per day of yoghurt (244g) decreases the relative risk of developing type 2 diabetes by 18%.

It suggests other dairy foods and consumption of total dairy are not associated with type 2 diabetes. It was not clear over what time period this risk reduction was achieved, as follow-up times varied, but the maximum was 30 years.

The research team pointed out that their findings on total dairy intake were consistent with some, but not all, previous studies. Differences between this and previous studies may be because the current study used longer-term follow-up (more than 10 years).

The study had a number of strengths, including its large sample size, use of prospective data and ability to take account of a large number of confounding factors. 

But, as with all studies, there are also limitations to consider.

What sort of yoghurt was consumed?

Firstly, what sort of yoghurt we are talking about here? Greek, natural or added sugar, low-fat or full-fat?

From the study data presented, there are few distinctions made and all types of yoghurt are lumped together in the analysis.

This means it is not possible to know which types of yoghurt are potentially beneficial. This may depend on the levels of sugar, fat and probiotic bacteria, or other constituents.

For example, many low-fat yoghurts are very high in sugar, which could contribute to weight gain and increase the risk of harms from other weight-related diseases.

Other health outcomes not considered

This study focused exclusively on the risk of developing type 2 diabetes. The effect of diet on other diseases was not studied, so any compensating effects would go unnoticed.

For example, those eating yoghurt may be at a reduced risk of developing type 2 diabetes, but at an increased risk of developing another disease.

Were all the confounders accounted for?

Also, despite adjusting for a number of potential confounding factors, it's difficult to know whether all relevant factors have been fully accounted for.

Yoghurt consumption may be a marker of a healthy lifestyle in general, which could be associated with reduced risk of this chronic disease.

This result seems to be consistently found across the three large cohort studies and 14 other studies, which gives it some credibility.

But a systematic review and meta-analysis would be the best way to assess the link. This would ensure that all relevant material is considered. There is no guarantee that important studies were excluded from the meta-analysis of the current study, which could influence its findings.

This type of study typically feeds into the development or updating of national guidelines, which consider all the available evidence before deciding on what dietary advice to give the public. 

For now, current lifestyle advice to reduce the risk of type 2 diabetes remains the same: aim for a balanced diet high in fruit and vegetables and low in sugar, salt and saturated fats, take regular exercise in line with recommendations, avoid smoking, and moderate your alcohol consumption.

Read more about what eating a healthy, balanced diet entails. 

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

A yoghurt a day could reduce your risk of diabetes, scientists find. The Independent, November 24 2014

How yoghurt could stave off diabetes: Just two spoonfuls a day cut odds of developing the disease by a fifth. Daily Mail, November 25 2014

A yoghurt a day may cut diabetes risk. The Times, November 25 2014

A yoghurt a day keeps diabetes away, say scientists. Daily Mirror, November 25 2014

A tablespoon of yoghurt could be key to beating diabetes, reveals new study. Daily Express, November 25 2014

Links To Science

Chen M, Sun Q, Giovannucci E, et al. Dairy consumption and risk of type 2 diabetes: 3 cohorts of US adults and an updated meta-analysis. BMC Medicine. Published online November 25 2014

Categories: NHS Choices

Therapy reduces risk of suicide or self-harm

NHS Choices - Behind the Headlines - Mon, 24/11/2014 - 11:30

“Talk therapy sessions can help reduce the risk of suicide among high-risk groups,” BBC News reports.

The headline is prompted by a large Danish study that took place over a 20-year period.

Researchers matched those who had received different psychosocial (“talking therapy”) interventions after a self-harm attempt with those who had not received a psychosocial intervention, and then compared relevant outcomes.

People who received psychological interventions had reduced risk of further self-harm, but not suicide, within the first year. Looking at longer-term follow-up, psychological interventions were associated with reduced risk of both self-harm and suicide.

However, it may be difficult to isolate the direct effect of the psychological intervention. People who had received psychological interventions were recruited from treatment clinics that required them not to be in need of psychiatric admission.

Meanwhile, those who did not receive psychological treatment were reported to include people who needed psychiatric admission, or chose not to receive suicide prevention treatment. These factors could mean that this comparison group were at increased risk of subsequent harm and death to begin with.

Also, the situation in the UK might be slightly different to Denmark. Despite this, any research that could help prevent suicides is always valuable.

 

Where did the story come from?

