NHS Choices

Can exercise offset some of the harms of regular drinking?

NHS Choices - Behind the Headlines -

"Adults who booze regularly but exercise for five hours a week are no more likely to die than teetotallers," the Mail Online reports.

A study suggests exercise may compensate for some, but certainly not all, of the harms associated with excessive alcohol consumption. This latest study looked at deaths from cancer and cardiovascular disease, as well as premature death in general (usually judged to be dying before the age of 75).

Researchers looked at around 10 years' worth of national survey data from UK adults aged over 40. Unsurprisingly, they found links between all-cause and cancer mortality in inactive people. But they also found increasing levels of physical activity generally removed the association with drinking habits. In fact, occasional drinking was associated with a significant reduction in all-cause mortality for the most active of people.

Although the study had strengths in its large sample size and regular follow-up, we can't be sure that any links observed were solely down to the interaction between alcohol and exercise. For example, people who are physically active may also avoid smoking and consume healthy diets. It is difficult to completely control for such influences when analysing data like this.

While regular exercise may mitigate against some of the harms associated with excessive alcohol consumption it certainly won't make you immune. Many world-class sportspeople, such as George Best and Paul Gascoigne, have had both their careers and lives blighted by drinking.

 

Where did the story come from?

The UK-based study was carried out by an international collaboration of researchers from Canada, Australia, Norway and the UK. The health surveys on which the study was based were commissioned by the Department of Health, UK. Individual study authors also reported receiving funding from the National Health and Medical Research Council and University of Sydney. 

The study was published in the peer-reviewed British Journal of Sports Medicine. 

The media coverage around this topic was generally overly optimistic, highlighting that by exercising, individuals can completely undo the harm caused by excessive alcohol consumption, which is untrue.

In particular, the Mail Online claimed "Adults who booze regularly but exercise for five hours a week are no more likely to die than teetotallers" which could send out the wrong message to the public.

 

What kind of research was this?

This cohort study analysed data from British population-based surveys: Health Survey for England (HSE) and the Scottish Health Survey (SHS) to investigate whether physical activity is able to moderate the risk between alcohol consumption and mortality from cancer and cardiovascular diseases.

Cohort studies like this are useful for assessing suspected links between an exposure and outcome. However, there are potentially other factors that have a role to play in such associations and therefore the study design doesn't allow for confirmation of cause and effect.

 

What did the research involve?

The researchers collected data on 36,370 men and women aged 40 or above from Health Survey for England (1994; 1998; 1999; 2003; 2004; and 2006) and the Scottish Health Survey (1998 and 2003). Among other things, the participants were asked about their current alcohol consumption and physical activity.

Alcohol intake was defined by six categories (UK units/week):

  • never drink (lifetime abstainers)
  • ex-drinkers
  • occasional drinkers (haven't drank anything in past seven days)
  • within (previous) guidelines: <14 units (women) and <21 units (men)
  • hazardous: 14-15 units (women) and 21-19 units (men)
  • harmful: >35 (women) and >49 (men)

Frequency and type of physical activity in the past four weeks was questioned and converted into metabolic equivalent task-hour (MET-hours, which are an estimate of metabolic activity) per week according to national recommendations:

  • inactive (≤7 MET-hours)
  • lower level of active (>7.5 MET-hours)
  • higher level of active (>15 MET-hours)

The surveys were linked to the NHS Central Register for mortality data and the participants were followed up until 2009 (HSE) and 2011 (SHS). There were 5,735 recorded deaths; deaths from cancer and cardiovascular disease were of most interest for this study.

The data was analysed for associations between alcohol consumption and the risk of death from all-causes, cancer and cardiovascular disease. The results were then analysed according to levels of physical activity.

Potential confounders (such as sex, body mass index and smoking status) were controlled for.

 

What were the basic results?

Overall, the study found a direct link between all levels of alcohol consumption and risk of cancer mortality. It also found that increasing levels of physical activity reduced this association with cancer mortality, and also reduced the link with death from any cause.

  • In individuals who reported inactive levels of physical activity (≤7 MET-hours), there was a direct association between alcohol consumption and all-cause mortality.
  • However, in individuals who met the highest level of physical activity recommendations a protective effect of occasional drinking on all-cause mortality was observed (hazard ratio: 0.68; 95% confidence interval (CI): 0.46 to 0.99). It should be noted that this result just skimmed the cut-off point for statistical significance.
  • In this high activity group, there was no link between all-cause mortality and alcohol consumption within guidelines, or even hazardous amounts, but the risk was still increased for those drinking harmful amounts.
  • The risk of death from cancer increased with the amount of alcohol consumed in inactive participants, ranging from a 47% increased risk for those drinking within guidelines to 87% increased risk for those with harmful drinking.
  • In people with higher activity levels (above 7.5 MET hours) there was no significant link between any amount of alcohol consumption and cancer mortality.
  • No association was found between alcohol consumption and mortality from cardiovascular disease, although a protective effect was observed in individuals who reported the lower and higher levels of physical activity (>7.5 MET-hours) and (>15 MET-hours) respectively.

 

How did the researchers interpret the results?

The researchers concluded "we found evidence of a dose–response association between alcohol intake and cancer mortality in inactive participants but not in physically active participants. [Physical activity] slightly attenuates the risk of all-cause mortality up to a hazardous level of drinking."

 

Conclusion

This study aimed to explore whether physical activity is able to moderate the risk between alcohol consumption and mortality from cancer and cardiovascular diseases. It found that increasing levels of physical activity reduced the association for death from both all-causes and cancer.

This study has strengths in its large sample size, comprehensive assessments and long duration of follow-up. The findings are interesting, but there a few points to bear in mind:

  • As the authors mention, cohort studies such as this are unable to confirm cause and effect. Though the researchers have tried to account for various potential health and lifestyle confounding variables, there is the possibility that others are still influencing the results. A notable one is dietary habits which weren't assessed. Also, for example, the former drinkers may have quit due to other health issues which may have introduced bias.
  • The study was unable to look at binge drinking levels of alcohol consumption which would have likely had important health implications.
  • Additionally, there is always the possibility with self-reported surveys that the participants either under or over-reported their drinking habits which can increase the chance of misclassification bias.
  • Though having a large sample size, fewer people reported harmful drinking levels, so links within this category may be less reliable.
  • The study has only looked at the link between alcohol and actually dying from cancer or cardiovascular disease. Links may be different if they looked at associations between alcohol and just being diagnosed with cancer or heart disease, for example.
  • The study is also only representative of adults over the age of 40.

Overall, maintaining a healthy lifestyle seems to be the best bet for reducing the risk of any chronic disease, be it through physical activity, balanced diet or reasonable alcohol consumption.

Current alcohol recommendations for both men and women are to drink no more than 14 units per week.  

Links To The Headlines

How exercise undoes the harm from drinking: Adults who booze regularly but exercise for five hours a week are no more likely to die than teetotallers. Mail Online, September 8 2016

Two hours a week of exercise could offset the dangers of alcohol. The Daily Telegraph, September 8 2016

Exercise can cut risk from alcohol-related diseases, study suggests. The Guardian, September 8 2016

Links To Science

Perreault K, Bauman A, Johnson N, et al. Does physical activity moderate the association between alcohol drinking and all-cause, cancer and cardiovascular diseases mortality? A pooled analysis of eight British population cohorts. British Journal of Sports Medicine. Published online August 31 2016

Does paracetamol taken in pregnancy affect masculinity?

NHS Choices - Behind the Headlines -

"Taking paracetamol when pregnant 'makes boys less manly, less aggressive and lowers their sex drive'," reports The Sun.

But the alarming headline doesn't explain that the research was in mice, not humans.

Researchers gave daily doses of paracetamol to pregnant mice, and looked into the effect on their male offspring.

They measured an area of the brain linked to male behaviours. They also carried out experiments to test how typically masculine their behaviour was, such as how much they urinated around their cages, bit other male mice, and copulated with female mice.

Importantly, the study only found that paracetamol had any effects at the equivalent of doses three times higher than the recommended maximum for human adults.

When mice were given the equivalent of the maximum daily dose for humans, paracetamol had no discernible effect in their offspring.

Paracetamol is commonly recommended for pain and fever relief for pregnant women, as it's thought to have fewer risks for the baby than other drugs.

Most women would only take paracetamol for a day or two as needed during pregnancy – not every day, as in this study.

This study doesn't provide evidence that standard-dose paracetamol, used from time to time as needed during pregnancy, carries any risk to a developing male baby.

Get more information on taking paracetamol in pregnancy

Where did the story come from?

The study was carried out by researchers from the University of Copenhagen, Universidade Federal do Paraná in Brazil, Icahn School of Medicine in the US, and INSERM in France, and was funded by the Danish Council for Independent Research. 

It was published in the peer-reviewed journal Reproduction and is free to read online.

Several UK media headlines were incorrect and scaremongering, not making it clear that the study was carried out in mice – for example, The Sun claimed that paracetamol "makes boys less manly".

Headlines aside, the media coverage did go on to explain that the study had been carried out in mice, and gave a reasonably accurate overview.

But most of the coverage stated that the mice had been given doses of paracetamol "comparable" to doses recommended for humans, including pregnant women. The Mail Online says: "Taking paracetamol at recommended doses could harm the masculinity" of an unborn boy.

The statement that mice were given "comparable" doses came from the study's press release. 

In fact, the study found no significant effects in mice given the equivalent of the recommended dose in humans, and only those given three times the recommended amount for humans showed brain and behavioural changes.

What kind of research was this?

This animal experimental study carried out in mice aimed to see whether taking paracetamol during pregnancy could affect the development of the male foetus' brain and male behaviour in later life.

Animal studies like this can give an indication of the possible biological effects of a drug, but results in animals don't always translate into the same effect in humans. 

What did the research involve?

Researchers fed pregnant laboratory mice daily with either plain water, water laced with standard-dose paracetamol, or water laced with high-dose paracetamol from the fifth day of pregnancy till they gave birth.

They then tested the behaviour of the male offspring when they were eight weeks old. They carried out experiments to assess typical masculine behaviour in mice, such as:

  • urinating to mark territory
  • aggressive behaviour towards other males
  • sexual activity with females on heat

After death, the brains of the male mice were also examined to calculate the size of an area called the sexually dimorphic nucleus (SND), which is typically larger in male animals than females.

Researchers looked for differences between mice given plain water and water laced with different doses of paracetamol.

The doses were designed to be "comparable" to those taken by humans. The standard dose of 50mg per kg of body weight is in line with the maximum dose recommended for adult humans.

The higher dose of 150mg per kg body weight, although three times higher than the maximum recommended dose, was still "in the range of human exposure", the researchers said.

The behavioural tests were carried out only on mice whose mothers had taken high-dose paracetamol.

The tests included:

  • recording the distribution, size and number of urine spots left around a cage
  • introducing an "intruder" male mouse into the cage of a study male mouse and counting how often the study mouse sniffed, attacked, rattled his tail at, and bit the intruder mouse
  • introducing a female mouse in heat into the cage of a study male mouse and counting how often the study mouse sniffed, mounted and copulated with the female mouse

As well as paracetamol, the researchers tested the effects of aniline, a pollutant used in industrial processes thought to have similar effects to paracetamol.

What were the basic results?

Researchers found no difference in the size of the brain SND between mice whose mothers had been fed standard-dose paracetamol and those who'd had plain water.

But mice whose mothers had the high-dose paracetamol had 50% fewer cells in the SND area. Aniline produced the same effect.

Mice whose mothers had been fed high-dose paracetamol and control mice whose mothers had plain water were tested in behavioural experiments. 

In these tests:

  • paracetamol-exposed mice urinated fewer, but bigger, drops when scent-marking their cages
  • paracetamol-exposed mice sniffed and rattled their tails at intruder mice less, and didn't bite them
  • paracetamol-exposed mice copulated with female mice less often and didn't ejaculate
How did the researchers interpret the results?

The researchers say paracetamol has an "anti-androgenic effect" that "could also include an effect on the masculinisation processes of the brain". They say this may cause "reduction in male sexual behaviour and lack of ejaculation", as well as "differences in aggression".

They say that, depending on the method used to compare human doses with mouse doses, "these exploratory experiments have relevance for human health".

Conclusion

Headlines like those in the media about this study are likely to alarm pregnant women who have taken or may need to take paracetamol in pregnancy.

While the study's results can't be dismissed altogether, there are three important things to bear in mind:

  • Studies in mice don't always translate into results in humans.
  • The doses of paracetamol that produced the effects in mice were the equivalent of three times higher than the maximum daily dose for adult humans.
  • The pregnant mice were fed paracetamol every day throughout the last two-thirds of their pregnancy.

Most pregnant women take paracetamol at the recommended dose, and for only a short time to manage pain or fever, when they need it. Nothing in this study suggests that women should stop doing that.

Pregnant women have few options when it comes to managing pain or fever, and it's important that they can take medicines they need that are unlikely to harm their baby.

Not treating pain or fever could be distressing for the pregnant woman, and carry greater risk to the overall health and wellbeing of the mother and pregnancy than not using short-term pain relief.

Current UK advice is that pregnant women can take paracetamol. But as with any medicine taken during pregnancy, it should be used at the lowest effective dose for the shortest possible time.

How much you can take depends on your age, your weight, the type of paracetamol you're taking, and how strong it is.

Adults can usually take one or two 500mg tablets every 4-6 hours, but shouldn't take more than 4g (eight 500mg tablets) in the space of 24 hours.

For more information, see Can I take paracetamol in pregnancy? and paracetamol.

Links To The Headlines

Paracetamol could be a risk to unborn boys. The Daily Mail, June 23 2017.

Sons less manly if mum on pain pill. The Sun, June 23 2017.

Paracetamol 'makes sons less masculine'. The Times, June 23 2017.

Taking paracetamol during pregnancy could make male child less masculine. inews, June 22 2017.

Links To Science

Hay-Schmidt A, Ejlstrup Finkielman OT, Jensen BAH, et al. Prenatal exposure to paracetamol/acetaminophen and precursor aniline impairs masculinisation of male brain and behaviour. Reproduction. Published online May 30 2017.

Sex link to older people's brain power, says study

NHS Choices - Behind the Headlines -

"Sex is the key to staying sharp in old age," reports the Mail Online after researchers found older people who have regular sex scored better on two of five brain tests.

Participants who had sex at least once a week scored higher on tests that measured their verbal fluency and spatial awareness compared with those who had no sex at all.

The verbal fluency test involved asking participants to say as many words beginning with a letter – in this case "f" – in a minute, and also name as many animals as they can.

In the spatial awareness test, participants had to draw an image, such as a square, triangle, cube or pyramid, and draw a clock face from memory.

These tests are part of the Addenbrookes Cognitive Examination III (ACE-III) test, a standard test to measure brain function.

The study involved 73 people aged between 50 and 83, and was conducted by researchers at the universities of Coventry and Oxford.

Researchers say their results "demonstrate that older men and women who engage in regular sexual activity have better cognitive functioning than those who do not … or do so infrequently".

But it's not clear why.

Previous studies have shown that older people who have active social lives and keep physically active are likely to have better cognitive function.

It's possible the social or physical elements of sexual activity are simply another aspect of this previous finding.

Researchers speculated it could also be caused by the release of dopamine, a chemical that transmits information in the brain during activities like sex.

We can't draw any conclusions from this study about whether sex keeps the brain functioning well, or whether people with better cognitive function are more likely to continue to have sex – or if the link is caused by something else entirely.  

Where did the story come from?

The study was carried out by researchers from Coventry University and the University of Oxford.

It was funded by the Coventry University Pump-Prime Research Grant Scheme. 

The study was published in the peer-reviewed Journals of Gerontology and is free to read online.

The Mail Online's story was mostly accurate, although the reporting assumed that increased sexual activity was the cause of better cognitive function, which may not be the case.

Most of the media coverage made the same error. The i newspaper stated that, "Having more sex can boost brain power", while The Sun incorrectly informed readers that, "Testers aged up to 83 were asked to keep a bonking diary".

What kind of research was this?

