“Today's adults are so unhealthy they are 15 years 'older' than their parents and grandparents at the same age,” reports The Daily Telegraph. This gloomy message is based on a study that found that despite a continuing trend of increasing life expectancy, overall, the adult population is less healthy than it used to be in the past.

Researchers drew these conclusions after comparing the prevalence of risk factors for stroke, heart disease and diabetes within different generations.

It found that more recently born generations had at a similar age a higher prevalence of obesity and high blood pressure than those born 10 years earlier. Diabetes was also more prevalent among younger men, at the same age.

The good news is that the prevalence of high cholesterol did not change – possibly thanks to the development of successful treatments, such as statins.

Researchers remain unclear why the number of deaths from heart disease is falling despite poorer health. Important factors could include a reduction in smoking, as well as improved treatments.

The message from this study is undeniable: it is never too soon to take up a healthy lifestyle, including a balanced diet and plenty of exercise.

 

Where did the story come from?

The study was carried out by researchers from the National Institute for Public Health and the Environment, and University Medical Center Utrecht, both in the Netherlands. It was funded by the Ministry of Health, Welfare and Sport of the Netherlands and the National Institute for Public Health and the Environment.

The study was published in the peer-reviewed European Journal of Preventive Cardiology.

It was reported fairly in the media, although both the Telegraph’s and the Daily Mail’s claim that today’s adults are ‘older’ than previous generations is not a particularly sensible, useful or accurate comparison.

There is currently no direct linear association between age and health, and people in their seventies can be as healthy as those in their thirties.

 

What kind of research was this?

This was a cohort study that followed more than 6,000 adults, who were between the ages of 20 and 59 years at baseline, over a period of 16 years.

It aimed to find out if there were any ‘generational shifts’ in the prevalence of ‘metabolic risk factors’ that increase the chance of developing heart disease, stroke, diabetes and some other health problems.

They include:

• being overweight or obese
• high cholesterol and/or having low levels of ‘good’ HDL cholesterol
• high blood pressure
• high blood sugar, which can increase the risk of developing diabetes

The authors point out that the health of elderly people in the future is partly determined by their exposure to such risk factors over their lifetime. But little attention has been paid to whether or not there are differences in levels of risk factors between the younger and older adult generations.

 

What did the research involve?

The researchers used data from a cohort study that began in 1987-1991 and followed up participants after six, 11 and 16 years.

Participants were randomly selected from civil registries of Doetinchem, a small town in the Netherlands, and were aged 20 to 59 years. After the initial visit (wave one) they were invited back in three further ‘waves’ - six, 11 and 16 years later. This resulted in:

• a total of 6,308 people in wave one
• 6,070 in wave two
• 4,898 in wave three 
• 4,517 in wave four

The researchers categorised people by ‘generations’ (10-year age groups) of 20-29 year olds, 30-39 year olds, 40-49 year olds and 50-59 year olds.

At each visit trained staff measured each participant for the metabolic risk factors mentioned above (with the exception of blood sugar levels). They also completed questionnaires on medical history, use of medication and lifestyle. Body weight and height were also measured and used to calculate body mass index (BMI).

Type 2 diabetes was self reported but usually supported by professional verification. Socioeconomic status was determined by highest level of completed education.

Researchers then analysed their results to find out if one generation had a different risk profile from one born 10 years earlier.

 

What were the basic results?

The results showed that the prevalence of overweight, obesity and high blood pressure increased with age in all generations, as to be expected. But in general, more recently born generations had, at a similar age, a higher prevalence of these risk factors than generations born 10 years earlier.

‘Unfavourable generation shifts’ were most pronounced for overweight or obesity, and were present in men between every generation. For example, 40% of men in their 30s at baseline were overweight. 11 years later (wave three), 52% of men in their 30s were overweight.

In women, these unfavourable changes in weight were only evident between the most recently born generations, in which the prevalence of obesity doubled in just 10 years.

Other findings from the study included:

• Unfavourable generation shifts in high blood pressure between every consecutive generation (except for the two most recently born generations of men).
• Unfavourable generation shifts in diabetes between three of the four generations of men, but not of women.
• No generation shifts for high cholesterol. Favourable shifts in ‘good’ HDL cholesterol were only observed between the oldest two generations.

In general, the pattern of generation shifts did not differ according to socioeconomic status, as they all worsened over time. The proportion of people in poorer socioeconomic groups with risk factors was, however, greater than the proportion with risk factors in the higher groups.

 

How did the researchers interpret the results?

The authors say that overall, based on increases in the prevalence of unhealthy weight and high blood pressure at younger age, "the more recently born adult generations are doing worse than their predecessors". Evidence to explain the changes is not clear, they add, but they note studies reporting an increase in physical inactivity.

In an accompanying press release, the lead author, Gerben Hulsegge, said that in terms of the findings on obesity: "The prevalence of obesity in our youngest generation of men and women at the mean age of 40 is similar to that of our oldest generation at the mean age of 55. This means that this younger generation is '15 years ahead' of the older generation and will be exposed to their obesity for a longer time."

He also argued that while reduction in smoking and improved healthcare have led to greater life expectancy, the current trends in obesity mean that "the rate of increase in life expectancy may well slow down".

 

Conclusion

This cohort study’s strength was its long follow-up period, with four measurements of risk factors taken over a period of 16 years. By following up people over time a cohort study such as this is able to track risk factors in the same people over extended periods. As long as people return for the follow-up checks, it is the best study design for tracking this sort of data and drawing the sorts of conclusions these authors make.

Another advantage is that the same group of trained workers objectively measured data on body weight, height, blood pressure and cholesterol, using standardised protocols, which reduced the chances of measurement errors.

However, it had some limitations:

• The study was based on data from people living in one town in the Netherlands and the results may not be generalisable to other populations.
• Although response rates during follow-up were good, those who dropped out before the end were more often lower educated and smokers, and were more likely to have certain risk factors, which could affect reliability of the results.
• The researchers recorded smoking at baseline (ranging from 25 to 40% among the men and women recruited) but did not report if this was measured at follow-up visits or how this has changed over the years. This appears to be an opportunity missed as it is well understood in existing research that these risk factors are often seen together.

Still, the study’s results support an important health message about establishing the need for a healthy body weight at a young age, although increased physical activity and a balanced diet should be encouraged at all ages.

Read more about exercise and healthy eating.

 

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

Today's adults 15 years 'older' than parents. The Daily Telegraph, April 10 2013

Why 30 is really 45: We're so unhealthy that we're 15 years older than our parents were at the same age. Mail Online, April 10 2013

Old before their time: Britons now ageing quicker than their parents. The Independent, April 11 2013

Links To Science

Hulsegge G, Susan H, Picavet J , et al. Today's adult generations are less healthy than their predecessors: generation shifts in metabolic risk factors: the Doetinchem Cohort Study. European Journal of Preventive Cardiology. Published online April 10 2013

“Couch potatoes can't help being lazy – they were born that way,” claims the Mail Online website. 

As this is such a sweeping statement, it may be a surprise to readers that the science behind this headline was based entirely on rats and involved no human participants or gyms.

Researchers bred two distinct groups consisting of ‘lazy rats’ (rats that showed little to no interest in running in a wheel) and ‘active rats’ (rats that appeared to be highly motivated to run).

At the end of the 10-generation breeding programme, a series of tests was run to see if there were significant genetic differences between the two groups.

The researchers did find a number of genetic differences. However, in the main, the results were mostly inconclusive and did not shed much light on the potential biological causes for the differences in rats, let alone humans.

Even if the results were more ‘earth shattering’, an obvious limitation is that humans are vastly different to rats. Reasons for someone choosing to exercise is unlikely to be purely down to their genes.

So the immediate implications to humans are minimal. The headline is speculative and not supported by the research in question.

 

Where did the story come from?

The study was carried out by researchers from the University of Missouri (US) and was funded by a grant from the College of Veterinary Medicine at the University of Missouri and funds from the College of Veterinary Medicine’s Development Office.

The study was published in the peer-reviewed American Journal of Physiology.

The Mail’s reporting of this study was largely speculative and the implications to humans overstated. This was a relatively inconclusive rat-based study that was presented in the headlines as a relatively conclusive study of immediate relevance to humans. This isn’t the case in reality.

While the research is of some value – it at least proves that it is possible to selectively breed ‘lazy rats’ – it was not conclusive and its immediate practical relevance to humans is minimal. 

The headlines claiming “Couch potatoes can't help being lazy – they were born that way” and “genes play major role in deciding whether we enjoy a trip to the gym or not” are not backed up by the science behind it.

 

What kind of research was this?

This was an animal-based study examining the characteristics of rats that had been selectively bred to show high and low levels of voluntary running behaviour.

Rats with vastly different voluntary running behaviour were used to mimic the human condition whereby increasingly large swathes of the population are voluntarily inactive, while some remain very active.

As the study involved running voluntarily, the researchers hoped it may give clues to the origins of motivation to exercise.

Rat studies are often used, as the short lifespan of a rat means researchers can selectively breed a characteristic of interest (e.g. high voluntary running activity) in a relatively short space of time.

This allows researchers to mimic equivalent human evolutionary pressures, such as the shift from most people being physically active for much of the day to a more sedentary lifestyle. The equivalent study in humans would take decades, or possibly even hundreds of years.

Both rats and humans are mammals, so findings in rats usually give a sense of what might be happening in humans and forms the basis of further theories and explanations. But there is no guarantee that what is found in rats will be found in humans and this is why studies on humans are important.

 

What did the research involve?

The researchers started with 159 rats. When they were adults (28 days old) they were introduced to running wheels and the distance they ran voluntarily was monitored for six days.

After this period the 26 rats (13 males and 13 females) with the highest voluntary average running distances were separated from the rest and allowed to mate. This was repeated for 10 generations and subsequently selecting the top 26 voluntary runners in each generation.

Similarly, at the other end of the spectrum the 26 lowest voluntary runners were also selectively bred in the same way for 10 generations.

This ultimately led to two distinct, selectively bred groups of rats – ‘active rats’ and ‘lazy rats’

At the end of this process the researchers analysed aspects of the active rats and compared them with the lazy rats in an attempt to uncover what lay behind the differences in voluntary running characteristics. Factors that were studied included:

• muscle characteristics in the hind limbs (the main muscles the rats use for running)
• body fat and muscle composition
• the way genes were switched on and off (gene expression) in the nucleus accumbens: a part of the brain thought to be associated with reward, motivating activities (e.g. running), as well as addictive behaviour such as drug addiction
• gene expression in the muscles

The main analysis compared the characteristics between the active and lazy groups.

 

What were the basic results?

After 10 generations of breeding, the voluntary running distances (measured as an average distance on days five and six of a six-day running window) were 8.5 times greater in male active rats than male lazy rats (9.3km vs 1.1km, p<0.001). The difference in female rats was 11.0 times greater (15.4km vs 1.4km, p<0.001).

The active rats also ran faster and for significantly longer for both sexes.

The researchers thought physical inactivity might be a result of larger body weights causing the rats to exercise less. However, they actually found running patterns were not related to differences in body weight.

No differences were found for the amount of food eaten, body fat percentage or weight gained between the two groups. This may appear slightly odd as one might expect the runners to eat more to balance the energy expenditure of running, or to be thinner if they didn’t eat more.

No significant differences in hind limb muscle characteristics were observed between the groups.

The analysis of gene expression in the brain uncovered eight gene transcripts that were expressed differently between the groups (that is, having a greater than a 1.5-fold difference).

The top differences were related to genes the researchers described as involved in “cell morphology, cell death and survival, dermatological diseases and conditions” as well as “nervous system development and function, cell signalling, and molecular transport”. They did not go into further detail.

 

How did the researchers interpret the results?

The researchers concluded that their selectively bred rats “can potentially be used to further study low motivation for voluntary running and any other phenotype [characteristic] co-selected along with this trait”.

The researchers discussed the possibility that certain brain signalling pathways may explain some of the reasons behind differences in voluntary exercise, but these were largely speculative.

They highlighted their finding that “increased fat mass alone was not a factor driving lower voluntary running distances”, as previous research had suggested a causal link between having more fat and being less inclined to exercise. This was in addition to the stronger relationship in the other direction, that is, less active people have more fat as a result.

 

Conclusion

This small study provides future animal researchers with a unique and interesting group of rats to study genetic factors behind differences in levels of voluntary exercise. Through selective breeding, the researchers produced a group of rats that were highly motivated to run and another group that were not. The current study did not shed much light on the potential biological causes for the differences in voluntary exercise behaviour, but did provide a solid base for their study in the future – in rats at least.

The findings in these selectively bred rats have limited immediate relevance to humans. However, further research into the genetic basis of motivation to exercise based on this preliminary work may potentially lead to implications for humans, although this is likely to be a long way off.

The research findings themselves are very limited in telling us any reasons for the differences in the high and low running groups. However, they did observe a small selection of genetic differences that could provide a rough clue as to what was different in the two groups.

These genetic differences require a lot more research to confirm if they are indeed involved or important in exercise motivation in rats. Yet more studies would then be needed to see if similar genetic factors were present or important in humans. There is no guarantee that the differences found in rats will be found in humans – humans have to be studied directly to be sure.

The reasons why someone chooses to exercise or not is unlikely to be entirely down to their genetic make-up. It is likely that there are a wide range of underlying factors including cultural and psychological, as well as individual circumstances.

While this research may of be of interest to animal behaviourists and the like, its immediate implications to humans are minimal and were overstated by the media.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

Couch potatoes can't help being lazy – they were born that way. Mail Online, April 9 2013

 

Links To Science

Roberts MD, Brown JD, Company JM, et al. Phenotypic And Molecular Differences Between Rats Selectively-Bred To Voluntarily Run High Versus Low Nightly Distances. American Journal of Physiology. Published online April 3 2013

"The Cuban diet – eat less, exercise more – and preventable deaths are halved," is the advice in The Independent.

This is not a new Latin diet and dance fad, but news based on research into how Cuba’s rollercoaster economic history has affected the health of the Cuban people.

During the early 1990s, Cuba suffered an economic downturn due to a tight US embargo on imports and the collapse of the Soviet Union, which had been supporting the country.

This led to a drop in the number of calories consumed in the average Cuban diet. Due to the embargo, petrol became virtually unobtainable, and more than 1 million bicycles were distributed by the government, leading to an increase in physical activity.

These factors contributed to an average weight reduction per citizen of 5.5kg over the course of the five-year economic crisis. During this time there was a significant drop in prevalence of, and deaths due to, cardiovascular diseases, type 2 diabetes and cancers.

But once the crisis was over and people started to eat more and exercise less, these trends began to reverse.

The study suggests that population-wide health initiatives that encourage people to eat less and exercise more could achieve significant positive health outcomes. The question is – how, in an affluent Western democracy, do you encourage people to eat less and exercise more if they are not forced to do so?

 

Where did the story come from?

The study was carried out by researchers from academic centres in Spain, Cuba and the US. There is no information about external funding.

The study was published in the peer-reviewed British Medical Journal.