The study was carried out by researchers from the University of Copenhagen in Denmark and the Johns Hopkins Bloomberg School of Public Health in the US, in addition to other research institutions in Denmark and Norway. Funding was provided by the Danish Health Insurance Foundation; the Research Council of Psychiatry, Region of Southern Denmark; the Research Council of Psychiatry, Capital Region of Denmark; and the Strategic Research Grant from Health Sciences, Capital Region of Denmark.

The study was published in the peer-reviewed medical journal The Lancet Psychiatry.

BBC News was generally representative of the research’s findings, but inaccurately described participants as having “attempted suicide”. The research included participants who had self-harmed. Not all instances of self-harm are suicide attempts, so it is a mistake to conflate the two terms. For some people, certain types of self-harming, such as cutting, are a way of coping with overwhelming emotional distress, rather than an attempt to end their life.

It was not clear from the study what proportion of the self-harming events were attempted suicide.

 

What kind of research was this?

This was a cohort study comparing people who did and did not receive a psychosocial (talking) therapy after deliberate self-harm, and examined the outcomes of further self-harm, suicide or death from other causes. 

The researchers say that self-harm is a strong predictor of suicide. Research indicates that within the first year after self-harming, about 16% of people self-harm again; 0.5 to 1.8% die by suicide; and 2.3% die from another cause. However, evidence for the effectiveness of psychological interventions following self-harm is said to be missing, and this study aimed to investigate this.

 

What did the research involve?

This study compared people in Denmark who received a psychological intervention following a first episode of self-harm with those who received standard care, over the 18-year period between January 1992 and December 2010. They calculated the risk of repeated self-harm, suicide and dying of any cause after the first instance of self-harm, and compared the risks between the two groups for differences that might be due to the psychological intervention. 

The people who received psychological interventions were identified from one of seven suicide prevention clinics in Denmark. These clinics are said to receive people who are thought to be at risk of suicide, but not in need of psychiatric admission or other outpatient programmes. For the purposes of this study, participation was considered to be attendance for at least one psychological treatment session that was focused on suicide prevention. The seven different clinics used various types of therapy, including cognitive, problem-solving, crisis, dialectical behaviour, integrated care, psychodynamic, systemic, psychoanalytic approaches and support from social workers.

The controls who did not receive a psychological intervention were people who had presented to hospital with an episode of self-harm during the study period, but who did not receive any psychological intervention. They could receive any form of standard care, including admission to a psychiatric hospital, referral to outpatient treatment or a general practitioner, or discharge without referral.

The reasons why these people did not receive a psychological intervention were variable, including:

  • living in an area remote from services
  • being referred for other treatment (including hospital admission)
  • not wanting to be referred for suicide prevention treatment

All people were linked via their Danish ID numbers to the Danish Civil Register, National Registry of Patients, Psychiatric Central Registry and Registry of Causes of Death. Follow-up was to the end of 2011, giving a follow-up period for the people in the study of 1 to 20 years.

The main outcomes examined were self-harm, death by suicide, and death by any cause. People who did and did not receive psychological interventions were matched for various potentially confounding factors, including:

  • study period (1992 to 2000 or 2001 to 2011)
  • age
  • gender
  • educational level
  • socioeconomic status
  • previous episodes of self-harm
  • specific psychiatric diagnoses

 

What were the basic results?

The study included a total of 5,678 people in the psychological intervention group and 17,034 matched people who had not received a psychological intervention after self-harm. Around two-thirds were women and most were in the 15 to 49 age bracket. Around 10% had a previous episode of self-harm.

During the first year of follow-up, 6.7% of people receiving a psychological intervention had a repeated self-harm attempt, compared with 9.0% of the no psychological intervention group. Psychosocial therapy was associated with a 27% reduced risk of self-harm within one year (odds ratio (OR) 0.73, 95% confidence interval (CI) 0.65 to 0.82). The absolute risk reduction (ARR), measuring how much the risk of self-harm is reduced in those who received the psychosocial therapy, was 2.3% (95% CI 1.5 to 3.1%). The number needed to treat (NNT) was 44 (95% CI 33 to 67), indicating that 44 people would need to receive psychosocial therapy after a self-harm attempt to prevent one person self-harming within one year.

There was no significant difference between groups in rates of suicide within one year, but overall mortality rates within one year were slightly lower in the psychological intervention group (1,122 compared with 1,824 per 10,000), which also meant a significant reduction in overall mortality rate (OR 0.62, 95% CI 0.47 to 0.82). When considering the longer term effects over the full 20 years of follow-up, psychological intervention was associated with a 16% decreased risk of repeated self-harm (OR 0.84, 95% CI 0.77 to 0.91), with an ARR of 2.6% (95% CI 1.5to 3.7) and NNT of 39 people (95% CI 27 to 69).

