Employees with very demanding jobs and not much freedom to make decisions have a much higher risk of having a heart attack compared to other people of their age whose jobs are less stressful, researchers from University College London reported in The Lancet.

If you have a very stressful job and are not given the freedom to make decisions, your chances of experiencing a heart attack are 23% higher, they explained.

A 2008 study carried out by researchers at the same university in London involving over 10,000 civil servants also linked job stress to a higher risk of heart disease.

Team leader, Mika Kivimäki from University College London, said:

“The pooling of published and unpublished studies allowed us to investigate the association between coronary heart disease (CHD) and exposure to job strain [defined by high work demands and low decision control] with greater precision than has been previously possible. Our findings indicate that job strain is associated with a small, but consistent, increased risk of experiencing a first CHD event such as a heart attack.”

The authors explained that prior studies that looked at an association between coronary heart disease and job-related stress have been unsatisfactory; either they were not large or wide-ranging enough, they were not set up comprehensively, or there was a reverse causation bias.

A study carried out by researchers from the Women’s Hospital, Boston, Mass., USA, found that women in highly stressful jobs are 40% more likely to suffer from heart and cardiovascular diseases, including heart attack, ischemic stroke and blocked arteries, than other females of the same age.

In this latest study, Kivimäki and team set out to determine whether work-related stress might impact on coronary heart disease risk. They conducted a meta-analysis covering 13 European countries, including the UK, Sweden, the Netherlands, France, Finland, Denmark, and Belgium. The studies spanned from 1985 to 2006. Participants were asked to complete a questionnaire at the beginning of their the studies – they were asked questions regarding how free they were to make decisions, their job demands, excessive workloads, and levels of time-pressure demands.

Out of 197,473 participants, 15% (30,214) reported job strain. 2,358 cases of coronary heart disease incidences (coronary death or first non-fatal heart attack) over a 7.5 year follow-up period.

Even after taking into account such factors as socioeconomic status, gender, age, and lifestyle, the 23% higher risk of coronary heart disease still stood.

Kivimäki said:

“The overall population attributable risk (PAR) for CHD events was around 3.4%, suggesting that if the association were causal, then job strain would account for a notable proportion of CHD events in working populations.

As such, reducing workplace stress might decrease disease incidence. However, this strategy would have a much smaller effect than tackling standard risk factors such as smoking (PAR 36%) and physical inactivity (PAR 12%).”

In a Comment in the same journal, Bo Netterstrøm from Bispebjerg Hospital, Copenhagen, Denmark wrote “Job strain is a measure of only part of a psychosocially damaging work environment, which implies that prevention of workplace stress could reduce incidence of coronary heart disease to a greater extent than stated in the authors’ interpretation of the calculated population-attributable risk for job strain. Exposures such as job insecurity and factors related to social capital and emotions, are likely to be of major importance in the future. The present economic crisis will almost certainly increase this importance.”

A 2008 study showed that stress at work hampers sleep; and that the lack of sleep leads to other negative health consequences.

Another study published by the British Psychological Society found that the health impact of work-related stress can be diminished if people believe in their own effectiveness in dealing with the challenges at work.

Written by Christian Nordqvist