It was reported accurately in the papers, although headlines like the Daily Mail’s “Lose weight the CUBAN way” and The Independent’s “The Cuban diet” trivialise the hardship that Cuban people underwent during the time in question. While they did enjoy a drop in cardiovascular disease and diabetes deaths during this period, they also experienced a sharp rise in malnutrition-associated disorders, such as neuropathies (nerve damage).

 

What kind of research was this?

The paper used data from regular cross-sectional health surveys of the Cuban population and drew on cardiovascular studies, chronic disease registries and vital statistics over three decades, from 1980 to 2010.

Its aim was to evaluate the associations between weight change across the whole Cuban population and the incidence, prevalence and death rates from diabetes and death rates from cardiovascular disease and cancer.

The authors say that the health effects of population-wide changes in body weight on a well-nourished population are unknown.

In Cuba, they point out, marked and rapid reductions in mortality from diabetes and coronary heart disease were observed after the economic crisis of the early 1990s when, in the aftermath of the dissolution of the USSR and during the US embargo on imports, there were severe shortages of both food and fuel.

These led to people eating less, and walking and cycling more (the government distributed more than 1 million bicycles during the crisis).

Since this time, the Cuban economy has shown a modest but constant recovery, especially since 2000.

 

What did the research involve?

The researchers used a variety of sources including national and regional surveys, to track changes in body weight, physical activity, smoking and daily energy intake between 1980 and 2010.

In particular, the authors drew on four cross-sectional surveys of adults aged 15 to 74, in the city of Cienfuegos, a relatively large city on the south of the island.

The surveys, of between 1,300 and 1,600 adults each, took place in 1991, 1995, 2001 and 2010 and included measurements of height and weight, which were used to assess body mass index.

The researchers also drew on national surveys of 14,304 people in 1995, 22,851 people in 2001, and 8,031 people in 2010, which assessed risk factors for chronic disease. They obtained data on diabetes rates from Cuban health registries spanning the period 1980–2009. They obtained information on mortality from diabetes, coronary heart disease, stroke, cancer and all causes for the period 1980–2010 from the Cuban Ministry of Public Health.

They analysed trends of change in disease prevalence and mortality over time and examined how this was related to changes in body weight.

 

What were the basic results?

Overall, between 1991 and 1995, the era of the economic crisis, the Cuban population experienced an average 5.5kg reduction in body weight. This was accompanied by rapid declines in death rates from diabetes and heart disease.

Between 1996 and 2002 (that is, with a lag of about five years after the crisis) there was an associated reduction in diabetes and cardiovascular disease mortality:

• diabetes death rates fell by 50% (13.95% annually)
• coronary heart disease (CHD) death rates fell by 34.4% (6.5% annually)
• deaths from all causes fell by 10.5%

After the crisis had passed, there was an average population-wide increase in weight of 9kg per person. In 1995, 33.5% of the population were overweight or obese and this increased to 52.9% by 2010.

This weight regain was followed by an increase in diabetes incidence and mortality:

• From 2006 to 2009, there was a 140% increase in diabetes incidence (new cases) and a 116% increase in diabetes prevalence (total number in the population with the condition).
• From 2002 onwards diabetes mortality increased by 49% (from 9.3 deaths per 10,000 people in 2002 to 13.9 deaths per 10,000 people in 2010).
• A slowing in the rate of decline in mortality from coronary heart disease was also observed.

 

How did the researchers interpret the results?

The researchers say that an average population-wide weight loss of 5.5kg per person was accompanied by diabetes mortality falling by half and mortality from coronary heart disease falling by a third. Increased body weight following the crisis was associated with an increase in diabetes incidence and mortality and a slowing down in the decline in mortality from CHD.

The authors suggest that a modest reduction in calorie consumption would “reverse the global obesity epidemic” and reduce deaths from diabetes by half and CHD by a third.

 

Conclusion

This is an interesting study that appears to show that modest weight loss within a relatively short period across the whole population is associated with a downward trend in diabetes and reductions in death rates from both diabetes and heart disease.

Similarly, weight regain was associated with an increase in diabetes incidence, prevalence and mortality as well as a slowing down in the decline of cardiovascular deaths.

This type of study draws on many different data sources and, as such, there is a possibility of error. Also, as the authors point out, data was missing on diabetes incidence during the crisis years and diabetes incidence showed wide fluctuations in subsequent years.

It is also difficult to conclude that changes in weight are solely responsible for changes in disease rates as other factors may also have a role. For example, smoking slowly decreased in Cuba during the 1990s.

It is not clear if the findings from the paper can be generalised to other countries. Cuba had, and continues to have, a highly centralised system of government where individual autonomy is limited.

To attempt to enforce a nationwide average reduction in body weight in the UK of 5.5kg per person would probably require a degree of social engineering that most people in this country would find intolerable. As the authors point out, an enforced situation of food and fuel shortages is not something anyone would wish to repeat.

While the study reinforces current health messages about the importance of diet and physical activity and a healthy weight, the best way for governments to attempt to reduce global obesity rates remains unclear.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

The Cuban diet: eat less, exercise more - and preventable deaths are halved. The Independent, April 10 2013

Hard times behind fall in heart disease and diabetes in 90s Cuba, says study. The Guardian, April 9 2013

Lose weight the Cuban way: Economic crisis triggered an average weight loss of 11lb and slashed the risk of heart disease and diabetes. Mail Online, April 9 2013

Losing just 8lb can be a lifesaver. Daily Express, April 10 2013

Links To Science

Franco M, Bilal U, Orduñez P, et al. Population-wide weight loss and regain in relation to diabetes burden and cardiovascular mortality in Cuba 1980-2010: repeated cross sectional surveys and ecological comparison of secular trends. BMJ. Published online April 9 2013

“A glass of wine a day will not affect a woman’s chance of beating breast cancer,” reports the Mail Online website.

It has long been known that higher alcohol intake is associated with increased risk of developing breast cancer. It is less clear whether the amount a woman drinks before or after a breast cancer diagnosis has any effect on her chances of survival.

The news is based on a new study that found that moderate alcohol consumption before breast cancer diagnosis is associated with a reduced risk of death due to breast cancer compared to never drinking. Similarly, alcohol intake after a breast cancer diagnosis was not associated with increased risk of death from breast cancer.

These findings suggest that although drinking alcohol increases your risk of getting breast cancer, it might not increase your risk of actually dying from breast cancer. For this reason, it’s best to stick with the NHS guidelines on alcohol consumption.

The researchers also found that moderate consumption of alcohol before diagnosis (one to nine drinks per week) was associated with a reduced risk of dying from heart disease and with reduced risk of death from any cause compared to never drinking at all. Women who consumed higher levels of alcohol after diagnosis were also less likely to die from cardiovascular disease or from any cause than women who never drank.

The findings do not change current alcohol recommendations – women should not drink more than two to three units a day.

 

Where did the story come from?

The study was carried out by researchers from the Fred Hutchinson Cancer Research Centre and the Harvard Medical School and Brigham and Women’s Hospital in the US in collaboration with an international team of researchers. It was funded by the US National Cancer Institute and the charity Komen for the Cure.

The study was published in the peer-reviewed Journal of Clinical Oncology.

This story was covered by the Mail Online website. The Mail concentrated on the link between wine intake and the reduction in risk of dying from heart disease (drinking beer and spirits did not have the same effect). The study did reach this conclusion (prior to diagnosis), but as it was based on a limited sample size the researchers did not attach the same level of significance to the findings as the Mail chose to.

The main focus of the study was the effect of alcohol on breast cancer deaths.

 

What kind of research was this?

This was a cohort study that aimed to analyse the relationship between alcohol consumption and breast cancer survival.

This is the ideal study design. However, like all cohort studies it can only show associations between alcohol consumption and changes in risk, and not direct cause and effect. This is because there may be other factors responsible for the association seen (confounders).

 

What did the research involve?

The researchers recruited to their study 22,890 women aged between 20 and 79 years old who were diagnosed with breast cancer between 1985 and 2006.

The women were asked to report their alcohol consumption prior to their diagnosis, and a sub-sample also reported on their drinking habits after their diagnosis (4,881 women, alcohol consumption reported on average 5.7 years after diagnosis) via telephone interview.

Separate questions were asked on the amount and frequency of beer, wine and spirits intake. Alcohol intake was classified as:

• never drinking
• one to two drinks per week
• three to six drinks per week
• seven to nine drinks per week
• 10 or more drinks per week

Women were also asked about other breast cancer risk factors, including:

• reproductive and menstrual history
• physical activity
• height
• weight
• family history of cancer
• use of oral contraceptives
• hormone replacement therapy

Information about their breast cancer was also collected (such as the stage that the disease had progressed to).

The women were followed up for a median of 11.3 years after their diagnosis. Deaths during follow-up were monitored using the National Death Index.

The researchers looked at the association between alcohol consumption and death from breast cancer, cardiovascular disease (diseases that affect the heart and blood vessels, such as heart disease) or from any cause, after adjusting for a number of potential factors that could explain any association seen (confounders).

 

What were the basic results?

During the 11.3 years of follow-up 7,780 deaths occurred, 3,484 of which were due to breast cancer. The researchers found that moderate alcohol consumption before diagnosis was associated with breast cancer survival.

Compared to non-drinkers, women who consumed three to six drinks per week had a significantly reduced risk of dying from breast cancer (hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.75 to 0.95).

The results were not statistically significant for other levels of alcohol intakes – one or two drinks, or more than six.

Women who drank spirits one or twice per week (compared to never drinking spirits) had a borderline significant reduced risk of death from breast cancer (HR 0.92, 95% CI 0.85 to 1.00), but in general results did not vary much by type of alcohol (beer, wine or spirits) consumed.

Consuming between one and nine drinks per week was associated with a reduced risk of death from cardiovascular disease, and of death from any cause, compared to never drinking.  

Looking at a sub-cohort of women who provided information about alcohol consumption after their breast cancer diagnosis (4,881 women), alcohol consumption at any level after diagnosis was not significantly associated with a reduced risk of death from breast cancer (after adjusting for how much they drank before their diagnosis). No type of alcohol was associated with any change in risk. However, women who consumed high levels of alcohol after diagnosis (10 or more drinks per week) were less likely to die from cardiovascular disease, and women who drank more than three drinks per week were less likely to die from any cause.

The researchers also looked to see if changing alcohol intake after diagnosis was associated with death from breast cancer, cardiovascular disease or any cause.

Increasing or decreasing alcohol intake was not associated with an increased risk of death from breast cancer.

However, women who increased alcohol consumption by more than one drink per week after diagnosis were at decreased risk of death from cardiovascular disease or death from any cause.

 

How did the researchers interpret the results?

The researchers conclude that, “overall alcohol consumption before diagnosis was not associated with disease-specific survival, but we found a suggestion favouring moderate consumption. There was no evidence for an association with post-diagnosis alcohol intake and breast cancer survival. This study, however, does provide support for a benefit of limited alcohol intake for cardiovascular and overall survival in women with breast cancer”.

The researchers also state that, “although women may alter their habits after breast cancer diagnosis, our results do not support a meaningful effect of changing consumption patterns on breast cancer survival”.

 

Conclusion

This large cohort study with a long follow-up has found that moderate alcohol consumption before breast cancer diagnosis (three to six drinks per week) is associated with a reduced risk of death due to breast cancer, but that alcohol intake after diagnosis did not have any benefit, but also did not cause any harm.

The study also found that consuming between one and nine drinks per week before a diagnosis of breast cancer is associated with a reduced risk of death from cardiovascular disease, and of death from any cause, compared to never drinking.

The study also suggested that women who consumed higher levels of alcohol after diagnosis (10 or more drinks per week) were less likely to die from cardiovascular disease. However, this group of women represented a much smaller sample, so these risk figures are less reliable.

Women who drank more than three drinks per week after diagnosis were less likely to die from any cause than women who never drank.

Women who increased their level of alcohol consumption after breast cancer diagnosis had better survival from cardiovascular disease and other causes, and did not affect their survival from breast cancer.

This research has the strengths of being a large cohort study with long-follow-up and it collected information on and adjusted for a number of potential confounding factors. However, it suffers from the inherent limitation of all cohort studies in that it can only show association and not cause and effect due to the possibility of confounding factors.

In addition, alcohol consumption was based on self-reported values for the previous two years, and may be subject to recall bias as well as possibly not being representative of alcohol consumption during the women’s lifetime.

Also, post-diagnosis alcohol consumption was collected on average 5.7 years after diagnosis, meaning that the results for post-diagnosis alcohol intake may only be applicable to women who survive several years after diagnosis.

Overall, this study suggests that moderate alcohol consumption prior to breast cancer diagnosis may be associated with improved breast cancer survival, but it found no link between any level of alcohol consumption after cancer diagnosis and breast cancer survival.

However, the study also suggests that alcohol intake is associated with improved cardiovascular and overall survival.

Taking into account the other health risks associated with alcohol consumption, this study would suggest that women living with or recovering from breast cancer should not worry about the occasional drink. But like all women, they should not regularly exceed the recommended consumption levels for women (two to three units a day, or 14-21 units per week).

Analysis by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

A glass of wine a day will not affect a woman's chance of beating breast cancer. Mail Online, April 8 2013

Links To Science

Newcomb PA, Kampman E, Trentham-Dietz A, et al. Alcohol Consumption Before and After Breast Cancer Diagnosis: Associations With Survival From Breast Cancer, Cardiovascular Disease, and Other Causes. Journal of Clinical Oncology. Published online April 8 2013

 

‘[Penis] Size does matter, study finds', The Daily Telegraph reports with almost identical headlines in the Daily Mail and The Independent.

The news is based on a study in which researchers asked a small group of women to rate the attractiveness of computer-generated images of naked men of various heights, body shapes and with different sizes of penis. The women were then asked to rate their sexual attractiveness on a scale of one to seven.

They found that males with a larger penis were rated as being more attractive, although only up to a certain size, and the finding applied more to taller men.

Before worried chaps starting popping blue pills or purchasing pressure pumps, it’s worth bearing in mind that this was a small study, and women were asked to rate attractiveness at a single point in time.

Computer-generated models are unlikely to reflect how attractive women really find a man in the flesh.

 

Where did the story come from?

The study was carried out by researchers from Australian National University, Monash University and La Trobe University, all in Australia, and the study was funded by the Australian Research Council.

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

The researchers say it is not clear whether penis size affects attractiveness when assessed along with other, arguably more important, body traits such as height or body shape.

The story was covered appropriately by the UK media, with The Independent taking a particularly tongue-in-cheek and hyperbolic approach.

Many internet-only news sources promoted the message as ‘it’s official!’ and ‘science has spoken’ that penis size ‘matters’. This reveals a disturbing lack of insight into how science works. A single study involving 105 women may add slightly to the body of evidence, but it certainly does not make something ‘official’. Very few things reach the status of ‘official’ in science.

 

What kind of research was this?

This was a survey carried out at one point in time, and the findings were analysed by the researchers to try and determine how women’s perceptions of male attractiveness vary depending on penis size in the context of different male body heights and shapes (shoulder-to-hip ratio).