When looking at overall follow-up, psychological therapy was also associated with a 25% reduced risk of death from suicide (OR 0.75, 0.60 to 0.94), with an ARR of 0.5% (95% CI 0.1 to 0.9) and a NNT of 188 people to prevent one suicide (95% CI 108 to 725). It was also associated with significant reduction of death from any cause (OR 0.69, ARR 2.7%, NNT 37).

The results altogether suggested that during the 20 years of follow-up, 145 self-harm episodes and 153 deaths were prevented by psychological interventions, with 30 of these deaths from suicide.

 

How did the researchers interpret the results?

The researchers conclude that their findings, “show a lower risk of repeated deliberate self-harm and general mortality in recipients of psychosocial therapy after short-term and long-term follow-up, and a protective effect for suicide after long-term follow-up, which favour the use of psychosocial therapy interventions after deliberate self-harm”.

 

Conclusion

The researchers report that this is the largest follow-up study of psychosocial interventions offered after deliberate self-harm attempts. Compared to standard care, it found that psychosocial interventions were associated with a reduced risk of repeated self-harm and death from any cause within the first year of follow-up. In the longer term, psychosocial interventions were associated with reduced risks of self-harm, death from any cause and suicide, specifically.

The study benefits from its large sample size, long duration of follow-up and reliable methods of identifying participants and their outcomes. There are, however, some points to be considered when interpreting the findings.

Possible selection bias

The reasons that people did not receive a psychological treatment could have put them at higher risk of subsequent harm to start with, potentially explaining all or some of the risk difference between the two groups. Though the people who did and did not receive psychological treatments were matched for various factors, this may not have been comprehensive, and some selection bias may still be present. For example, all the people who were receiving psychological treatments had been referred to suicide prevention clinics because they were not considered to be in need of psychiatric admission or other outpatient treatment following their self-harm attempt. Meanwhile, those who did not receive psychological treatment were reported to include people who needed psychiatric admission, or chose not to receive suicide prevention treatment after their self-harm attempt.

This makes it difficult to isolate the effect of the psychological intervention compared with selection biases and other confounding factors. It could be that the reduced risk seen in the psychological intervention group is not solely a result of the intervention, but that there were other risk factors among the non-treated group that were increasing their risk of further self-harm/suicide attempts and so confounding the association.

However, some degree of selection bias is inevitable in this type of study. The only way to remove it completely would be to randomise people to treatment or no treatment, which could never be done for ethical reasons.

Uncertainty about most effective intervention

It is also difficult to conclude many treatment implications from this study in terms of what would be the best type of psychological intervention to use after a self-harm attempt (a wide variety of interventions were used in this study), whether the optimal type differs according to the individual (e.g. according to mental health diagnosis[es]), and what would be the optimal treatment duration.

Results may not be applicable to the UK

The results also apply to Denmark, which may differ from other countries – for example, in terms of healthcare and mental health services, and population health, psychosocial and environmental influences. This may mean that the results are less applicable to this country.

People in the UK who present to health services following self-harm or a suicide attempt receive assessment by specialist mental health professionals, followed by referral, hospital admission or discharge, and follow-up care and treatment as appropriate to their individual situation.

Getting help

If you are reading this because you are having suicidal thoughts, try to ask someone for help. It may be difficult at this time, but it's important to know you are not beyond help and you are not alone.

Speak to a person you trust (such as a friend or family member), make an urgent appointment with your GP or contact your local A&E department. The Samaritans (08457 90 90 90) also operates a 24-hour service available every day of the year.

Read more about getting help for suicidal or self-harming thoughts, as well as spotting possible warning signs in family members and friends.

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

Suicide risk reduced after talk therapy, study suggests. BBC News, November 24 2014

Talking therapy 'can stop suicide'. Mail Online, November 24 2014

Links To Science

Erlangsen A, Lind BD, Stuart EA, et al. Short-term and long-term effects of psychosocial therapy for people after deliberate self-harm: a register-based, nationwide multicentre study using propensity score matching. The Lancet Psychiatry. Published online November 24 2014

Categories: NHS Choices

Vegetarian diet 'could have slight benefits in diabetes'

NHS Choices - Behind the Headlines - Mon, 24/11/2014 - 11:30

"Vegetable diet will beat diabetes: Meat-free lifestyle cures killer disease," is the typically overblown headline in the Daily Express.

But researchers actually found a vegetarian diet led to a quite modest fall in only one measure of blood glucose called HbA1C, a measure of blood glucose control.

