Effort-reward imbalance at work and incident coronary heart disease: a multi-cohort study of 90,164 individuals

Abstract

Background: Epidemiologic evidence for work stress as a risk factor for coronary heart disease is mostly based on a single measure of stressful work known as job strain, a combination of high demands and low job control. We examined whether a complementary stress measure that assesses an imbalance between efforts spent at work and rewards received predicted coronary heart disease. Methods: This multi-cohort study (the 'IPD-Work' consortium) was based on harmonized individual-level data from 11 European prospective cohort studies. Stressful weappork in 90,164 men and women without coronary heart disease at baseline was assessed by validated effort-reward imbalance and job strain questionnaires. We defined incident coronary heart disease as the first non-fatal myocardial infarction or coronary death. Study-specific estimates were pooled by random-effects meta-analysis.

Results: At baseline, 31.7% of study members reported effort-reward imbalance at work and 15.9% reported job strain. During a mean follow-up of 9.8 years, 1078 coronary events were recorded. After adjustment for potential confounders, a hazard ratio of 1.16 (95% confidence interval 1.00-1.35) was observed for effort-reward imbalance compared to no imbalance. The hazard ratio was 1.16 (1.01-1.34) for having either effort-reward imbalance or job strain, and 1.41 (1.12-1.76) for having both these stressors compared to having neither effort-reward imbalance nor job strain.