This was a cross-sectional observational study. This type of study can show an association between different things, but can't tell whether one thing (in this case sexual activity) causes the other (cognitive function), or whether other factors are at play.

What did the research involve?

Researchers recruited 73 volunteers over the age of 50: 45 women and 28 men.

They were asked to say how often they'd had sex over the past year:

  • never
  • once a month
  • once a week

They then filled out a general health questionnaire and took a range of tests designed to assess their mental abilities.

Researchers then looked at whether people who said they'd had sex never or monthly did better or worse on the tests than people who said they'd had sex weekly.

The researchers used the Addenbrookes Cognitive Examination III (ACE-III) test, which includes brief measures to assess people's abilities in attention, memory, fluency, language, and visual-spatial fields (how well people can visualise things in relation to those around them).

They adjusted their figures to account for people's age, years in education, gender, and cardiovascular health, as these factors might affect both how often they had sex and their cognitive abilities.

What were the basic results?

Frequency of sexual activity didn't vary significantly by age, education level, cardiovascular health, or other factors measured.

People who said they'd not had sex in the past year had on average lower scores for overall cognitive function and fluency compared with those who said they'd had sex weekly.

People who reported having sex monthly had on average lower scores for fluency and spatial awareness, although the difference here was small and may just have been down to chance.

More people in the group of 73 said they'd had sex weekly than monthly or never. All 10 of the respondents who said they never had sex were women.

More women than men said they'd had sex monthly (65% women and 35% men), and about equal numbers of men and women said they'd had sex weekly.

How did the researchers interpret the results?

The researchers say their results "demonstrate that older men and women who engage in regular sexual activity have better cognitive functioning than those who do not … or do so infrequently".

They suggest this might be because of the biological effect of dopamine, a chemical that transmits information in the brain, and is linked to pleasure and reward pathways.

They say that, "We can only speculate that continued engagement in regular sexual activity may have a positive influence on cognitive function", but add "the findings have important implications for the maintenance of intimate relationships in later life".

Conclusion

This study got widespread and enthusiastic coverage in the media, as many studies about sex do. But the findings are limited and it's difficult to draw conclusions from them.

As the researchers point out, we already know that a healthy social life and staying physically active seem to help keep people's cognitive abilities sharper as they age.

It's not a surprise that sexual activity, which has elements of both social and physical activity, is also linked to better cognitive function.

But this small observational study only provides a snapshot in time of how sexual activity may link to brain function.

We can't draw any firm conclusions about whether sexual activity keeps the brain functioning well, or whether people with better cognitive function are more likely to continue to have sex.

The results of the study are quite limited. Although overall scores of cognitive function were better for people who reported having sex weekly, this seems to have been driven by only two of the five types of mental ability, and the relationships weren't consistent.

And it's hard to explain how having sex monthly could give you worse spatial awareness than either having sex weekly or not at all, for example.

While continued sexual activity may be pleasurable and generally healthy into older age, this study doesn't mean it's a panacea for keeping the brain sharp.

If you're older and don't want to engage in sexual activity, the results of this study don't mean there's any reason to worry about it.

Links To The Headlines

Sex is the key to staying sharp in old age! Regularly getting intimate improves vocabulary and visual awareness. Mail Online, June 22 2017

Over 50s 'should have more sex to boost their IQ'. iNews, June 22 2017

Hump away brain decay: Over-50s who have more sex have better memory and visual awareness, says study. The Sun, June 22 2017

Frequent sex is officially good for your health and it can boost your brain performance. Daily Express, June 22 2017

 

Links To Science

Wright H, Jenks RA, Demeyere N. Frequent Sexual Activity Predicts Specific Cognitive Abilities in Older Adults. Journals of Gerontology: Psychological Sciences. Published online June 21 2017

'Contaminated air' on planes linked to health problems

NHS Choices - Behind the Headlines -

"Toxic fumes in aircraft cabins could cause serious health problems, scientists warn," reports The Sun. This is based on a UK study investigating air contamination on aircraft and its possible effects on the health of pilots and cabin crew.

The researchers say the air supply on planes can become contaminated by leaks of oil or other chemicals from the engines and they wanted to find out if this was associated with any health problems.

The study, published in the World Health Organization journal, found there is a link between exposure to contaminated air and short-term problems such as drowsiness, loss of consciousness, headache and tremors, and longer-term issues such as problems with memory or concentration and fatigue.

This is mainly worrying for pilots and staff on aircrafts, but could also be a concern for passengers if exposure to highly contaminated air causes a pilot to feel drowsy or pass out. However, only a few case studies of serious air contamination were investigated in this study, suggesting these events are rare.

The study didn't look in detail at whether exposure to contaminated air on planes was harmful to passengers, so it's not possible to draw firm conclusions about whether there's a health risk for people who fly regularly or only occasionally.

Where did the story come from?

The study was carried out by researchers from the University of Stirling and the University of Ulster in the UK, as well as a consultant respiratory physician from Melbourne in Australia. It received no sources of funding.

The study was published in the peer-reviewed journal Public Health Panorama, a journal of the World Health Organization. It is open access, meaning you can read it online for free (PDF, 314kb).

The UK media generally reported the story accurately, although the Sun's message of "Flying should 'come with a health warning' as toxic fumes contaminate air in cabins leading to serious health problems, research suggests" is fairly misleading as it suggests the research was done on passengers, when it was actually only carried out on aircraft staff.

What kind of research was this?

This was a combination of two studies, one involving a survey of pilots from the UK and the second an analysis of 15 case reports of potential cabin air quality incidents. They both aimed to look at the circumstances and symptoms of aircrew working in the pressurised air environment of aircraft. 

There have been concerns over the years regarding the health effects of exposure to aircraft contaminated air for aircrew. Unfiltered breathing air is provided to the cabin by the engine compressor. If oil leaks over the engine oil seals, chemicals can enter the air being supplied to the cabin. This might mean those on board may be exposed to some potentially harmful substances.

By combining these two types of studies, the authors aimed to carry out a more in-depth investigation of aircrew involved in suspected aircraft contaminated events by seeing if the reported symptoms were consistent with exposure to pyrolysed (heated) jet engine oil and other chemicals.

What did the research involve?

Researchers carried out two independent studies to investigate the circumstances and symptoms of aircrew who worked in the pressurised air environment of aircraft.

The first was a survey of UK British Airways pilots between 2005 and 2009 who agreed to a telephone interview or responded to a written questionnaire.

The pilots were asked:

  • whether they were aware of exposure to contaminated air
  • how they thought the contaminated air affected them
  • about any medical diagnoses they had

Of all the pilots who were contacted, 274 (14%) agreed to participate.

The second study involved 15 case reports from Australia, the US, Germany and the UK, of potential cabin air quality incidents. These particular cases were chosen because the health problems reported were suggestive of exposure to contaminated air.

Data sources included: the airlines, crew and maintenance reports, incident investigation and regulator reports, health effects and medical records, as well as media, union and legal reports.

Symptoms for both studies were recorded. 

The substances found in the engine oils and other chemicals were then measured against European standards to see if they were at hazardous levels or not.

What were the basic results?

From the survey:

  • Of the 274 pilots surveyed, 88% reported exposure to aircraft contaminated air, mostly in the form of fumes, and 34% reported frequent exposure.
  • 142 pilots reported specific symptoms and diagnoses, 30 reported health problems but gave no specific details, 77 reported no health effects and 25 failed to respond either way.
  • Acute adverse effects most commonly reported were: breathing problems, exhaustion or fatigue, dizziness and reduction in performance level.
  • Long-term effects most commonly reported were: breathing problems, poorer levels of performance, memory impairment and chronic fatigue.

Among the case studies:

  • In 33% of the incidents both pilots ability to fly the plane was affected during the air contamination.
  • 53% of events included long-term adverse effects for one or more crew members.
  • Chronic health problems diagnosed at some point after the exposure event included asthma, post-traumatic stress disorder (PTSD), problems with memory or concentration, seizures (fits) and cancer.
  • Nine pilots either became unfit to fly or died.
  • 80% of incidents occurred during take off or landing and 87% were linked to positive maintenance findings of oil leakage.
How did the researchers interpret the results?

The authors concluded that "aircraft air supplies contaminated by pyrolysed [heated] engine oil and other aircraft fluids can reasonably be linked to acute and chronic symptoms, findings and diagnoses, thus establishing causation".

They further add that "there is an obvious need for a clearly defined internationally recognised medical protocol, occupational syndrome and disease recognition, and health and environmental data collection".

Conclusion

These findings indicate that on rare occasions, pilots have not been able to perform as usual due to poor air quality in the cabin. Also poor air quality has been linked to health problems in the long term.

However, there are some limitations of the study that need to be considered:

  • The authors claim they have demonstrated a cause-and-effect relationship based on certain criteria. But with the exception of the acute air toxicity incident investigation reports in the second study, these types of study cannot prove causality. While it is likely that exposure to chemicals is toxic, this study did not link many of the symptoms with on-board air samples. There is still a possibility that the acute symptoms experienced by the pilots and crew were brought on by other things too, not just the contaminated air. With regard to the potential chronic effects, it is even harder to eliminate other factors that may have played a role.
  • The data in the pilot survey was self-reported, which might be subject to bias as people might not remember accurately or might exaggerate health outcomes. There was also a high risk of selection bias as only a small proportion of pilots invited to participate agreed. It is likely that those who didn’t participate hadn’t experienced any obvious health problems.
  • The data from the case studies comes from multiple sources that might not have consistent ways of reporting things, so analysing them as a group might lead to inaccuracies.
  • We do not know if frequency of exposure affects the health outcomes (if the symptoms get worse the more times staff are exposed to contaminated air). This might have some consequence for frequent flyers, so it’s important to know.

Links To The Headlines

Contaminated air on flights can lead to long-term sickness and airlines are ignoring the problem, study claims. The Independent, June 19 2017

Toxic fumes in aircraft cabins could cause serious health problems, scientists warn. The Sun, June 19 2017

Contaminated air on planes linked to crew ill-health, study finds. The Guardian, June 19 2017

Air in a plane cabin can damage your health, say scientists. Mail Online, June 19 2017

Flight safety 'degraded' by contaminated air. BBC, June 19 2017

Links To Science

Michaelis S, Burdon J, Vyvyan Howard C. Aerotoxic syndrome: a new occupational disease? (PDF, 314kb). Public Health Panorama. Published online June 2017

Cholesterol-lowering jab 'shows promise' for heart disease

NHS Choices - Behind the Headlines -

"Cholesterol-lowering jab to help prevent heart disease," reports BBC Online.

The headline refers to a recent mouse study that aimed to see whether a new vaccine could reduce cholesterol and lower the risk of heart disease.

Mice bred to develop heart and vascular disease were given the AT04A vaccine or a control vaccine, and were then fed a high-fat diet for 18 weeks.

The research found that, compared with the control, the vaccine reduced total and LDL cholesterol levels in the mice, as well as reducing signs of fatty build-up in the arteries.

The vaccine has now moved on to the first stage of human trials to see if it's safe to use in humans.

If this shows promise, there would then be more trial stages to see if it's safe and effective at lowering cholesterol, and how it compares with statins and other newer drugs already licensed to treat LDL cholesterol.

These trials can take years and, although the vaccine showed promising results in mice, there's no guarantee this will ever become a licensed vaccine for use in humans.

For now, the best way to prevent high cholesterol is to eat a balanced diet, be physically active, and not smoke.

Where did the story come from?

The study was carried out by researchers from several institutions, including Leiden University Medical Center and the Netherlands Organization of Applied Scientific Research (TNO) in the Netherlands.

Four of the researchers are also employees of AFFiRiS, the biotech company responsible for inventing and developing the vaccine currently under trial. AFFiRiS also partially funded this study.

The study was published in the peer-reviewed medical European Heart Journal. It's available on an open access basis and is free to read online.

Although some media coverage implied that this vaccine was coming on to the market very soon, most of the reporting was accurate and made it clear that this research is still in its early stages.

What kind of research was this?

This animal study evaluated the potential of the AT04A vaccine to reduce cholesterol and signs of heart and vascular disease in genetically engineered mice.

High blood cholesterol levels – particularly high levels of low density lipoproteins (LDL), also known as "bad" cholesterol – are linked to cardiovascular disease, including stroke and heart attacks.

The new AT04A vaccine works by blocking an enzyme called proprotein convertase subtilisin/kexin type 9 (PCSK9), which stops LDL cholesterol being cleared from the body.

Animal studies are useful for giving an indication of whether new treatments have potential for humans. But even though mice and humans have similarities, we aren't identical.

Animal research is the very first step in trialling a drug or vaccine to see whether it's safe and effective enough to move on to human trials. After that, there are many more stages of development before it can be licensed for use in humans.

Only a very small proportion of animal research makes it through to this stage.

What did the research involve?

The researchers used 7-9-week-old mice bred to develop heart and vascular disease or atherosclerosis (a build-up of fatty material inside the arteries).

These mice were then either immunised with AT04A or given a control vaccine. The vaccine was given five times at twice-weekly intervals.

For the first four weeks after the first vaccine shot was given, the mice were fed a normal diet. After this they were put on a high-fat, high-cholesterol diet for 18 weeks.

Blood samples were taken to analyse cholesterol levels at the start of the trial prior to vaccination and then every four weeks for the remainder of the trial.

At the end of the 18-week trial, researchers also analysed the level of atherosclerosis in the aorta, the large artery coming out of the heart.

The data for mice immunised with AT04A was compared with mice given the control vaccine.

What were the basic results?

The research showed that the AT04A vaccine was able to induce a successful and long-lasting immune response.

Mice given the vaccine started to produce antibodies against PCSK9. This wasn't seen in mice immunised with the control.

Mice vaccinated with AT04A showed a significant reduction in total blood cholesterol levels, with a 53% reduction at week 18 compared with mice in the control group (AT04A: 7.8mM versus control: 12.1mM).

The AT04A vaccination had no effect on high density lipoprotein (HDL), or "good" cholesterol, levels. But it did reduce LDL levels compared with the control group.

AT04A was found to reduce the overall area of atherosclerosis in the aorta by 64% compared with the control group. It also reduced biological markers of blood vessel inflammation by 21-28%.

How did the researchers interpret the results?

The researchers concluded that, "The present study shows that active immunisation against PCSK9 with the [AT04A vaccine] elicits antibodies that effectively bind and remove PCSK9 from the circulation and reduce circulating [cholesterol] and biomarkers of inflammation, which is accompanied by reduction of vascular inflammation and atherosclerotic lesions in the aortas of a mouse model of atherosclerosis."

Conclusion

This mouse study evaluated the potential of the AT04A vaccine to lower cholesterol levels and potentially reduce or prevent heart disease.

The results were promising, showing that mice given the vaccine produced antibodies against the enzyme that stops LDL cholesterol being cleared from the body. This resulted in reduced total and LDL blood cholesterol levels, as well as reduced atherosclerosis.

No major safety concerns or side effects were reported.

Following this research, AT04A has now moved on to a phase I clinical trial. A small number of people will be given the vaccine to see if it's safe for use in humans.

If it's shown to be safe, the next step would be to carry out a trial in a slightly larger number of people.

If this shows promise, it could then move to larger randomised controlled trials comparing the vaccine with other established cholesterol treatments, such as statins.

If further trials are successful, the AT04A vaccine could be a safe, cost effective way of lowering LDL cholesterol and preventing and treating heart disease.

But it's far too early to know at this stage. There are many more trials to go, and it'll probably be years before it's known if this could be a new vaccine licensed for use in humans.

For now, the best way to control your cholesterol level is to eat a balanced diet, stay physically active, and not smoke.

See more tips on preventing high cholesterol.