The paper reports on a systematic review which combined the results of six trials that involved 255 people with type 2 diabetes. They examined whether vegetarian or vegan diets improved blood glucose control compared with a control diet.

Overall, the pooled results of five of these trials found a vegetarian or vegan diet reduced HbA1c by 0.39%. There was no significant effect on fasting glucose levels, an assessment of how efficiently the body can process glucose in the short term.

This slight reduction in HbA1c is no cure. As the researchers themselves pointed out, the reduction is less than you would expect if a patient was being treated with the drug of choice for type 2 diabetes, metformin.

This review also has various important limitations, including the variable design and quality of the six trials included. So, it does not prove that a vegetarian or vegan diet is better for a person with type 2 diabetes, and any media claims of a "cure" for the condition are entirely baseless.

 

Where did the story come from?

The study was carried out by researchers from Keio University in Japan and The George Washington University School of Medicine in the US.

Funding was provided by the Japan Society for the Promotion of Science and the Nestlé Nutrition Council, Japan.

One of the co-authors declared a non-financial conflict of interest. This author serves as president of the Physicians Committee for Responsible Medicine, without financial compensation.

This organisation is described in the publication as one that, "promotes the use of low-fat, plant-based diets and discourages the use of animal-derived, fatty, and sugary foods". This represents a potential conflict of interest in the interpretation of the results.

The study was published in the peer-reviewed medical journal, Cardiovascular Diagnosis and Therapy and the study is open access, so it is free to read the study online.

The Daily Express' coverage of the study is accurate and contains some useful background information, so it is frustrating that its headline is totally misleading, especially as it was on the front page.

In fact, this review of studies found vegetarian or vegan diets caused a slight reduction in HbA1c compared with non-vegetarian diets. This is not a cure in any sense of the word.

The current thinking is that there is no such thing as a cure for type 2 diabetes. The condition can be successfully managed, but not cured.

The study is also only applicable to type 2 diabetes, so the headlines do not apply to type 1 diabetes.

 

What kind of research was this?

This was a systematic review and meta-analysis combining the results of controlled trials that examined the effects of vegetarian diets on blood sugar control in type 2 diabetes.

As the researchers say, previous research has suggested a link between a vegetarian diet and improved blood sugar control, but the relationship is not well established.

As an interesting aside, the researchers highlight how diabetes levels were found to be lower in Seventh-day Adventists, a Protestant Christian denomination whose followers are encouraged to adopt a vegetarian diet.

This review aimed to examine this grey area. A systematic review and meta-analysis of randomised controlled trials is the best way of examining the evidence to date that has assessed this question.

 

What did the research involve?

The researchers searched a number of literature databases (from their inception to 2013) to identify published clinical trials examining the effects of a vegetarian, vegan or omnivorous diet on blood sugar control in people with type 2 diabetes who were over the age of 20.

A vegetarian diet was defined as one excluding meat, poultry and fish, while a vegan diet excluded all animal products.

Eligible trials had an intervention duration of at least four weeks and examined the main outcome of changes in HbA1c.

This gives an indication of blood sugar control in the longer term, as it indicates the amount of sugar being carried by red blood cells, which have a lifespan of around three months. Change in fasting blood sugar measures was a secondary outcome.

In an added effort to find all relevant information for the review, the research team scoured the reference lists of all articles they found from the search of electronic databases, and also contacted research experts for additional material.

The researchers assessed the quality of the studies included, and pooled studies calculating the average difference in HbA1c and fasting blood sugar between vegetarian or vegan and comparison diets.

 

What were the basic results?

A total of six trials met the inclusion criteria, involving 255 people with type 2 diabetes with an average age of 52-and-a-half. The average trial duration was 23.7 weeks, or about six months.

Five of the studies examined vegan diets and one studied vegetarian diets. Four trials were conducted in the US, one in Brazil and one in the Czech Republic.

Of the six studies, three were randomised controlled trials, one was a cluster randomised controlled trial, and two were non-randomised controlled trials.   

In the pooled analysis of five trials, the vegetarian or vegan diet was associated with a significant reduction in HbA1c (-0.39%, 95% confidence interval [CI] -0.62 to -0.15) compared with omnivorous control diets.

But the pooled analysis of four trials did not find a statistically significant reduction in fasting blood sugar: the average difference with the vegetarian or vegan diet compared with control was -0.36 mmol/L, 95% CI -1.04 to 0.32.

Compared with control, the vegetarian or vegan diets were also associated with significant reductions in the amount of total energy the diet provided, either through carbohydrate, protein, total fat, cholesterol and fibre.

