"Eating more saturated fats raises risk of early death, says US study," The Guardian reports.
A major study involving more than 80,000 women would seem to contradict recent high-profile reports that a diet rich in saturated fat is safe.
The latest – a long-term study conducted in the US including more than 120,000 people – found that swapping saturated fat and / or trans fats for polyunsaturated fat such as olive oil could reduce the risk of dying by 27%.
The case for and against saturated fats, including butter and cheese, has changed with different scientific studies in recent years. A recent report, published by the Public Health Collaboration, argued that the official advice on low-fat diets was actually making the obesity epidemic worse; though the report was far from systematic, as we discussed earlier this year.
A more rigorous summary of research published in 2015 found no link between saturated fats and death.
The difference in the conclusions, say the latest researchers, could be because the previous summary of research could not say what people who ate less saturated fat ate instead. In a Western diet, they say, people who eat less saturated fat might eat more sugar or refined carbohydrates, which are known to be linked to type 2 diabetes and cardiovascular disease. This study, they say, allows researchers to calculate the effects of swapping one type of fat for another.
Overall, the study supports official dietary advice to replace saturated and trans fat with unsaturated fat.
Where did the story come from?
The study was carried out by researchers from Harvard TH Chan School of Public Health and Brigham and Women's Hospital and Harvard Medical School and was funded by the US National Institutes of Health.
The study was published in the peer-reviewed journal JAMA Internal Medicine and has been reported accurately by the UK media.
The UK media highlights the recent confusion and controversy regarding the place of saturated fats in a healthy diet; without acknowledging that much of the confusion has been driven by its own coverage.
For example, The Sun says: "Scientists have been so split in recent years over the dairy food's effect on health that consumers often don't know who to believe." But the so-called "split" is actually a small number of researchers who have argued against official advice.
There is nothing wrong with questioning received wisdom. If nobody ever did that then we would still think that the Earth is flat and at the centre of the universe.
What is misleading is when the media presents a minority opinion as a sudden sea-change in scientific consensus. Official guidelines, whether from the Department of Health, the World Health Organization, or the US Food and Drug Administration, have remained consistent about the dangers of saturated fats.
What kind of research was this?
This study combines results from two ongoing cohort studies that started in the US in the 1980s, with a combined total of 126,236 participants. The authors wanted to compare what people reported about their diets (measured around every four years) with their health records, during the three decades since the studies began.
Large, prospective cohort studies with long follow-up periods are the best ways to look at links between lifestyle factors such as diet and health, because it's impractical to do a long-term randomised controlled trial of something like diet (it would be hard to ensure someone eats the same thing every day for 30 years). However, observational studies can never prove that one factor causes another.
What did the research involve?
Researchers followed two big groups of health professionals for around 30 years. They assessed their health, lifestyle and diet at the start of the study and every two to four years. After adjusting their figures to take account of known risk factors, the researchers calculated the effect on the chances of having died from any cause, or from specific causes, of consuming different types of dietary fat.
Data came from the Nurses' Health Study (83,349 women, starting 1980) and the Health Professionals Follow-Up Study (42,884 men, starting 1986), up to 2012. Researchers calculated the effect of the total dietary fat (compared to total carbohydrate in the diet), then looked at the effect of specific dietary fats compared to carbohydrates.
Specific fats included:
- saturated fat (from red meat and dairy products)
- polyunsaturated fat (for example sunflower oil or soyabean oil) or monounsaturated fat (for example olive oil and peanut oil)
- trans fats (chemically converted fats) – most people in the UK don't eat a lot of trans fats as in recent years many UK food manufacturers have removed trans fats from their products
- omega 3 and 6 fatty acids
Finally, they calculated the effect of swapping 5% of dietary energy intake from saturated fats or trans fats with polyunsaturated or monounsaturated fats. The researchers took account of a wide range of confounding factors, including:
- body mass index (BMI)
- physical activity
- medical history
They also carried out a number of sensitivity analyses to check whether it might affect the results if people changed their diet as a result of being diagnosed with an illness.
What were the basic results?
The study found:
- People who ate more saturated fats (compared to carbohydrates) were 8% more likely to have died during the study than those who ate least saturated fats (hazard ratio (HR) 1.08, 95% confidence interval (CI) 1.03 to 1.14).