Links To The Headlines

Cholesterol-lowering jab to help prevent heart disease. BBC News, June 20 2017

Heart attack 'vaccine' available in just six years to knock cholesterol busting statins off the shelves. The Sun, June 20 2017

Cholesterol-lowering vaccine jab to stop heart attacks could be close. The Guardian, June 20 2017

The vaccination that staves off high cholesterol: Once-yearly injection could be alternative to statins. Mail Online, June 20 2017

 

Links To Science

Landlinger C, Pouwer M, Juno C, et al. The AT04A vaccine against proprotein convertase subtilisin/kexin type 9 reduces total cholesterol, vascular inflammation, and atherosclerosis in APOE*3Leiden.CETP mice. European Heart Journal. Published online, June 19 2017

Blood test may show if prostate cancer treatment is working

NHS Choices - Behind the Headlines -

"Prostate cancer blood test helps target treatment," BBC News reports.

A study found a blood test could detect which men with advanced prostate cancer would benefit from new drug treatment.

Researchers analysed blood samples from nearly 50 men taking part in a trial of a new drug (olaparib) for prostate cancer that has spread to other parts of the body.

They wanted to see whether changes to tumour DNA circulating in the men's blood could indicate whether the treatment was working or not. 

They found that levels of circulating tumour DNA halved after four weeks of treatment in men who had the best progression-free survival (period of time when the cancer doesn't get worse).

They also found that in men who initially responded to olaparib, the development of new gene mutations could indicate when the tumour was becoming resistant to the drug and the treatment was no longer working.

This suggests that a blood test looking at tumour DNA early in the course of treatment could indicate which men the drug was working for and which men would be better off trying an alternative treatment. 

The findings are a promising step forward in helping men with advanced prostate cancer receive the best treatment for them.

But this research is still in its early stages, with findings in a relatively small sample of men, and needs further follow-up.

Where did the story come from?

The study was carried out by researchers from the UK Institute of Cancer Research, the Royal Marsden NHS Foundation Trust, the University of Michigan, and the Peter MacCallum Cancer Centre.

Funding was provided by several sources, including the Movember Foundation, the Prostate Cancer Foundation, Prostate Cancer UK, and Cancer Research UK.

The study was published in the peer-reviewed journal, Cancer Discovery. It's available on an open access basis and is free to read online.

The way the media covered the study is generally representative of its findings, reporting the trial details and quoting experts involved in the research.

What kind of research was this?

This was pre-planned laboratory analysis of blood samples collected as part of a trial of a new treatment for prostate cancer that's spread to other parts of the body (metastatic prostate cancer). 

Metastatic prostate cancer is a major cause of cancer deaths among men worldwide. It can't be cured – the aim is to try to control it and give men a good quality of life for as long as possible.

Previous research identified that up to a third of men with advanced prostate cancer have certain gene mutations, such as BRCA1 and 2.

The TOPARP-A trial tested the effectiveness of the drug olaparib (brand name Lynparza), which is specifically licensed for people with BRCA gene mutations.

It works by blocking a particular enzyme, poly ADP-ribose polymerase (PARP), and this stops the growth of tumours with BRCA mutations.

The researchers considered that circulating tumour DNA in the blood could give an indication of the person's likely response or resistance to treatment.

They therefore assessed the DNA of blood samples collected from men in the trial to see whether DNA changes could have prognostic significance.

What did the research involve?

The TOPARP-A trial included 50 men with metastatic prostate cancer that hadn't responded to previous hormone treatment and chemotherapy, and were subsequently treated with the drug olaparib.

Blood samples were collected from trial participants at the start of the study, then at 1, 4, 8 and 16 weeks of treatment, and at the time when the disease got worse (known as disease progression).

Researchers analysed the circulating DNA in these blood samples and looked at how DNA changes were associated with responses, such as a fall in prostate specific antigen (PSA) levels and circulating tumour cells in the blood. 

What were the basic results?

Of 46 men with DNA data available, 16 (a third) responded to treatment and 30 did not.

The researchers found a greater than 50% decline in circulating DNA concentration was associated with improved progression-free survival by four weeks and overall survival by eight weeks.

Looking at specific gene mutations, six of the men in the trial had mutations linked to advanced prostate cancer (BRCA2, ATM and PALB2).

These were all detected in circulating DNA at the start of the study, but the concentration fell to less than 5% in the five of six men who responded to the treatment.

Ten of the 16 men who responded had blood samples available at the time their disease progressed again.

The researchers observed new mutations developing – for example, in the BRCA2 gene – which suggests possible mechanisms of resistance to the PARP-inhibitor drug.

How did the researchers interpret the results?

The researchers concluded that their data "supports the role of liquid biopsies as a predictive, prognostic, response, and resistance biomarker in metastatic prostate cancer".

They used the term "liquid biopsy" to refer to accessing tumour DNA in a man's blood, acquired from plasma by a simple blood test.

Conclusion

This pre-planned analysis of blood samples collected as part of a trial for metastatic prostate cancer suggests that looking at circulating tumour DNA could act as a form of biopsy to inform whether the cancer is responding to treatment.

The findings indicate that a decrease in tumour DNA could suggest treatment is working, while the development of new DNA mutations could suggest the cancer is becoming resistant to treatment.

But there are several points to bear in mind. Though the findings show promise, this study only looked at blood samples taken from a relatively small sample of 46 men. Only six of these men had gene mutations linked to a poor prognosis.

On that basis, the study isn't able to give definite answers at this stage about particular levels of circulating DNA, or any specific mutation changes, that have prognostic significance.

The findings need to be followed up in further studies of other men receiving olaparib for advanced prostate cancer.

The findings also can't be applied to men with metastatic prostate cancer being treated with any drug other than olaparib, or men being treated for other stages of prostate cancer.

And even if a blood test could indicate whether or not a man is responding to treatment for metastatic prostate cancer, these findings don't represent a cure for this advanced stage disease: in the majority of men who initially responded to olaparib, the cancer still eventually progressed. 

Nevertheless, if a test were developed, this may allow treatment to be changed at an early stage if blood results indicate it isn't working.

This could hopefully help men with this advanced stage disease have the best quality of life by making sure they only receive treatment likely to bring benefits.

Links To The Headlines

Prostate cancer blood tests 'helps target treatment'. BBC News, June 19 2017

New blood test could see personalised prostate cancer treatment. Guardian online, June 19 2017

Links To Science

Goodall J, Mateo J, Yuan W, et al. Circulating free DNA to guide prostate cancer treatment with PARP inhibition. Cancer Discovery. Published online April 27 2017, fully published June 19 2017

 

Is a new flu pandemic just three mutations away?

NHS Choices - Behind the Headlines -

"Just three mutations are needed to make bird flu a potential pandemic strain that could kill millions," is the alarming headline from the Mail Online. However, the chance of all three mutations occurring has been described as "relatively low".

Bird flu hit the headlines in 1997 when it was found that a strain of flu virus was spreading from poultry to humans in Hong Kong. The good news is that this strain didn't spread quickly between humans and therefore didn't spark a global pandemic in the same way as swine flu in 2009-10.

In a new study researchers analysed a strain of bird flu (H7N9) to see whether a particular surface protein on the virus could bind to human tissue. If it could, this would make human-to-human transmission of the H7N9 flu virus more likely.

The researchers found that three mutations of amino acids helped the virus bind specifically to human tissue and, in theory, could allow a human-to-human type transmission.

It is important to note however that the researchers did not actually engineer a virus capable of passing between people.

Although the media coverage has suggested that a "pandemic" of bird flu in humans could happen very soon, we have not seen the combination of mutations investigated in this study occur naturally. For now, these findings are useful for monitoring flu strains and to further our understanding of transmission but they are not a cause for alarm.

 

Where did the story come from?

The study was carried out by researchers from several institutions in the US and the Netherlands, including The Scripps Research Institute and Utrecht University. It was funded by National Institutes of Health Grants, the Scripps Microarray Core Facility, the Centers for Disease Control (CDC), and the Kwang Hua Educational Foundation (JCP).

It was published in the peer-reviewed scientific journal PLOS: Pathogens and is available on an open-access basis so can be read for free online.

Some of the UK media's headlines were over-dramatic and needlessly alarming; suggesting that a pandemic of "human" bird flu could be on its way and millions could die.

This is absolutely not what this research suggests. Human-to-human transmission of these mutations was not tested, nor have we seen this combination of mutations occurring naturally.

The body of the Mail and The Independent's reporting was more measured and accurate.

 

What kind of research was this?

This was a laboratory study on the H7N9 strain of bird flu. Researchers wanted to explore whether it could mutate into a strain capable of human-to-human transmission, similar to other infectious flu strains.

During an avian flu outbreak in 2013, the H7N9 influenza strain was transmitted from poultry to humans.

This occurred as a result of mutations in what are known as receptors – specialised cells that respond to external stimuli such as another flu virus. In the case of the H7N9 influenza strain, mutations caused a switch in what were once purely avian-type receptors to human-type receptors.

Once this happens there is also a chance subsequent mutations could enable transmission of the virus between humans, such as that seen in previous strains of H2N2 and H3N2.

Until now, H7N9 has only mutated to allow transmission of the virus from poultry to humans. The researchers involved in this study wanted to investigate how many further mutations would be needed for human-to-human transmission to become possible.

Laboratory studies such as this are useful as early stage research to get an indication of how biological processes may work. However, it isn't necessarily possible to accurately predict how these mutations would occur in nature, or how long they would take.

 

What did the research involve?

The researchers analysed both chicken and human "receptors" so that they could investigate which mutations are needed for the surface proteins on the H7N9 virus to attach to human tissues.

They introduced mutations previously seen in human pandemic strains of flu which had caused a switch between avian-type receptors to human-type receptors. For example, they looked at one called G228S which was involved in the H2N2 and H3N2 viruses.

The model was then validated using artificially constructed H7 proteins found to be able to bind to human tissue in the same way as the human influenza virus.

 

What were the basic results?

The researchers found they had to alter three amino acids before the flu virus could target human cells.

If all three mutations took place naturally then the virus could potentially spread from human to human (or mammal to mammal).

The researchers were unable to test this possibility using mammals such as ferrets as that type of experiment is currently legally prohibited under US law.

 

How did the researchers interpret the results?

The researchers concluded: "In this study, we show that recombinant H7 proteins need three amino acid mutations to change specificity to human-type receptors. Although we are not allowed to assess if these mutations would lead to efficient transmission in the ferret model, this knowledge will aid in surveillance. If these amino acid mutations are observed to arise during natural selection in humans, timely actions could be taken."

 

Conclusion

This laboratory study analysed an H7N9 strain of bird flu. Researchers wanted to explore whether a particular change to the surface proteins of a virus was capable of allowing the strain to bind to human tissue. This would theoretically lead to human-to-human transmission of the flu virus.

It is worth noting that this ability to attach to human cells does not necessarily mean a mutated bird flu virus will be able to infect, replicate and transmit between humans. Other changes would also be required.

However, they were unable to further investigate whether this surface change could lead to human-to-human transmission of the virus because this type of experiment is not permitted under US law.

This research attracted the attention of several experts in the field.

Dr Fiona Culley, spokesperson for the British Society for Immunology, & Senior Lecturer in Respiratory Immunology at Imperial College London commented:

"This is a good, thorough study which specifically aimed to identify which changes in bird flu would allow the virus to attach to human cells."

"The authors found that certain combinations of three mutations were needed for the bird flu to be able to attach to human lung cells. They could potentially happen, but there is currently no evidence that they have ever occurred and the chances of all three occurring together is relatively low."

Links To The Headlines

Just THREE mutations are needed to make bird flu a potential pandemic strain that could kill millions, experts warn. Mail Online, June 15 2017

Scientists create 'mutant bird flu' to prepare for possibility of deadly global pandemic. The Independent, June 16 2017

Links To Science

de Vries RP, Peng W, Grant OC, et al. Three mutations switch H7N9 influenza to human-type receptor specificity. PLOS Pathogens. Published online June 15 2017

Obese mums more likely to give birth to babies with birth defects

NHS Choices - Behind the Headlines -

"Women who are obese when they conceive are more likely to have a baby with serious birth defects," The Guardian reports.

Swedish researchers looked at more than a million health records and found a link between excess body mass index (BMI) and the risk of a child being born with birth defects.

The researchers found there was a sliding scale of risk: the heavier the mother, the higher the risk.

Very obese women (women with a BMI of 40 or more) were 37% more likely to give birth to a baby with a birth defect than a woman of a healthy weight.

But although a 37% increase in risk sounds alarming, the actual risk only goes up by 1.3%.

Defects affecting the heart, also known as congenital heart disease, were the most common type of defect.

The researchers recommend that women planning a pregnancy try to achieve or maintain a normal body weight and lead a healthy lifestyle before getting pregnant.

This seems a good approach to take, not only for the health of your baby, but also for yourself.

Read more about body weight and pregnancy.

Where did the story come from?

The study was carried out by researchers from the Karolinska Institutet in Sweden.

It was funded by the US National Institute of Diabetes and Digestive and Kidney Diseases, as well as grants from the Swedish Research Council for Health, Working Life and Welfare, and the Karolinska Institutet.

The study was published in the peer-reviewed British Medical Journal (BMJ). It's available on an open access basis, so it's free to read online.

UK media coverage on this research was generally accurate, though the Daily Mirror exaggerated the risk without putting it into context – they reported a 38% increased risk.

Not only was this slightly inaccurate (the actual figure was 37%) but it only applied to very obese women, not overweight or obese women in general.

The Mail Online and The Guardian were more responsible, reporting the actual risk for each group to show that it went from around 3.4% for women of a healthy weight to up to 4.7% for the heaviest women in the study.

As mentioned, although a 37% increase in risk sounds alarming, the actual risk goes up by 1.3%.

What kind of research was this?

This Swedish prospective cohort study assessed whether the risk of defects in infants increased with a mother's level of obesity during pregnancy.

Cohort studies are useful when trying to understand whether a link exists between an exposure and an outcome.

But it's important to keep in mind that even when confounding factors are accounted for, it isn't possible to fully rule out the effect of other external factors. As such, this study design can't confirm cause and effect between two variables.

For research questions like this, where conducting a randomised controlled trial (RCT) wouldn't be ethical, cohort studies are the best way to test for an association.

What did the research involve?

This study used data on 1,243,957 births and maternal information recorded on the Swedish medical birth register.

Maternal BMI during early pregnancy was calculated using measured weight and self-reported height at the first prenatal visit, which took place at 14 weeks.

Using the BMI, mothers were categorised into the following:

  • underweight (BMI <18.5)
  • normal weight (18.5 to <25)
  • overweight (25 to <30)
  • obesity class I (30 to <35)
  • obesity class II (35 to <40)
  • obesity class III (≥40)

The main outcome was the presence of major birth defects in infants as defined by the European Surveillance of Congenital Anomalies Classification (EUORCAT):

  • nervous system
  • ear, face, neck
  • heart defects
  • digestive system
  • genital organs and urinary system
  • limb
  • other
  • genetic syndromes

The data was then analysed to assess for the risk of defects by comparing data between the offspring of obese mothers and normal weight mothers.

The following potential confounding factors were adjusted for:

  • maternal age
  • height
  • the number of previous pregnancies
  • smoking status during early pregnancy
  • level of education
  • mother's country of birth
  • sex of offspring
  • whether or not the mother lived with a partner

As diabetes can sometimes also cause defects in offspring, mothers with pre-gestational and gestational diabetes were excluded from the analysis.

What were the basic results?

Out of the 1,243,957 infants included in the cohort, 43,550 (3.5%) were born with major birth defects. Heart defects were the most common, with 20,074 infants born with one.

The proportion of infants born with defects in each weight category is as below:

  • underweight mothers – 3.4%
  • normal weight mothers – 3.4%
  • overweight mothers – 3.5%
  • obesity class I – 3.8%
  • obesity class II – 4.2%
  • obesity class III – 4.7%

The analysis showed that, compared with women in the healthy weight range, the risk of a major birth defect increased with maternal BMI by:

  • 5% for overweight mothers (adjusted risk ratio [aRR] 1.05, 95% confidence interval [CI] 1.02 to 1.07)
  • 12% for those in obesity class I (aRR 1.12, 95% CI 1.08 to 1.15)
  • 23% for those in obesity class II (aRR 1.23, 95% CI 1.17 to 1.30)
  • 37% for those in obesity class III (aRR 1.37, 95% CI 1.26 to 1.49)

Additionally, the risk was higher in boys (4.1%) than in girls (2.8%).