The researchers say that novels, magazines and popular articles often allude to the relationship between penis size and sexual attractiveness or masculinity.

In contrast, there have been previous studies in which women have reported that penis size is of minimal or no importance when selecting a partner.

 

What did the research involve?

The researchers were interested in testing the effects of three main traits on women’s perception of male sexual attractiveness:

• flaccid (unerect) penis size
• body shape – specifically the shoulder-to-hip ratio, known to influence male sexual attractiveness
• height, also known to influence male sexual attractiveness

The researchers presented life size, computer-generated naked male figures to 105 heterosexual Australian women with an average age of 26 years. Each male figure was an animated video and the figure was able to rotate 30 degrees to each side to allow the women to more easily assess it.

The figures presented to the women each had different ‘traits’ that the researchers had manipulated to make the men appear shorter or taller and broader- or narrower-shouldered.

Each of the traits had several possible shapes and sizes that were considered within the normal ranges based on previous survey findings. Height ranged from 1.63 to 1.87 metres and penis length ranged from 5cm (2in) to 13cm (5.1in) – although the researchers do not explain where this is measured from (a common controversy).

The researchers noted that as part of the program used to generate the figures, penis width (girth) grew relative to the increase in penis length, and so the term ‘penis size’ was used throughout the research. Overall, there were 343 trait combinations that were possible as a result of varying each trait independently.

The researchers asked the women to view 53 randomly generated figures and asked them to, ‘rate each figure based on how sexually attractive they are to you’. The women were not informed of which traits varied and were only told that the study was on male attractiveness.

Included in the 53 images were four of the same figures that acted as controls and had the averages of all traits.

The researchers used these figures to determine whether women consistently assessed these figures the same. Attractiveness was rated on a Likert scale that ranged from 1 to 7.

Rating of the figures was anonymous and there was no interviewer in case they influenced responses. Traits of the women were also assessed to see if they had any correlation to the answers they provided. 

The researchers then analysed the ‘attractiveness’ data appropriately to determine any interactions between the traits.

 

Links To The Headlines

Size does matter, study finds. The Daily Telegraph, April 8 2013

Sorry boys, size really does matter in the bedroom: Study reveals well-endowed men get the girls. Mail Online, April 8 2013

Size really does matter: Homo sapiens' 'larger than necessary' penis may have evolved through natural selection by prehistoric women. The Independent, April 8 2013

 

Links To Science

Mautz BS, Wong BBM, Peters RA, et al. Penis size interacts with body shape and height to influence male attractiveness. PNAS. Published online April 8 2013

“A nutrient abundant in red meat… could raise the risk of heart disease,” the Mail Online website warns.

Its story is based on a study of the nutrient L-carnitine, which is found in red meat, dairy products and some dietary supplements.

A diet high in red meat has been thought to increase heart disease risk, although a very recent study has cast doubt on this, suggesting that only processed meat increases heart disease risk. The study looked at one of the supposed factors in any possible heart disease-related risk from red or processed meat.

In a series of experiments, researchers found evidence that naturally occurring gut bacteria broke down L-carnitine into a product called trimethylamine-N-oxide (TMAO). TMAO is known to contribute towards the hardening of the arteries (atherosclerosis) – a major risk factor for heart disease.

Overall, this study provides some evidence of an association between L-carnitine and heart disease, not a direct cause and effect.

Even if L-carnitine does have this effect, sticking to current UK recommendations (no more than 70g of red or processed meat daily) would mean you were consuming only minimal levels of L-carnitine and therefore not at the level of risk seen by this research, which looked at much higher levels of L-carnitine consumption.

 

Where did the story come from?

The study was carried out by researchers from Cleveland Clinic in Ohio, US and was funded by various grants from the US National Institutes of Health. The study was published in the peer-reviewed journal, Nature Medicine.

The headline somewhat exaggerated the findings and implications of the research, but overall this story was covered appropriately in the media and coverage reported correctly that part of the study was carried out in mice.

The Mail Online deserves praise for providing a comprehensive and detailed, yet easy to understand, summary of what was a complex series of related experiments.

 

What kind of research was this?

This was a series of experimental studies looking at the effect of a nutrient called L-carnitine (found in red meat and dairy products) on heart disease risk.

The researchers wanted to assess (as previous research had suggested) whether naturally occurring bacteria converted L-carnitine into a waste product called TMAO (trimethylamine-N-oxide).

TMAO is thought to speed up the build-up of plaque in the arteries (known as atherosclerosis), which is a risk factor for heart disease.

Although the researchers carried out part of their investigations in humans, some testing was performed in mice. It is often difficult to interpret the results of animal research, and caution should be exercised when trying to generalise the findings to humans.

 

What did the research involve?

In this study. the researchers carried out a series of investigative tests on both humans and mice.

For the human tests, researchers gave the nutrient L-carnitine (found in red meat and dairy products) in the form of a supplement to 77 healthy volunteers, including 26 who were vegans or vegetarians. Some of the meat-eating volunteers were given an extra eight-ounce sirloin steak (equivalent to 180mg of L-carnitine).

The participants were then given antibiotics for one week to supress bacteria in the gut from converting L-carnitine into TMAO. They were then given L-carnitine again. Their blood and urine were tested at the start of the experiment and up to three weeks after ingestion of L-carnitine. Some people also had their faeces tested.

As part of their investigations, the researchers separately checked the levels of L-carnitine in the blood of 2,595 people who were having heart check-ups. They did this to see if there was an association between L-carnitine levels and known cardiovascular disease, or risk of a cardiovascular event (such as a heart attack).

Finally, the researchers looked at the build-up of plaque in the mice’s arteries by comparing a group of mice fed L-cartinine for 10 weeks with normally fed mice. Some of these mice were pre-treated with antibiotics.

 

What were the basic results?

The main results from this study include:

• Meat-eating volunteers produced more TMAO than vegans or vegetarians following ingestion of L-carnitine
• There was a significant association between L-carnitine concentrations and risk of cardiovascular event among people undergoing heart check-ups, but only in those that had high TMAO concentrations. The researchers noted that this result suggests that TMAO rather than L-carnitine is the main driver of this association.
• Faecal analysis showed significant associations of L-carnitine with levels of TMAO in the blood.
• Feeding L-carnitine to mice doubled the risk of the animal developing plaque build-up in the arterial walls, but only when they had their usual gut bacteria. When the animals were treated with gut-clearing antibiotics, L-carnitine in the diet did not lead to arterial wall build-up.

 

How did the researchers interpret the results?

One of the lead researchers, Dr Stanley Hazen from the Cleveland Clinic in Ohio, is reported as saying “discovery of a link between L-carnitine ingestion, gut microbiota metabolism and cardiovascular disease risk has broad health-related implications. Carnitine metabolism suggests a new way to help explain why a diet rich in red meat promotes atherosclerosis”.

He goes on to say that “a diet high in carnitine actually shifts our gut microbe composition to those that like carnitine, making meat eaters even more susceptible to forming TMAO and its artery-clogging effects. Meanwhile, vegans and vegetarians have a significantly reduced capacity to synthesize TMAO from carnitine, which may explain the cardiovascular health benefits of these diets”.

The study concludes that there is ‘public health relevance, as L-carnitine is a common over-the-counter dietary supplement’. In an accompanying press release, Dr Hazen recommends that people not use L-carnitine supplements unless advised to for medical reasons.

 

Conclusion

Links To The Headlines

Red meat nutrient used in weight-loss and muscle-building supplements could cause heart disease. Mail Online, April 7 2013

Red meat chemical 'damages heart', say US scientists. BBC News, April 8 2013

Eating a lot of red meat can cause heart disease. Daily Express, April 8 2013

Links To Science

Koeth RA, Wang Z, Levison BS, et al. Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis. Nature Medicine. Published online April 7 2013

“Appetite control could be rewired, say researchers”, BBC News reports, based on findings that it notes “could eventually offer a permanent solution for tackling obesity”.

The news comes from complex cellular research looking at a part of the brain called the hypothalamus, which helps regulate appetite.

This research confirms suggestions that the nerve cells in the hypothalamus are not ‘fixed’ from birth, but can be generated later. Researchers identified a type of cell known as ‘Fgf10-expressing tanycytes’ that could add new nerve cells to the hypothalamus after birth in mice.

This provides clues as to how this part of the brain could be adapted. The researchers suggest that this knowledge could eventually be used to develop novel treatments for obesity and other eating disorders.

However, these experiments were performed in mice, and the researchers did not investigate whether they could control the generation of new nerve cells to control the appetite of obese mice. For these reasons, any chance of ‘rewiring’ human appetite – as the researchers point out – is an incredibly long way off.

 

Where did the story come from?

The study was carried out by researchers from the University of East Anglia, UK; the University of Helsinki, Finland; University Justus Liebig, Germany; and the University of Los Angeles, US. It was funded by the Wellcome Trust.

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

The story was covered by the BBC News, the Daily Express and the Mail Online. BBC News strikes an appropriate note of caution in its coverage and includes a quote from one of the researchers pointing out that this is just a single first step towards a possible, and by no means certain, treatment for obesity in humans.

The coverage in the Mail Online and the Express is a bit more excitable; with claims in their headlines that an ‘obesity pill’ may be available ‘within years’.

Although this research suggests the appetite and energy-balance regulating centres in the brain are not fixed at birth and could possibly adapt, a safe and effective ‘obesity pill’ in humans is still the stuff of science fiction, at least until further research is carried out. The genes and processes involved in this cell addition, and how they could be modified, need to be investigated first.

 

What kind of research was this?

This was animal-based research studying a type of cell found in the brain, called Fgf10-expressing tanycytes (Fgf stands for fibroblast growth factor-10).

The researchers wanted to see if Fgf10- expressing tanycytes could act in the same way as stem cells or progenitor cells in the production of new cells. They specifically wanted to see if they could stimulate formation of nerve cells (neurons) in a part of the brain called the hypothalamus, after birth. The hypothalamus regulates sleep cycles, appetite, thirst and other critical biological functions.

Some areas of the brain can change and adapt over the course of a lifetime (this is known as plasticity) while others remain relatively unchanged. Until recently it was thought that the majority of the nerve cells in hypothalamus were generated during the embryonic period. However, there is increasing evidence, that this study adds to, that new nerve cell formation occurs after birth and into adulthood.

Animal studies are ideal for investigating this type of question. However, further experimental studies will have to be performed in mice to find out which genes and processes are involved and whether these can be modified.

While it is likely that similar processes to those observed in mice occur in humans, this also needs to be confirmed. The ability to ‘rewire’ the human appetite seems a long way off.

 

What did the research involve?

The researchers looked at what happened to Fgf10- expressing tanycytes and their ‘daughter’ cells (new cells produced from Fgf10- expressing tanycytes) in the brains of mice.

 

What were the basic results?

The researchers found that Fgf10- expressing tanycytes resemble neuron stem cells and can divide and generate neurons and glial cells (cells that support and protect neurons).

The researchers found that Fgf10- expressing tanycytes continually add new neurons to the parts of the hypothalamus that regulate appetite and energy balance. Some of these cells expressed a signalling molecule involved in the regulation of appetite.

Some cells responded to fasting, as well as responding to signals from the hormone leptin, which inhibits appetite.

 

How did the researchers interpret the results?

The researchers conclude that this study provides evidence that new neurons grow in the hypothalamus after birth, into adulthood. They also conclude that they identified Fgf10- expressing tanycyte cells as a source of these neurons, and that these cells have a possible role in appetite and energy balance.

 

Conclusion

In this study, researchers identified a type of cell that – in mice – can add new nerve cells to the hypothalamus after birth. The new neurons were created in parts of the hypothalamus with a role in regulating appetite, energy balance and feeling full.

Some cells also expressed a signalling molecule involved in the regulation of appetite, and that some cells responded to fasting and signals from the hormone leptin (which inhibits appetite).

Until recently, it was thought all the nerve cells in the brain associated with appetite regulation were produced during the embryonic stage of development so the circuitry controlling appetite was believed to be ‘fixed’.

However, this new research adds to increasing evidence that new nerve cell formation occurs after birth, and into adulthood in the hypothalamus of mammals. Adding new cells could mean there may be ways to adapt appetite, energy balance and satiety, and if these processes could be modified, may lead to treatments for obesity and other eating disorders.

There are, however, a couple of points worth noting; firstly, the researchers did not investigate whether the creation of these additional cells actually had any effect on the appetite or weight of overweight or obese mice. It will also need to be determined if, and how, the process of cell generation in the hypothalamus could be modified. Secondly, and probably more importantly, results of animal studies do not necessarily ‘translate’ over into humans.

Further experimental studies will have to be performed in mice before any studies in humans could be considered. The ability to ‘rewire’ human appetite seems a long way off.  

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

Appetite control could be rewired, say researchers. BBC News, April 6 2013

Obesity pill that re-wires the brain so it feels full could be available within years after scientific breakthrough. Mail Online, April 8 2013

Diet pill to re-wire the brain into feeling full. Daily Express, April 6 2013

Links To Science

Haan N, Goodman T, Najdi-Samiei A, et al. Fgf10-Expressing Tanycytes Add New Neurons to the Appetite/Energy-Balance Regulating Centers of the Postnatal and Adult Hypothalamus. The Journal of Neuroscience. Published online April 3 2013

A brisk walk is "healthier than running", The Guardian reports, while the Daily Mail more accurately claims that walking "is as good as a run for cutting the risk of heart disease".

This news was based on a large and long-term study of runners and walkers, which found that when the same total energy was used, both activities were associated with largely similar reductions in the risk of:

• high blood pressure
• high cholesterol
• diabetes
• possibly coronary heart disease (CHD)

The study does have limitations but, generally, it seems to confirm that moderate intensity exercise (such as brisk walking) has important health benefits.

For anyone now thinking that a stroll to the shops is as good as running the marathon, there is a catch. The study compared the reductions in risk associated with the same amount of energy expenditure, whether from walking or running. Running is a vigorous intensity exercise, meaning runners use more energy than walkers over the same period. Using up the equivalent energy in walking is always going to mean you’ll have to cover more ground.

 

Where did the story come from?

The study was carried out by researchers from the Lawrence Berkeley National Laboratory and Hartford Hospital, both in the US. It was funded by the US National Heart, Lung and Blood Institute.

The study was published in the peer-reviewed journal Arteriosclerosis, Thrombosis and Vascular Biology.

Generally, the science was reported accurately in the media, with the Mail correctly pointing out that those walking would have to spend the same amount of energy as those running to achieve the same benefits. The Mail also included a comment from an independent UK expert. The Guardian’s claim that walking is associated with greater health benefits than running was misleading. There was no significant difference between the benefits of running and those of walking.

 

What kind of research was this?

The research was based on two national cohort studies. It set out to examine whether equivalent energy expended on walking (a moderate intensity exercise) and running (a vigorous intensity exercise) was associated with equivalent reductions in risk of:

• high blood pressure
• high cholesterol
• diabetes
• coronary heart disease

The researchers say that while both moderate and vigorous physical intensity is recommended in national guidelines, it remains uncertain whether the same “dose” of both types has the same long-term health benefits.

