CardioExchange Archive

A new study in the Lancet provides the best evidence yet that work-related stress and, in particular, job strain — “the combination of high job demands and low control at work” — plays a small but important role in causing heart disease. In order to address the limitations of previous studies on this topic, including a publication bias which might exaggerate the effect, European investigators performed a large collaborative meta-analysis of published and unpublished studies.

The IPD-Work (individual-participant-data meta-analysis in working populations) consortium found that 15% of nearly 200,000 individuals reported having job strain. With a mean follow-up of 7.5 years, job strain was significantly associated with increased risk for heart disease. The effect was higher in published studies, though it still achieved significance in the unpublished studies:

• Overall hazard ratio (HR) for job strain: 1.23,CI 1.10–1.37
• HR in published studies: 1.43, CI 1.15−1.77
• HR in unpublished studies: 1.16, CI 1.02−1.32

The investigators calculated that the population attributable risk for job strain was 3.4%, which, they noted, was substantially lower than the major risk factors of smoking, obesity, and physical inactivity.

“Our findings suggest that job strain is associated with a small, but consistent, increased risk of an incident event of cardiovascular heart disease,” they concluded.

In an accompanying comment, Bo Netterstrøm writes that “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.”