How did the researchers interpret the results?

The researchers concluded that, "We found that risks of major congenital malformations [birth defects] in offspring progressively increase with maternal overweight and severity of obesity.

"This underlines the importance of having a maternal BMI in the normal range before pregnancy.

"Thus, efforts should be made to encourage women of reproductive age to adopt a healthy lifestyle and to obtain a normal body weight before conception." 

Conclusion

This study assessed whether the risk of birth defects increased with the severity of obesity during pregnancy.

It found the risk of a defect increased with an unhealthy maternal BMI, and was higher in boys than in girls.

This interesting research had a large sample size and is particularly important given the increasing rates of obesity in the UK.

But the study was only able to collect data on maternal BMI during early pregnancy. It would have been interesting to see whether BMI before conception and during the later stages of pregnancy had any effect on the prevalence of defects.

Additionally, the research split the background of mothers into "Nordic" or "non-Nordic". It would have been useful to have a more granular breakdown of ethnicities, as genetics inevitably plays a role in this.

It isn't surprising that the researchers recommend women who want to start a family should maintain a normal body weight and healthy lifestyle before getting pregnant.

This seems a good approach to take, not only for the health of your baby, but also for yourself.

Links To The Headlines

Obese women more likely to have babies with serious birth defects, says study. The Guardian, June 15 2017

Overweight women should adopt a healthy lifestyle and slim down before starting a family: Risk of birth defects increases in correlation with the mother's weight, major study shows. Mail Online, June 15 2017

Obese women are 'more likely to give birth to ill babies'. Daily Mirror, June 14 2017

Links To Science

Persson M, Cnattingius S, Villamor E, et al. Risk of major congenital malformations in relation to maternal overweight and obesity severity: cohort study of 1.2 million singletons. BMJ. Published online June 14 2017

Vegetarian dieting may lead to greater weight loss

NHS Choices - Behind the Headlines -

"Dieters who follow a vegetarian eating plan lose nearly twice as much weight," the Daily Mail reports following the results of a new study.

Researchers randomly assigned two groups of people with type 2 diabetes to either a vegetarian diet or a standard weight loss diet. They found those on the vegetarian diet lost more weight and more body fat.

Both diets involved reducing daily calorie consumption by 500 calories a day. The standard weight loss diet in this study is a diet recommended for people with diabetes. The vegetarian diet consisted of leafy vegetables, nuts, fruit, and grains.

After six months, researchers found those in the vegetarian group had lost about twice as much weight as those in the other group – 6.2kg, compared with 3.2kg.

But this isn't surprising – more people stuck to this diet compared with those on the standard weight loss diet.

The media failed to make it clear that the study was carried out on overweight people with type 2 diabetes, and therefore the findings may not apply to other people trying to lose weight.

If you have type 2 diabetes and you're overweight, you should aim to lose weight as this will help control your symptoms. Some people may benefit from switching to a vegetarian diet, but it's not a magic bullet.

The important thing if you're trying to lose weight is to reduce your daily calorie intake and get more exercise. Learn more in the weight loss guide.

Where did the story come from?

The study was carried out by researchers from the Institute for Clinical and Experimental medicine, Charles University, and the Institute of Endocrinology, all in the Czech Republic, and the Physicians Committee for Responsible Medicine in the US.

It was funded by a project grant from the Ministry of Health in Prague.

The study was published in the peer-reviewed Journal of the American College of Nutrition on an open access basis, so it's free to read online.

The UK media's coverage of the study was generally accurate, although the Mail's claim that "vegetarian dieters find their eating plan and exercise routine easier to stick to" was unfounded. 

There may be many reasons why a few more participants in the vegetarian group stuck to their diet. And, because of the small numbers involved in the study (37 in each group), the results could be down to chance.

What kind of research was this?

This randomised controlled trial (RCT) involved participants with type 2 diabetes who either had a vegetarian diet or a conventional diabetic diet. They then had their fat measures taken.

An RCT is the best way of comparing the effect of diets on health outcomes, as it allows control over other variables that might potentially affect the results.

What did the research involve?

The researchers took a group of 74 men and women who had type 2 diabetes and assigned half of them to a vegetarian diet and the other half to a conventional diabetic diet.

All the participants had a body mass index (BMI) over 25, meaning they were overweight.

The researchers followed them at three months and six months to measure how much weight they'd lost.

Both diets were calorie restricted (reduced by 500 kcal per day). The vegetarian diet consisted of vegetables, grains, legumes, fruits, and nuts, and was around 60% carbohydrates, 15% protein and 25% fat. The conventional diabetic diet was made up of around 50% carbohydrates, 20% protein, and less than 30% fat.

Adherence to the diets was measured as part of the research. High adherence was defined as daily energy intake of no more than 100kcal in excess of what had been prescribed, while medium adherence was no more than 200kcal in excess. 

Participants were asked to not alter their existing exercise habits for the first 12 weeks, and were then prescribed tailored exercise programmes to do three times a week.

MRI scans of the participants' thigh muscles were taken at baseline, three months, and six months. Two types of fat were measured: fat just under the connective tissues (subfascial) and fat just under the skin (subcutaneous).

What were the basic results?

The vegetarian diet was almost twice as effective at reducing body weight compared with the conventional diet.

Overall, participants lost 6.2kg (95% confidence interval [CI] -6.6 to -5.3) on the vegetarian diet, versus 3.2kg (95% CI -3.7 to -2.5) on the standard weight loss diet.

The greater weight loss seen in people on the vegetarian diet was also accompanied by greater muscle loss of -5.0cm2 (95% CI -5.7 to -4.3) versus -1.7cm2 (95% CI -2.4 to -1.0).

Subfascial fat was only reduced in those who were on a vegetarian diet (-0.82 cm2, 95% CI -1.13 to -0.55).

When it came to sticking to the diet, there was:

  • high adherence in 55% of the participants on the vegetarian diet and in 32% on the conventional diet
  • medium adherence in 22.5% of participants on the vegetarian diet and in 39% on the conventional diet
  • low adherence in 22.5% of participants on the vegetarian diet and in 29% on the conventional diet
How did the researchers interpret the results?

The authors concluded that their data "indicate that a vegetarian diet is more effective in reducing subfascial fat and tends to also reduce intramuscular fat more than a conventional hypocaloric diabetic diet.

"Our data suggest the importance of both subcutaneous and subfascial fat in relationship to glucose and lipid metabolism."

They say that, "Further research is needed to determine how dietary interventions with different diet composition can influence thigh fat distribution in relationship to glucose and lipid metabolism." 

Conclusion

This research appears to show that there's some association between following a vegetarian diet and a greater reduction in body mass and subfascial fat.

But this study has a number of limitations, and the conclusions drawn by the researchers should be interpreted cautiously.

  • There was lower adherence to the diet in the conventional diet group than the vegetarian one. This means the finding of a greater reduction in body mass in the vegetarian group is unsurprising.
  • The thigh was the only part of the body where fat measurements were taken. It could be the case that reduction in abdominal fat – a big risk factor for type 2 diabetes – didn't differ between the groups.
  • The proportion of fat recommended in the vegetarian diet was lower than in the conventional diet, so it would be expected that fat reductions would be greater in the vegetarian group.
  • The vegetarian diet was actually almost vegan, as the only animal product allowed was a small amount of yoghurt. Following a vegetarian diet without these extra restrictions might not bring about the same results.
  • The vegetarian group also lost more muscle mass than the conventional group, particularly when doing their usual exercise routine. This might be an unwanted outcome and a disadvantage when compared with the usual diet.
  • The study involved a relatively small sample of overweight people with type 2 diabetes. The findings may not be applicable to the general population.

Based on the findings of this study, we can't say that a vegetarian diet is more beneficial than a conventional diet for people with type 2 diabetes.

What we can say is that the vegetarian diet resulted in greater weight loss, and a reduction in some types of bodily fat, for the people who took part in this small study.

The additional loss of muscle mass might mean it's not preferable to the conventional diet currently recommended for people with diabetes.

If you have type 2 diabetes and are concerned about your weight, talk to your GP or diabetes care team. Achieving a healthy weight should help you control your symptoms and reduce the risk of complications.

Find out more about living with type 2 diabetes.

Links To The Headlines

Vegetarian diets twice as effective for weight loss as carnivorous meal plans, says study. The Independent, June 13 207

Why a vegetarian diet guarantees slimming success: Cutting out meat nearly doubles weight loss by changing how we store fat. Daily Mail, June 14 2017

Links To Science

Kahleova H, Klementova M, Herynek V, et al. The Effect of a Vegetarian vs Conventional Hypocaloric Diabetic Diet on Thigh Adipose Tissue Distribution in Subjects with Type 2 Diabetes: A Randomized Study. Journal of the American College of Nutrition. Published online June 10 2017

Risk of aspirin-related bleeding is higher in the over-75s

NHS Choices - Behind the Headlines -

"People over 75 taking daily aspirin after a stroke or heart attack are at higher risk of major – and sometimes fatal – stomach bleeds than previously thought," BBC News reports.

Aspirin can help thin the blood, so it is often given to people thought to be at risk of blood clots, which could trigger a heart attack or stroke. A potential downside is that it can trigger bleeding in the digestive system or brain.

The study involved around 3,000 adults from Oxford who were prescribed aspirin due to previous heart attack or stroke. Researchers followed these patients for up to 10 years to see how many of them were admitted to hospital with bleeds.

They found that for under-75s the annual risk of bleeding is around 1%. However adults over the age of 75 have three times the risk of a major bleed compared with younger adults, particularly bleeds of the stomach and upper digestive tract.

The researchers estimate that routinely prescribing proton pump inhibitor (PPIs) could drastically reduce these risks in older adults. PPIs are drugs that help protect the lining of the stomach and so reduce the risk of a bleed.

Current guidelines do not carry a recommendation for the routine use of PPIs in over-75s, but this could change.

People should continue to take aspirin as prescribed by their health practitioner, as not doing so may increase the risk of a blood clot leading to a heart attack or stroke.

 

Where did the story come from?

The Oxford Vascular Study was carried out by researchers from the University of Oxford and funded by the Wellcome Trust, Wolfson Foundation, British Heart Foundation, Dunhill Medical Trust, National Institute of Health Research (NIHR), and the NIHR Oxford Biomedical Research Centre.

The study was published in the peer-reviewed medical journal The Lancet on an open access basis so it is free to read online.

The UK media's coverage of the study was broadly accurate, with most news sources making clear that it would be unwise to stop taking aspirin if it had been prescribed without first speaking to a doctor.

 

What kind of research was this?

This was a population-based cohort study which aimed to assess the bleeding risk for people taking aspirin for the secondary prevention of cardiovascular events. Secondary prevention means that people have already had a stroke or heart attack and are taking aspirin to try and prevent them having another.

Aspirin is a long established effective treatment to prevent blood clots. The authors say that up to two-thirds of adults over 75 take daily aspirin (or similar drugs). However, this anti-clotting effect is known to increase risk of bleeds, particularly bleeding in the digestive tract.

Drugs called proton pump inhibitors (PPIs) can considerably reduce the risk of digestive bleeding in people taking regular aspirin. However, they are not routinely prescribed because of concerns over side effects such as nausea and constipation. Current clinical guidelines make no recommendations about their use.

This study aimed to assess bleeding risk in people taking aspirin for secondary prevention, and look at the effect PPIs could have in reducing this risk.

 

What did the research involve?

This Oxford Vascular Study included 3,166 patients (half aged over 75) from across nine GP surgeries in Oxford who had their first heart attack or stroke between 2002 and 2012 and were treated with aspirin (or a similar drug, but excluding anti-clotting drugs like warfarin).

A quarter of patients were prescribed stomach protection such as PPIs, though this increased to a third after one year of being treated with aspirin.

Researchers gathered information on baseline risk factors for bleeding, such as history of stomach ulcers, cancer, liver or kidney disease and excess alcohol use.

Patients were followed up with clinic visits six months, one year, five years and 10 years after they first had a heart attack or stroke. These visits documented further cardiovascular events and bleeding events. Bleeding episodes were also identified through hospital admissions records.

All deaths and the cause of death during follow-up period were identified from death certificates.

Bleeding was classified as being in the brain, upper or lower digestive tract, genitourinary system or other. Medical criteria were used to define bleeding events as non-major, major, life-threatening or fatal. Researchers also documented whether the bleed resulted in a change of functional independence or disability.

 

What were the basic results?

405 bleeding events required medical attention during follow-up, 187 of which were major bleeds, 40% of bleeds were in the upper digestive tract. The average annual risk of bleeding was 3.36% (95% confidence interval [CI] 3.04 to 3.70) and 1.46% (95% CI 1.26 to 1.68) for major bleeds.

Major bleeding

Non-major bleeding was not linked with age but the risk of major bleed was higher in older adults. People under 75 had a 1.1% annual risk of a major bleed increasing to a 4.1% annual risk for those aged 85 or older.

People over the age of 75 had triple the risk of a major bleed compared with younger adults (hazard ratio [HR] 3.10, 95% CI 2.27 to 4.24) and four times the risk of a major upper digestive tract bleed (HR 4.13, 95% CI 2.60 to 6.57).

Older adults also had poorer outcomes after a bleed than adults under 75. Of people surviving a bleed outside of the brain, only 3% of those under 75 were left with increased disability compared with 25% of those over 75.

The risk of disabling or fatal bleeding of the upper digestive tract was 10 times higher for over-75s compared with younger adults (HR 10.26, 95% CI 4.37 to 24.13).

Links with age were independent of gender, vascular risk factors or past history of stomach ulcer.

There were also 697 cardiovascular events (such as heart attacks and strokes) during follow-up (208 fatal). The risk ratio of bleeds to the number of cardiovascular events increased with increasing age.

Effects of proton pump inhibitors

A previous review estimated that PPIs reduce the risk of upper digestive bleeds by 74%. The researchers estimate that the benefit of prescribing PPIs greatly increases after the age of 75.

The number of people you would need to treat with PPIs to prevent one major upper digestive bleed over five years was estimated at:

  • 80 patients under 65 years
  • 75 patients aged 65–74 years
  • 23 patients aged 75–84 years
  • 21 patients aged 85 or older

When looking at the prevention of disabling or fatal upper digestive bleeds specifically, the number needed to treat with PPIs fell dramatically from 338 for under-65s, to 25 for patients aged over 85.

 

How did the researchers interpret the results?

The researchers conclude: "In patients receiving aspirin … without routine PPI use, the long-term risk of major bleeding is higher and more sustained in older patients … than in the younger patients in previous trials, with a substantial risk of disabling or fatal upper gastrointestinal bleeding."

They say that: "Given that half of the major bleeds in patients aged 75 years or older were upper gastrointestinal, the estimated [number needed to treat] for routine PPI use to prevent such bleeds is low, and co-prescription should be encouraged."

 

Conclusion

This valuable cohort study helps to quantify the extent of bleeding risk in people taking aspirin for secondary prevention of cardiovascular disease.

Aspirin is well known to carry bleeding risk – particularly in older adults – but this study suggests the risk may be higher than previously thought. The researchers say that for adults under the age of 75, the annual bleeding risk at around 1% is similar to that suggested by previous trials, as is the ratio of bleeds to the number of cardiovascular events. However, this risk increases for older adults, especially for major bleeds of the stomach and upper digestive tract.

This doesn't mean that aspirin isn't beneficial for adults – the number of cardiovascular events would probably be much greater if people weren't taking aspirin at all. However, it does suggest, as the authors say, a need to routinely co-prescribe stomach protection such as PPIs for those at greatest risk. This is a view that has been supported by several experts who have reacted to the findings.

There are some points to note:

  • The findings only apply to people taking regular aspirin for secondary prevention of cardiovascular events. Though the risks may be similar, they cannot be applied to people taking aspirin for primary prevention (that is people with risk factors for cardiovascular disease but who have not yet had an event such as a stroke or heart attack), or to people using aspirin for brief periods for example to treat pain or fever.
  • It's likely that the risks from this large sample in Oxford would apply to people nationwide but we don't know this for sure.
  • The data only considers bleeds needing medical attention and does not include minor bleeds, such as bruising.
  • The size of risk estimates may not be entirely accurate, as suggested by some of the wider confidence intervals.
  • This cohort includes long-term data from a large number of patients and as such is the best sort of data you can get on treatment side effects. However, it is still observational.

