Tuesday September 23 2014
Stress is a known asthma trigger
“People fearful of losing their jobs are 60% more likely to develop asthma,” The Independent reports.
Researchers have looked at whether perceived job insecurity (specifically, the likelihood that they would lose their jobs) affected people’s risk of developing asthma in Germany during the “Great Recession” (the global economic downturn that lasted from 2008 to 2012).
They found that people who felt there was more than a 50:50 chance of them losing their jobs in the next two years were about 60% more likely to be diagnosed with asthma in this period.
Despite finding a link between job insecurity and asthma, there are a number of things to bear in mind. Associations between mental health, genetic and environmental factors, and physical health can be complex, so it is often difficult to tease out precise causal relationships.
For example, people who reported high levels of job insecurity in this study were also more likely to smoke and be in jobs that might increase their risk of asthma. The researchers tried to take this into account, but it is difficult to know whether factors such as these had an effect.
It does seem plausible that job insecurity – a potentially stressful situation – could cause adult asthma attacks, given that stress can be a trigger. However, we cannot be certain, based on this study alone, whether job insecurity directly increases the risk of developing adult asthma.
Where did the story come from?
The study was carried out by researchers from the University of Düsseldorf in Germany, and other universities in the Netherlands and New Zealand. No funding for the study was reported, and the authors declared that they had no competing interests.
The study was published in the peer-reviewed Journal of Epidemiology and Community Health.
The Independent’s headline wrongly suggests that the study looked at workplace stress, which it did not – rather, it assessed just job insecurity. For the purpose of this study, high job insecurity was defined as a person perceiving that there was more than a 50:50 chance of them losing their job in the next two years. While the majority of us would find such as prospect stressful this may not be the case for everyone – for example, if you hate your job and have a good redundancy package you may even welcome redundancy. A person may also have a very secure job, but still have high levels of work stress.
The Independent, however, does report both the actual risk of people developing asthma in the study as well as the relative increase in risk, which helps put the increase into a meaningful context.
What kind of research was this?
This was a cohort study looking at whether there was a link between job insecurity and new diagnoses of adult asthma. Studies have suggested that job insecurity may increase risk of poor health, and that job-related stress may be a risk factor for asthma, but have not looked at whether job insecurity might be linked with asthma. This latest study used data collected as part of the German Socio-Economic Panel (GSOEP) study, between 2009 and 2011 – during the European economic crisis, when job insecurity increased.
This study design is the best way to look at the link between an exposure and outcome when it is not feasible or ethical to randomly assign people to have the exposure or not (in this case job insecurity). It allows researchers to establish that the exposure did in fact occur before the outcome, and could therefore potentially be contributing to it.
The main limitation is that factors other than the exposure (called confounders) that differ between the exposed and unexposed groups could be causing any differences seen, rather than the exposure itself. Researchers can use statistical methods to try to remove their impact, but these methods are not 100% effective. They also can’t remove the effect of factors the researchers didn’t know about or measure.
What did the research involve?
The researchers analysed data on employed adults who did not have asthma when assessed in 2009. They measured how insecure the participants thought their jobs were at this point and then checked whether they had been diagnosed with asthma two years later, in 2011. They then assessed whether those who felt more job insecurity were more likely to develop asthma.
The data used in this study was collected in face-to-face interviews. Asthma was assessed in both 2009 and 2011 by asking participants if they had ever been diagnosed with this condition by a doctor.
Participants were asked in 2009 to rate on an 11-point scale, from 0% to 100%, how likely they thought they were to lose their job in the next two years. This allowed the researchers to classify and analyse their job insecurity as:
- less than 50%, or 50% and higher
- no insecurity (0%), low job insecurity (10% to up to 50%), high job insecurity (50% and over)
- a continuous measure based on how many standard deviations they were from the average
In their analyses, the researchers took into account confounders that could affect results, including:
- demographic characteristics – such as age and gender
- job factors – such as type of contract and working in a profession which could cause a high risk for asthma
- health behaviours and conditions – such as smoking, overweight and obesity, and depression
Of the approximately 20,000 participants in GSOEP, this latest study analysed the 7,031 who were employed and did not have asthma in 2009, and had answered questions on all the factors included in the analyses.
What were the basic results?
The researchers found that just under a quarter of participants (23%) reported high levels of job insecurity in 2009. These people tended, on average, to be slightly younger, have less education, lower income, and were more likely to be unmarried, be smokers, do less exercise, work in a high-risk asthma occupation, have a non-permanent contract, and to have been diagnosed with depression.
In total, 105 people (1.5%) reported having been diagnosed with asthma during the study period. Among those reporting low or no job insecurity, 1.3% developed asthma, compared to 2.1% of those who reported high job insecurity.
After taking into account the potential confounders, this equated to those with high job insecurity being at 61% higher risk of developing asthma (relative risk 1.61, 95% confidence interval 1.08 to 2.40). The researchers also found similar results if they analysed the effect of job insecurity in different ways.
How did the researchers interpret the results?
The researchers concluded that “perceived job insecurity may increase the risk of new-onset adult asthma”.
This latest study has found that people who reported feeling less secure about their job during the economic crisis were more likely to develop asthma.
It collected data prospectively from a large sample representative of the German population, and excluded people who already reported having asthma at the start of the study. This meant the researchers could be sure that the job insecurity came before the asthma diagnosis.
However, there are also some limitations that mean we should interpret its findings cautiously. Firstly, the researchers tried to take into account some factors that differed between those experiencing high levels of job insecurity and those who did not and might affect results. However, this may not remove their effect entirely. For example, they only had data on smoking at one point in time (in 2008), and did not assess how much a person smoked, or whether this changed over time. People who felt more insecure in their job may have been more likely to start smoking or smoke more, and this could contribute to the link seen.
Secondly, the study only asked people whether they had been diagnosed with asthma by a doctor. It did not check their medical records to confirm this, or give all participants a medical to see if they did have asthma. Some people who already had the condition might not have been diagnosed at the start of the study.
Thirdly, a lot of the participants in the overall study (more than 4,000) could not be analysed as they had missing data. These people differed from the ones who could be analysed in terms of their age, smoking habits and incomes, but not in their reported job insecurity or reported levels of asthma. If these people had been followed up, this could have altered the results.
Finally, it is also worth noting that only a relatively small proportion of people in both groups developed asthma in the study – 2.1% of those reporting high job insecurity and 1.3% reporting low or no insecurity. So most people, regardless of job security, did not develop asthma
The exact causes of asthma development are uncertain, though it is thought to be a combination of hereditary and environmental influences (such as being exposed to smoke as a child). In people who are susceptible to asthma, various things can then trigger an asthma attack – one of which is known to be emotions, which can include stress. For this reason, it is plausible that a stressful situation (job insecurity) could also be a trigger.
Overall, although this study has found a link, there is no certainty that perceived job insecurity was directly causing the development of asthma in people previously without the condition.
If you are worried that concerns about job insecurity are affecting your health, there are a number of steps you can take, such as:
- not working longer hours than you need to just because you want to demonstrate your commitment; you have to have a good balance of work and leisure if you want to be resilient
- being focused; it’s more effective to work in short, intense bursts and then take a break
- if you’re feeling really insecure about your job, talk to your boss or to a trusted colleague and tell him or her how you’re feeling; rumours are often worse than the reality
If you're still feeling anxious or low after a few weeks, see your GP. You may find that talking to a professional therapist helps, and your GP can advise you on talking therapy services in your area.
Read more about coping better with job insecurity
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.