 

What did the research involve?

Participants for national runners’ and national walkers’ health studies were originally recruited in 1998 and 1999, respectively, and they comprised more than 63,000 runners and 42,000 walkers. For the current research, 33,060 runners (21% men) and 15,945 walkers (51.4% men) participated. This was about half of the original runners and about a third of the original walkers. The participants were 18 to 80 years old and they completed baseline and regular follow-up questionnaires on their height, weight, medical history, lifestyle and education.

The participants were also asked how many miles they walked or ran each week and how many hours a week on average they spent on running, walking and other exercises. They were also asked for their usual pace (minutes per mile) during walking or running.

Researchers calculated from this their estimated energy expenditure, called the metabolic equivalent hours per day (or MET h/d). A MET is the measure of energy expended at rest, with 3-6 METs being the energy expended in moderate exercise. In this study the runners used up the equivalent of about 5.3 METs in an hour each day and the walkers 4.7.

During 6.2 years of follow-up, participants also self-reported any new diagnoses of high blood pressure, high cholesterol, diabetes and coronary heart disease (including heart attack and angina) or surgical treatment for CHD (including coronary artery bypass and coronary angioplasty). They also reported whether they had started medications for any of these conditions since the beginning of the study.

Researchers compared energy expenditure in both groups with the risks of these cardiovascular conditions occurring during follow-up. They analysed the data using standard statistical methods and adjusted their results for confounders such as age, sex, race, education and smoking.

 

What were the basic results?

For each MET h/d, running was associated with:

• a 4.2% reduction in the risk of high blood pressure
• a 4.3% reduction in the risk of high cholesterol  
• a 12.1% reduction in the risk of diabetes 
• a 4.5% reduction in the risk of CHD

The corresponding reductions for walking were:

• a 7.2% reduction in the risk of high blood pressure
• a 7.0% reduction in the risk of high cholesterol  
• a 12.3% reduction in the risk of diabetes
• a 9.3% reduction in the risk of CHD

Researchers also found that the more energy used the greater the reduction in risk of these conditions.

 

How did the researchers interpret the results?

The researchers say that the equivalent energy expenditure from walking and running exercise produced similar risk reductions for high blood pressure, high cholesterol, diabetes and possibly CHD.

They also point out that there were additional benefits associated with exceeding current US guidelines for exercise levels.

 

Conclusion

This large study appears to show that moderate exercise such as brisk walking is as beneficial for health as vigorous exercise such as running, when the same energy is expended.

This study had several limitations, including its dependence on people self-reporting both their exercise levels and whether they had been diagnosed with the conditions being studied. However, this may be unavoidable in cohort studies of this type.

As the comparison was made between the results of two separate cohort studies combined as one (an indirect comparison), it is possible that the populations differed by some factor other than the intensity of exercise and particularly in how the participants were selected for study. The researchers explain that both cohorts were recruited over the same time interval, using the same questionnaire (modified slightly for the different activities). They say that both studies used subscription lists to running and walking publications and running and walking events for recruitment and the same people carried out the surveys, all funded by the same grant. This negates some of the concerns about whether the studies can be compared.

If the results of this study hold true there are a few things to bear in mind. First, in order to get the health benefits, walking needs to be faster than a stroll. To achieve ‘moderate intensity exercise’ your heart rate needs to be raised and you should experience a mild sweat.

Adults need to do around 150 minutes of moderate intensity physical activity a week. The current advice for people trying to stay fit through walking is to try to walk 10,000 steps a day.

 

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

Brisk walk healthier than running – Scientists. The Guardian, April 5 2013

Walking IS as good for your health as running - but you'll need to do it for longer. Daily Mail, April 5 2013

Walking as good as jogging for your heart. The Times, April 5 2013

Links To Science

Williams PT, Thompson PD. Walking Versus Running for Hypertension, Cholesterol, and Diabetes Mellitus Risk Reduction. Arteriosclerosis, Thrombosis, and Vascular Biology. Published online April 4 2013

‘More bananas and fewer crisps can help ward off strokes’, the Daily Mail reports, saying a study has found that people with high potassium intake have a 24% reduced risk of stroke. Researchers are also reported to say that lowering salt intake could increase benefits further.

Advice to switch from eating crisps to eating bananas is sound, but do we really need to boost our potassium intake?

The headlines stem from a well-conducted systematic review of global evidence on the effects of higher potassium concentration on cardiovascular health in healthy adults.

Good quality evidence suggests that boosting potassium intake to the recommended daily levels is associated with a decrease in blood pressure (by a few mmHg) compared to lower intakes. However, this effect was only found for people with high blood pressure.

Other evidence suggested that higher potassium intake could reduce stroke risk by 24%. However, it’s unwise to draw firm conclusions from these studies about how people’s health is affected by increased potassium intake.

A balanced diet featuring lots of fruit, vegetables and protein should give you all the potassium you need, without the need for supplements. In fact, too much potassium can be harmful, particularly for people with kidney disease or those already on certain blood pressure drugs.

Before you start scoffing bananas or popping potassium pills, it may be wise to talk about your blood pressure with your GP.

 

Where did the story come from?

The focus of this appraisal is on a study into potassium, carried out by researchers from the World Health Organization’s (WHO) Department of Nutrition for Health and Development, Geneva, Switzerland and other institutions in the UK. Funding was provided by various sources, including WHO funds, the Kidney Evaluation Association Japan, and the governments of Japan and the Republic of Korea. The study was published in the peer-reviewed, British Medical Journal.

The news reports are generally representative of this research.

 

What kind of research was this?

This was a systematic review that aimed to examine the global literature looking at the effects of potassium intake on health.

The researchers claim that historically, humans tended to have a much higher intake of potassium – above 200mmol/day. Now our intake is much less, due to diets high in processed foods and low in fresh fruit and vegetables, they say, with intake in many countries below the WHO-recommended daily intake of 70 to 80mmol/day.

Because previous studies have linked lower potassium intake to increased risk of high blood pressure and stroke, the researchers consider that increasing potassium intake may help to reduce people’s risk of such chronic conditions.

The researchers say that previous reviews have had inconsistent findings. The WHO initiated the current review to systematically gather the results of studies in healthy adults and children without illnesses that could compromise the body’s potassium balance. The WHO did this to inform future guidelines. The researchers wanted to identify randomised controlled trials (RCTs) looking at:

• how increased potassium intake affected blood pressure, death from any cause and cardiovascular disease in apparently healthy adults
• how increased potassium intake affected blood pressure in apparently healthy children
• how increased potassium intake affected blood lipid (fat) concentrations, kidney function and hormones released from the adrenal glands (such as adrenaline) in apparently healthy adults and children
• what level of potassium intake would result in the maximum benefit for reducing blood pressure, and risk of death and cardiovascular diseases
• whether the effects of increased potassium are affected by factors such as people’s health, diet, or by the type of intervention used to help them increase their potassium intake

If insufficient RCTs were identified, the researchers planned to include less robust study designs, including non-randomised trials and observational studies.

 

What did the research involve?

The researchers used systematic review methods recommended by the Cochrane Collaboration. They searched numerous electronic databases and manually searched reference lists of studies and reviews. They identified randomised and non-randomised trials which had allocated at least one group of participants to increased potassium intake (intervention) and one group to lower potassium intake (control) for at least four weeks. To be included in the analyses, trials had to have measured potassium from urine samples collected every 24-hours (which can be used to estimate potassium intake). The researchers excluded studies involving:

• acutely ill people
• HIV-positive people
• people admitted to hospital
• people whose urinary potassium excretion was impaired due to a medical condition or drug treatment

Researchers were looking for outcomes related to blood pressure, all-cause mortality, all cardiovascular disease, and specifically stroke and coronary heart disease. They also looked at potential adverse effects of changes in concentrations of blood fat (cholesterol and triglycerides), concentrations of catecholamine (hormones such as adrenaline produced by the adrenal glands at the top of the kidneys) and kidney function. In children, the researchers wanted to find out about blood pressure, blood fats or catecholamine concentrations.

The researchers assessed studies for quality and risk of bias. Where possible, they pooled the results in meta-analyses to estimate the effects of higher potassium intake compared to lower.

 

What were the basic results?

The researchers identified 37 relevant studies, 35 of which were included in the meta-analysis. Of these, 22 were RCTs of adults, 11 were cohort studies of adults, and one was an RCT of children and one a cohort study of children. Due to the limited search results for children, the researchers broadened their inclusion criteria and identified a further RCT, one non-randomised study, and one additional cohort study in children. The two randomised trials in children included a total of 250 boys and girls aged 13-15 years.

Results for adults

The 22 RCTs in adults included 1,606 participants (individual study size 12 to 353 people) and were conducted across countries worldwide. In 20 studies, participants were given potassium supplements (as the intervention), in one study, participants were given potassium supplements and dietary advice or education, and in two studies the intervention was dietary advice or education alone. The cohort studies in adults included 127,038 people.

Links To The Headlines

Halve our salt intake and save millions of lives, says new report. The Independent, 5 April 2013

More bananas and fewer crisps can help ward off strokes, say scientists. Daily Mail, 5 April 2013

Cutting back on salt key to saving lives. Daily Express, 5 April 2013

Increase potassium and cut salt to reduce stroke risk. BBC News, 5 April 2013

Eat more bananas to reduce risk of stroke, say scientists. The Times, 5 April 2013

 

Links To Science

Anurto NJ, Hanson S, Gutierrez H, et al. Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses. BMJ. Published online 5 April 2013

He FJ, Li J, MacGregor GA. Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials. BMJ. Published online 5 April 2013

"Men with a bald pate are at significantly greater risk of heart disease than their less follicly challenged peers," reports The Daily Telegraph. There are similar headlines across much of the media.

The headlines refer to research into an association between baldness and coronary heart disease. The researchers estimate that the risk of developing coronary heart disease over 10 years or more is 32% higher in bald men compared with those with a full head of hair.

This study can’t reveal what causes the link between baldness and risk of coronary heart disease, it can only tell us that the two are linked.

Men concerned by these headlines should not lose sleep – or any more hair – over it. There isn’t much men can do about balding, but there are plenty of ways to reduce risk of heart disease. The quote from the British Heart Foundation that appears in most media reports is particularly apt: “it’s more important to pay attention to your waist line than your hairline”.

 

Where did the story come from?

The study was carried out by researchers from the University of Tokyo and was carried out without any external funding. It was published in the open-access peer-reviewed BMJ Open.

This report was generally covered appropriately by the media, with most reporting that even the significant associations were modest compared with the increases seen with well established risk factors. However, the Daily Mail headline that “losing your hair before your 50s can almost double the risk of heart attack” is not an accurate reflection of the research. First, the studies examined more than just heart attacks and, second, the increase in risk for men under 55 or 60 ranged from 44% to 84%, which is not a doubling.

The Guardian should be commended for quoting an independent statistician, Professor David Spiegelhalter, who cautions readers about the difficulties of concluding that balding causes heart disease (or vice versa).

 

What kind of research was this?

This was a meta-analysis of observational studies that estimated the association between male pattern baldness (or androgenetic alopecia) and coronary heart disease (CHD). The authors report that several studies have identified an association between these two factors, and this research sought to combine the results from multiple studies to establish the overall risk.

CHD is the most common cause of death among men in the UK. In CHD the arteries that pump blood to the heart become narrow. This narrowing occurs when fatty material builds up within the artery walls. If the arteries become too narrow, the heart does not receive enough oxygen-rich blood, which causes chest pain known as angina. This narrowing can escalate to the point that the artery is blocked, which can cause a heart attack, where the lack of oxygen-rich blood causes permanent damage to the heart.

As this was a meta-analysis of observational studies, it can only provide information on the association between baldness and CHD, and cannot say why they are associated or if one causes the other.

 

What did the research involve?

Links To The Headlines

The bald facts: hair loss could be the first sign you have heart disease. The Independent, 3 April 2013

Bald men at greater heart disease risk. The Daily Telegraph, 3 April 2013

Bald truth about heart disease. Daily Express, 3 April 2013

Bad news for baldies: Losing your hair before your 50s can almost DOUBLE the risk of heart attack. Daily Mail, 3 April 2013

Male baldness linked to risk of coronary heart disease, research claims. The Guardian, 3 April 2013

Male baldness 'indicates heart risk'. BBC News, 3 April 2013

Links To Science

Yamada T, Hara K, Umematsu H and Kadowaki T. Male pattern baldness and its association with coronary heart disease: a meta-analysis. BMJ Open. Published 3 April 2013

“Daily stresses take toll on long-term mental health,” The Daily Telegraph reports. It goes on to say, “that little row with your spouse or stress of finding yourself stuck in a traffic jam may be taking a heavier toll on your mental health than previously thought”.

So should we obsess about daily stress, or should we maintain a firm British stiff upper lip? While the news correctly reflects the conclusions of a decent piece of research, there are problems drawing any major conclusions from the science.

The Telegraph story is based on a long-term US study that measured what people said were their daily stress triggers (‘stressors’), and how they said they emotionally responded to them. It then compared these findings with symptoms of mental health conditions a decade later.

Experiencing negative mood and emotions at the beginning of the study was linked with whether people had symptoms indicative of major depression, dysthymia (a form of long-term depression) or generalised anxiety disorder after 10 years. People’s reported emotional response to daily stressors predicted whether people reported they had mental health conditions, but not whether they had a diagnosis based on symptoms of these conditions.

Overall, the study’s limitations – such as low participation and high drop-out rates – make it difficult to conclude that our mood today predicts our mental health in 2023.

 

Where did the story come from?

The study was carried out by researchers from the University of California Irvine, California State University Fullerton and Pennsylvania State University in the US, and was funded by the US National Institutes of Health.

The study was published in the peer-reviewed journal, Psychological Science.

The research was reported appropriately by the Telegraph.

 

What kind of research was this?

This was a prospective cohort study that assessed the association between response to daily stressful events and common mental health disorders 10 years later.

Being prospective in nature, this study reduces the likelihood that any associations are found due to individuals incorrectly recalling their past emotional responses to stress. Having such a long follow-up period does, however, increase the risk that many people who participated at the beginning of the study may drop out by the end of the study, which could potentially bias the results.

 

What did the research involve?

Researchers recruited people aged 25 to 74 in 1995 and 1996. These people completed questionnaires assessing their physical and mental wellbeing, their experience of daily stress triggers (which the researchers call ‘stressors’), and their affective (emotional) reaction to these stressors. Ten years later they were followed up and their mental health assessed, including whether they suffered from common mental health disorders such as depression and generalised anxiety disorder.

The questionnaires at the beginning of the study measured general affective distress, where participants reported how often during the previous 30 days they had felt worthless, hopeless, nervous, restless or fidgety, and how often they felt that ‘everything was an effort’ or that they were ‘so sad that nothing could cheer them up’. Participants were also asked at this time whether they had experienced or been treated for ‘anxiety, depression or some other emotional disorder’ during the previous 12 months. Researchers then employed a commonly used tool, called the Composite International Diagnostic Interview – Short Form (CIDI-SF) to diagnose major depressive disorder, dysthymia (a form of long-term depression) or generalised anxiety disorder (GAD).