It's likely that the findings of this important research will be considered when national clinical guidelines are updated. But it remains to be seen whether there will be a change in recommendations to routinely prescribe stomach protection to anyone who has been prescribed aspirin for the secondary prevention of cardiovascular events.

Doctors will always consider the risks and benefits of prescribing a treatment to a person on an individual basis. People should continue to take aspirin as prescribed by their doctor as not doing so may increase the risk of serious vascular events, such as a heart attack or stroke.

Signs of a serious bleed in the digestive system include vomiting blood. Bleeding in the brain can cause a severe headache, vision problems, stroke symptoms, such as slurred speech and weakness on one side of the body.

Call 999 for an ambulance if you suspect symptoms of bleeding in your stomach or brain.

Links To The Headlines

Aspirin 'major bleed' warning for over-75s. BBC News, June 14 2017

Risk of bleeds and death with daily aspirin use higher than thought. The Guardian, June 14 2017

Taking a daily aspirin to prevent heart attacks or stroke 'is ten times riskier for the elderly': Warning use by over-75s is leading to 3,000 preventable deaths each year. Daily Mail, June 14 2017

Daily aspirin behind more than 3,000 deaths a year, study suggests. The Daily Telegraph, June 14 2017

Aspirin killing 3,000 Brits A YEAR as docs blame popping pills daily for 20,000 ‘major bleeds’ annually. The Sun, June 14 2017

Daily aspirin risk for older patients. The Times, June 14 2017 (subscription required)

Links To Science

Li L, Geraghty OC, Mehta Z, et al. Age-specific risks, severity, time course, and outcome of bleeding on long-term antiplatelet treatment after vascular events: a population-based cohort study. The Lancet. Published online June 13 2017

Being overweight, not just obese, still carries serious health risks

NHS Choices - Behind the Headlines -

"Four million people died in 2015 as a result of being too tubby, struck by cancer, heart disease, diabetes and other killer conditions," reports The Sun.

This is based on a global study that looked at how the proportion of people who are overweight and obese has changed over time. This was determined by recording body mass index (BMI), where a BMI of 25-29.9 means being overweight and 30 or above is being obese.

Researchers then assessed the link between having an unhealthy BMI and health outcomes including cardiovascular disease, diabetes and cancer.

It found that, despite public health efforts, obesity is on the rise in almost every country and in both adults and children. Prevalence has doubled in most countries over the past 30 years. Researchers also estimated that having a high BMI accounted for 4 million deaths globally, 40% of which occurred in people who were overweight but not yet obese.

This demonstrates that being overweight may almost be as risky to health as being obese. The rate of increase in obesity was also greater in children, showing the need for interventions to halt and reverse this trend to avoid future disease and deaths.

What is considered a healthy weight – BMI 20 to 25 – was unsurprisingly found to be the category with the lowest health risk. The best way to obtain and maintain a healthy BMI is to eat a healthy calorie-restricted diet and exercise regularly; two concepts that are at the core of the NHS Weight Loss Plan.

 

Where did the story come from?

The study was carried out by researchers from a wide range of global institutions and universities, but was led by the Institute for Health Metrics and Evaluation (IMHE), based at the University of Washington in Seattle. It was funded by the Bill and Melinda Gates Foundation.

The research was published in the peer-reviewed The New England Journal of Medicine on an open-access basis, which means it is free to read online (PDF, 2.3Mb).

A surprising key finding, as the BBC reported, is that "of the 4 million deaths attributed to being overweight in 2015, nearly 40% were not considered clinically obese". The BBC accurately explains how merely being overweight, and not just obese, can increase risk of death.

 

What kind of research was this?

This was a review and report of evidence from around the world that looked at how the prevalence of being overweight and obese has changed over time. The researchers then looked at how being overweight affects the risk of various health outcomes, including cardiovascular disease and death.

Gathering high quality data from across many studies over time is the best way to see whether prevalence has changed and to see which health conditions are most strongly related to high body mass index (BMI). However, it is difficult to know how big a role BMI plays in raising your risk of certain health conditions, as other factors also have an influence.

 

What did the research involve?

The researchers analysed data from 68.5 million people from 195 countries looking at the burden of disease related to BMI between 1990 and 2015, and according to age, sex, and country. They looked at both children and adults.

Disease burden was defined as deaths and disability-adjusted life years (accounting for years of life lost or lived with disability) due to high BMI.

Information on adult BMI was provided by 1,276 unique sources from 176 countries, and 1,211 sources from 173 countries provided data on children's BMI.

For adults, "overweight" was defined as a BMI between 25 and 29 and "obese" was 30 or above. In children, the International Obesity Task Force definitions of childhood overweight and obesity were used. These definitions are based on the principle of a child being heavier for their age than you would expect. The results were broken down by sex and by 5-year age groups.

They looked at the effect of high BMI on health outcomes and estimated the increase in risk associated with a change of five units of BMI in 5-year age groups for:

  • ischemic heart disease (eg angina and heart attack)
  • ischemic stroke (caused by a blood clot)
  • haemorrhagic stroke (caused by a bleed)
  • hypertensive heart disease (strain on the heart caused by high blood pressure)
  • diabetes

To understand where most of the burden of disease occurs, they looked at three ranges of BMI (20 to 24; 25 to 29 and 30 or over) and for five overarching groups of diseases:

  • cardiovascular disease
  • diabetes
  • chronic kidney disease
  • cancers
  • musculoskeletal disorders

They also determined the BMI associated with the lowest overall risk of death.

 

What were the basic results?

In 2015, globally 107.7 million children and 603.7 million adults were obese. The prevalence has doubled in more than 70 countries since 1980 and continuously increased in most other countries.

Obesity now affects an estimated 5% of all children and 12% of all adults. In all adult age brackets, prevalence was generally higher among women.

Worldwide findings included:

  • High BMI contributed to 4 million deaths in 2015 (95% confidence interval [CI] 2.7 to 5.3), representing 7.1% (95% CI 4.9 to 9.6) of all deaths globally.
  • High BMI contributed to 120 million disability-adjusted life years lost (95% CI 84 to 158).
  • A total of 39% of the deaths and 37% of the disability-adjusted life years were in people with a BMI of less than 30 (i.e. not obese).
  • Cardiovascular disease was the leading cause of death and disability-adjusted life years with 2.7 million deaths (95% CI 1.8 to 3.7) and 66.3 million disability-adjusted life years (95% CI 45.3 to 88.5).
  • Diabetes was the second leading cause and contributed to 0.6 million deaths (95% CI 0.4 to 0.7) and 30.4 million disability-adjusted life years (95% CI 21.5 to 39.9).

A normal BMI of 20 to 25 in adults was associated with the lowest risk of death (the UK defines this as a healthy level).

 

How did the researchers interpret the results?

The researchers concluded that their study "provides a comprehensive assessment of the trends in high BMI and the associated disease burden. Our results show that both the prevalence and disease burden of high BMI are increasing globally. These findings highlight the need for implementation of multicomponent interventions to reduce the prevalence and disease burden of high BMI."

 

Conclusion

This impressively large global study demonstrates that the prevalence of obesity is increasing worldwide among both children and adults. It supports what has long been thought, that increased body mass index (BMI) contributes to a range of illnesses and is ultimately responsible for a large number of deaths, particularly from cardiovascular disease.

One potential limitation is the use of self-reported BMI or health outcome data in some of the studies, although the majority used a specific independent measurement so this is unlikely to have biased results too much.

It is also always difficult from observational data to be certain of the exact amount of years of life lost or lived with disability that are directly caused by high BMI. It is possible that being overweight or obese may contribute to the risk of getting a particular disease, for example cancer, in combination with other health and lifestyle factors. Therefore, though based on a large quantity of data, the results must still be considered as estimates.

Nevertheless the study highlights what we already know – that being obese is linked to a large number of chronic diseases. Perhaps more notable was that it also shows that almost half of the years of life lost or lived in poor health could be attributed to people being overweight, not just obese.

This study design cannot explain the increasing prevalence of overweight and obesity. However, the fact that obesity has increased in countries of all levels of development indicates it is no longer a problem solely for high income countries. As the authors suggest, there are multiple factors contributing to this continuing trend, including reduced opportunities for physical education with growing urbanisation, along with increased availability, affordability and accessibility of energy-rich but nutritionally poor food.

There is an ongoing need for effective interventions to tackle overweight and obesity, both at the public health and the individual level. Otherwise the public health burden of obesity could be for the 21st Century what smoking was to the 20th Century – an entirely preventable cause of disability and death.

Links To The Headlines

Two billion people across the world are obese – with one in four battling fat-related diseases, experts warn. The Sun, June 12 2017

Weight-related deaths can affect non-obese too. BBC News, June 12 2017

Being overweight – not just obese – kills millions a year, say experts. The Guardian, June 12 2017

World's obesity crisis: One THIRD of the global population are now deemed overweight or obese, major study reveals. Daily Mail, June 13 2017

Links To Science

The GBD 2015 Obesity Collaborators. Health Effects of Overweight and Obesity in 195 Countries over 25 Years. The New England Journal of Medicine. Published online June 12 2017

Antibiotics and vitamin C could kill cancer cells

NHS Choices - Behind the Headlines -

"Vitamin C and antibiotics could be up to 100 times more effective than drugs at killing cancer cells – without the side effects," reports the Mail Online.

The news comes from the results of a study that found a new two-pronged approach using the antibiotic doxycycline followed by vitamin C could kill cancer cells.

Doxycycline killed many cancer cells, but others became resistant. The resistant cells were then destroyed by vitamin C.

While this is encouraging news, it needs to be put into context. The experiments all took place in the laboratory. Researchers used human breast cancer stem cells, but didn't perform any studies on animals or humans.

This means we don't know how successful this strategy could be – and the Mail's claim there would be no side effects is unsupported.

Though both doxycycline and vitamin C are safe to use in humans, more research is needed to find out how they interact with other cancer treatments and therapies before this can be recommended as a new approach to treating cancer.

Where did the story come from?

The study was carried out by researchers from the University of Calabria in Italy, and the University of Manchester and the University of Salford in the UK.

It was funded by both UK universities, the Healthy Life Foundation, the Associazione Italiana per la Ricerca sul Cancro (AIRC), the European Union, and various private donations.

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

The Mail reported on the study reasonably accurately, but didn't point out clinical trials are needed to see if the approach would be effective – and safe – in humans.

What kind of research was this?

This research involved a series of laboratory experiments performed on human cancer stem cells.

Although both doxycycline and vitamin C are safe to use in humans, we don't know whether the dose and combination required to kill cancer cells would be toxic in other ways.

Trials in animals first and then in humans are needed to eliminate this possibility.

What did the research involve?

The researchers performed a variety of experiments on human breast cancer stem cells. These are cells that are able to divide and become any type of cell the tumour needs in order to grow.

Cancer stem cells are different from most normal cells in that they can produce energy from glucose through a variety of pathways. This is one of the reasons they're able to grow and replicate better than normal cells.

Most also have an increased number of mitochondria – the powerhouse of cells – which can convert glucose into energy using oxygen. And one of the side effects of doxycycline is it inhibits the production of proteins required by mitochondria.

Previous research has suggested that by stopping the protein production, doxycycline could kill the cancer cells because they wouldn't be able to make energy.

But because cancer cells are good at adapting, there were concerns that some cancer cells would become drug resistant by using a different pathway to create energy, such as glycolysis.

This happens when certain cells, such as muscles, continue to work hard without oxygen, producing a build-up of lactic acid, and doesn't require oxygen or mitochondria.

This study looked at whether two natural products and six different drugs already approved for use in humans could kill cancer cells reliant on making energy using glycolysis – or in other words, kill the cancer cells that had resisted the initial treatment with doxycycline.

The natural products were vitamin C and berberine, a type of salt found in many plants.

The drugs included:

  • chloroquine (antimalarial)
  • atovaquone
  • irinotecan
  • sorafenib
  • niclosamide
  • stiripentol
What were the basic results?

Doxycycline reduced the cancer cells' ability to use different energy pathways. It did this by supressing the production of proteins important for mitochondrial function.

This wiped out many cancer cells, although some did became drug resistant. The doxycycline-resistant cells were then mostly reliant on the glycolysis pathway for energy production.

All of the drugs and natural products had some success in preventing these doxycycline-resistant cancer stem cells dividing. Vitamin C was the most successful.

The cells were 4-10 times more sensitive to vitamin C than cancer cells not resistant to doxycycline.

How did the researchers interpret the results?

The researchers concluded that doxycycline can kill some cancer cells and make others reliant on one energy pathway: glycolysis.

The doxycycline-resistant cells are then susceptible to natural products like vitamin C and drugs including chloroquine.

This, they say, "suggest[s] a new synthetic lethal strategy of i) doxycycline (to target mitochondria) and ii) vitamin C (to target glycolysis)." 

Conclusion

This isn't the first time vitamin C has been studied for use against cancer: it has previously been shown to kill cancer cells in the laboratory and stop cancer growth in mice.

This new two-pronged approach may well prove to be useful in eradicating cancer stem cells in humans, but robust clinical trials are necessary first as cells can behave very differently in a laboratory environment.

Although all the drugs and natural products used in this study are already approved for use in humans, we don't know for certain what concentration would be required to obtain similar effects without being toxic.

This study also only looked at breast cancer stem cells. We don't know what effect the combination would have on other types of cancer cells, which stage of treatment this might be useful for, or for which types of cancer.

Links To The Headlines

Vitamin C and antibiotics could be up to 100 times more effective than drugs at killing cancer cells – without the side effects. Mail Online, June 9 2017

Links To Science

De Francesco EM, Bonuccelli G, Maggiolini M, et al. Vitamin C and Doxycycline: A synthetic lethal combination therapy targeting metabolic flexibility in cancer stem cells (CSCs). Oncotarget. Published online June 9 2017

Owning a dog may encourage older people to exercise

NHS Choices - Behind the Headlines -

"NHS should prescribe dogs to keep over-65s fit," the Daily Mail reports.

The headline was prompted by the results of a new study with the rather unsurprising finding that older adults who own dogs walk more than those who don't.

The study included around 80 adults with an average age of 70 from three regions in the UK, half of whom owned dogs. They wore activity monitors for three one-week periods spread over the course of a year.

Dog owners walked around 22 minutes longer each day and were more likely to meet physical activity recommendations of 150 minutes of exercise a week.

It seems plausible that owning a dog directly causes people to go out and walk when they wouldn't otherwise do so.

But you can't rule out the possibility that people who lead more active lifestyles – and so would be active anyway – are more likely to have a dog. Similarly, people with chronic health conditions may be less likely to care for dogs.

The small number of people involved in the study also means we can't provide definite answers around differences in walking times among dog owners – or tell whether this affects health outcomes.

Of course, not everyone wants or can have a dog. That doesn't mean you can't fit exercise into your life – you just need to stick to a routine.

Read more about physical activity guidelines for older adults.

Where did the story come from?

The study was carried out by researchers from several international institutions, including Glasgow Caledonian University and the University of Lincoln in the UK, and State University of New York in the US.

It was funded by the ISAZ/WALTHAM Award, which is administered by the International Society for Anthrozoology (ISAZ). ISAZ is an organisation that provides funding for research into human and animal interaction.

The study was published in the peer-reviewed journal BMC Public Health. This is an open access journal, so the study is free to read online.

The Mail's coverage is accurate, but the suggestion that the NHS should prescribe dogs to older people oversteps the mark.

The study's authors only suggest that public health campaigns should encourage dog ownership to promote exercise. In any case, it's exercise that's important, and you don't need a dog to do this.

What kind of research was this?

This was a cohort study where a sample of dog owners and non-dog owners, matched on sociodemographic factors, wore activity monitors for three weeks over the course of a year.

The research aimed to see whether dog ownership has a direct effect on physical activity and sedentary behaviour in older adults.