- People who ate more polyunsaturated fats or monounsaturated fats were slightly less likely to have died during the study than those who ate least unsaturated fats (HR polyunsaturated fats 0.81, 95% CI 0.78 to 0.84; HR monounsaturated fats 0.89, 95% CI 0.84 to 0.94).
- People who ate more trans fats were 13% more likely to have died during the study than those who ate least trans fats (HR 1.13, 95% CI 1.07 to 1.18).
In addition, they found that swapping 5% of energy from saturated fats with the equivalent energy from polyunsaturated fats would reduce death rates by 27% (HR 0.73, 95% CI 0.7 to 0.77). Swapping saturated fat for monounsaturated fat would also have an effect, but not as big, they found.
How did the researchers interpret the results?
Researchers said their findings showed different types of fat had different effects on health, and that "these findings support current dietary recommendations to replace saturated fat and trans-fat with unsaturated fat".
They say previous studies might have produced different findings because they didn't look at what people in studies were eating instead of saturated fat, and did not calculate the effects of swapping one type of fat for another.
It's confusing when advice about healthy eating seems to change with each study published, and the experts say different things. However, when you look closely, the two studies mentioned here do not necessarily contradict each other.
The researchers who carried out last year's summary of research warned that their conclusions might change based on future studies, and said they had "very low" confidence in the results, because of the quality of the studies that had previously been carried out. We concluded last year that the summary did not rule out the possibility that saturated fat might be harmful, and that we need to know what people should eat instead of saturated fat.
This study has several strengths. It is very big, carried out over several decades, and checked people's diet every few years, so the researchers can assess the effects of changing diet over time. The researchers also adjusted their figures to take account of confounding factors. By calculating the possible effects of saturated and unsaturated fat compared to carbohydrate, it allows the researchers to calculate the effects of swapping one type of fat for another.
The findings about trans-fats are unsurprising and not controversial. These artificially created fats, used in baked goods, are being phased out because of their effects on health.
Cohort studies can never prove causality beyond doubt, so we cannot say that this shows saturated fat causes earlier deaths. However, the study does provide evidence that different types of fats have different effects on health, and swapping to healthier fats may be preferable.
Links To The Headlines
Eating more saturated fats raises risk of early death, says US study. The Guardian, July 6 2016
Fat may be less harmful than previously thought, but it's still not a 'health food'. The Daily Telegraph, July 6 2016
Links To Science
Wang DD, Li Y, Chiuve SE, et al. Association of Specific Dietary Fats With Total and Cause-Specific Mortality. JAMA Internal Medicine. Published online July 5 2016
A guide to getting active if you have an impairment or a long-term health condition.
This guide will help you:
The Government recommends doing at least 150 minutes of activity a week as well as strength exercises on two or more days a week.
But don't worry about hitting these targets straight away: every little helps. What's more important is choosing an activity you enjoy.
The easiest way to increase your activity levels is to build activity into the things you do every day, like going to work, shopping and seeing friends.
Tips to build activity into your day:
- walk or ride part of your journey to work or the shops
- get off a bus or tube stop before your destination
- if you drive, park further away from your office and walk or ride the rest of the way
- go for a walk or a ride with your friend rather than meeting for coffee
- exercise before or after work, or during your lunch break.
- lots of gardening can provide a good workout
- exercise in front of the TV
- try an online video workout
Some charities have their own workouts online, for example the Multiple Sclerosis Society.
Find an inclusive gym on the English Federation of Disability Sport (EFDS) website.
Use the EFDS event finder to find an activity in your area.
Browse through activities on the BBC's Get Inspired section.
Get into Paralympic sports
Find a sport based on your impairment and find a club near you using the Parasport website.
Most sports organisations actively encourage disabled people to get involved. The list of organisations below is by no means exhaustive.Sport-specific organisations
The British Disabled Angling Association supports disabled people of all ages and abilities to get into fishing in the UK.
The British Wheelchair Archery Association supports archers with all impairments from grassroots to elite level with expert advice and coaching.
If you're looking to start in athletics, Parallel Success offers great opportunities for disabled athletes.
England Badminton Players Association for Disabled aims to get more disabled people into badminton at any standard or level.
Boccia England is responsible for all aspects of the sport, from beginner to expert, providing for all levels of participation.
Disability Bowls England aims to be the first port of call for anyone with a disability looking to get into bowls.
Organisations working to boost participation in cricket include the English Cricket Board, the Cricket Federation for People with Disabilities and the England Cricket Association for the Deaf.