Another questionnaire asked about participant experiences with daily stressful events. This was completed every evening for eight days at the beginning of the study, and included items such as having an argument; a problem at work or home; having a friend, associate or someone else within one’s social network experience an upsetting problem; and other potentially stressful situations. Participants also reported their mood and emotions on these eight days. The items included were identical to those described above, but related only to the previous 24 hours instead of the previous 30 days. The researchers estimated emotional response to stressors (or ‘affective reactivity’) by calculating the difference in mood and emotion on days without stressors compared to days with stressors.

In their analyses, the researchers controlled for several potential confounders including gender, education and age, as well as negative feelings on non-stressor days.

 

What were the basic results?

During the first wave of the study, 1,483 people completed the questionnaires on their general emotional distress (affective distress) over the previous month, what daily stressors they had experienced, and daily emotional distress.

Ten years later, only 793 participants (53.4%) completed the follow-up questionnaires. A further 82 participants were not included in the analysis because data was incomplete on either the initial or follow-up questionnaire. This left 711 people who were included in the analysis of the association between emotional response to daily stressors and long-term mental health.

Among those participants included in the analyses, 12.2% reported symptoms at the beginning of the study consistent with either major depressive disorder, dysthymia or generalised anxiety disorder. At the follow-up interviews 10 years later, 10.3% met the same criteria.

The researchers found that people with a symptom-based diagnosis of depression, dysthymia or generalised anxiety disorder at baseline were likely to have one of these diagnoses 10 years later (odds ratio (OR) 3.98, 95% confidence interval (CI) 2.03 to 7.81). Negative emotions on days that were free from stressors at the beginning of the study also predicted a symptom-based diagnosis of these conditions 10 years later (OR 1.31, 95% CI 1.05 to 1.63).

While emotional response to daily stressors did not significantly predict mental health outcomes 10 years later (OR 1.25, 95% CI 0.92 to 1.70), it did predict a self-reported experience or diagnosis of such disorders (OR 1.56, 95% CI 1.21 to 2.01). The average number of daily stressors reported at baseline was not predictive of a diagnosis either (OR 0.91, 95% CI 0.65 to 1.28).

 

How did the researchers interpret the results?

The researchers conclude that, ‘the average levels of negative affect that people experience and how they respond to seemingly minor events in their daily lives have long-term implications for their mental health’.

 

Conclusion

This study suggests that the daily experience of negative emotions may predict the presence of common mental health disorders a decade later.

The researchers highlight the theory that, ‘affective responses to seemingly minor daily events have long-term implications for mental health’, and that their findings support this. While the study did reportedly include a large, nationally representative sample of adults, there are several limitations. Many of these limitations were reported by the study authors, and they include the facts that:

• The researchers did not report how many people were initially invited to participate, only how many people agreed to participate. If there was a big discrepancy in numbers and the characteristics of those who did and did not agree to participate, it could mean there was an initial selection bias, but we cannot tell if this is the case because the figures were not reported.
• There was a very high loss to follow-up over the course of the study, with 46.6% of participants dropping out of the study for various reasons. The researchers did not report whether, or how, the people who could not be followed up differed from those who continued to participate in the study.
• Diagnoses of major depression, dysthymia and generalised anxiety disorder were based on self-reported symptoms over the previous year, and such reports may not be completely reliable.
• Information was collected only at the start of the study and 10 years later. It is not known whether similar levels of negative mood persisted throughout the study period, or when disorder symptoms first appeared. Information was also collected on negative affect (emotions) and negative daily events – it is not known how positive mood and events influence this association.
• The individuals included in the final analyses were more likely to be of European American descent and tended to have higher education levels. Assuming the results hold – regardless of the other limitations – they may not be generalisable to groups other than educated individuals of European descent.

Overall, the authors say that their results suggest that daily stress triggers (stressors) cause ‘wear and tear’ on emotional wellbeing. They say that this is consistent with theories that suggest the manner in which people experience negative emotions and respond to negative events in their lives has an impact on their future mental health.

Further studies that address some of the drawbacks of this study, especially the potential for selection and misclassification bias, would help to more firmly establish the link between our current emotional state and our future mental health.

 

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

Daily stresses take toll on long-term mental health, study finds. The Daily Telegraph, April 4 2013

Links To Science

Charles ST, Piazza JR, Mogle J, et al. The Wear and Tear of Daily Stressors on Mental Health. Psychological Science. Published online April 4 2013

The NHS "should remove more tonsils," reports The Daily Telegraph, describing how we should "return closer to the 1950s culture of whipping tonsils out in spite of the cost."

It's tempting to take this news at face value, given that it is based on a study that found that adults with recurrent severe sore throats had fewer sore throats if they had their tonsils removed.

However, this small short-term Finnish study adds little weighty evidence to the ongoing debate about whether surgery is the best option for treating this problem.

The study found that surgery did reduce the number of people visiting their doctor with a sore throat within five months: 4% of patients who had their tonsils removed saw their GP, compared with 43% who had not yet had surgery.

The researchers therefore concluded that removing tonsils may be effective at preventing severe sore throats. However, there was no difference in the number of people who had a severe sore throat after five months.

The Telegraph's story failed to highlight potential problems with the research, or point out that it would not be the basis for a substantial change in medical practices in this country.

Despite this slightly wayward reporting, The Telegraph does well to reignite the debate about whether tonsillectomies should be performed more often. Medical and surgical practices that have fallen out of favour should always be re-evaluated using the most up-to-date research evidence.

However, any change in medical practices will be the result of the progressive accumulation of larger, more robust studies showing more conclusive results than this current research.

 

Where did the story come from?

The study was carried out by researchers from Oulu University Hospital in Finland. No funding source was explicitly stated, but no competing interests were declared.

It was published in the peer-reviewed Canadian Medical Association Journal.

There is limited evidence about the benefits of tonsillectomy in adult patients. This research wanted to look at the short-term effectiveness of tonsillectomy for patients with recurring pharyngitis.

The media reporting was generally accurate, but overstated the importance of this research. It failed to highlight many of the important limitations of this study, including its size and whether its findings can be applied to English patients.

 

What kind of research was this?

This study was a small randomised control trial that wanted to see if tonsillectomies were an effective way of reducing the number of episodes of severe pharyngitis among adult patients with recurrent pharyngitis of any origin.

Pharyngitis is a sore throat usually caused by a viral or bacterial infection. It is common in children and teenagers as they haven't yet built up immunity for the common viruses and bacteria that cause sore throats.

Most people are familiar with the notion that taking out tonsils will remedy tonsillitis (inflamed tonsils). It is important to note, however, that this study looked at whether removing the tonsils was effective for reducing the number of episodes of inflammation of the throat in general (pharyngitis).

 

What did the research involve?

The researchers recruited 86 patients referred from a specialist ear, nose and throat centre in Oulu, Finland. These patients were referred for tonsillectomy because of recurrent pharyngitis. The participants were recruited from 260 eligible patients referred to the centre between 2007 and 2010.

To be included in the study, patients had to have experienced three or more episodes of pharyngitis within the previous 12 months. These episodes had to be 'disabling': they had to prevent normal functioning, be severe enough for the patient to seek medical attention, and the tonsils had to be thought to be involved in each episode. Children under the age of 13 were excluded, as were those with chronic tonsillitis.

Participants were randomly assigned to either:

• be placed on a waiting list (the control) for tonsillectomy to have surgery in five to six months (40 people), or
• undergo surgery as soon as possible (46 people)

Patients were told to visit the study physician or their general practitioner whenever they had short-term symptoms suggestive of pharyngitis. Patients were also told that it was important to seek medical advice for their symptoms during the trial exactly as they had done before.

Both patient groups were followed-up five months after randomisation. During this time, they kept study notebooks to remind them about how the study should work and allow them to document ongoing treatments and doctor consultations.

The researchers primarily wanted to compare the difference in the proportion of patients who had a severe episode of pharyngitis within the five-month period.

 

What were the basic results?

Of 260 eligible participants, 86 took part. Most who were excluded either had too few previous episodes of tonsillitis, had chronic tonsillitis, or lived outside the study region. A further 42 declined to participate altogether. All patients in both groups were followed-up at five months.

The main analysis found that at follow-up, one patient in the control group and no patients in the tonsillectomy group had experienced an episode of severe pharyngitis. This difference was not statistically significant.

When looking at other outcomes, the researchers found 17 (45%) patients in the control group and two (4%) in the tonsillectomy group had consulted a doctor for pharyngitis (difference 38%, 95% confidence interval 22% to 55%). This difference was statistically significant.

Significant differences that favoured the tonsillectomy group were also found for:

• the number of patients experiencing acute pharyngitis over the five-month period
• the overall rate of pharyngitis
• the number of days with throat pain, fever, runny nose and cough
• days absent from school or work

 

How did the researchers interpret the results?

The researchers concluded that, "Adult patients with recurrent pharyngitis of any origin had very few severe episodes of pharyngitis, regardless of whether they underwent tonsillectomy."

However, "Patients who did undergo surgery had fewer episodes of pharyngitis overall and less frequent throat pain than did patients in the control group. These reductions resulted in fewer medical visits and fewer absences from school or work."

 

Conclusion

This small-scale research adds relatively little evidence to settle the debate about when and how often to use tonsillectomy, as the media outlined.

The research has many limitations to consider that make it less reliable, or applicable to the UK:

• This was a very small study based in Finland that looked at outcomes for just 86 patients. This means it may not be representative of people who would generally be considered for tonsillectomy in the UK.
• The waiting time for surgery in Finland is restricted to six months by law, so the research could only follow-up people in the control group for around five months before they had surgery. This limits the study's ability to assess whether a significant number of the control group would spontaneously improve during a longer follow-up period, and leaves open the possibility that the beneficial effect of tonsillectomy may be temporary if pharyngitis recurred after six months.
• There is likely to have been bias in the selection of the control group, as they were told that they would undergo surgery eventually. Those that wanted surgery earlier are likely to have declined to participate in the study.
• There were relatively few eligible cases of recurrent pharyngitis in this study, shown by the fact only 86 were recruited over a three-year period. For this reason, it does not seem to be a particularly common problem for people. However, it does suggest that tonsillectomy may be beneficial to this group of patients. 
• The study authors highlight a recent Cochrane systematic review on tonsillectomy for recurrent tonsillitis that found only a single trial involving adults. It included adults severely affected by a specific infective cause (recurrent group A streptococcal pharyngitis, known as 'strep throat'). This means there is relatively little evidence available on this topic to reliably inform decision-making.
• Tonsillectomy is usually carried out under a general anaesthetic and, as with all surgeries, carries a risk of complications. A common complication is bleeding at the site where the tonsils are removed. This is estimated to affect around one in 30 adults and one in 100 children. Minor bleeding is not usually cause for concern and heals itself, but heavier bleeding can cause vomiting and coughing up blood, requiring immediate medical advice.

This research adds little to the debate about how many tonsillectomies the NHS should be performing. The debate rumbles on, largely because there is a lack of good quality evidence that can tell us how effective tonsillectomies are for adults.

 

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

Doctors back a return to 1950s-style tonsil surgery. The Daily Telegraph, April 2 2013

Links To Science

Koskenkorva T, Koivunen P, Koskela M. Short-term outcomes of tonsillectomy in adult patients with recurrent pharyngitis: a randomized controlled trial. Canadian Medical Association Journal. Published online April 2 2013

‘Putting an organic label on ordinary foods can trick shoppers into believing that they are healthier, taste better and have fewer calories’, says the Daily Mail.

This news was based on a small US study and provides the intriguing suggestion that an “organic” label can influence people’s perception of a food’s qualities – a phenomenon known as the “health halo” effect.

In the study, people at a shopping centre were asked to taste and evaluate pairs of cookies, crisps and yoghurt. Although all the food was organically produced, only one item from each pair was labelled ‘organic’, while the other was (falsely) labelled ‘regular’.

Researchers found that after tasting the foods, people perceived food with an organic label to be lower in calories, lower in fat, higher in fibre and worth paying more for, than the same food without the organic label. However, the taste perceptions provided unclear results.

People’s choice to eat organic food is likely to be influenced by factors such as production without using synthetic pesticides (which they may perceive to be harmful). However, there is currently little evidence to suggest that organic food is nutritionally different from non-organic food.

Consumers, food producers and advertising regulators alike are bound to want more research into this area of nutrition and health psychology.

 

Where did the story come from?

The study was carried out by researchers from Cornell University, in the US. No information about external funding has been provided.

The study was published in the peer-reviewed journal, Food Quality and Preference.

Contrary to the Mail’s claim, people’s evaluation of how the food tasted did not seem to be influenced by the “organic” label, but it did influence what they thought of the nutritional content. The Daily Telegraph’s coverage does convey that only the organic crisps were deemed more ‘appetising’ and the organic yoghurt more ‘flavourful’. However, it failed to point out the conflicting result that the ‘regular’-labelled cookies were believed to be more ‘flavourful’ than the organic-labelled cookies.

 

What kind of research was this?

This was a small study of consumers recruited from a shopping centre who were asked to taste and evaluate three identical pairs of food products – cookies, crisps and yoghurt. One item from each pair was labelled organic while the other was labelled regular. In fact, all the foods in the study were organic and identical.

The researchers say previous research has suggested package labels can influence how consumers evaluate a food product. In particular, the “health halo effect” of the organic label may influence people’s purchasing decisions.

 

What did the research involve?

Researchers recruited 115 people from a local New York shopping centre over a two-day period. Of the participants, 50 were male, 60 female and five of unreported gender. The participants ranged in age from 16 to 76. In the centre’s food court, they were each randomly assigned to a tray with three paired food samples and were asked to taste and evaluate the food.

The food consisted of two cookies, two portions of crisps and two cups of yoghurt. All foods in each pair were identical and had been organically produced, but one item of each pair was labelled “organic” and one falsely labelled “regular”. The order of the six items and the way they were arranged on the tray varied for each participant.

After the tasting, participants answered a questionnaire asking them to rate the organic and non-organic items for taste, nutritional attributes, overall calories and what they would be willing to pay for each food. Specifically, on a scale ranging from one (strongly disagree) to nine (strongly agree), they were asked whether the food: 

• was appetising, flavourful, tasted good, tasted artificial (taste related)
• tasted high in fat, tasted high in calories, was nutritious, contained a lot of fibre (nutrition related)

They were also asked to estimate:

• the number of calories a snack-sized portion of each item would contain 
• the highest amount of money they would be willing to pay for a snack-sized portion

The participants were also asked to complete a questionnaire about their shopping habits, eating behaviour, and “pro-environmental activities”. Specifically, on a scale of one to nine, they were asked whether they:

• usually read nutritional labels on foods 
• usually bought organic
• liked to recycle
• recycled whenever they could
• enjoyed nature hikes or leisurely walks
• enjoyed spending time with nature

They were asked to complete a 10-item “restrained eating” scale to assess eating behaviour.
 