Such a study may well demonstrate that dog ownership has a direct effect on physical activity, but this isn't really that surprising given that the need to walk a dog means a person goes for a walk when they may not have otherwise done so.

What did the research involve?

This study included 43 dog owners and 42 non-dog owners over the age of 65 recruited from Lincolnshire, Derbyshire and Cambridgeshire through advertisements.

Dog owners and non-dog owners were matched by age, gender, ethnicity, and socioeconomic status.

Participants had activity data collected in three one-week periods spread evenly over the course of a year to capture a range of seasons (March to June, July to October, and November to February).

They wore activity monitors and kept diaries reporting walking times and sleep/wake times during the assessment weeks.

Participants also provided data on numerous variables, including:

  • their height and weight
  • their history of chronic health conditions
  • the distance they felt they could walk continuously
  • the breed, gender, length of ownership, and extent of personal responsibility for their dog

Researchers, blinded to whether the participants owned a dog or not, assessed walking times and looked at how they adhered with national physical activity recommendations (150 minutes a week of moderate physical activity).

What were the basic results?

Eleven people dropped out of each of the two groups (25% drop out). But compliance with wearing the activity monitors for a full week in each assessment period was very high, at 92%.

Two-thirds of participants were women, with an average age of 70 and an average body mass index (BMI) on the borderline of overweight (25.6kg/m2).

Allowing for variance in dog ownership characteristics, dog owners walked for significantly longer than non-dog owners.

Each day, they walked 2,762 additional steps, and walked 23 minutes longer in total and 21 minutes longer at a moderate walking pace.

Dog owners were also more likely to meet guideline physical activity recommendations (87% versus 47%; odds ratio [OR] 75, 95% confidence interval [CI] 3-2,167).

But this is a surprisingly high confidence interval, which undermines the validity of this result. 

There was no difference in sedentary times or sleep/wake times.

How did the researchers interpret the results?

The researchers concluded that, "The scale of the influence of dog ownership on [physical activity] found in this study indicates that future research regarding [physical activity] in older adults should assess and report dog ownership and/or dog walking status."

Conclusion

This relatively small observational study shows that dog owners over the age of 65 walk more than matched controls who don't own dogs.

This finding is perhaps not surprising, given that dogs need to be walked every day. People without dogs may not have this sort of incentive to get out walking.

So, it could be assumed that the dog is the direct cause of the increased walking time.

But it's also possible that more active people who enjoy spending time outdoors may be more likely to own dogs.

For all we know, the dog owner group may have been more active even if they didn't have dogs.

There are some points to note about this study:

  • The study had a fairly small sample and quite a high drop out rate. This means the differences in walking time can't be taken as definite – larger samples of dog walkers and non-dog walkers, or those from different regions, could have given different time differences.
  • The big improvement in meeting physical activity recommendations may not be accurate because of the high confidence intervals around the figures.
  • If reliable, the roughly 22-minute difference in how much dog owners walked each day may be expected to make a difference to health outcomes, but we can't be certain about that.
  • Normal walking/sedentary habits and information about the person's health were self-reported, which may introduce inaccuracies. The research doesn't focus on the health of participants, but it's possible that people with more chronic health conditions could walk less or be less likely to be the main person looking after a dog.
  • The sample mainly included women, all the people involved were White British, and all were over the age of 65. This means the results can't easily be generalised to the whole population.

Current public health guidelines recommend taking at least 150 minutes of moderate aerobic activity like cycling or fast walking every week, and strength exercises on two or more days a week.

You don't need to have a dog to be more active – read more about exercise as you get older.

Links To The Headlines

NHS 'should prescribe dogs' to keep the over-65s fit: Pensioners who have a pet get an extra 22 minutes of exercise each day. Daily Mail, June 9 2017

Links To Science

Dall PM, Ellis SLH, Ellis BM, et al. The influence of dog ownership on objective measures of free-living physical activity and sedentary behaviour in community-dwelling older adults: a longitudinal case-controlled study. BMC Public Health. Published online June 9 2017

An egg a day may prevent stunted growth in infants

NHS Choices - Behind the Headlines -

"An egg a day appears to help young children grow taller," BBC News reports.

Research involving young children in Ecuador found babies given one egg a day for six months had improved growth compared with controls, as well as a reduced risk of stunted growth.

Stunted growth is when a child fails to meet the expected height or weight for their age. It can lead to long-term health problems, including difficulties affecting both physical and mental development. It's caused by malnutrition, repeated infection or, in some cases, both. 

The researchers point out that eggs – an excellent source of protein – are a relatively cheap and convenient way to ensure children are getting high-quality food, and could be an ideal intervention for at-risk children in the developing world.

In the study, babies who were given a daily egg also ate less sugary food, such as sweets and cakes. This suggests eating eggs might help reduce childhood obesity.

We don't know if the results would apply to children in the UK or elsewhere in the world, where stunted growth is much less common.

Previous scares about salmonella in eggs may have put some people off giving young children eggs, but advice from the Food Standards Agency says hen eggs produced in the UK under the Lion branding scheme are "very low" in risk, including for pregnant women and young children.

Babies should be exclusively breastfed until they're around 6 months of age. Mashed-up hardboiled eggs can be offered to babies when they're around 6-8 months old. 

Where did the story come from?

The study was carried out by researchers from Washington University, the University of Maryland and the University of California Davis in the US, and Universidad San Francisco de Quito in Ecuador.

It was funded by the Mathile Institute, a not-for-profit organisation that funds child nutrition research. 

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

The Mail Online's headline suggests the study's main finding was that eggs "help babies stay healthy" – but the study primarily looked at babies' growth and weight, not their overall health.

Their news article also doesn't make it clear that the research may only apply to children in resource-poor communities, such as rural Ecuador.

BBC News carries a clearer story with a balanced overview.

What kind of research was this?

This was a randomised controlled trial. This is usually the best type of study to see whether one intervention (such as giving a child an egg every day) works.

What did the research involve?

Researchers recruited 163 mothers (or other caregivers) with a child aged 6-9 months who was in good health.

All the babies were weighed and measured, and information was taken from their caregivers at the start of the study and again after six months.

At the start of the study, the researchers asked about the situation at home – for example, access to clean water and sanitation, the baby's usual diet, and any recent illness.

Children with severe malnutrition, heart defects or egg allergies weren't included.

Families were visited weekly to monitor any ill health among the babies and for the families in the egg group to receive their eggs for the week.

At the end of six months, after adjusting their figures to take account of the children's age, sex and measurements at the start, researchers looked at whether children who'd been given eggs were less likely to be underweight or have stunted growth.

In randomised controlled studies of drugs, researchers usually try to ensure patients don't know whether they're taking the treatment or not. That obviously wasn't possible in this study.

The main outcome measures were children's length and weight for their age, and whether they were below a certain marker that suggests they were much shorter or lighter than other children their age. This was used to assess whether they were underweight or had stunted growth. 

What were the basic results?

At the start of the study, 26% of children in the control group and 37% in the egg group had stunted growth for their age.

By the end of the study, that had changed to 29% of children in the control group and 21% of those in the egg group.

Taking other factors into account, children given an egg daily were 47% less likely to be stunted at the end of the study (95% confidence interval [CI] 0.37 to 0.77).

They were also 74% less likely to be underweight (effect size 0.26, 95% CI 0.10 to 0.70), although far fewer children were underweight to start with.

In both groups, children were likely to be eating more sugar-sweetened drinks, cakes, chocolate, pastries, or biscuits at the end of the study than at the start.

However, those in the egg group ate 29% less sweet food than the control group (0.71, 95% CI 0.51 to 0.97).

There were no reports of egg allergy, although caregivers of children in the egg group were more likely to report that the children had experienced diarrhoea.

How did the researchers interpret the results?

The researchers say their results show including an egg a day as part of a baby's diet from 6 months of age "significantly improved linear growth and reduced stunting" in this population.

They go on to say that, "In our view, eggs have the potential to be an affordable and environmentally sustainable high-quality food source in populations at risk for both undernutrition and overweight and obesity." 

Conclusion

This study sounds like good news for undernourished children in parts of the world where stunted growth or being underweight are common, such as the Andean mountains of Ecuador.

The study showed that eggs seem to be a safe and practical way of boosting children's nutrition in this population.

But this research has some limitations. Adding one food to a diet is likely to affect the rest of the diet, too.

And caregivers for the children may have given them different foods in addition to the eggs, or treated them differently in some ways.

The children in the control group may also have eaten more eggs than they would have done had their caregivers not been involved in the study. 

But, more importantly, we don't know whether the results are applicable to a very different population, such as the UK, where most babies are well nourished and a wide variety of foods are available. Egg allergy may also be more common in the UK.

As long as your child doesn't have an egg allergy, there's no reason not to give them eggs. Eggs are a good source of protein and other nutrients that children need for a healthy, balanced diet.

As younger children are more vulnerable to the effects of food poisoning, it's important to store, handle and prepare eggs properly.

Links To The Headlines

An egg a day appears to help young children grow taller. BBC News, June 7 2017

They've cracked it! An egg a day helps babies stay healthy: Daily consumption reduces chance of stunted growth or being underweight. Daily Mail, June 7 2017

Links To Science

Iannotti LL, Lutter, CK, Stewart CP, et al. Eggs in Early Complementary Feeding and Child Growth: A Randomized Controlled Trial. Pediatrics. Published online June 6 2017

Is white bread just as healthy as brown?

NHS Choices - Behind the Headlines -

"Sliced white bread is 'just as healthy as brown', shock findings reveal," The Sun reports.

A small study looking at the effects of eating different types of bread – white versus brown sourdough – found no significant differences.

But the researchers also reported responses varied from person to person, depending on their gut bacteria.

The study measured 20 health markers, but was mainly focused on increased blood sugar levels after eating (glycaemic control).

Researchers found no overall differences in glycaemic control when people ate white bread compared with wholemeal sourdough bread.

But when they looked at people's individual responses to bread, they found some responded better to white bread, while others responded better to wholemeal sourdough bread.

The researchers said the response could be predicted by the types of bacteria living in the gut.

The question of whether wholemeal or white bread is healthier isn't settled by this study, which only lasted two weeks and involved just 20 people.

Wholemeal bread is a good source of fibre – a diet higher in fibre reduces the risk of bowel cancer, helps digestion, and may help people feel fuller, avoiding weight gain.

Where did the story come from?

The study was carried out by researchers from the Weizmann Institute of Science in Israel. We don't know who funded it.

Two of the researchers declared a conflict of interest as they are paid consultants for a company that promotes personalised nutrition based on gut biome analysis.

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

The Sun reported "shock results" that "white bread is just as healthy as a brown loaf", a claim echoed by the Daily Mail – although this isn't really what the research found.

But both newspapers did quote nutrition experts, who pointed out that a week-long trial in just 20 people doesn't provide a conclusive result.

The Guardian rightly highlighted the fact that there were different results for different people. None of the papers mentioned the researchers' conflict of interest.

What kind of research was this?

This was a small randomised cross-over trial of two types of bread, eaten by healthy volunteers for one week each.

One week may not be long enough to show meaningful results.

What did the research involve?

Researchers recruited 20 healthy people. They were provided with either white bread or wholemeal sourdough bread, and instructed to eat at least a certain amount each day for a week, but no other wheat products.

They had a two-week break after seven days, then switched to the other type of bread for one week.

The participants were tested on a range of health markers before, during and after the study.

Researchers looked at whether the markers were different when the people were eating one type of bread compared with the other.

They took blood tests to measure triglycerides (fats), LDL and HDL cholesterol ("bad" and "good" cholesterol), and levels of liver enzymes (ALT, AST, GGT, LDH), iron, calcium, creatinine, urea, thyroid stimulating hormone, and C-reactive protein (a measure of inflammation).

They measured blood pressure, weight and metabolic rate, and tested people's stools for bacteria. 

Blood glucose levels were measured in the 15 minutes after waking up, and blood glucose response to a glucose test (the body's response to consuming glucose syrup) was also tested.

The researchers did a post-hoc analysis to see whether people's results were different after eating any type of bread compared with their usual diet before the study, and whether their gut bacteria (measured from stool samples) were different.

They also tested people individually on their response to eating white or brown sourdough bread, and looked at whether their gut bacteria could predict how they would respond.

What were the basic results?

Researchers found no significant differences between results in any of the clinical parameters measured, including blood glucose (glycaemic) response after seven days of eating white bread or wholemeal sourdough bread.

Glycaemic response increased after a week of eating white bread for some people, while for others it decreased. The same was true for wholemeal sourdough bread.

The researchers found two types of bacteria were more common after people had eaten white bread for a week, but the clinical significance of this isn't clear. They showed that for most people, eating bread of any type had little effect on gut bacteria.

The researchers say there was more "interpersonal variability" between glycaemic response to the type of bread than you would expect by normal distribution.

They go on to say analysis of glycaemic response according to six measures of gut bacteria could "predict" individual people's response to each type of bread.

How did the researchers interpret the results?

The researchers concluded that, "Understanding the interpersonal variation in the effect of bread, one of the most consumed staple foods, would allow the personalisation of bread-related nutritional recommendations and optimisation of food choices worldwide."

They say their study "underlines the importance of personalisation in dietary recommendations", and suggests that "universal dietary recommendations may have limited efficacy". 

Conclusion

Studies that suggest "everything you thought you knew about healthy eating is wrong" create great headlines, but rarely stand up to much analysis.

There are many reasons why you might choose wholemeal bread over white bread, and results from a week-long study in 20 people aren't going to change all of those.

The main measure of interest in the study is glycaemic control, a measure of how quickly the body can process glucose consumed in the diet.

Poor glycaemic control is seen as a risk factor for type 2 diabetes, where the body can't process glucose properly, leading to high blood sugar, which can damage blood vessels.

The study showed no overall difference over the course of a week in people's ability to process glucose, assessed by which type of bread they ate.

It may be that the study was too short to show a change. But there are other reasons to eat wholemeal bread, including the benefits of eating plenty of fibre, which can help digestion and has been linked to a lower risk of bowel cancer.

What the study did seem to find was that different people react differently to different foods, which isn't a big surprise.

It's interesting that this seems to be linked to the bacteria that live in your gut. This might be of interest to dietitians and doctors treating people with diabetes or poor glycaemic control.

But there's no need to worry about getting tests of your gut bacteria or swapping from your preferred type of bread if you have normal blood glucose.

While conflicts of interest are common in scientific research, it's worth keeping in mind that two of the researchers involved in this study work for a company that offers to "balance your blood sugar with personalised nutrition", offering dietary advice based on the results of stool tests.

Find out more about how wholegrain foods are an important part of a healthy diet.

Links To The Headlines

Sliced white bread is 'just as healthy as brown', shock findings reveal. The Sun, June 6 2017

Is white bread better for you than brown sourdough? It depends on your gut. The Guardian, June 6 2017

Is wholemeal bread really any better for you? People who eat white are no less healthy, study finds. Daily Mail, June 6 2017

Links To Science

Korem T, Zeevi D, Zmora N, et al. Bread Affects Clinical Parameters and Induces Gut Microbiome-Associated Personal Glycemic Responses. Cell Metabolism. Published online June 6 2017

Even moderate drinking may damage the brain

NHS Choices - Behind the Headlines -

"Even moderate drinking can damage the brain," The Guardian reports. A new study, involving brain scans and cognitive testing, suggests that moderate drinking, over many years, could damage areas of the brain linked to memory and cognitive function.

The results showed that the higher the amount of alcohol consumed a week, the higher the risk of damage to certain areas in the brain, including those involved in memory.

This association was not found for "light" drinkers (people who consume between one and seven units a week). However, the scan was only performed once so we don't know if and when the brain structures changed or whether the changes were caused by other factors.

The researchers also found that people drinking alcohol in moderate or heavy quantities (over seven units a week) had a faster decrease in ability to name words beginning with the same letter but no difference for any other brain test.

Despite anecdotal reports to the contrary, many of which were promoted by the media, no protective effect of "light" drinking on cognitive function compared to completely abstaining from alcohol was found.