Organisations helping disabled people get into cycling include Cycling UK, Hand Cycling UK and Companion Cycling.
If you enjoy dancing for fun or to stay active, find a disability dance class near you with the Wheelchair Dance Sport Association.
Find out where you can play disability football near you using the Football Association's Play Football section and the Disability football directory.
Find out how to get into sledge hockey with the British Sledge Hockey Association.
Look up clubs and find out more about getting into disabled fencing with the British Disabled Fencing Association.
Visit Goalball UK to find out more about the sport and how to get involved.
Golf organisations supporting and promoting disability golf are listed on England Golf's disability section.
Find an accessible gymnastics club near you using the British Gymnastics website.
Find a riding group near you using the Riding for the Disabled Association.
Find a club near you using the English Karate Federation website.
Find out how to get into adaptive rowing at British Rowing.
Find an accessible sailing venue near you using the Royal Yachting Association website.
Look up accessible shooting clubs on the Disabled Shooting Project website.
Find a local ski group, book lessons and find skiing activities near you at Disability Snowsports UK.
Strength and flex
Improve your strength and flexibility with this five-week exercise plan. Not adapted for wheelchair users.
Find a swimming pool near you with disability access and local disability swimming clubs at Swimming.org.
Table Tennis England works to increase the numbers of disabled people participating in table tennis.
Find out about how to take part in tennis if you have a disability with the Tennis Foundation.
Find a sitting volleyball centre near you using the Volleyball England website.
Several websites provide information about local walking groups for the disabled, such as Disabled Ramblers and Walking for health.
Find a club near you and all you need to know about wheelchair basketball with British Wheelchair Basketball.
If you want to give wheelchair rugby a try, find your local club on the GB Wheelchair Rugby website.
Back Up – supporting people with spinal cord injury
LimbPower – supporting amputees and people with limb impairments to reach their sporting potential
Mencap Sport – supporting people with a learning difficulty
Metro – London-focused resource for blind and partially sighted people
Special Olympics GB – supporting people with learning disabilities
WheelPower – supporting wheelchair sport
"Pasta DOESN'T make you fat – it actually helps weight loss," the Daily Mail reports. In the latest round of the nutrition wars, carbs are fighting back, with a study showing that a diet rich in pasta was linked to lower body mass index (BMI).
The researchers used survey data and body measurements taken from over 23,000 Italian adults and found that pasta, as part of a healthy Mediterranean diet, is associated with lower BMI and smaller waist circumference and waist-to-hip ratio.
The researchers speculate that healthy amounts of pasta may make people feel fuller so they are less likely to stray or snack outside their recommended diet.
Before we reach for the rigatoni, it is important to note the study's limitations.
The researchers attempted to adjust variables that might be responsible for the link, such as the level of physical activity, however this is always an educated guess. Also, as this was an entirely Italian-born, white population we don't know if similar findings would be seen in other populations.
Overall this study tells us that eating pasta as part of a nutritious Mediterranean diet may be a good way to maintain a healthy weight and shape.
Despite frequent media claims to the contrary, there is no such thing as a magic food type – be it carbs, fats or proteins – that will make or keep you thin.
How much you eat, in terms of calories, is far more important than what you eat, when it comes to preventing obesity.
Where did the story come from?
The study was carried out by researchers from the Istituto Neurologico Mediterraneo Neuromed in Italy.
Funding for the Moli-sani study was provided by the Pfizer Foundation, the Italian Ministry of University and Research-Programma Triennale di Ricerca, and Instrumentation Laboratory. While funding for the INHES study was provided by Barilla and by the Italian Ministry of Economic Development.
While many newspapers highlighted the fact that this was an Italian study (Italy being the land of pasta) there were no conflicts of interest reported.
This story has been reported enthusiastically in the media, however stating that pasta can make you slim is a step too far. Many reports have mentioned that carbohydrates have been demonised in recent times (mainly by the same newspapers now reporting this study) and it is important to reassure that they can be enjoyed as part of a healthy balanced diet.
What kind of research was this?
This was an analysis of two cohort studies that aimed to assess the link between pasta intake and body mass index (BMI) and waist-to-hip ratio.
The researchers used data from two large Italian cohorts to further investigate the Mediterranean diet as a model for healthy eating. Pasta is a popular component of the diet, but as it has not been studied in detail the team wanted to investigate further.
What did the research involve?