The researchers used a method called ‘within-participants analysis of variances’ to examine if the organic label influenced people’s evaluations of the food for taste and nutrition and for how much they would be willing to pay. They also examined possible interactions between how people evaluated the food, their shopping habits and their environmental activities.

 

What were the basic results?

Overall, participants estimated foods with organic labels to be lower in calories, lower in fat and higher in fibre than the ‘regular’ foods. They were also willing to pay more for foods with the organic label (22.8% more for organic yoghurt, 23.4% more for organic crisps and 16.1% more for organic cookies).

While these effects were seen for everyone, the effects of the organic label on people’s estimates of the amount of calories were less pronounced if they typically read nutritional labels, bought organic foods, or engaged in pro-environmental activities.

However, the taste-related evaluations were inconsistent, contrary to some of the media interpretation.

 

How did the researchers interpret the results?

Organic labels on foods are intended to advocate the benefits of organic methods of production. However, the researchers in this study conclude that the organic label may give an “undue perception of increased healthfulness” of food items. More caution is needed in determining whether and how the organic label should be included on food products, they argue.

 

Conclusion

This was a small study involving consumers from one US shopping centre and its results may not be applicable to other populations. It focussed on only three food items, and as the researchers say, more reliable conclusions might be drawn had it included a wider range of foods (such as fresh produce rather than just processed food items).

It is also possible that participants were influenced by each others’ responses. Or they gave what they thought were the “correct” – rather than genuine – answers about organic food, for example, in terms of what they might pay for organic food.

That said, the study does seem to indicate that people have mistaken perceptions of food labelled as organic. There are other factors that influence people’s choice to eat organic (such as the restricted use of synthetic pesticides, fertilisers, additives, hormones and antibiotics), the label has become an attractive marketing tool. This study appears to suggest that more evidence-based information should be made available about organic foods.

 

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on twitter.

Links To The Headlines

Organic food labels 'trick' us into thinking food is healthier and tastier. Daily Mail, 3 April 2013

Health 'halo effect' of organic food can trick shoppers. The Daily Telegraph, 3 April 2013

 

Links To Science

Wan-chen JL, Shimizu M, Kniffin KM and Wansink B. You taste what you see: Do organic labels bias taste perceptions? Food Quality and Preference. Published online 9 February 2013

"Eating fish in old age 'can extend life'," The Daily Telegraph proclaims, among several mainstream papers covering the story. But before you head out to buy some MSC-certified sustainably sourced mackerel, it's worth having a look at whether this really is such good news for you.

The headlines only really apply to over-65s, and no fish were involved in the research. The news is actually based on the results of a large long-term study looking at whether blood levels of omega-3 fatty acids are associated with cardiovascular disease and mortality among older adults. These omega-3 fatty acids are found in fatty fish and seafood, as well as nuts and other dietary sources.

This research found that higher levels of omega-3 in the blood were associated with a 27% reduction in risk of death from any cause, and a 35% reduction in risk of death from heart disease. People with the highest omega-3 levels lived 2.2 years longer on average than those with lower levels.

While this study has several limitations, it is one of the few studies that have objectively measured blood levels of omega-3 fatty acids. This eliminates problems with previous research based on people merely recording what they ate.

It is worth doing more research to find which omega-3 fatty acids may help prevent cardiovascular disease and if they can reduce the number of deaths from this disease.

 

Where did the story come from?

The study was carried out by researchers from Harvard Medical School and the Harvard School of Public Health, the University of New Mexico, and the University of Washington. It was funded by the US National Institutes of Health.

It was published in the peer-reviewed journal Annals of Internal Medicine.

Much of the news concentrated on the benefits of eating fish. Although omega-3 fatty acids are found in fatty fish and seafood, this study did not look directly at fish consumption. Instead, it looked at levels of omega-3 fatty acids in the blood.

However, the media has been led astray by a press release put out by the Harvard School of Public Health. In it, the study's lead author suggests that their findings mean that people should eat a modest amount of fatty fish. The Independent, the Daily Express, the Daily Mail and The Daily Telegraph have all largely cut-and-paste their text, including quotes, from this press release.

 

What kind of research was this?

This was a cohort study looking at three fatty acids:

• docosahexaenoic acid (DHA)
• eicosapentaenoic acid (EPA)
• docosapentaenoic acid (DPA)

It looked at whether there is an association between the levels of these three fatty acids and total levels of omega-3 fatty acids in the blood, and the total number of deaths and the number of cause-specific deaths in healthy older adults who did not take fish oil supplements.

Although this is the ideal design for this sort of study, cohort studies cannot exclude the possibility that other factors (confounders) are responsible for any associations seen. This study would also have been stronger if levels of omega-3 fatty acids in the blood had been measured at multiple time points, so that the possibility that they changed over time could be excluded.

 

What did the research involve?

The researchers recruited 2,692 healthy adults aged 65 years or older (average age 74 years) into the Cardiovascular Health Study.

At the start of the study (in 1992), the researchers measured the participants' levels of fatty acids in the blood, and also assessed their cardiovascular risk factors. The participants were then followed-up for 16 years (until 2008) to see if they had died, and if so, from what causes.

The researchers analysed the levels of omega-3 fatty acids – including the three specific ones (DHA, EPA, or DPA) – in participants' blood at the start of the study. They investigated whether they were associated with cardiovascular disease or the risk of death from any cause.

 

What were the basic results?

During the study there were:

• 1,625 deaths
• 359 fatal and 371 non-fatal cardiovascular disease events
• 130 fatal and 276 non-fatal strokes

After adjusting for demographic, cardiovascular, lifestyle and dietary factors, the researchers found that the three omega-3 fatty acids were associated with a significantly lower risk of mortality. This was true for the three omega-3 fatty acids individually and when the results for all three were combined.

Having blood levels of omega-3 fatty acids in the top 20% was associated with a 27% reduced risk of death from any cause when compared with having blood levels of omega-3 fatty acids in the lowest 20%. For the specific fatty acids analysed:

• blood levels of EPA in the top 20% were associated with a 17% reduced risk of death from any cause compared with blood levels of EPA in the lowest 20%
• blood levels of DPA in the top 20% were associated with a 23% reduced risk of death from any cause compared with blood levels of DPA in the lowest 20% 
• blood levels of DHA in the top 20% were associated with a 20% reduced risk of death from any cause compared with blood levels of DHA in the lowest 20%

The reduction in risk of death from any cause was mainly due to a reduction in risk of cardiovascular death. None of these fatty acids were strongly related to other non-cardiovascular causes of death.

People with omega-3 levels in the top 20% lived an average of 2.22 more years after the age of 65 than those with omega-3 levels in the lowest 20%.

 

How did the researchers interpret the results?

The researchers conclude that higher circulating individual and total omega-3 polyunsaturated fatty acid levels are associated with lower total mortality – especially deaths caused by cardiovascular disease – in older adults.

 

Conclusion

This study has found that higher levels of omega-3 in blood at the start of the study were associated with a 27% reduction in risk of death from any cause, and a 35% reduction in risk of death from heart disease in healthy older adults (aged 65 years or older) who were not taking fish oil supplements. The older adults with the highest levels of omega-3 lived 2.2 years longer on average than those with lower levels.

This research has several limitations. Omega-3 fatty acid levels were only measured at the start of the study and could have changed over time. Deaths also could have been misclassified, and the possibility that there are other factors that may be responsible for the association seen (confounders) cannot be excluded.

However, this study is one of the few to objectively measure blood levels of markers for omega-3 fatty acids. Further research is warranted to find out whether certain omega-3 fatty acids can help prevent cardiovascular disease and reduce mortality. 

It should be noted that although omega-3 fatty acids are found in fatty fish and seafood, this study did not look directly at fish consumption. Instead, it looked at the levels of omega-3 fatty acids in the blood. For this reason, it is wise to take the newspaper headlines with a pinch of salt for now.

 

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

Eating oily fish twice a week could help you live two years longer. Daily Mail, April 1 2013

Eating oily fish 'can extend life'. The Independent, April 1 2013

Eating fish in old age 'can extend life'. The Daily Telegraph, April 1 2013

Fish is key to a longer life. Daily Express, April 2 2013

Links To Science

Mozaffarian D, Lemaitre RN, King IB, et al. Plasma Phospholipid Long-Chain Omega-3 Fatty Acids and Total and Cause-Specific Mortality in Older Adults. Annals of Internal Medicine. Published online April 1, 2013

A rise in bowel cancer among men has been reported across the UK media.

The news is based on figures released by Cancer Research UK, coinciding with the start of bowel cancer awareness month and the launch of the Make Bobby Proud awareness and fundraising campaign. The figures show that bowel cancer rates have increased by nearly a third in men, and by 6% in women, over the past 35 years.

Many of the news articles linked the increasing rates of bowel cancer to our lifestyles, blaming obesity and the consumption of diets high in red and processed meat and low in fibre. In reality, the reasons why the number of cases have increased are not certain. Why there is a difference in the rate of increase in bowel cancer between men and women is also not yet understood.

We know that certain factors increase your chances of getting bowel cancer. These include modifiable factors such as diet, inactivity, obesity, smoking and alcohol. Other factors such as family history and digestive and genetic conditions can also be involved. However, the increasing incidence of bowel cancer has not been conclusively linked to changes in these or other factors over the past 35 years.

 

What do the Cancer Research UK figures show?

In 1975 to 1977, there were 45 cases of bowel cancer per 100,000 men. By 2008 to 2010, this had risen to 58 cases per 100,000, an increase of 29%. Cases in women increased from 35 to 37 per 100,000 in the same period, a rise of 6%.

People in their 60s and 70s experienced the largest increase in the number of cases.

It is not currently known why the number of cases has increased, or why there are differences between men and women.  

Encouragingly, bowel cancer survival is also increasing, with half of all patients living for at least 10 years after a diagnosis. This compares well to 10-year survival rates for pancreatic cancer (2.4% for women and 2.9% for men), but is some way short of the 10-year survival rate for women with breast cancer (77%).

 

What is bowel cancer?

Bowel cancer, also called colorectal cancer, is cancer of the large bowel (colon cancer) and cancer of the back passage (cancer of the rectum).

Bowel cancer is the fourth most common cancer in the UK, but is the second most common cause of cancer death in the UK.

 

What are the signs and symptoms of bowel cancer?

If you have any of the following symptoms for more than three weeks without a reason, you should make an appointment with your GP so that they can rule out (or detect) bowel cancer:

• bleeding from the back passage
• a persistent change in your bowel habit towards looser or more frequent bowel motions
• bloating, swelling, pain, or an unexplained lump in the tummy
• unexplained weight loss
• tiredness or looking pale

 

Can I be screened for bowel cancer in the UK?

Links To The Headlines

Bowel cancer on the rise among men. The Daily Telegraph, April 2 2013

Male bowel cancer on the increase, says Cancer Research UK. BBC News April 2 2013

Bowel cancer rate among men rises by nearly 30% in 35 years. The Guardian, April 2 2013

Bowel cancer rates in men soar by a quarter in 35 years - and obesity, smoking and drinking are to blame. Daily Mail, April 2 2013

Male bowel cancer diagnosis rates soaring by 29% while for women it's 6%. The Mirror, April 2 2013

Male bowel cancer cases soar by 30 per cent. Metro, April 2 2013

Shock rise in bowel cancer. Daily Express, April 2 2013

"Almost 2,000 British children a year die from 'avoidable' causes because family doctors lack training in paediatric care," The Independent alarmingly claims.

The story comes from a review of health services for children across 15 countries in the European Union. It found that while child survival rates have improved greatly in the past 30 years, many countries are not keeping pace with changing patterns in child health.

Increasingly, non-infectious chronic disorders such as asthma have become causes of disability and death, as have accidental causes such as poisoning and injury.

The review found that the UK is second-to-last in the 'league table', with nearly 2,000 more child deaths each year than Sweden, which had the lowest death rates.

The authors of the review point out that in the UK, the first point of contact for families – the GP – often receives no specific training in child health beyond undergraduate degree level. It goes on to argue that UK services should be reorganised so that they are able to respond to children's health needs more successfully.

 

Where did the story come from?

The study was carried out by researchers from several European centres, including the UK institutions the London School of Hygiene and Tropical Medicine, the University of Oxford, and Imperial College London. It was supported by the European Observatory on Health Systems and Policies and the National Institute for Health Research.

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

Understandably, the Independent's report concentrates on the UK, although its claim that untrained GPs are to blame for 2,000 child deaths annually conflates two separate pieces of information from the review.

The report found that in the UK there are 1,951 excess child deaths every year compared with Sweden. It is also critical of the lack of specialist training in child health for GPs in the UK, pointing out that recent inquiries into child deaths have drawn attention to the failure of primary care to recognise and manage severe illness.

But while a link between excess child deaths and a lack of specialist training in child health for GPs may be implied by the review, it cannot be proven. There may be other factors at work that could also account for the difference between UK and Swedish mortality rates.

 

What kind of research was this?

This review of child health services forms part of a series published by The Lancet examining the health of people in Europe. 

The authors say that the healthcare needs of European children are changing, with infectious diseases easier to prevent or cure and other chronic disorders such as asthma, diabetes and behavioural problems becoming more important.

Their paper looks at the way the 15 countries that joined the EU before 2004 (Luxembourg, France, Austria, Finland, Denmark, Spain, Belgium, Sweden, Italy, Germany, Netherlands, UK, Ireland, Portugal and Greece) are responding to common challenges.

The paper reviews child health in these countries and the evidence for how well healthcare needs are met in each country. It also examines different approaches to services for children with chronic disorders, as well as the quality of 'first contact', or primary, care. In the UK, this is usually provided by the family GP.

 

What did the research involve?

The researchers carried out comprehensive reviews of the relevant medical literature using a range of search strategies for all relevant reports published by the WHO, the UN, the EU, the Organisation for Economic Co-operation and Development, and European professional societies.

They defined children as those aged 18 years or younger. However, as data was not always available some comparisons were restricted to children younger than 14 years.

To compare child health and services in the 15 pre-2004 countries of the EU, they focused on child mortality data from the World Health Organization (WHO). 

 

What were the basic results?

The study does not publish results in the same way a scientific trial would. Instead, it highlights and compares the outcomes on child health in different countries and discusses the different ways that services are organised.

Survival overall

It found that child survival has improved greatly in all 15 countries in the last 30 years as a result of improvements in public health, healthcare and wider social factors. Deaths from infectious and respiratory causes have fallen, while those attributable to other (non-communicable) diseases have risen.

It found that the three most common causes of non-communicable disease are neuropsychiatric disorders (mainly depression), congenital abnormalities, musculoskeletal disorders (lower back
pain), and respiratory diseases (mainly asthma).

The UK

The report says that there are wide variations in child health between the 15 countries, as well as within each country. These variations are in terms of health outcomes, life chances and mortality. The report found that the country with the lowest child mortality rate (at 29.27 per 100,000 children aged under 14) is Sweden.

