Job strain and incident cardiovascular disease: the confounding and mediating effects of lifestyle habits. An overview of systematic reviews.

This overview of systematic reviews (SR) aims to determine how the potential confounding and/or mediating effects of lifestyle habits were taken into consideration in SR examining the job strain effect on cardiovascular disease (CVD) incidence. Thirteen SR were identified. Lifestyle habits were often considered as confounders (n = 8). Authors reported that the job strain and CVD association remained after adjusting for lifestyle habits (n = 6); discussed lifestyle habits as potential mediators (n = 8) and postulated a total effect underestimation due to over-adjustment (n = 4). None investigated the magnitude of this bias.The effect of job strain on CVD is independent of lifestyle habits, supporting its causal effect on CVD. Lifestyle habits are also potential mediators. The current practice of adjusting for lifestyle habits can therefore lead to an underestimation of the total effect. Research using meditation methods is needed.