The researchers used data from two large cohorts to investigate the association between pasta intake and BMI and waist to hip ratio.
The Moli-sani study recruited participants between March 2005 and April 2010 from the Molise region in Italy. Participants were required to complete a food frequency questionnaire adapted for an Italian population. The questionnaire was used to determine their nutritional intake during the previous year. They only included white people born in Italy, and excluded those with incomplete medical or dietary questionnaires and those on a special diet.
The Italian Nutrition and Health Survey (INHES) was a telephone-based survey that took place between November 2010 and November 2013. The survey was designed to collect information on dietary habits and participants reported on their food and drink consumption in the previous 24 hours using computer software.
Data collected from the surveys was used to analyse pasta consumption (calculated as grams per day and grams/kcal of total daily energy intake), as well as adherence to a Mediterranean diet (on a score from 0 (low) to 11 (high)). The researchers also collected information on socioeconomic status and level of physical activity. Bodyweight, height and waist/hip circumference were measured in the Moli-sani population and self-reported in the INHES population.
Statistical modelling was used to evaluate the link between pasta consumption and BMI and waist-to-hip ratio, adjusting for potential confounders.
What were the basic results?
A total of 14,402 adults (35 years and over) were included from the Moli-sani cohort and 8,964 from the INHES study (18 years and over).
Analyses in the Moli-sani population found that increased pasta consumption was associated with increased BMI. Pasta consumption was also associated with greater adherence to the Mediterranean diet. When the analysis was adjusted for possible confounders, including the greater Mediterranean diet adherence, the association changed direction and greater pasta intake was linked with reduced BMI.
In the INHES study, consuming higher quantities of pasta was associated with higher BMI in women, but not in men. However, similarly adjusting for confounders reversed the link.
In the Moli-sani study, higher quantities of pasta were associated with smaller waist and hip circumference and waist-to-hip ratio in both genders.
How did the researchers interpret the results?
The researchers conclude: "As a traditional component of MeD [Mediterranean diet], pasta consumption was negatively associated with BMI, waist circumference and waist-to-hip ratio and with a lower prevalence of overweight and obesity."
This analysis of data collected from two Italian cohorts has assessed the link between pasta intake, BMI and waist-to-hip ratio.
It seemed initially that higher pasta consumption was associated with higher BMI – as may be expected. However, when you took into account this being a component of a Mediterranean diet, the link reversed and it was associated with lower BMI, smaller waist and hip circumference and waist-to-hip ratio.
While these findings sound great it is important to consider the limitations of the research.
- The population being considered are from Italy and were mainly Caucasian, so we don't know if similar findings would be seen in other populations. This is an important limitation – particularly given that adherence to the Mediterranean diet seemed to have a significant influence on the effect of pasta intake on BMI. Higher intakes of vegetables, olive oil, lean meat and fish may be contributing to the healthier bodyweight – not just the pasta.
- There were a large number of potential participants in the Moli-sani study who were excluded due to incomplete medical or dietary questionnaires – over 2,000 people. Depending on their consumption and body measurements, this may affect findings.
- The researchers attempted to adjust for possible confounders, such as physical activity and energy intake, however this will never be perfect. Residual confounding could still be having an effect and may be responsible for the negative association seen.
- Self-reported data – as is the case with all food frequency assessments – is always subject to bias. In the INHES study, participants were also asked to measure their own bodyweight and height, which may not have been accurate.
The study does have strengths in its large sample size and the careful analysis that aimed to adjust for potential sources of error, such as the possible bias from underreporting of energy intake.
Overall this study tells us that eating pasta as part of a nutritious Mediterranean diet may be a good way to maintain a healthy bodyweight and waist-to-hip ratio. That being said, when it comes to diet the best approach is to consume energy-dense products, such as pasta, in moderation.
Read more advice about eating a balanced diet.
Links To The Headlines
Pasta DOESN'T make you fat - it actually helps weight loss, (Italian) researchers claim. Daily Mail, July 4 2016
Pasta does not make you gain weight, according to (Italian) scientists. The Independent, July 5 2016
Eating pasta helps you lose weight, says Italian study. The Daily Telegraph, July 4 2016
Eating this one (very surprising) food could make you thinner. Daily Mirror, July 4 2016
GREAT NEWS, SPAG BOL FANS! Pasta can actually help you LOSE weight… not put it on. The Sun, July 4 2016
Pasta makes you slim, say (Italian) scientists. The Times, July 5 2016 (subscription required)
Links To Science
Pounis G, Di Castelnuovo A, Costanzo S, et al. Association of pasta consumption with body mass index and waist-to-hip ratio: results from Moli-sani and INHES studies. Nutrition & Diabetes. Published online July 4 2016
"Women who take paracetamol during pregnancy 'risk having a child with autism or ADHD'," the Mail Online reports. But the Spanish study it reports on provides no evidence of a direct link to either condition.