• the UK, with a rate of 47.73 per 100,000, is second-to-last
• the UK has the highest number of excess child deaths a year (1,951) compared with Sweden
• the UK also has the highest rates of deaths from pneumonia among children aged 0-14 years (1.76 per 100,000)
• of eight countries in the EU (Sweden, Portugal, Finland, Italy, Austria, Germany, Spain and the UK), the UK has the highest mortality rates from asthma both among children aged 6-7 and children aged 13-14

Health systems and models of care

The authors point out that while care for chronic disorders in adults has been high on the agenda in many European countries, the same is not true for children. Close co-operation between different services for child care has been developed in some countries such as Sweden and the Netherlands.

The report points out that although there are incentives to provide similar 'joined-up' multi-agency chronic care treatment for adults in the UK, almost no such measures exist for children.

First-contact care

The report focuses on various issues for children's first-contact care, highlighting that training for family doctors in child health remains highly variable between countries. It says that most GPs in Sweden receive at least three months' specialist training in child health, and often work closely with doctors and nurses specialising in child health. The UK has a more segregated model where GPs may not receive any specific training in child health beyond what they received as an undergraduate, and they tend to work separately from paediatricians.

 

How did the researchers interpret the results?

The researchers say that:

• Child health systems in Europe are not adapting sufficiently to children's evolving health needs, leading to "avoidable deaths, suboptimum outcomes, and inefficient use of health services".
• If all the 15 countries had child mortality similar to that of Sweden (the country with the best rate), a total of more than 6,000 deaths per year could be prevented.
• New chronic care models for children are needed to improve care and outcomes for non-communicable diseases and ensure better quality-of-life for children and families. Several countries have made progress in development of chronic care services and offer lessons for others.
• The quality of first-contact care services (primary care) and outcomes for children in Europe are highly variable. Flexible models, with teams of primary care professionals trained in child health working closely together, might offer a way to balance expertise with access.
• Awareness of the importance of investment in health in the earliest years is growing. Individual countries and European Union-wide organisations should strengthen investment in child health and health services research.
• Politicians and policy makers should do more to translate high-level goals for child health into policy. Investment in social protection policies for the earliest years and the most vulnerable children will improve health, reduce inequities and accumulate advantages throughout life.

They argue that, "Policy makers often seem reluctant to translate into policies the increasing evidence showing that the foundations of life-long health are built through greater investments in the early years of life," continuing that, "Until national and European governing bodies are willing to accept this challenge, the outlook for child health in Europe will remain uncertain."

 

Conclusion

This is an important paper that has found large variations in both child mortality rates and the delivery of health services to meet children's needs within the initial 15 countries of the EU.

As the authors say, child health has improved over the last 30 years but the healthcare needs of children are changing. It is important that policies, systems and practices are developed that can face this challenge and that countries learn from each other.

This does not mean, as The Independent's headline suggests, that Britain's GPs do not have enough training to give children the medical care they need.

 

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

Untrained GPs blamed for 2,000 child deaths. The Independent, March 27 2013

Britain 'worst in Europe' for child deaths. The Daily Telegraph, March 26 2013

Links To Science

Wolfe I, Thompson M, Gill P, et al. Health services for children in western Europe. The Lancet. Published online March 27 2013

Most of the UK media have reported on what has been described as landmark research into the genetics of breast, ovarian and prostate cancer. Many commentators state that this will lead to cheap and reliable screening tests for the cancers within "five years".

The news is based on the results from the Collaborative Oncological Gene-environment Study (COGS), which is an international collaboration involving hundreds of researchers. It looked at the genetic markers of more than 200,000 people to detect genetic variants that were associated with an increased risk of three types of cancer:

• breast cancer 
• prostate cancer 
• ovarian cancer

Previous research has identified genetic mutations that can increase the risk of breast cancer, such as the BRAC1 and BRAC2 mutations. The latest research identified more than 70 new variants, located in specific areas of human DNA (known as positions or loci), that are associated with an increased risk of breast, prostate and ovarian cancer, including 41 loci that are associated with increased risk of breast cancer.

This research does have the potential to lead to more accurate screening for certain types of cancer using relatively simple and cheap DNA testing, such as saliva or blood tests. But claims that these tests are “five years away” could be premature. It remains to be seen what effects these new insights into the genetics of cancers will actually have.

 

Where did the story come from?

An international team of researchers is participating in the Collaborative Oncological Gene-environment Study (COGS). COGS is a European Union funded project, with additional funding from Cancer Research UK and the US National Institutes of Health.

COGS has today published 13 papers in five journals. Several of the papers have been published together in a special iCOGS Focus issue of Nature Genetics, along with commentaries and a guided tour of the research. All of this is open access, meaning that it is available for free from the Nature Genetics website.

In this story we will be concentrating on the identification of 41 new genetic regions associated with breast cancer.

This study was led by researchers at the University of Cambridge and funded by Cancer Research UK and the European Community. It was published as part of the iCOGS Focus issue in the peer-reviewed journal Nature Genetics.

Much of the news reporting concentrates on the possibility of using the results of these studies to design a genetic test for cancer. It is possible that future cancer screening could be improved by the use of genetic information – for ‘risk-stratification’, which is determining how great someone’s risk of developing cancer is. However, it is likely that such a programme would be complex, and the issue of how genetic data will be stored and used will have to be addressed.

It also remains to be seen whether routine screening using gene testing would be affordable or cost-effective. So claims that genetic screening for cancer is five years away could be premature.

 

What kind of research was this?

This was a case-control study that aimed to identify genetic variations that increased the risk of developing breast cancer.

 

What did the research involve?

The researchers were looking at what are known as single nucleotide polymorphisms or SNPs.

The human genetic code (human genome) is made up of information contained within our DNA. This sequence is made up of strings of molecules called nucleotides, which are the building blocks of DNA.

SNPs occur when the DNA sequence varies by a single nucleotide. Some SNPs have been associated with significant effects on human health.

While the entire COGS project looked at SNPs thought to be associated with prostate, ovarian and breast cancer, the study we are analysing just looked at breast cancer.

SNPs associated with risk of breast cancer were identified by combining the results of nine previous studies. The researchers investigated whether these SNPs were present more frequently in people who developed breast cancer by comparing 45,290 people of European ancestry who developed breast cancer with 41,880 who did not.

 

What were the basic results?

Variations in the DNA sequence at 27 different positions (loci) in the genome have previously been found to be associated with breast cancer risk. In this study, all but four of these previously identified loci showed clear evidence of association with breast cancer in this study (three others showed weaker association, and the other one was not investigated).

In addition, the researchers identified 41 new loci that were statistically significantly associated with the risk of breast cancer. Each locus was associated with a small increase in risk of breast cancer.

The researchers estimate that the 41 newly associated loci explain approximately 5% of the familial risk of breast cancer.

The researchers also state that a larger number of loci could contribute to susceptibility to breast cancer, suggesting that 1,000 additional loci are involved in breast cancer susceptibility.

 

How did the researchers interpret the results?

The researchers conclude that they have identified “more than 40 new susceptibility loci, more than doubling the number of susceptibility loci for breast cancer”.

The researchers go on to state that “the currently known loci now define a genetic profile for which 5% of the female population has a risk that is [equivalent to] 2.3-fold higher than the population average and for which 1% of the population has a risk that is [equivalent to] 3-fold higher”.

 

Conclusion

This interesting research has identified 41 new genetic loci that are associated with increased risk of breast cancer. Other studies performed by the COGS identified a further eight genetic loci, which, combined with the 27 previously identified loci, brings the total identified to 76. This is in addition to mutations in ‘high risk’ genes such as BRAC1 and BRAC2.

This research has the potential to lead to genetic profiling that may aid in identifying women at an increased risk of developing breast cancer (as well as women at increased risk of ovarian cancer and men at increased risk of prostate cancer).

However, it is likely that such a programme would be complex because, in addition to genetic testing, the results would have to be integrated into a risk assessment process, and care pathways for people in different groups would have to be developed. The issue of how genetic data would be stored and used would have to be addressed. Therefore, it seems unlikely that genetic screening will be introduced in the near future.

Nonetheless, this remains important and impressive research. Any advances in our understanding of the genetics of cancer are valuable and the study could be the first step to improving screening programmes for breast, ovarian and prostate cancer. It may also improve our knowledge of these diseases, and aid in the design of prevention and treatment strategies. But much more work will need to be done to reach these goals.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on twitter.

Links To The Headlines

DNA test reveals 80 markers for inherited cancer risk. BBC News. March 27 2013

Genetic testing for prostate and breast cancer comes a step closer. The Guardian, March 27 2013

Breakthrough? Scientists unveil the 'single biggest leap forward' in tackling prostate cancer. The Independent, March 27 2013

Genetic screening for cancer 'within five years'. The Daily Telegraph, March 27 2013

The £5 test that predicts the risk of cancer - and it could be available on the NHS within five years. Daily Mail, March 28 2013

£5 test could spot patients with biggest risk of cancer. Daily Express, March 28 2013

Cancer Detection: DNA Study Brings 'New Era'. Sky News, March 27 2013

 

Links To Science

Michailidou K, Hall P, Gonzalez-Neira A, et al. Large-scale genotyping identifies 41 new loci associated with breast cancer risk. Nature Genetics. Published online March 27 2013

"Men who visit saunas may be damaging their sperm," the Mail Online website warns. This warning comes from the results of a tiny study involving just 10 men asked to follow a Scandinavian-style sauna programme.

Researchers wanted to look at the effect of long-term sauna use on sperm quality, as previous research has indicated that higher scrotal temperatures in men can lead to poorer sperm health.

The men, who all had healthy sperm at the start of the study, were found to have lower sperm counts and reduced sperm motility (the ability to 'swim' towards an egg) after the prescribed sauna programme, but other aspects of sperm health were unchanged.

However, these negative effects were reversed after the men avoided sauna use for three months, so any damage appears to have been temporary.

Given that only 10 men were involved, the results of this study need to be confirmed by much larger studies. The effects of sauna exposure in men with abnormal sperm also needs to be tested further.

Still, most fertility experts would advise that men having trouble conceiving should keep their testicles cool. Hot baths, showers and wearing tight-fitting underwear can all raise the temperature of the testicles. This advice was bolstered by research published earlier this month that suggests that sperm quality drops during the summer.  

 

Where did the story come from?

The study was carried out by researchers from the University of Padova, Italy. No external funding was reported for this study.

It was published in the peer-reviewed medical journal Human Reproduction.

While the Mail Online's reporting of the story was broadly accurate, it failed to mention the crucial fact that the study only recruited 10 men. This may have led many readers to wrongly assume that it was a much larger study and its findings were therefore conclusive.

 

What kind of research was this?

This was a tiny cohort study exploring the effects of repeated sauna exposure on various aspects of sperm quality.

The researchers reported that many previous studies found higher testicular temperatures had negative effects on the ability of the testicles to produce sperm. Heat could also cause alternations in the sperm DNA and cause it to self-destruct.

This type of very small-scale study is generally useful for testing a scientific hypothesis at a low cost. In this case, the theory being tested was that regular sauna use may damage or reduce sperm quality.

Small studies like this are generally undertaken to prove an idea rather than prove something with any degree of certainty. Being so small, they are potentially unreliable, biased and unrepresentative of the wider population. This means they don't really provide any sizeable evidence to prove a theory. Much larger studies involving hundreds or thousands of people are required to give any weight to an idea.

 

What did the research involve?

The researchers recruited 10 healthy male volunteers (average age 33.2 years) to take part in a Finnish sauna programme consisting of two sauna sessions per week for three months at 80-90°C, each lasting 15 minutes. Very few details about the men were reported, so their nationality, demographics and lifestyle behaviours are unknown. Men who had used a sauna in the previous year were not included in the study, so the 10 men didn't have a history of regular sauna exposure.

Sex hormones, sperm parameters, sperm DNA structure, sperm death ('apoptosis', a process where the sperm self-destructs in response to external stimuli) and the expression of genes involved in sperm response to heat and lack of oxygen were all evaluated at the start (baseline). Further measurements were then taken:

• at the end of each sauna exposure
• at the end of the sauna programme (three months after the baseline)
• six months after the baseline (three months after the men had stopped using saunas)

Scrotal temperature was measured with an infrared thermometer before and immediately after each sauna session.

The statistical analysis was basic and compared sperm measures at baseline with the different time points so the effect of the sauna visits on sperm health could be measured.

 

What were the basic results?

The average scrotal temperature before the sauna sessions was 34.5°C, which increased to 37.5°C after the session, a statistically significant increase of 3°.

The study found a statistically significant impairment of sperm count and sperm motility both at the end of each sauna session and again at three months. No significant difference in sex hormones was found.

Decreases in the percentage of sperm with normal DNA structure and other internal biological sperm structures were also observed after each sauna session and three months after sauna exposure.

This corresponded with an increase in the activity of sperm genes associated with coping with heat stress and lack of oxygen, which the researchers believe was brought on by the sauna experience.

The major effects of the sauna were to reduce sperm count and motility. Semen volume, sperm structure, and how often the sperm self-destructed did not change throughout the study.

Crucially, the researchers reported that all the effects were reported to be reversed at the six-month time point. This suggests the adverse effects of sauna exposure appear to be temporary, at least in men with healthy sperm.

 

How did the researchers interpret the results?

The researchers concluded that in men with normal sperm, "sauna exposure induces a significant but reversible impairment of spermatogenesis [making sperm], including alteration of sperm parameters, mitochondrial function and sperm DNA packaging."

They went on to suggest that, "the large use of Finnish sauna in Nordic countries and its growing use in other parts of the world makes it important to consider the impact of this lifestyle choice on men's fertility."

 

Conclusion

Past research has shown that higher scrotal temperatures in men can lead to poorer sperm health. This proof of concept study tells us that this may also apply to men who use saunas regularly.

The study found that in men with initially healthy sperm, repeated sauna exposure over a three-month period lowered sperm count and reduced sperm motility. Many other aspects of sperm health were unchanged.

Crucially, it also showed that these negative effects were completely reversed at the six-month time point – that is, following a further period of three months without using a sauna.

On its own, this research provides very weak evidence due its tiny sample size – just 10 men were recruited. A study that plucks 10 men from a general population of millions is prone to chance findings and significant bias that may not be applicable to the vast majority of men. For these findings to have more weight, more men would need to be recruited to participate in a larger study.

Other areas that need further investigation include the effects of sauna exposure in men who already have abnormal sperm. These findings may be different (for example, the negative effects may not be as reversible) and this issue was not addressed by this study.

It is also worth pointing out that the majority of British men may not use saunas twice a week for months at a time, so the results are only applicable to the minority that do. Even then, larger studies need to confirm this theory before it can be believed with any certainty.

Overall, this research is consistent with existing fertility advice for men hoping to conceive. Men are advised to keep their testicles cool at around 34.5°C, a few degrees colder than the rest of the body. This helps your body produce the best quality sperm.