UK guidelines on alcohol were changed last year to reflect evidence that there is no such thing as a "safe level" of drinking; just a level when harms were at their lowest.

The guidelines now recommend that both men and women drink no more than 14 units of alcohol per week – the equivalent of around six pints of beer, and this study seems to support these guidelines.

 

Where did the story come from?

The study was carried out by researchers from the University of Oxford and University College London in the UK and was funded by the UK Medical Research Council, the Gordon Edward Small's Charitable Trust and the HDH Wills 1965 charitable trust. There were no reported conflicts of interest.

The study was published in the peer-reviewed British Medical Journal on an open-access basis, meaning it is freely available to access and read online.

The UK media's reporting of the study was generally accurate, with the noticeable exception of the headline printed by The Sun, which claimed that "less than a pint a day means you're 'THREE TIMES more likely to develop early signs of Alzheimer's'". This is not an accurate reflection of the study findings as none of the participants had developed Alzheimer's disease.

 

What kind of research was this?

This was a prospective cohort study, following adults over 30 years to look at their weekly alcohol intake and cognitive performance over time and brain structure at the end of the study.

This type of study is best for looking at things like alcohol intake, as a randomised controlled trial where participants get allocated to a weekly alcohol intake level would be unethical. Following people over time and asking them to record their weekly intake is a much better way of studying the effects of alcohol on the brain and cognitive performance.

 

What did the research involve?

Researchers took 550 participants who were already enrolled in the Whitehall II study, a study that started in 1985 aiming to investigate the relationship between socioeconomic status, stress and cardiovascular health in civil servants.

Over 30 years sociodemographic, health and lifestyle variables (including alcohol use) were measured at intervals:

  • phase I: 1985-88
  • phase 3: 1991-93
  • phase 5: 1997-99
  • phase 7: 2003-04
  • phase 9: 2007-09
  • phase 11: 20011-12

Average alcohol use across the study was calculated as mean consumption a week averaged over all study phases. Participants were categorised as:

  • "abstinent" if they consumed less than one unit of alcohol a week
  • "light drinking" was defined as between one and less than seven units
  • "moderate drinking" was defined as seven to less than 14 units a week for women and seven to less than 21 units for men
  • "unsafe drinking" was defined according to pre-2016 (21 units a week for men and 14 units for women) and newly revised UK Department of Health guidelines (more than 14 units for men and women)

The researchers looked at brain structure including grey matter density, hippocampal atrophy and white matter by carrying out a magnetic resonance imagining (MRI) scan on participants at the end of the study (between 2012 and 2015).

Grey matter consists of a range of specialised nerve cells while white matter mainly consists of cells that help send signals through the brain. The hippocampus is an area of the brain involved with memory.

Cognitive function was also assessed at phases 3, 5, 7, 9 and 11 and at the time of scanning with tests including :

  • semantic fluency – naming as many words as possible in the same category, such as animals
  • lexical fluency – naming as many words beginning with same letter as possible
  • performance on the Montreal cognitive assessment – which checks for mild cognitive impairment
  • trail making test – connecting dots to look at visual search speed and mental flexibility
  • Rey-Osterrieth complex figure test – reproduce a complex line drawing
  • Hopkins verbal learning test – asking a person to remember and then recall a short list of words
  • Boston naming test – to measure word recall and naming ability
  • digit substitution test – matching symbols with their corresponding digits

Age, sex, education, smoking, social activity, blood pressure, smoking, history of cardiovascular events and cardiovascular drugs were assessed by questionnaire. Social class, lifetime history of major depressive disorder and drug use were also taken into account.

 

What were the basic results?

Median alcohol consumption was 11.5 units a week for men and 6.4 units for women and this did not increase significantly over the phases of the study for the group as a whole.

Brain Structure:
  • Compared with abstinence, greater alcohol consumption was associated with increased odds of hippocampal degeneration in a dose dependent way – the more alcohol, the more atrophy.
  • In light drinkers, (one to less than seven units a week) there was no difference in brain structure compared with those who abstained from alcohol.
  • Those consuming more than 30 units a week were at five times higher risk of right sided hippocampal atrophy compared with abstainers (odds ratio [OR] 5.8, 95% confidence interval [CI] 1.8 to 18.6). The total number of people this was based on was small though; 24 out of 31 heavy drinkers had signs of atrophy compared to 13 out of 37 abstainers.
  • Overall, moderate drinkers (14 to less than 21 units a week) had a three times higher risk of hippocampal atrophy compared with abstainers (OR 3.4, 95% CI 1.4 to 8.1).
  • Women who drank moderately had no significant difference with abstainers, but men who drank moderately did.
Cognitive functioning:
  • Of the 10 tests of brain function, only one result was significant; lexical fluency.
  • Higher alcohol consumption predicted a faster decline in lexical fluency. Over the 30 years, people drinking seven to less than 14 units experienced 14% greater reduction in lexical fluency, those drinking 14 to less than 21 units 17% greater reduction and those drinking more than 21 units a 16% greater reduction than those who abstained from alcohol.

 

How did the researchers interpret the results?

The researchers concluded: "the finding that alcohol consumption in moderate quantities is associated with multiple markers of abnormal brain structure and cognitive function has important potential public health implications for a large sector of the population."

They further add that their findings "support the recent reduction in UK safe limits and call into question the current US guidelines, which suggest that up to 24.5 units a week is safe for men, as we found increased odds of hippocampal atrophy at just 14-21 units a week, and we found no support for a protective effect of light consumption on brain structure. Alcohol might represent a modifiable risk factor for cognitive impairment, and primary prevention interventions targeted to later life could be too late."

 

Conclusion

The results in this study indicate a link between alcohol intake – even moderate intake – and structural changes in the brain and decline in the ability to list words beginning with the same letter. The majority of cognitive functioning tests showed no association with alcohol intake.

This 30 year-long study has the ability to investigate changes in cognitive ability over a long period of time but does have some limitations:

  • The participants are all people who were civil servants in the 1980s and were mostly male and more middle class and higher IQ than the general population, meaning results might not be applicable to the UK as a whole.
  • The effect of hippocampal atrophy was found in men and not women which may be down to the lower sample size of women and that few of them drank heavily.
  • The information on alcohol intake was self-reported and therefore might be inaccurately reported by participants.
  • It is difficult to link brain structure with alcohol intake when it might have been down to other confounding factors such as intelligence, cognitive stimulation and other lifestyle factors.
  • The MRI scan only took place once, at the end of the study, so it is difficult to tell if and when any changes in brain structure took place and rule out other influencing factors.

The structural changes in the brain were found to be statistically significant but it is not known if these changes are clinically significant – if they actually impact health in the long run.

As we are still unsure of the potential effect of alcohol on our brains, and the well known increased risks of cancer and liver disease, it is wise not to exceed the weekly UK limit of 14 units for both men and women.

Links To The Headlines

Even moderate drinking can damage the brain, claim researchers. The Guardian, June 6 2017

Less than a pint a day means you're 'THREE TIMES more likely to develop early signs of Alzheimer's'. The Sun, June 7 2017

Just one pint or glass of wine a night can make people 3 times more likely to see their brain shrink in size. Daily Mail, June 7 2017

Two glasses of wine a night can damage brain. The Times, June 7 2017

Links To Science

Topiwala A, Allan CL, Valkanova V, et al. Moderate alcohol consumption as risk factor for adverse brain outcomes and cognitive decline: longitudinal cohort study. BMJ. Published online June 6 2017

Babies put into their own room at six months 'sleep longer'

NHS Choices - Behind the Headlines -

"Babies moved into their own room at six months sleep better and are lower risk of obesity, poor sleep patterns and tantrums," reports The Sun.

This is based on a US study looking at room-sharing of 230 mother-infant pairs and infant sleep patterns.

However, despite the headlines, the study did not look at babies' ongoing sleep patterns or the risk of obesity.

The study found that infants who slept independently (not in the same room as their mother) by 4 months or after 4-9 months did sleep for longer in both the short and longer-term. At 9 months "independent sleepers" slept around 40 minutes per night longer than "room-sharers".

Worryingly, researchers also found an association between room-sharing and unsafe sleep practices that have been linked with sudden infant death syndrome (SIDS), such as use of blankets and pillows, or parents bringing the baby into bed with them. But no cases of SIDS were reported.

The results would appear to contradict recent US guidelines, which recommend room-sharing for the first year. This differs from NHS guidance, which recommends keeping your baby in a separate cot in your room for just the first six months.

 

Where did the story come from?

The study was carried out by researchers from Penn State College of Medicine, the University of Connecticut, the University of Buffalo and the University of Georgia, all in the US.

The research was funded by grants from a range of US institutions including Penn State College of Medicine, the Children's Miracle Network at Penn State Children's Hospital, the US Department of Agriculture, the Penn State Clinical and Translational Science Institute and the National Institutes of Health.

The study was published in the peer-reviewed medical journal Pediatrics on an open-access basis, meaning it is free to read online.

The quality of the UK media's reporting of the study was patchy in places. As mentioned, The Sun inaccurately implied that the researchers looked at obesity risk. While other research has found an association between poor sleep and obesity in later life, this was not investigated in this study.

Also, the Mail Online's claim that infants put in their parents' room after the age of six months "lose the ability to soothe themselves" is not something the study researched or reported either.

 

What kind of research was this?

This was a secondary analysis of data collected in a randomised controlled trial comparing a parenting intervention with a control group in mothers and their infants.

The researchers specifically set out to look at the associations between room-sharing (but not bed sharing) and sleep patterns of the infants. They also wanted to look for links between independent sleeping and risk factors for sudden infant death syndrome (SIDS).

Secondary data analysis is a useful way of carrying out a study using data that already exists. However, because the study has already been carried out, researchers are only able to analyse and draw conclusions from the limited data they have.

 

What did the research involve?

Researchers took 230 mother-infant pairs from the US who were participating in the Intervention Nurses Start Infants Growing on Healthy Trajectories (INSIGHT) study and looked at the association between independent sleeping and sleep outcomes.

Infants were first-borns and of a healthy weight. Mothers were English speaking and over 20 years of age. Parents who reported bed-sharing with their infant were excluded.

Research nurses visited homes when infants were 3 to 4 weeks old and then again at 4, 6 and 9 months.

The Brief Infant Sleep Questionnaire was used to assess sleep at 4 and 9 months of age, with a shorter version used at 12 and 30 months.

This survey assesses infant sleep location, activities before bedtime, and sleep patterns. Sleep duration is split into night time (7pm-7am) and daytime (7am-7pm).

At 4 and 9 months, other questions regarding sleep were asked, including night waking, night feedings and duration, infant sleep behaviours and environment and parenting responses to night waking.

Background characteristics included child race/ethnicity, maternal education, annual income and marital status. They also assessed maternal age, pre-pregnancy weight, pregnancy weight gain, whether the infant was born at term, and the infant's body measurements.

 

What were the basic results?

The results showed that of the 230 infants:

  • 62% were "early independent sleepers", meaning that by 4 months, they were sleeping independently without room sharing
  • 27% were "later independent sleepers", meaning that by 4-9 months they were sleeping independently
  • 11% were still room-sharing at 9 months

At 4 months, early independent sleepers had longer periods of uninterrupted sleep, with a longest "sleep stretch" averaging 469 ± 189 minutes compared with 423 ± 158 minutes for room-sharers.

Independent sleepers also had fewer night feedings (1.1 vs 1.4) at 4 months compared with room-sharers.

At 9 months, early independent sleepers slept 627 ± 67 minutes per night compared with 601 ± 73 minutes for later independent sleepers and 587 ± 83 minutes for those still room-sharing at 9 months. Early independent sleepers also slept for longer stretches at a time than late independent sleepers or room sharers.

At 30 months, both early and later independent sleepers slept on average over 45 minutes longer at night than those who were room-sharing at 9 months (614 ± 51 vs 617 ± 70 vs 569 ± 79).

At 4 months, room-sharing infants had higher odds of having unapproved objects on their sleep surface, such as a blanket, pillow, or positioner (adjusted odds ratio [aOR] 2.04, 95% confidence interval [CI] 1.17 to 3.57).

At both 4 and 9 months, room-sharing parents had 4 times higher odds of bringing their infant into their bed overnight (aOR 4.24, 95% CI 1.64 to 10.95).

Room-sharing was associated with demographic factors such as race/ethnicity, lower income and education, unmarried and/or not cohabiting with a partner, having fewer bedrooms in the home and having extended family or other people living at home.

 

How did the researchers interpret the results?

The researchers concluded that "room-sharing at ages 4 and 9 months is associated with less night-time sleep in both the short and long-term, reduced sleep consolidation, and unsafe sleep practices previously associated with sleep-related death."

 

Conclusion

The study shows an association between infant and parent room-sharing at 4 and 9 months and infants sleeping for less both in the short and longer term. It also showed a link between room-sharing and unsafe practices such as leaving objects such as blankets in the cot.

However, the results of this study need to be treated cautiously as there are some limitations to the research:

  • The findings do not prove that putting babies in their own room helps them sleep for longer. It might be that some parents of infants who were not sleeping very well anyway decided to keep their baby in the room with them.
  • The data collected was self-reported by the parents. There might be inaccuracies in their memory of how long their infant slept, which could have biased results.
  • The sample was relatively small to draw certain comparative results. It also included mostly white mothers with a relatively high income who were married or living with a partner and all had at least two bedrooms. This might mean that the results are less generalisable to other demographics. The study was also carried out in the US and therefore might not be as relevant to a UK setting.
  • Other factors such as who the main caregiver is and how many caregivers are involved in bedtime practices were not taken into account and may have biased the findings.

The researchers discuss past studies that have linked infant sleeping practices with risk of sudden infant death syndrome (SIDS). However this study reported no cases of SIDS. Even if there had been, the findings would not have shown that room sharing increases risk of SIDS.

Current UK guidance about reducing the risk of SIDS is:

  • Place your baby on their back to sleep, in a cot in the same room as you for the first six months.
  • Don't smoke during pregnancy or breastfeeding and don't let anyone smoke in the same room as your baby.
  • Don't share a bed with your baby if you've been drinking alcohol, if you take drugs or you're a smoker.
  • Never sleep with your baby on a sofa or armchair.
  • Don't let your baby get too hot or cold.
  • Keep your baby's head uncovered. Their blanket should be tucked in no higher than their shoulders.
  • Place your baby in the "feet to foot" position (with their feet at the end of the cot or Moses basket).

Links To The Headlines

Moving your baby into their own room at six months means you’ll get 45 minutes EXTRA sleep a night. The Sun, June 5 2017

Babies sleep LESS if they're in your room: Infants aged six months or older lose 40 minutes a night if they stay with their parents. Mail Online, June 5 2017

Links To Science

Paul IM, Hohman EE, Loken E, et al. Mother-Infant Room-Sharing and Sleep Outcomes in the INSIGHT Study. Pediatrics. Published online June 5 2017

TV in bedroom 'risk factor' for child obesity

NHS Choices - Behind the Headlines -

"Children who have TVs in their bedrooms are more likely to be overweight than those who do not," BBC News reports. A UK study found a link between children having a TV in their room and an increased risk of obesity.

Researchers followed children from seven to 11 years old to see whether the number of hours watching TV, playing on the computer or having a TV in the bedroom influenced the risk of having higher body fat in a couple of years.

It found that, compared to children who didn't have a TV in their bedroom at age seven, children who did had a significantly higher body mass index (BMI) and body fat at the age of 11. The association was higher for girls than boys.

Although this is an interesting study with potentially useful findings, it cannot prove there is a direct connection between using screens and body weight. But it would seem plausible that at least some children who spend a lot of time staring at a screen are not meeting the recommended levels for physical activity.

Almost a fifth of UK children are obese. As the study itself puts it: "Ironically, while our screens have become flatter, our children have become fatter."

Read more advice about helping your child to become more active and what to do if you are worried your child is overweight.

 

Where did the story come from?

The study was carried out by researchers from University College London (UCL) and was funded by a grant from the Economic and Social Research Council. The study was published in the peer-reviewed International Journal of Obesity.