Researchers assessed paracetamol use in more than 2,000 pregnant women, and then performed various developmental and behavioural tests on the children at the ages of one and five.
However, there was no link with full diagnostic criteria for attention deficit hyperactivity disorder (ADHD) or autism symptoms in all children. Nor was there any link with development or intellect.
Importantly, the study cannot prove using paracetamol in pregnancy caused these symptoms.
The causes of both conditions are poorly understood and may involve many hereditary, health and environmental influences, which this study has not been able to account for.
For example, the study did not assess whether the women smoked in pregnancy, and also did not take the child's secondhand smoke exposure into account.
Smoking has been linked to both conditions – though, as with this study, the link is unproven – so this seems an odd oversight.
The current viewpoint is occasionally using paracetamol as needed, and at recommended doses, is safe during pregnancy. This study alone is unlikely to have provided sufficient evidence to the contrary to change this.
Where did the story come from?
The study was carried out by researchers from various institutions in Spain, including Hospital del Mar Medical Research Institute and Universitat Pompeu Fabra.
It received funding from multiple sources, including the Instituto de Salud Carlos III and the Spanish Ministry of Health. The authors declared that they had no conflicts of interest.
The Mail, The Times and The Daily Telegraph are all guilty of publishing headlines that could cause women undue alarm. This study did not prove there is a link between women using paracetamol in pregnancy and autism or ADHD.What kind of research was this?
This population-based Spanish cohort study aimed to see whether using paracetamol during pregnancy is associated with any neurodevelopmental or behavioural outcomes in the child up to the age of five.
As the researchers say, paracetamol is widely used during pregnancy, but some studies have linked it with adverse outcomes in the child.
Attention deficit hyperactivity disorder (ADHD) and autism spectrum disorders (ASD) have increased in prevalence over the years.
No cause has been definitively established for these conditions, but it has been speculated various environmental factors may play a role.
The researchers wanted to see if there could be a link between maternal paracetamol use and ADHD or ASD in their children.
The main limitation of cohort studies is they can demonstrate an association between an exposure and an outcome, but can't prove cause and effect.What did the research involve?
This study used the INfancia y Medio Ambiente (INMA) birth cohort, which recruited 2,644 expectant mothers from four different regions in Spain between 2004 and 2008.
The mothers were interviewed at 12 and 32 weeks of pregnancy, when they were asked whether they had taken any medication (sporadically or continuously) since a month before becoming pregnant or during the pregnancy.
If they answered yes, they were then asked about the specific medication, dose and frequency of use.
Women were classed as paracetamol users if they'd used any paracetamol from one month before pregnancy to up to 32 weeks.
More than 80% of children were available for assessment between the ages of one and five years.
At one year of age they were assessed using the Bayley Scales of Infant Development (BSID). They were tested again at the age of five.
The tests included:
- McCarthy Scales of Children's Abilities (MCSA) – to assess cognitive and psychomotor development
- California Preschool Social Competence Scale (CPSCS) – to assess social competence
- Childhood Autism Spectrum Test (CAST)
- Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for ADHD symptoms
- Conner's Kiddie Continuous Performance Test (K-CPT) – a computerised test to look at attention, reaction time, accuracy and impulse control
The researchers took various confounders into account in their analyses, such as:
- child gender
- mother's health
- social class
- educational level
The researchers did not look at maternal smoking habits.What were the basic results?
Overall, around 42% of children had been exposed to paracetamol during pregnancy, with pain relief being the mothers' main reason for use.
Children exposed to paracetamol were more likely to have hyperactivity and impulse symptoms on ADHD criteria than non-exposed children – a link that only just reached statistical significance (rate ratio 1.41, 95% confidence interval 1.01 to 1.98).
Paracetamol use was also associated with more of certain types of errors on the Kiddie Continuous Performance Test. Higher paracetamol use was linked with more symptoms.