 

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

Men who regularly use saunas have lower sperm counts. Mail Online, March 26 2013 

Links To Science

Garolla A, Torino M, Sartini B, et al. Seminal and molecular evidence that sauna exposure affects human spermatogenesis. Human Reproduction. Published online February 14 2013

BBC News is reporting that there is a new ‘Guide to help parents to spot 'problem behaviour’’, while The Daily Telegraph claims that ‘More than one million parents could be offered state-funded lessons in how to play with their children under NHS guidelines’.

Both reports are based on new guidelines, published today by the National Institute for Health and Clinical Excellence (NICE) and the Social Care Institute for Excellence (SCIE), into a condition known as conduct disorder.

Conduct disorder is a relatively common but often overlooked mental health condition in children and young people, which causes defiant behaviour (‘I won’t do what you tell me’) and sometimes severe aggressive and /or antisocial behaviour.

The guideline says half of children with conduct disorders not only miss out on parts of their childhood but go on to develop serious mental health problems, such as antisocial personality disorders, as adults. They also have an increased risk of ending up in prison and developing a drug misuse problem. 

The guidelines argue that early intervention in at-risk children is essential to break this chain.

The new guidelines highlight the key role of parents and other carers in detecting and managing conduct disorders and recommends specific training for health and social care workers to help them.

 

What is meant by conduct disorders?

Conduct disorders are the most common type of mental and behavioural problem in children and young people. They are characterised by repeated and persistent patterns of antisocial, aggressive or defiant behaviour, much worse than would normally be expected in a child of that age. Types of behaviour include stealing, fighting, vandalism, and harming people or animals.

Younger children often have a type of conduct disorder called “oppositional defiant disorder”. In these children, the antisocial behaviour is less severe and often involves arguing (“opposing”) and disobeying (“defying”) the adults who look after them.

In teenagers with conduct disorders, the pattern of behaviour can become more extreme and include:

• aggression towards people or animals
• destruction of property
• persistent lying and theft
• serious violation of rules

Children with conduct disorders often have other mental health problems, particularly attention deficit hyperactivity disorder (ADHD).

 

How common are conduct disorders?

These disorders are the most common reason for children being referred to mental health services, with 5% of all children between five and 16 years old diagnosed with the condition.

The proportion of children with conduct disorders increases with age and they are more common in boys than girls. For example, 7% of boys and 3% of girls aged five to 10 years have conduct disorders; in children aged 11 to 16 years, the proportion rises to 8% of boys and 5% of girls.

 

What causes conduct disorders?

It is not yet clear why conduct disorders develop. A prevailing view is that, like many mental health conditions, a combination of environmental and biological factors may be involved.

Possible environmental factors include:

• a “harsh” parenting style
• parental mental health problems such as depression and substance misuse
• parental history, such as the breakup of a marriage
• poverty
• individual factors, such as low achievement
• the presence of other mental health problems

In terms of biology, researchers who looked at the brain structures of teenage boys with conduct disorders have found differences in areas of the brain associated with emotions such as empathy and behaviours such as risk-taking.

There may be certain genetic variants that a child inherits that may also make them more prone to develop conduct disorders.

 

What happens to children with conduct disorders?

Children and young people diagnosed with conduct disorders often fail at school or college and become socially isolated. In adolescence, they may misuse drugs and alcohol or become involved with the criminal justice system. As adults, this group do badly in terms of education and jobs, are often involved in crime and also have high levels of mental health problems such as antisocial personality disorder.

 

How can conduct disorder be treated?

Several approaches have been developed for children at risk of, or diagnosed with, conduct disorders. In particular, parenting programmes are run by health and social care professionals to help parents improve their children’s behaviour. Treatment for the children themselves includes psychological therapies and sometimes, medication. The treatment of children with conduct disorder can involve many different agencies including health professionals, social services, school and college.

 

What are the warning signs and symptoms I should look out for in my children?

Recognising that a child may be at risk of, or has developed conduct disorder at an early age may help prevent problems later.  

Conduct disorder is different from the occasional tantrum or “naughtiness” in a child.

The behaviour of a child with conduct disorder may depend on their age. Younger children (aged under 11) may repeatedly argue with, disobey and defy those looking after them.

Older children with conduct disorder may consistently exhibit antisocial behaviour, such as:

• being highly aggressive towards people and animals
• stealing or damaging property
• lying
• fighting
• violating rules

If you are concerned about your child’s behaviour, seek advice from your GP as soon as possible.

 

What recommendations have NICE made about diagnosing conduct disorders?

NICE has made a number of recommendations about the diagnosis and treatment of conduct disorders. Its key recommendations are outlined below.

 

Selective prevention

One of the key messages contained in the NICE guidelines is the importance and usefulness of selective prevention. Selective prevention means identifying individual children with an above average risk of developing a conduct disorder and then providing treatment to try and prevent that from occurring. The rationale being that it is usually easier to prevent a disease than to cure one.

NICE recommend that younger children aged three to seven years should be considered for selective prevention if:

• they are growing up in a poor household
• they are underachieving at school
• there is a history of child abuse or parental conflict
• their parents are separated or divorced
• one or both of the parents has a history of mental health problems and /or substance abuse problems
• one or both parents have come into contact with the criminal justice system

 

Assessment

NICE recommends that children or young people at risk of developing a conduct disorder or who are suspected of having a conduct disorder are assessed by qualified health or social care professionals.

Initial assessment should involve checking for the following complicating factors:

• a coexisting mental health problem (for example, depression or post-traumatic stress disorder)
• a neurodevelopmental condition (in particular ADHD and autism)
• a learning disability or difficulty
• substance misuse (in older children)

The initial assessment should then be followed by a more comprehensive assessment. This should include asking about and assessing the following:

• core conduct disorder symptoms in younger children (aged under 11) – particularly symptoms associated with oppositional defiant disorder, defined by NICE as “patterns of negativistic, hostile, or defiant behaviour”
• core conduct disorder symptoms in older children (aged over 11) such as aggression to people and animals, destruction of property, deceitfulness or theft, and serious violations of rules” in children aged over 11 years
• current functioning at home, school or college, and with peers
• parenting quality
• history of any past or current mental or physical health problems

 

What recommendations have NICE made about treating conduct disorders?

In younger children aged between three and 11 years, a type of treatment programme known as group parent training programme is recommended.

In older children, aged from nine to 14 years, a type of treatment programme known as child-focused programmes are recommended.

Older children and younger people aged 11-17 years also benefit from what are known as multimodal interventions (involving many services).

In some cases, drug treatments may also be recommended.

 

Parent/foster parent/guardian training programmes

NICE recommend that this treatment should be offered to children who:

• have been identified as being at high risk of developing oppositional defiant disorder or conduct disorder
• have oppositional defiant disorder or conduct disorder
• are in contact with the criminal justice system because of antisocial behaviour

Parent/foster parent/guardian training programmes are based on the premise of helping parents make the most of their parenting skills so they can help improve their child's behaviour. The programmes are run by specially trained health or social care professionals. They cover communication skills, problem-solving techniques and how to encourage positive behaviour in children.

It is best if both parents, foster carers or guardians attend the programme if this is possible and in the best interests of the child or young person.

The programmes are usually run on a group basis involving 10 to 12 parents, over the course of 10-16 meetings, with each meeting lasting around 1½ to 2 hours.

 

Child-focused programmes

NICE recommend that this treatment should be offered to children who have been identified as:

• being at high risk of developing oppositional defiant disorder or conduct disorder
• have oppositional defiant disorder or conduct disorder
• are in contact with the criminal justice system because of antisocial behaviour

Child-focused programmes involve group work with other children or young people of a similar age and similar issues. The therapist encourages the children to better understand their thoughts, feelings and behaviour, and the connections between them. This is designed to help the children learn how to get along better with other people.

The children usually meet with their group once a week for about 10 to 18 weeks. Each meeting should last for about two hours.

 

Multimodal interventions

Multimodal interventions involve psychological therapies that encourage individuals to look at different aspects of their life and talk with a wider circle of people, including their family, people at their school or college and other people who are important in their life. This type of treatment should be provided by a specially trained professional called a case manager. The case manager should visit you three or four times a week for three to five months.

 

Medication

In cases where ADHD is thought to be a contributing factor, then medications used to treat ADHD, such as methylphenidate or atomoxetine, may be recommended.

In a minority of cases, where a child or young person is finding it especially difficult to control their anger, a medication called risperidone, which helps reduce aggressive tendencies, may be recommended.

However, this is seen as a treatment of last resort when other treatments have failed. And risperidone should only be prescribed under the supervision of a professional with experience in treating conduct disorders.

Children and young people taking risperidone should have their health carefully monitored due to the risk of side effects. The most common side effects of risperidone include:

• Parkinson’s like symptoms such as muscle jerks and problems with body movements
• headaches
• insomnia

 

Research recommendations

NICE have also made a number of research recommendations in order to improve patient care in the future. These include:

• research into what the effectiveness of parent training programmes for older children
• research into how to get children to become more engaged with psychological treatments
• research into the best way to prevent relapses in people who have responded well to treatment
• research into whether classroom based interventions can be effective in treating conduct disorders

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

Guide to help parents to spot 'problem behaviour'. BBC News, March 27 2013

Learn to play with your child the NHS way. The Daily Telegraph, March 27 2013

Expert: Treating conduct disorders could save money. ITV News, March 27 2013

 

"Social isolation is associated with a higher risk of death in older people regardless of whether they consider themselves lonely," BBC News has reported.

Previous research has suggested that people who have limited social contact are at increased risk of death. Many researchers have suggested that this is possibly due to the emotional effects of isolation – that feeling lonely is bad for health.

But this new, large UK study implies that the relationship between social isolation, feeling lonely and risk of death is more complex. The researchers looked at whether these factors were linked in a large group of UK adults aged 52 or above.

The study found that both social isolation and loneliness were associated with increased risk of death. However, if demographic factors and initial health were taken into account, loneliness was no longer significantly associated with risk of death. There was still a significant link between social isolation and risk of death, however, after these other factors and even loneliness had been taken into account.

This suggests that factors other than loneliness – such as having no-one to check on a person’s health – may contribute to increased risk of death.

Efforts to reduce social isolation are likely to have positive outcomes for wellbeing and mortality rates.

 

Where did the story come from?

The study was carried out by researchers from University College London. The English Longitudinal Study of Ageing, from which the study participants were taken, was funded by the National Institute on Aging and a consortium of UK government departments co-ordinated by the Office for National Statistics.

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

This article is open access, meaning that it can be accessed for free from the PNAS website.

In general, the story was well reported by the UK media. But The Daily Telegraph’s headline on “The toll of loneliness” falls into the trap of confusing loneliness and social isolation. This is precisely the distinction the researchers were trying to make. You can be socially isolated without feeling lonely and you can feel lonely even when surrounded by people.

The Telegraph's mistake is understandable given that it is possible that there is an intricate link between loneliness and social isolation that this study has not been able to evaluate fully.

 

What kind of research was this?

This was a cohort study. It aimed to determine whether there is an association between social isolation and loneliness, and death from any cause, in a representative sample of the UK population.

The researchers also aimed to determine whether loneliness is partly responsible for the association between social isolation and mortality.

A cohort study is the ideal type of study to address this question.

However, a cohort study cannot show causation. There is still a possibility that other factors (confounders) explain the relationship seen.

There is likely to be an intricate link between social isolation and loneliness. It is difficult to tell whether the methods used by the researchers fully accounted for the complexity of the association.

 

What did the research involve?

This study included 6,500 men and women aged 52 or over who were part of the English Longitudinal Study of Ageing between 2004 and 2005. The researchers assessed social isolation using a social isolation index, assigning one point for each marker of isolation, for example:

• unmarried/not cohabiting
• less than monthly contact with family and friends
• non-participation in ‘civic organisations’ (such as social clubs or religious groups)

They assigned an overall isolation score on a scale of 0 to 5.

Loneliness was assessed with the three-item short form of the revised UCLA (University of California, Los Angeles) loneliness scale. One example question was “How often do you feel you lack companionship?”. The response options were:

• hardly ever or never
• some of the time
• often

The overall loneliness score ranged from 3 to 9. Participants who scored in the top 20% were defined as being socially isolated or lonely, respectively.

Death from any cause was monitored up to March 2012 (mean follow-up 7.25 years).

The researchers looked at the association between social isolation or loneliness and death from any cause.

The researchers adjusted their analyses for the following confounders:

• age
• sex
• demographic factors (such as wealth, education, marital status and ethnicity)
• baseline health indicators (including long-standing illness, mobility impairment, cancer, diabetes, chronic heart disease, chronic lung disease, arthritis, stroke and depression)

 

What were the basic results?

By March 2012, 918 participants had died.

• Mortality was higher among more socially isolated and more lonely participants.
• Social isolation was significantly associated with mortality (hazard ratio (HR) 1.26, 95% confidence interval (CI) 1.08 to 1.48) after adjusting for demographic factors and baseline health indicators.
• Loneliness was not significantly associated with mortality (HR 0.92, 95% CI 0.78 to 1.09) after adjusting for demographic factors and baseline health indicators.
• The association of social isolation with mortality was unchanged when loneliness was adjusted for (HR 1.26 95% CI 1.08 to 1.48).

 

How did the researchers interpret the results?

The researchers conclude that “although both isolation and loneliness impair quality of life and well-being, efforts to reduce isolation are likely to be more relevant to mortality”.

 

Conclusion

This cohort study found that social isolation in older people was associated with increased risk of death from any cause in the UK, and this relationship was independent of demographic factors and baseline health.

It also found that loneliness, which is often thought to be a result of social isolation, is not the reason why social isolation is linked with risk of death.

This study included a large group of people representative of the UK population. The researchers took into account demographic and health factors. However, this was a cohort study and, as such, it cannot show causation. There may be other factors that explain the relationship seen (confounders), that cannot be excluded.

A particular difficulty with this piece of research is that feelings of social isolation and loneliness are highly subjective. It is not possible to say whether they have been satisfactorily assessed by the methods used in this study.

The researchers assessed isolation by creating a social isolation index and giving a score for certain factors. However, these particular factors may not have been relevant to the individual being assessed and may not accurately represent how isolated they feel. For example, the researchers report that they gave equal weight to all social contacts, whereas some relationships may be more important than others.

Similarly, loneliness was assessed using a three-item scale and it is not possible to know whether this could accurately assess loneliness. Overall, there is likely to be an intricate link between the subjective experiences of social isolation and loneliness, which the objective methods used in this study have not been able to evaluate fully.

Nevertheless, efforts to reduce the social isolation of older people are likely to have positive outcomes for wellbeing, and this research suggests that they could also reduce mortality.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on twitter.

Links To The Headlines

Social isolation 'increases death risk in older people'. BBC News, March 26 2013

Toll of loneliness: isolation increases risk of death, study finds. The Daily Telegraph, March 26 2013

The more the merrier! A higher number of friends in later life, rather than how well you know them, is key to reaching a ripe old age. Daily Mail, March 25 2013

 

Links To Science

Steptoe A, Shankar A, Demakakos P, Wardle J. Social isolation, loneliness, and all-cause mortality in older men and women. PNAS. Published online March 25 2013