'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

“IVF advance triples couples' chances of having a baby”, The Daily Telegraph reports.

The innovation in question is actually based on an old imaging technique called time-lapse photography, where a camera is set to record a series of images at regular intervals. This technology is now available for monitoring the development of IVF embryos before they are transferred into the womb.

The researchers in this study developed a way of using the information collected to identify which embryos had a low or high chance of having an abnormal number of chromosomes (called aneuploidy). Aneuploidy can reduce the chances of embryos successfully implanting and resulting in a healthy live birth.

In this study, the researchers looked back at time-lapse imaging for embryos from 69 couples who had IVF. They wanted to know if their technique correctly identified embryos which were more likely to result in a pregnancy or live birth.

The time-lapse cameras allowed the researchers to potentially ‘screen’ embryos for risk of aneuploidy. From this, they would then be able to choose the low risk embryos for implantation.

The researchers found that 73% of the embryos their assessment would have classed as low risk resulted in a pregnancy at five to six weeks, and 61% resulted in a live birth. These rates were higher compared to the overall rate for all embryos (at any risk level), where the pregnancy rate was 42% and the live birth rate was 39%. However, it is important to restate that the new system was not used to intervene, so the results are based purely on observation.

While the results are promising, the technique is still in its early stages. Further research is needed to more widely test the technique and directly compare its results to standard methods.

Where did the story come from?

The study was carried out by researchers from CARE Fertility, an independent provider of fertility treatment and related services in the UK and Ireland. No sources of financial support were reported and the authors reported that they had no financial or commercial conflicts of interest.

The study was published in the peer-reviewed medical journal, Reproductive Biomedicine Online.

The study was well reported in the media, with BBC News coverage including an informative video to explain the technique.

However, potentially confusing figures are reported in other parts of the media.

The Times reported that the new technique “could give a 78% chance of success” while the Daily Mail reports that “Early trials show 78% of women having the test will have a healthy baby”.

The Guardian’s reporting suggests that “Doctors in Nottingham who devised the procedure say it could raise live birthrates at their clinic to 78%...” and this may be where this figure has come from.

However, this 78% figure does not come from the research paper itself, which reports that 61% of the low risk embryos successfully resulted in a live birth – not 78%.

What kind of research was this?

This study looked at whether the novel technique based on time-lapse images of IVF embryos might help select the embryos most likely to successfully produce a baby.

Until now, the researchers say that the vital decision about which IVF embryo should be selected and transferred into the mother’s womb is mainly based on between two and six observations of the developing embryo under the microscope.

To observe the embryo’s development, doctors have had to remove the culture dish containing the embryos from the very controlled environment of the incubator and place them under a microscope in the ambient air of the laboratory. This is usually only performed once a day to minimise disturbance to the embryo.

The authors of the study report that a major reason for IVF failure and miscarriage is that the implanted embryo has an abnormal number of chromosomes (aneuploidy). To accurately detect any chromosomal abnormality requires an invasive biopsy of the developing embryo, followed by genetic testing.

Currently it is not possible to reliably identify those embryos with an increased chance of aneuploidy with the normal microscopic observations of the embryo.

The current study tested a way of identifying the embryos at low risk of having abnormal numbers of chromosomal, using time-lapse imaging of the embryo. A relatively new system now allows doctors to obtain a stream of thousands of microscopic images of developing embryos (time-lapse images), without having to remove embryos from the incubator.

Using this system, the researchers previously found that embryos with an abnormal number of chromosomes take a different length of time to reach certain developmental stages than normal embryos. Based on this, they developed a method to identify those embryos at low, medium, and high risk of having an abnormal number of chromosomes.

In their current study, the researchers looked back at the results of IVF procedures where the embryos had been assessed using time-lapse imaging. They wanted to see if their method could identify those embryos which were more likely to go on to successfully implant, develop and be born.

It is important to note that the study did not actually use the method to select embryos for implantation – it only looked at what might have happened if the method had been used.

This is an appropriate first step for this type of research and, if the results are promising, the method would need to go on to be tested “for real” to select embryos, to see if it performed better than standard methods.

What did the research involve?

This study looked at the treatment outcomes for 88 embryos from 69 couples who attended the CARE Fertility clinic in Manchester between April 2011 and December 2012, and who had a known outcome from their IVF.

This meant that they knew if transfer of the embryo(s) had resulted in:

• failed implantation – where the woman had a negative pregnancy test
• clinical pregnancy – defined as the presence of a developing embryo with a heart beat at between six and eight weeks of pregnancy
• a live birth – identified through the mother completing a clinic delivery outcome form, which according to regulations is reported to the UK Human Fertilisation and Embryology Authority

The researchers excluded cases where two embryos were implanted but did not both have the same outcome, as they would not be able to tell which embryo had which outcome.