There was, however, no significant link with meeting ADHD criteria overall, or with inattention symptoms specifically.
Nor was there any link with Childhood Autism Spectrum Test results overall for all children, though the researchers did find paracetamol use was significantly linked with ASD symptoms in boys specifically. There was also no clear link with ASD symptoms for girls.
There was no link with neurodevelopmental outcomes on the Bayley Scales of Infant Development (BSID) at age one, or the McCarthy Scales of Children's Abilities (MCSA) at age five.How did the researchers interpret the results?
The researchers say being exposed to paracetamol during pregnancy was associated with a greater number of autism symptoms in boys, and more ADHD-related symptoms in both genders.
They also say how these associations seem to be dependent on the frequency of exposure.Conclusion
This birth cohort study found some significant links between using paracetamol in pregnancy and hyperactivity or impulse symptoms at the age of five and ASD symptoms in boys.
However, this research cannot prove paracetamol use is directly responsible for these findings.
Not all links were statistically significant – for example, paracetamol was not linked with ADHD when looking at full diagnostic criteria, or with ASD when looking at the full sample of children.
It is possible the significant links identified may not be true causative links and would not be replicated if another birth cohort was used.
The researchers have tried to take account of various confounders, but given that the causes of ADHD and ASD are not clearly established, it is difficult to take account of all the hereditary, health and environmental factors that could have an influence.
And some notable factors are missing – for example, the mother's alcohol consumption, or whether or not she or anyone else in the home smoked during pregnancy or in the child's younger years – and do not appear to have been assessed.
Although the researchers have tried to look at frequency of use, they couldn't assess the effects of different paracetamol doses due to mothers' difficulties recalling the exact dose taken. This would have been useful to assess, especially with regards to potential future guidance.
Assessments of frequency of use highlight the need for caution when taking these statistical links at face value.
Despite the large initial sample size, the smaller sample sizes decrease the reliability of these links when further broken down into frequency of use – for example, less than 50 women reported persistent use of paracetamol.
And the smaller the sample size, the greater the possibility that the results have been affected by chance.
There were also only two assessments carried out at one and five years of age. Longer term and more regular follow-up of the children may have given a better indication of whether these assessments truly indicated more persistent behavioural and social difficulties.
Importantly, no link was found with developmental or intellectual outcomes in the child.
Overall, the link is worthy of further investigation, but does not prove that paracetamol use during pregnancy could cause ADHD or autism symptoms.
The current viewpoint is that occasionally using paracetamol as needed, and at recommended doses, is safe during pregnancy. This study has not provided sufficient evidence to the contrary to change this advice.
If you are experiencing chronic pain and feel the need to take painkillers frequently during your pregnancy, you should speak to your GP or midwife about alternative treatment options.
Links To The Headlines
Women who take paracetamol during pregnancy 'risk having a child with autism or ADHD'. Mail Online, July 1 2016
Paracetamol in pregnancy may be linked to autism. The Daily Telegraph, July 1 2016
Paracetamol during pregnancy linked to autism. The Times (subscription required), July 2 2016
Links To Science
Avella-Garcia CB, Julvez J, Fortuny J, et al. Acetaminophen use in pregnancy and neurodevelopment: attention function and autism spectrum symptoms. International Journal of Epidemiology. Published online June 28 2016
"More women think shaving pubic hair is 'hygenic' [sic] despite greater health risks," The Independent reports.
A US survey found more than half of women who groomed their public hair did so for hygiene reasons, despite evidence that shaving pubic hair can make the vagina more vulnerable to irritation and infection.
The online survey involved more than 3,000 US women. It asked them about their grooming habits, the reasons they shaved (if they did), as well as factors such as their race, income and relationships.
A key finding was that 59% of women who reported grooming their pubic region said they did so because they thought it would make their vagina "cleaner" or "more hygienic".
However, like most things we have on the body, pubic hair does have a purpose. It acts as a barrier, protecting against potentially harmful bacteria and viruses entering the body. And the regular act of shaving can lead to skin irritation and damage.
While you may decide to shave your public hair for aesthetic reasons, you should be aware that there are no health benefits, with the exception of preventing pubic lice, now uncommon in England.
These warnings aside, the survey did not look at the impact of pubic grooming on sexual or vaginal health, so no firm conclusions can be drawn.Where did the story come from?
The study was carried out by researchers from the University of California, San Francisco and was funded by a grant from the US National Institutes of Health.