Generally, UK media coverage on this study was accurate.

 

What kind of research was this?

This was an analysis of data obtained from a large prospective ongoing cohort study: the UK Millennium Cohort Study, which aimed to assess long-term associations between television and computer use and body fat in children.

In the UK, out of all screen based media, TV remains the most popular amongst children aged five to 11. Concurrently, the prevalence of obesity in childhood continues to increase.

The researchers wanted to investigate the link between TV use and obesity in children by following children over a period of time – between the ages of seven and 11.

Cohort studies such as this are useful for evaluating potential links between exposure and outcome. However, due to the study design it isn't always possible to fully rule out the influence of other confounding factors such as diet and physical activity. Therefore confirmation of cause and effect between the two variables can't be proven.

What did the research involve?

Researchers analysed data on 12,556 children from the UK Millennium Cohort Study (MCS). The Study is a prospective cohort study which follows children born between September 2000 and January 2002 in all four countries of the UK.

The dataset is nationally representative of the UK general population and includes children from economically disadvantaged areas and different ethnic minorities.

This analysis specifically looked at the data for 12,556 children (6,353 boys and 6,203 girls) who had been followed from the age of seven until 11. Two outcome variables were assessed: use of screen based media and body fat in children.

Body fat

Body fat at the age of 11 was measured using three indicators:

  • body mass index (BMI)
  • fat mass index (FMI) – total fat mass divided by height squared to reveal the amount of fat in the body
  • overweight – based on specific International Obesity Task Force (IOTF) criteria
Screen-based media

The use of screen-based media was measured in children at age seven. Three indicators were used:

  • whether the child had a bedroom TV
  • number of hours spent watching TV or DVDs
  • number of hours spent playing on the computer

The following confounding factors were adjusted for:

  • child age
  • child BMI at nine months old and three years old
  • breastfeeding duration
  • child ethnicity
  • maternal BMI
  • maternal education
  • family income

The researchers then analysed the data to look for any associations between screen-based media use and body fat in children.

 

What were the basic results?

This study had some interesting background findings:

  • at the age of seven, 55% of boys and 53% of girls in the sample had a TV in their bedroom
  • at the age of eleven, 25% of boys and 30% of girls were found to be overweight

Overall in this sample, compared to children who didn't have a TV in their bedroom, those who did have a TV in their bedroom at age seven had a significantly higher BMI and FMI at the age of 11. The associations were higher for girls than boys.

Additionally, following regression analysis (a statistical tool used to estimate the relationship between different variables), children who had a TV in their room at the age of seven had a higher relative risk of being overweight at age 11. The associations were stronger for girls.

 

How did the researchers interpret the results?

The researchers concluded: "Our longitudinal analysis has shown that having a TV in the bedroom is an independent risk factor for increased body fatness in this nationally representative sample of UK children.

"Girls who had a TV in their bedroom at age 7 were at an approximately 30% higher risk of being overweight at age 11 compared to those who did not have a TV in their bedroom, and for boys the risk was increased by about 20%."

 

Conclusion

This analysis used data from the UK Millennium Cohort Study to assess for long-term associations between television and computer use and body fat in children.

It found that compared to children who didn't have a TV in their bedroom at age seven, children who did had a significantly higher BMI and FMI at the age of 11. The association was higher for girls than boys.

This is an interesting study however there are a few points to note:

  • Although the researchers adjusted for potential confounding factors, diet and physical activity were not adjusted for. An unhealthy diet and lack of physical activity are two of the biggest contributors to obesity so it's surprising that these weren't looked into. It's quite likely that children who spend a large amount of time in front of screen-based media don't spend quite as much time getting exercise outdoors or through team sports etc. However as we don't have data on the level of physical activity of these children, we are unable to make that conclusion either.
  • Interestingly, the dataset for the MCS represented different ethnicities but in this particular analysis 84.6% of the children were white. Genetics and cultural differences do have an impact on children's behaviours so it would have been interesting to see whether children from different ethnic backgrounds had different results.

Overall this study doesn't prove that watching TV or having a TV in your bedroom directly increases body fat. However, the link between increased sedentary time in general, along with low physical activity and poor diet, and overweight and obesity is quite well established.

Current guidelines recommend children and young people need to do at least 60 minutes of physical activity every day.

Read more about how to help your child get more active.

Links To The Headlines

TVs in children's bedrooms 'increase risk of obesity'. BBC News, June 2 2017

TVs in the bedroom linked to childhood obesity, study finds. The Guardian, June 2 2017

Children with TVs in their bedroom have a higher risk of becoming obese - and it's worse for girls, study finds. Daily Mail, June 2 2017

Links To Science

Heilmann A, Rouxel P, Fitzsimons E, et al. Longitudinal associations between television in the bedroom and body fatness in a UK cohort study. International Journal of Obesity. Published online June 1 2017

'Everyday chemicals' linked to cancer

NHS Choices - Behind the Headlines -

"Chemicals in everyday items like cosmetics linked to cancer," The Independent reports. Research involving genetically engineered human cells found that a class of chemical called aldehydes damaged a gene that prevents cancer from developing.

Aldehydes are organic chemical compounds naturally present in the environment and also found in many man-made products and substances such as cosmetics and car exhaust fumes. Examples of aldehydes include acetaldehyde, which is created when the body breaks down alcohol and formaldehyde, used in many products, from paint to explosives.

The research centred on the BRCA2 gene. Healthy BRCA2 genes – they come in pairs – produce a protein that helps repair DNA and regulate cell growth. Mutations to the BRCA2 genes can lead to uncontrollable cell growth which can trigger breast and ovarian cancer in women, and prostate cancer in men.

In this study the researchers found that exposure to aldehydes reduces the amount of DNA repair protein the gene can make. In people who are carrying abnormal BRCA2 genes to start with – so make less repair protein in the first place – aldehydes further reduce the amount they can make. This leads to DNA damage which could progress to cancer.

This is early stage research so we cannot say what would be a safe or toxic level of exposure to aldehydes.

Unless you are willing to take drastic steps, there is not much you can do to limit your exposure to aldehydes, with the important exception of sticking to the recommended weekly limits for alcohol consumption.

 

Where did the story come from?

The study was carried out by researchers from the University of Cambridge and two Swiss institutions: the Institute of Molecular Systems Biology and the University of Zurich. It was funded by grants from the Medical Research Council.

The study was published in the peer-reviewed scientific journal Cell, on an open access basis so it is freely available to access online.

Some of the media reports are a little over dramatic, placing a lot of emphasis on individual products. For example The Sun says: "Boozing gives you cancer, and now scientists think they know why." The Daily Mail lays the blame on "shampoo, booze and car fumes". These chemicals are present in many products and occur naturally. We can't place the blame on single products, or say that these provide the whole answer.

The Mail and Sun also give little attention to the fact that the findings were mostly relevant to carriers of BRCA2 mutations and not the general population.

The Independent provides the most accurate and balanced reporting of the study, pointing out that it is "rather misleading to suggest that products containing aldehydes could be an 'important cause of cancer'".

 

What kind of research was this?

This was laboratory research which aimed to see how chemical compounds (aldehydes) present in the environment or in products we use can affect our DNA and cancer risk.

The researchers' particular focus was on what causes mutations of the BRCA2 gene which can make people susceptible to cancers including breast and ovarian.

The researchers explain how normally the BRCA2 genes produce a protein that helps to maintain and repair the DNA in our chromosomes – structures in our cells which carry genetic information. Other lab studies in mice and human cells have shown that disruption to the BRCA2 gene often leads to altered chromosome structure and sensitivity to toxic chemicals.

In this study the researchers investigated the toxic effect of formaldehyde or acetaldehyde compounds, which naturally occur in the environment, are found in various products, and accumulate in our body tissues.

 

What did the research involve?

The experiments were conducted on various female human cancer cells.

The laboratory methods are complex. Essentially the cells were incubated with formaldehyde and acetaldehyde. Following this, the researchers studied the DNA to see what effect there was on the BRCA2 protein and chromosome structure.

The researchers looked at what happened when cells had two normal copies of the BRCA2 gene and when they were heterozygous, with one normal copy and one abnormal copy with a mutation.

 

What were the basic results?

The researchers found that aldehydes (both formaldehyde and acetaldehyde) break down the BRCA2 protein.

When a person has two normal copies of the gene they are still able to produce a functional amount of the protein that repairs and maintains chromosome structure.

However, when a person only has one normal copy of the gene they are not able to produce enough of the repair protein. When the DNA replicates it then produces what are called R-loops, three-stranded nucleic acid structures. This damages the structure and stability of the chromosomes and as such could potentially lead to cancer development.

How did the researchers interpret the results?

The researchers conclude that this study raises a potential model where environmental compounds could lead to cancer development in people carrying BRCA2 mutations.

 

Conclusion

This valuable laboratory study gives a further insight into how BRCA2 mutations could lead to cancer development. Aldehydes could further reduce the amount of DNA repair protein that people with an abnormal BRCA2 gene copy are able to produce.

However, we shouldn't jump to any conclusions from this. For one thing, aldehydes are naturally present in the environment, as well as included in diverse products, from cosmetics to fossil fuel. We can't lay the blame on individual products and it's difficult to completely eradicate exposure to aldehydes.

This study alone can't inform on a safe or toxic exposure level, either for people with or for people without BRCA2 mutations.

We also can't conclude that aldehydes provide the whole answer as to why people with BRCA2 mutations are susceptible to cancer.

All of us can reduce our cancer risk by avoiding smoking, taking regular exercise, limiting consumption of red meat and alcohol and avoiding excessive exposure to sunlight.

Read more about cancer prevention.

Links To The Headlines

Chemicals in everyday items like cosmetics linked to cancer in controversial new study. The Independent, June 1 2017

Booze, shampoo and car fumes ALL ’cause cancer – and now scientists think they know why'. The Sun, June 1 2017

How chemicals in shampoo, booze and car fumes cause cancer by damaging our ability to repair faults in our genes. Daily Mail, June 2 2017

Links To Science

Tan SLW, Chadha S, Liu Y, et al. A Class of Environmental and Endogenous Toxins Induces BRCA2 Haploinsufficiency and Genome Instability. Cell. Published online June 1 2017

Cold water 'just as good as hot' for handwashing

NHS Choices - Behind the Headlines -

"Antibacterial handwash is NO better than soap – and cold water kills as many germs as hot, experts claim," The Sun reports.

These were the main findings of a study looking at various methods of handwashing.

But the researchers only tested for E.coli bacteria, a leading cause of food poisoning. And for safety reasons, they used a strain of E.coli that isn't infectious.

The study found using colder water (15C) was just as effective at getting rid of bacteria as using hot water (38C), and antibacterial soap was not significantly more effective at removing bacteria than plain soap.

It also found washing your hands for slightly longer – 30 seconds as opposed to 15 seconds – is more effective at getting rid of the bacteria.

The researchers hope their study could be used by policymakers to inform handwashing guidelines.

But the study only compared two products, and also only looked at one organism, which doesn't cause infection in humans.

Examining the effectiveness of a wider range of products against other types of infectious organisms, such as viruses and fungi, as well as other strains of bacteria, would be required before we can safely say whether cold water is just as effective as hot.

Perhaps the most useful piece of advice to come from the study is to wash your hands for 30 seconds if you want to protect yourself against food poisoning or infections like the flu.

Where did the story come from?

The study was carried out by researchers from Rutgers University and GOJO Industries, both in the US.

No external sources of funding were reported, though it should be noted that GOJO Industries produce hand soaps and sanitiser products.

The study was published in the peer-reviewed Journal of Food Protection.

The Sun, the Daily Mail and BBC News all covered the study. Their reporting was accurate.

What kind of research was this?

This experimental study aimed to assess handwashing techniques by testing the most effective soap volume, water temperature, and lather time for getting rid of harmful bacteria.

Handwashing techniques have generated interest and been a topic of debate for a long time, with particular reference to frequency, duration, and technique.

But handwashing recommendations aren't always backed by evidence. The researchers wanted to address this gap in the data.

What did the research involve?

Researchers recruited 20 volunteers from Rutgers University to take part in this study – 10 men and 10 women with an average age of 25.

Volunteers were asked not to use any type of antimicrobial soap or hand sanitisers for the full duration of the study.

Before beginning the experiment, 1ml of a strain of E.coli that doesn't cause infection in humans was added to each volunteer's hands.

The experiment evaluated four variables as part of handwashing technique:

  • lather time (5, 10, 20 and 40 seconds)
  • soap volume (0.5, 1.0 and 2.0ml)
  • water temperature (15, 26 and 38C)
  • product formulation (plain soap versus antimicrobial soap)

One variable would be changed while the other variables remained constant to study the effect of each one. Each experiment was replicated 20 times.

Volunteers were given instructions on how much soap to use (number of pumps), when to wet their hands, when to stop lathering, and when to stop rinsing.

They were asked not to dry their hands at the end of the experiment so any remaining bacteria weren't removed.

Samples were collected from the volunteers' hands immediately after they were washed.

Comparisons were then made between each handwashing technique and the number of bacteria left on the volunteers' hands after each experiment.

What were the basic results?

Overall, there were some interesting findings:

  • Using an antimicrobial soap formulation wasn't found to be significantly more effective than the plain soap at removing bacteria during any test washes. The mean reduction in bacteria for antimicrobial soap was 1.94 log colony forming units (CFU) (range: 1.83 to 2.10) whereas for the bland soap it was 2.22 log CFU (range: 1.91 to 2.54). CFU logs are a measurement of live bacteria in a sample.
  • There was no significant reduction in bacteria after handwashing between the lowest and highest water temperatures of 15C or 38C.
  • Washing for 30 seconds (20 seconds of lathering and 10 seconds rinsing) was found to significantly reduce bacterial count compared with washing for 15 seconds (10 seconds of lathering and 5 seconds rinsing) when using plain soap. Lather time didn't affect bacterial count for antimicrobial soap.
How did the researchers interpret the results?

The researchers concluded that, "The results of this study indicate that water temperature is not a critical factor for the removal of transient micro-organisms from hands.

"Overall, the length of lather time and volume of soap used did not make a large difference, but a minimum of 0.5ml of soap and 10s of lather time is recommended based on our findings.

"Understanding which behaviours, human factors, and physiological differences influence handwashing the most may allow future studies to focus on which techniques can optimise the effectiveness of handwashing and thereby reduce infection transmission risk and improve food safety." 

Conclusion

This experimental study aimed to assess handwashing techniques by testing the most effective soap volume, water temperature, and lather time for getting rid of bacteria.

Contrary to current guidelines, which recommend using hot water when we wash our hands, this study found using colder water (15C) was just as effective at getting rid of bacteria.

It also found washing your hands for longer – 30 seconds – was found to be more effective than washing for 15 seconds.

The researchers hope their study will help policymakers such as the US Food and Drug Administration (FDA) to make evidence-based recommendations around handwashing techniques.

But this was a very small study with a sample size of just 20 participants. It only compared two products: a plain soap with no specific antimicrobial ingredients and an antimicrobial soap that included 1% chloroxylenol.

A more comprehensive assessment is needed, studying many more products and organisms, before we can consider changing handwashing recommendations. 

Current guidelines recommend that we wash our hands with water and soap for at least 20 seconds:

  • after using the toilet
  • after handling raw foods like chicken, meat, and vegetables
  • before eating or handling ready to eat food
  • after having contact with animals, including pets

Read more advice about handwashing.

Links To The Headlines

Antibacterial handwash is NO better than soap – and cold water kills as many germs as hot, experts claim. The Sun, May 31 2017

Washing your hands with cool water is just as effective in killing germs as using hot water – and antibacterial soap is no better than a normal cleanser, reveals study. Daily Mail, May 31 2017

Washing hands in cold water 'as good as hot'. BBC News, June 1 2017

Links To Science

Jensen DA, Macinga DR, Shumaker DJ, et al. Quantifying the Effects of Water Temperature, Soap Volume, Lather Time, and Antimicrobial Soap as Variables in the Removal of Escherichia coli ATCC 11229 from Hands. Journal of Food Protection. Published online May 15 2017

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