'A stressful job really can kill you – by raising your cholesterol,' reports the Mail Online website. This headline is based on Spanish research that looked at the relationship between job stress and lipid (fat) levels in the blood of more than 90,000 people.

The research found that people who reported difficulties coping with their job had higher levels of what has been dubbed "bad cholesterol" (LDL cholesterol) and lower levels of "good cholesterol" (HDL cholesterol). High levels of LDL cholesterol can clog up the arteries, increasing an individual's risk of developing cardiovascular diseases such as coronary heart disease.

A significant strength of this study is its size – an impressive 90,000 people participated. But the study did not look at diet, which can also affect cholesterol levels. It could well be the case that people in stressful jobs tend to have unhealthy diets and it is this, rather than stress itself, that is to blame for their higher "bad" cholesterol rates.

While increased LDL levels are a risk factor for cardiovascular diseases, this study did not explore the effect this would have on people's long-term health. The Mail Online's claim that a stressful job will kill you is therefore not supported by this study.

Where did the story come from?

The study was carried out by researchers from Ibermutuamur – a mutual insurance company dealing with work-related accidents and occupational illnesses – and two universities in Spain. There were no external sources of funding for the study.

It was published in the peer-reviewed Scandinavian Journal of Public Health.

The Mail Online's headline over-interprets the research, as the study did not assess whether people in stressful jobs were more likely to die. The body of the story was reasonably accurate, but it did not highlight that this type of study cannot prove that one factor is definitely causing another.

What kind of research was this?

This was a cross-sectional study that explored whether there is a link between job stress and abnormal levels of fats (lipids) in the blood.

Some studies have found a link between job stress and an increased risk of coronary disease. There are various theories about how this link might come about – for example, by stress increasing the likelihood of unhealthy habits such as smoking.

Some studies have also suggested that stress could directly influence levels of lipids in the blood by possibly adversely affecting the body's metabolism. However, these studies have been small and in selected populations, and have had mixed results.

In the current study, researchers wanted to assess stress and lipid levels in a large representative sample of workers. As this study is cross-sectional, both stress and lipid levels were assessed at the same time. This means the study cannot establish whether participants' lipid levels were directly influenced by their stress levels.

What did the research involve?

The study involved workers covered by the Ibermutuamur insurance company who had yearly medical check-ups. More than 430,000 participants were recruited between 2005 and 2007, and a study questionnaire was sent out to more than 100,000 randomly selected individuals. Completed questionnaires were returned by 91,593 of these people.

The questionnaire included the question, "During the last year, have you frequently felt that you cannot cope with your usual job?". Participants who answered "yes" were considered to have job stress.

The questionnaire also included 11 questions relating to anxiety and depression symptoms, such as "Have you felt keyed up, on edge?" and "Have you had difficulty relaxing?".

The researchers took fasting blood samples from participants and measured levels of total cholesterol, HDL cholesterol (so-called "good" cholesterol), and levels of a type of lipid called triglycerides. The levels of so-called "bad" cholesterol were calculated based on these measurements.

Participants were classed as having abnormal lipid levels based on pre-specified levels if they reported taking lipid-lowering medication or had been diagnosed as having abnormal lipid levels.

The researchers then looked at whether abnormal lipid levels are linked to job stress. They took into account the following confounders:

• age
• gender
• smoking
• basic measures of alcohol consumption and physical leisure activity
• obesity 
• type of job ("blue collar" or "white collar")

What were the basic results?

Job stress was reported by 8.7% of participants. Participants reporting job stress also had higher levels of anxiety and depression symptoms.

After the researchers took into account factors that could affect the results and adjusted them accordingly, people who reported job stress were found to have 10% higher odds of having abnormal lipid levels (odds ratio [OR] 1.1, 95% confidence interval [CI] 1.04 to 1.17).

They also had increased odds of:

• high levels of "bad" cholesterol (LDL)
• low levels of "good" cholesterol (HDL)
• a high total cholesterol to "good" cholesterol ratio
• a high "bad" cholesterol to "good" cholesterol ratio
   

How did the researchers interpret the results?

The researchers concluded that their results support an association between job stress and abnormal lipid levels in the blood.

Conclusion

This study has found an association between job stress and abnormal lipid levels in the blood. Its strengths include the large number of workers assessed (more than 40,000) and the use of the same methods to assess all of the participants.