The Independent's reporting was broadly accurate, despite the typo in the headline ("hygenic").
The Mail Online's coverage of this study was also generally accurate. However, the headline, which links shaving to sexually transmitted infections (STIs), was based on comments made by one of the researchers about their previous work, rather than the findings of this particular study.What kind of research was this?
This cross-sectional study aimed to characterise current pubic hair grooming practices in the US.
Pubic hair grooming is a prevalent modern practice in the developed world, thought to have become widespread in the late 1990s, being popularised by TV shows of the time, such as Sex and the City.
Some feminist critics have argued that the trend has been driven by pornography, where shaved actors are the norm, rather than for any legitimate health reasons.
Cross-sectional studies are useful for investigating the incidence and prevalence of lifestyle behaviours or disease, but are unable to confirm cause and effect between an exposure and outcome.
For example, in this case it would be the idea that pubic hair grooming leaves you at increased risk of developing an STI. Many other factors are likely to be at play, however.
A prospective cohort study would be one of the best ways to validate these findings.What did the research involve?
The researchers surveyed 3,372 women between the ages of 18 and 65 residing in the US. The participants were broadly representative in terms of age and racial diversity.
The questionnaire asked about demographic characteristics (age, race, educational level, method of grooming); motivation behind grooming (who do you groom for? why do you groom? preference about ideal hairiness); and frequency (how often they groom).
Of the women who completed the questionnaire, 3,316 women were included in the analysis. Differences in characteristics between groomers and non-groomers were explored.
The data was then analysed to see which factors had the greatest influence for grooming. Potential confounders were controlled for.What were the basic results?
Overall, 83.8% of women reported a history of pubic hair grooming, and 16.2% reported having no history of pubic grooming. The mean frequency was monthly.
Common motivations for grooming included for hygiene purposes (59%), being part of their routine (46%), and partner preference (21%).
When asked about the situations for which they groom, common reasons were for sex (56%), holidays (46%), and visits to the doctor (40%).
During further analysis, significant links to grooming were found:
- older women aged above 45-55 years were less likely to report grooming compared with women aged 18-24 (odds ratio [OR] 0.05, 95% confidence interval [CI] 0.01 to 0.49)
- women with a bachelor's degree (OR 2.39, 95% CI: 1.17 to 4.88) or some college education (OR 3.36, 95% CI 1.65 to 6.84) were more likely to report grooming than those with less than high school education
- white women were more likely to report grooming than black or Hispanic women
- women who groomed had twice the mean number of lifetime partners compared with those who did not groom (9.0 versus 4.4 respectively)
- no association was found between grooming and income, relationship status or geographical location
The researchers conclude: "Overall, the prevalence of pubic hair grooming in women is substantial.
"We found many factors associated with pubic hair grooming, including age, race, educational level, and the number of lifetime partners."Conclusion
This study aimed to characterise current pubic hair grooming practices in the US. It found that race, age, educational level and the number of lifetime partners were associated with grooming.
The study had a large sample size, which was nationally representative and therefore generalisable to the US population of women.
However, cross-sectional studies like this one are unable to confirm a causal link between grooming practices and sexual health, as reported in the media. We cannot know the exact reasons why women choose to employ certain grooming practices.
The analysis also only looked at women – results may be very different among men. And we also don't know whether these findings are representative of women in the UK.
This survey is sensitive in nature, and some participants may not have felt comfortable answering questions about their grooming practices and sexual relations, which may have introduced some reporting bias.
This study provides a useful database revealing the common pubic grooming habits of women in the US. The researchers hope this study can inform healthcare professionals so they can offer advice about the risks of pubic grooming.
One of the researchers, Dr Benjamin Breyer, told the media: "We believe grooming practices are also associated with personal injury and potentially sexually transmitted infection.
"We're analysing these associations in the hope of finding risk factors that can be modified, such as instrument use."
It would be useful if women who do choose to shave received evidence-based advice about the safest ways to do so.
Links To The Headlines
More women think shaving pubic hair is 'hygenic' despite greater health risks. The Independent, July 1 2016
Most Women Prefer to Go Bare, Citing Hygiene (and Baffling Doctors). The New York Times, June 29 2016
Links To Science
Rowen T, Gaither TW, Awad MA, et al. Pubic Hair Grooming Prevalence and Motivation Among Women in the United States. JAMA Dermatology. Published online June 29 2016