 

How did the researchers interpret the results?

The researchers concluded that, "Consumption of vegetarian diets is associated with improved [blood glucose] control in type 2 diabetes."

 

Conclusion

This systematic review has identified six trials assessing whether vegetarian or vegan diets improve blood sugar control in type 2 diabetes compared with control.

It found the vegetarian or vegan diet gave significant improvement in one measure of blood sugar control (HbA1c), but not in another (fasting blood glucose).

However, there are some important limitations to consider before we can categorically conclude that people with type 2 diabetes should switch to a meat and fish-free diet:

The improvement in blood sugar control was quite small

The pooled results of five trials found a vegetarian or vegan diet was associated with a 0.39% reduction in HbA1c, but we don't know that this would have made any meaningful clinical difference in diabetes control for the individual.

Overall, although any reduction is likely to be a good thing, the precise benefit would depend on what a person's HbA1c level was to start with.

The target HbA1c is usually set at a level below around 7%, so it may be more useful knowing whether a vegetarian or vegan diet improved the proportion of people achieving their target HbA1c level. The review also found no improvement in fasting blood glucose control.

The intervention diets were varied

Despite the publication tending to refer to the intervention diets as vegetarian, they were actually quite varied across the trials.

Four of the trials were described as low-fat vegan, one as lacto-vegetarian (a diet that includes dairy products but not eggs), and one lacto-ovo low-protein (similar to a lacto-vegetarian diet but, as the name suggests, with a focus on low-protein foods).

The control diets were also quite varied across the trials

The researchers included diets described as omnivorous, low fat, "diabetic diet" and those that followed American Diabetic Association guidance.

Overall, this doesn't give a very clear picture of what diets were being compared, which makes it hard to conclude that a particular diet is associated with an improvement in blood sugar control compared with a particular control.

The trials had variable quality evidence

Only three of the six trials studied were true randomised controlled trials. They varied in the duration of the dietary intervention between four and 74 weeks.

Also, only one of the six trials (a controlled trial) is reported to have made any adjustment for potential confounders (sex, baseline HbA1c level and medication). The others report no adjustment.

We also don't know how the trials checked that the diets were being followed as assigned, or of any other intervention or advice that may have been given to the participants alongside the dietary intervention (such as advice about physical activity).

The review only included published trials

In their assessment of possible publication bias, the researchers observed that smaller trials that found reductions in HbA1c level were perhaps more likely to have been published and therefore included in this review.

The small number of participants

Despite this being a systematic review of trials, the total number of participants was still quite small, at only 255. This is a very small number of patients, and it might be unwise to base any firm or generalisable conclusions on such small numbers.

A vegetarian or vegan diet can be a healthy lifestyle choice for a person with type 2 diabetes if it provides balanced nutrition. But such diets can still be high in fat, salt and sugar if this is not controlled carefully.

A healthy diet needs to be combined with regular exercise for people to be able to reap further health benefits, as well as avoiding smoking and only consuming alcohol at or below nationally recommended levels.

Overall, this review does not appear to conclusively prove that a vegetarian or vegan diet is better for a person with type 2 diabetes. It certainly provides no evidence that this diet cures diabetes, as one of the news headlines suggests.

Provided you do your homework, it is possible to eat healthily on a vegetarian or vegan diet. But if you do have type 2 diabetes, we recommend that you talk to the doctor in charge of your care before making any radical changes to your diet. 

Analysis by Bazian. Edited by NHS Choices.
Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Vegetable diet WILL beat diabetes: Meat-free lifestyle cures killer disease, experts claim. Daily Express, November 24 2014

How becoming a vegetarian can CURE diabetes: Plant-based diets improve blood sugar levels, scientists claim. Mail Online, November 24 2014

Links To Science

Yokoyama Y, Barnard ND, Levin SM, Watanabe M. Vegetarian diets and glycemic control in diabetes: a systematic review and meta-analysis. Cardiovascular Diagnosis and Therapy. Published online October 10 2014

Categories: NHS Choices

Air dryers 'blown away' by paper towels in germ tests

NHS Choices - Behind the Headlines - Fri, 21/11/2014 - 11:50

"Hand dryers 'splatter' users with bacteria," The Daily Telegraph reports.

The headline is prompted by an experimental study that compared the potential transfer of germs to the surrounding environment, users and bystanders when using three methods of hand drying:

  • paper towels
  • warm air dryers – the sort you see in most public toilets
  • modern "high-tech" jet air dryers, such as the Dyson Airblade model

Testers wore gloves coated in a solution of bacteria. Air samples taken after drying with the hand dryers showed significantly higher bacterial counts than when drying with paper towels, and were highest for the jet air dryers.