However, the fact that both job stress and lipid levels were assessed at the same time means it is not possible to say for certain whether job stress might have directly caused changes in blood lipid levels.

There are also other limitations and points to note:

• The study did not assess diet. People with job stress may have less healthy diets, which could account for the differences seen in the blood lipid levels, rather than these differences being a direct impact of job stress.
• Job stress was assessed by a single question, which may not fully capture all aspects of job stress. Also, different people may consider different things stressful, and the question did not disentangle the exact stressful workplace situations and an individual's ability to cope with them.
• Workers who were off sick would not have had the routine medical check-up. This means the sample may have missed some people with more serious health problems with stress.
• The authors acknowledge that the effect of job stress seen is relatively small – a 10% increase in the odds of having abnormal lipid levels.

Overall, it is not clear from this study whether stress is a direct cause of the increased lipid levels seen. Studies looking at whether interventions to reduce work stress can reduce lipid levels in the blood would provide an indication if this is in fact the case.

Despite these limitations, there is a wide range of good quality evidence that workplace stress can have a harmful effect on your physical and mental health.

While some people may thrive on pressure, persistent high levels of stress are likely to be harmful.

Read more about what you can do to reduce your levels of workplace stress.

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

Links To The Headlines

A stressful job really CAN kill you - by raising your cholesterol. Mail Online, May 17 2013

Links To Science

Catalina-Romero C, Calvo E, Sánchez-Chaparro MA, et al. The relationship between job stress and dyslipidemia. The Scandinavian Journal of Public Health. Published online January 2 2013 

”Sunshine vitamin 'may treat asthma'”, BBC News informs us, as a new lab-based study suggests vitamin D could help control symptoms of severe asthma.

Asthma is caused by inflammation of the airways, related to malfunctioning of the body’s immune system. In theory, the immune system mistakes harmless substances, such as dust mites, as a threat and triggers inflammation of the lungs and airways (which causes the symptoms of asthma).

The study in question looked at IL-17A, which is one of the molecules thought to be associated with the malfunctioning immune response seen in asthma. Researchers examined whether vitamin D had an effect on the levels of the molecule produced by white blood cells in a laboratory experiment.

Researchers found that vitamin D reduced the levels of IL-17A produced by cells from people with asthma. This included cells from people who had previously failed to respond to the treatment of choice for severe asthma – oral corticosteroids – often referred to as steroids.

While this study suggests that vitamin D can have an effect on IL-17A levels in the laboratory, it is certainly too early to hail vitamin D as a potential “cure” for asthma. A positive effect on cells in the lab does not guarantee vitamin D supplements will improve symptoms for people with asthma. Clinical trials in people with asthma are ongoing to test whether this will be the case.

Where did the story come from?

The study was carried out by researchers from King’s College London; Queen Mary, University of London, and the Homerton University NHS Foundation Trust. It was funded by Asthma UK and the National Institute for Health Research, and some researchers received Medical Research Council Funding. The study was published in the peer-reviewed Journal of Allergy and Clinical Immunology.

This study was reported by the BBC, Daily Mail, and the Daily Express. The BBC correctly points out that treating asthma patients with vitamin D “has not yet been tested”. The main text of the Mail’s coverage is generally accurate, although their headline suggests that “Vitamin D ‘helps beat the symptoms of asthma’”, when this was not assessed by the study. The Express’s coverage over-interprets the results by suggesting that “Soaking up sun could be a cure for asthma” or could be “the best way of treating asthma”.

What kind of research was this?

This was a laboratory study looking at the effect of vitamin D on one type of white blood cell (T helper cells called TH17 cells) from people with asthma.

One type of T helper cell called TH2 is known to be involved in inflammation of the airways in asthma. However, some evidence suggests that other T cells may also play a role.

TH17 cells are involved in defending the body against bacterial and fungal infections. There is some evidence that these cells may be involved in severe asthma. Also, one of the inflammatory substances produced by these cells, called IL-17A, may exacerbate asthma and reduce patients’ ability to respond to standard treatment for severe asthma – oral corticosteroids (steroids).

Previously, studies had shown that vitamin D could influence the T cells from patients with severe asthma, and also affect TH17 cells. The researchers in the current study wanted to see if vitamin D affected IL-17A production by TH17 cells collected from asthma patients. They also wanted to see whether this effect was different in people who were resistant to steroid treatments.

What did the research involve?

