IPD-Work consortium: pre-defined meta-analyses of individual-participant data strengthen evidence base for a link between psychosocial factors and health.

Established in 2008 and comprising over 60 researchers, the IPD-Work (individual-participant data meta-analysis in working populations) consortium is a collaborative research project that uses pre-defined meta-analyses of individual-participant data from multiple cohort studies representing a range of countries. The aim of the consortium is to estimate reliably the associations of work-related psychosocial factors with chronic diseases, disability, and mortality. Our findings are highly cited by the occupational health, epidemiology, and clinical medicine research community. However, some of the IPD-Work's findings have also generated disagreement as they challenge the importance of job strain as a major target for coronary heart disease (CHD) prevention, this is reflected in the critical discussion paper by Choi et al (1). In this invited reply to Choi et al, we aim to (i) describe how IPD-Work seeks to advance research on associations between work-related psychosocial risk factors and health; (ii) demonstrate as unfounded Choi et al's assertion that IPD-Work has underestimated associations between job strain and health endpoints; these include the dichotomous measurement of job strain, potential underestimation of the population attributable risk (PAR) of job strain for CHD, and policy implications arising from the findings of the IPD-Work consortium; and (iii) outline general principles for designing evidence-based policy and prevention from good-quality evidence, including future directions for research on psychosocial factors at work and health. In addition, we highlight some problems with Choi et al's approach.