They then assessed the potential for spread to users and bystanders, this time using the proxy of gloves coated in black paint and a white body suit.

They found there was no contamination of the body after towel drying, but paint spots were on the body after the use of air dryers, which again was higher with jet dryers than standard warm air dryers.

One important limitation of this study is it essentially replicates the scenario of someone going to the toilet and then proceeding straight to the hand dryer without washing their hands first.

A more suitable test may have been to coat the gloves with the marker, wash them with soap and water as recommended, and then proceed to the hand dryers.

But the overall message of this study is consistent with current hand washing recommendations, including the use of disposable paper towels in healthcare settings.

 

Where did the story come from?

The study was carried out by researchers from the University of Leeds and the microbiology department at Leeds General Infirmary.

It was funded by the European Tissue Symposium (ETS), from whom one author reports having received honoraria.

The ETS produces paper tissue, including toilet paper, household towels and paper napkins, which may be seen as a potential conflict of interest.

The study was published in the peer-reviewed Journal of Hospital Infection.

The Daily Telegraph and the Mail Online's reporting was accurate, but neither appeared to have considered some of the limitations of this research.

 

What kind of research was this?

This was an experimental study that aimed to compare the tendency for three common hand drying methods – jet air, warm air hand dryers, and paper towels – to spread germs and contaminate the environment, users and bystanders.

Like thorough hand washing, thorough hand drying is just as important to prevent the transfer of germs from person to person or the surrounding environment.

According to hand washing protocols, the optimal way to dry hands is to use a disposable paper towel, which is then used to turn off the tap to avoid re-contaminating hands.

The main concern with using hand dryers is that people may not dry their hands as completely as they would with paper towels, and may go away while they are still damp. If hand dryers are used, it is advised that the hands are rubbed together under the dryer until they are totally dry.

However, another unclear and often speculated issue when using hand dryers is the possible transfer of aerosolised germs to the surrounding environment and people, possibly increasing the spread of infection.

This study aimed to compare the different hand drying methods, looking at whether they can contaminate the surrounding environment, users and bystanders.

 

What did the research involve?

The researchers carried out a series of hand drying tests in a single room with standard ventilation (not air conditioned). They first tested the possible contamination of the environment, and then people.

Gloved hands were immersed in a solution of lactobacilli bacteria (cultured from Actimel Danone yoghurt) before being dried with either:

  • a warm air dryer – hands were rubbed together for 30 to 40 seconds until dry
  • a jet air dryer – hands were placed into the unit and slowly drawn up and down for 15 seconds until dry
  • paper towels – four paper towels were taken from the dispenser and were rubbed over hands for 15 seconds until dry

The tests were conducted over six weeks. A total of 120 air samples were taken – 60 made after drying contaminated hands (20 collections after each drying method: 10 in close proximity, 10 one metre away) and 60 control air samples taken before hand drying. Air samplers were left running for 15 minutes after each drying process. 

They then repeated the tests, this time looking at the possible contamination of people standing nearby. This time, gloved hands were coated in black water-based paint rather than bacteria, and the user wore a disposable white hooded suit.

Another bystander in a similar suit stood diagonally adjacent to the dryer user one metre away to replicate the scenario of another user waiting to dry their hands. There was a total of 30 drying tests in this manner, 10 for each drying method.

 

What were the basic results?

The researchers found the lactobacillus count in air samples taken in close proximity to the dryers were 4.5-fold higher for the jet dryer (70.7 colony forming units, or cfu) compared with the warm air dryer (15.7cfu), and 27-fold higher compared with paper towels (2.6cfu).

Counts for the warm air dryer were also significantly higher than with paper towels.

A similar pattern was seen for the air collection one metre away, where counts were 89.5cfu with the jet dryer, 18.7cfu with the warm air dryer, and 2.2cfu with paper towels.

"Settle plates" underneath each hand dryer had the highest bacterial count for the warm air dryer (190cfu) compared with the jet air dryer (68.3cfu) and the paper towel drying (11.9cfu). Respective figures at plates one metre away were 7.8cfu, 2cfu and 0.7cfu. 

As would be expected, the control air samples taken before drying found no lactobacilli.

On the person-contamination experiments, no paint spots were seen on paper towel users. For both the jet air and warm air dryers, spots predominated in the upper body area, with the number of spots significantly higher with jet dryers (144.1) compared with warm air dryers (65.8).