The researchers took blood from 10 healthy adults and 28 patients with moderate to severe asthma and extracted white blood cells, including T cells. The patients had to have had diagnosed asthma for at least six months. Of the patients, 18 had asthma that did not respond as well to oral steroid treatment (steroid resistant asthma), and 10 had asthma that responded to steroids.

The researchers grew the white blood cells in the laboratory, either with or without vitamin D and the steroid dexamethasone, and looked at how much IL-17A was being produced. They assessed whether this varied between people with and without asthma, or in people with steroid resistant asthma.

What were the basic results?

White blood cells from people with asthma produced higher levels of IL-17A than those from non-asthmatic patients. Furthermore, white blood cells from people with steroid resistant asthma produced the highest levels of IL-17A.

Treating the white blood cells with vitamin D reduced the production of IL-17A. This reduction occurred in cells from people with steroid-resistant asthma and steroid-sensitive asthma, and was not affected by adding the steroid dexamethasone.

How did the researchers interpret the results?

The researchers concluded that their results support the hypothesis that vitamin D could improve disease control in people with asthma by reducing IL-17A levels, regardless of whether the person’s asthma is steroid-resistant.

Conclusion

The current laboratory study suggests that vitamin D can reduce white blood cell production of an inflammatory molecule implicated in asthma.

These results were obtained from cells in the laboratory, and further research will be needed to determine whether this effect will also be seen if people with asthma are given vitamin D.

While the results perhaps give a reason to investigate vitamin D further, not all treatments showing initially positive results in laboratory studies go on to have a positive effect on real-world clinical outcomes.

The good news is, as the Daily Mail reports, the results of this study are being followed up with a randomised controlled trial in participants with steroid resistant asthma.

Randomised controlled trials are the best way of testing if treatments are effective. This trial, and others, will tell us if vitamin D works as a treatment for asthma and if so, who it might be effective at treating. 

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

Links To The Headlines

Sunshine vitamin 'may treat asthma'. BBC News, May 20 2013

Vitamin D 'helps beat symptoms of asthma’. Daily Mail, May 20 2013

Soaking up sun could be a cure for asthma. Daily Express, May 20 2013

Links To Science

Nanzer AM, Chambers ES, Ryanna K, et al. Enhanced production of IL-17A in patients with severe asthma is inhibited by 1α,25-dihydroxyvitamin D3 in a glucocorticoid-independent fashion. The Journal of Allergy and Clinical Immunology.

"Children are picking up the caring roles the state has abandoned," The Guardian says, while The Independent says that 180,000 children work as unpaid carers.

These new figures come from the Office for National Statistics, which has pulled together data on unpaid care in England and Wales from the 2011 census.

The census (which has been carried out every 10 years since the middle of the nineteenth century) reveals an increase in the proportion of the population who are providing unpaid care.

This has risen from 11.5% in 2001 to 11.9% in 2011 in women, and from 8.8% to 9% in men. There tend to be more female carers than male, with the highest burden of care falling on the 50-64 age group for both sexes.

A related report produced by the charity The Children’s Society – based on the same data – has highlighted the issue of children acting as unpaid carers.

The charity's report describes how the census data estimated that there are around 160,000 unpaid young carers in England. It goes on to explain that this is likely to be an underestimate.

What does the ONS find about the gender of carers?

Just over half (58%) of the 5.41 million people providing some level of unpaid care in England are female and 42% are male. This higher proportion of female carers is consistent across all regions. Female carers are representative of 11.9% of the total female population of England and Wales, and male carers are representative of 9% of the male population. Ten years ago these figures were 11.5% and 8.8%.

The level of care provided was most often between one and 19 hours a week. However, 2.9% of the female population and 2% of the male population provided 50 or more hours of care a week. In 2011 in England, 9.5% of the male working population and 13.3% of the female working population were also providing some level of unpaid care. In England, 1.2% of the female population and 1% of the male population were in full-time employment at the same time as providing 50 or more hours of unpaid care. If you are a working carer, read the NHS Choices advice on combining caring with working or studying.

Links To The Headlines

180,000 children work as unpaid carers for relatives. The Independent, May 16 2013

Carers putting their own health at risk, census shows. The Daily Telegraph, May 16 2013

Children are picking up the caring roles the state has abandoned. The Guardian, May 16 2013

Young carers: Quarter of a million children provide care for others. BBC News, May 16 2013