The egg cells collected from the women had been fertilised using intra-cytoplasmic sperm injection (ICSI), where a single sperm is injected directly into the egg. The fertilised eggs were then placed into the time-lapse incubator for culturing and imaging for five to six days.

The inbuilt microscope took images of the fertilised egg cell every 20 minutes. The image-analysis software recorded the precise timing of developmental events as they occurred. The embryos had been selected using standard existing methods before being transferred into the womb (that is, not using the new risk assessment method).

The researchers used this previously collected data model to assess the embryos, and grade whether the embryos were at low, medium or high risk of having an abnormal number of chromosomes. They then looked at what proportion of each of these three groups of embryos had achieved clinical pregnancy and live birth, and if this differed between the groups.

What were the basic results?

The researchers found that of the 88 embryos they assessed, 33 were at low risk for having an abnormal number of chromosomes, 51 at medium risk, and four at high risk.

Overall, 42% of the embryos successfully implanted and had a fetal heart beat at five to six weeks.

Among the low risk embryos, almost three-quarters (73%) successfully implanted and had a fetal heart beat at five to six weeks, compared to a quarter (25.5%) of medium risk embryos and no high risk embryos.

This meant that the 73% figure for low risk embryos is a relative increase of 74% compared with the rate for all embryos (42%) – what the media has translated as a ‘74% chance of successful pregnancy’.

The researchers had data on whether or not women had a live birth for 46 of the embryos (18 low risk, 26 medium risk, two high risk). The rest of the pregnancies had not reached term during the study period.

Overall, 39% of the embryo transfers resulted in a live birth. Among the low risk embryos, 61% resulted in a live birth. Among medium risk embryos, 19% resulted in live birth. None of the high risk embryos resulted in a live birth.

Therefore, the 61% figure for low risk embryos is a relative risk increase of 56% compared with the rate for all embryos (39%) – this is where media reports of the ‘increasing live birth rates to above 50%’ come from.

How did the researchers interpret the results?

The researchers say that their risk classification model using time-lapse imaging introduces a non-invasive way of selecting the embryos that are at a low risk of having an abnormal number of chromosomes. They say that this can result in higher likelihood of successful pregnancy and live birth.

Conclusion

This study reports on a new technique using ‘time-lapse imaging’ to non-invasively identify the IVF embryos least likely to have abnormal numbers of chromosomes.

An embryo having an abnormal number of chromosomes is one of the reasons IVF can be unsuccessful.

By looking back at the results of previous IVF procedures, the study showed that embryos identified as being low risk using the new method were the most likely to result in a live birth.

To date, IVF techniques rely on removing the embryo from the incubator about once daily over the course of five to six days to view its development under the microscope. As such, current methods only allow for a few static images which cannot give a reliable indication of whether an embryo has chromosome abnormalities, and also disturb the developing embryo. To select the best embryo for implantation, biopsies of the embryo have to be taken to examine the genes. The new technique potentially offers a non-invasive way to assess the risk of chromosome abnormality using detailed time-lapse images.

The results of this study are promising, but there are some limitations:

• It only assessed the outcomes for only 69 couples who received care at one fertility service. Larger numbers of embryos would ideally need to be assessed to confirm the results. Ideally, prospective studies comparing this new technique with standard techniques would also be carried out.
• The researchers note that their methods and results may not be directly transferable to other laboratories or other types of patient populations. 

The technique, while potentially promising, is still in an early stage of development. 

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

Links To The Headlines

IVF could be revolutionised by new technique, says clinic. The Guardian, May 17 2013

'Most exciting breakthrough in IVF treatment in 30 years' could triple number of births. The Independent, May 17 2013

IVF advance triples couples' chances of having a baby. The Daily Telegraph, May 17 2013

IVF test that 'trebles the chance of a baby': Photo method helps doctors implant best embryo. Daily Mail, May 17 2013

IVF 'may be boosted by time-lapse embryo imaging'. BBC News, May 17 2013

New IVF Technique Could Triple Number Of Births. Sky News, May 17 2013

IVF time lapse photographing technique breakthrough could help avoid miscarriages and triple number of births. Daily Mirror, May 17 2013

New IVF technique using time-lapse photos to increase number of healthy births. Metro, May 17 2013

Links To Science

Campbell A, Fishel S, Bowman N, et al. Retrospective analysis of outcomes after IVF using an aneuploidy risk model derived from time-lapse imaging without PGS. Reproductive BioMedicine Online. Published online May 13 2013