The number of paint spots was higher for all body areas with jet dryers, with the exception of both arms. With both hand dryers, however, there were relatively few paint spots remaining on the hands.

The number of paint spots detectable on the bystander was generally low for both air dryers and was not significantly different between the two (average count 1.6 spots for jet dryers and 1.5 for warm air dryers).

 

How did the researchers interpret the results?

The researchers concluded that, "Jet air and warm air dryers result in increased bacterial aerosolisation when drying hands.

"These results suggest that air dryers may be unsuitable for use in healthcare settings, as they may facilitate microbial cross-contamination via airborne [spread] to the environment or bathroom visitors."

 

Conclusion

Overall, this experimental study found the airborne spread of lactobacilli bacteria from contaminated hands was significantly higher with air dryers than with paper towels. Of the two, jet dryers caused higher air bacterial counts than standard warm air dryers.

Similarly, when assessing spread on to the body of the user and bystander using the proxy measure of black paint dispersal, there was no contamination of the body with paper towels, but paint spots were on the body after use of air dryers, again higher with jet dryers than standard warm air dryers.

It is well known that thorough hand drying is as key to preventing spreading infection as thorough hand washing. One of the recognised problems with hand dryers is that people may not dry their hands as completely as they would with paper towels.

What is less clear, and is often speculated about, is the possible transfer of aerosolised germs to the surrounding environment and people, possibly increasing the spread of infection.

This study appears to demonstrate cause for this concern. However, there are some points worth consideration when interpreting this study:

  • One important limitation of the study is it may not replicate the real-life condition of someone having just thoroughly washed their hands with soap and water, and then drying their hands. In this experimental situation, the users had gloved hands contaminated with either lactobacilli or black paint and then dried their hands. In effect, this may be seen more to replicate the scenario of someone going to the toilet and then proceeding straight to the hand dryer without washing their hands first. A more suitable test may have been to coat the gloves with either bacteria or black paint, wash them with soap and water as recommended, and then proceed to the hand dryers to see how many bacteria or paint were spread.
  • The spread of heavier black paint may also not be equivalent to the spread of viruses and bacteria, though it may represent the spread of water.  
  • Aside from the assessment of the surrounding environment and bystanders, another important area of consideration would also be to compare how much bacteria remained on the surface of the users' hands after drying with each of the three methods. This is of equal importance in knowing how much bacteria remains on the users' hands that could be transferred to other surfaces. It would be valuable to know whether there was any difference. This study has not specifically examined this aspect, though in fact it did note few paint spots remained on the hands after drying with either of the hand dryers.
  • It also would have been valuable to consider comparing the amount of bacteria or paint left on the towel dispenser or hand dryers after use, and how much of this would usually be transferred to the next person's hands during hand drying.

Despite these limitations, the overall message of this study is consistent with current handwashing recommendations, particularly when it comes to healthcare settings.

Of course, disposable paper towels are not available in all facilities. If only hand dryers are available, hands need to be rubbed together until they are completely dry.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Hand dryers 'splatter' users with bacteria, scientists warn. The Daily Telegraph, November 20 2014

Modern hand dryers are 'much worse' at spreading germs around a room than paper towels, study claims. Mail Online, November 20 2014

Links To Science

Best E, Parnell P, Wilcox MH. Microbiological comparison of hand-drying methods: the potential for contamination of the environment, user, and bystander. The Journal of Hospital Infection. Published online August 26 2014

Categories: NHS Choices

Breastfeeding voucher scheme 'shows promise'

NHS Choices - Behind the Headlines - Fri, 21/11/2014 - 11:50

"Initial results of a controversial scheme offering shopping vouchers to persuade mothers to breastfeed have shown promise," BBC News reports.

The scheme, which has attracted controversy since it was announced, aimed to tackle the problem of low rates of breastfeeding in the UK compared with other developed nations. Mothers who live in the poorest areas of the country have been found to be more likely to prefer bottle feeding.

This pilot scheme has tested whether it is possible to try to boost breastfeeding rates by offering new mothers shopping vouchers if they breastfeed their baby until specific ages.

The scheme was available to just over 100 women who gave birth to babies over a six-week period and lived in three areas of Derbyshire and south Yorkshire. The breastfeeding rate in these areas at six to eight weeks was 21-29%.

In the period where vouchers were available, 34.3% of women were breastfeeding at six to eight weeks. Both mothers and healthcare staff reported high levels of satisfaction with the scheme.

The researchers report they are now planning further studies in the form of a randomised controlled trial to see how effective the voucher scheme is at boosting breastfeeding rates.

