Healthy Worker Effect

The term healthy worker effect (HWE) refers to the fact that employed persons are generally healthier than persons who are not employed. For this reason, studies based on samples drawn from employed people may produce results that are biased due to the selection effect of employment. This is particularly important in cohort studies involving occupational exposures, when studies comparing working cohorts with the general population may not find effects on morbidity and mortality attributable to hazardous occupational exposures due to the healthy worker effect. Study designs that do not account for the selection of healthier workers at the time of employment as well as the removal of sick workers during employment can result in masked health effects and may cause harmful exposures to appear healthful. ...