 

Where did the story come from?

The study was carried out by researchers from the University of Sheffield and was funded by the Medical Research Council National Prevention Research Initiative.

The meeting abstract was published in the peer-reviewed medical journal, The Lancet.

It has been published prior to being presented at The Lancet's annual conference on Public Health Science, held jointly with the London School of Hygiene and Tropical Medicine, University College London, the UK Health Forum, and in partnership with the European Public Health Association.

The media reporting of the study was good, providing background information about the scheme and why some people are opposed to it – most critics have questioned why a scheme should reward mothers for doing the best for their child while penalising mothers who are unable to breastfeed.

It is a fair point, though a pragmatic answer would be that it's not about the mother, but the child. Also, increased breastfeeding rates may lead to a reduction in the number of childhood illnesses the NHS has to deal with, so a voucher scheme could actually save the NHS money in the long term.

But we will need to wait for the results of the planned randomised controlled trial before more detailed effectiveness and cost benefit information becomes available.

 

What kind of research was this?

This was a feasibility study to see whether it was both acceptable and possible to give women financial incentives to increase breastfeeding rates, prior to performing a randomised controlled trial to see if these financial incentives were effective. 

The results of this study have been published in the form of a meeting abstract. This means the method and results are only described briefly, and a full appraisal of the strengths and limitations of the study can't be performed. This study is actually still ongoing and the results from some time points are still being collected.

 

What did the research involve?

The researchers wanted to test whether it was acceptable and possible to give women financial incentives for breastfeeding, as young women in deprived areas are less likely to breastfeed.

They offered vouchers for breastfeeding to women with babies born within a 16-week period who lived in three neighbourhoods in Derbyshire and south Yorkshire, where breastfeeding rates were less than 30%.

The vouchers were available when their babies were five different ages:

  • two days
  • 10 days
  • six weeks
  • three months
  • six months

The vouchers were for supermarkets and high street shops for a value of £40 at each time point, so each woman could receive a maximum of £200.

To receive the vouchers, the woman and her healthcare professional had to sign statements saying she had been breastfeeding.

The researchers then interviewed 36 healthcare providers and 18 women to get their views on the scheme.

 

What were the basic results?

Fifty-eight of the 108 women (53.7%) who could have joined the scheme chose to do so.

  • 48 women (44.4%) claimed vouchers when their babies were two days old
  • 45 women (41.7%) claimed vouchers when their babies were 10 days old
  • 37 women (34.3%) claimed vouchers when their babies were six to eight weeks old

The researchers are still collecting data for the three and six-month time points.

Mothers and healthcare staff who participated reported high levels of satisfaction with the scheme.

 

How did the researchers interpret the results?

The researchers say that, "The scheme was both deliverable and acceptable to mothers and healthcare staff in this field of study.

"The scheme was extended (and will continue until at least December 2014) in all three areas. A randomised controlled trial testing the effectiveness of the scheme is now planned."

 

Conclusion

This study tested whether it is possible and acceptable to try to boost breastfeeding rates by offering new mothers vouchers if they breastfeed their baby until specific ages.

The scheme was available to just over 100 women who gave birth over a six-week period, and who lived in three areas of Derbyshire and South Yorkshire. In these areas, the breastfeeding rate at six to eight weeks was 21-29%.

In the period where vouchers were available, 34.3% of women were breastfeeding at six to eight weeks. Both mothers and healthcare staff reported high levels of satisfaction with the scheme.

The researchers report they are now planning a randomised controlled trial to see how effective the voucher scheme is at boosting breastfeeding rates.

The results of this study have been published in the form of a meeting abstract. This means the methods and results are only described briefly, and a full appraisal of the strengths and limitations of the study can't be performed.

Similarly, there is no information provided about the women who took part in the study, such as their age, medical history, family circumstances and support network.

In addition, this study is actually still ongoing and the results from some time points are still being collected.

Hopefully, the publication of the upcoming randomised controlled trial, which could be in either 2015 or 2016, will help assess how effective the scheme is and whether it is likely to be cost effective.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Early results in breastfeeding vouchers trial. BBC News, November 20 2014

Scheme offering shopping vouchers to mothers who breastfeed to be extended. The Guardian, November 20 2014

NHS to 'bribe' thousands of mothers to breastfeed. The Daily Telegraph, November 20 2014

Links To Science

Relton C, Whelan B, Strong M, et al. Are financial incentives for breastfeeding feasible in the UK? A mixed methods field study. The Lancet. Published online November 19 2014

Categories: NHS Choices

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