A review of the healthy worker effect in occupational epidemiology.

This review article aims to anatomize sources of the healthy worker effect (HWE) and to summarize advantages and limitations of several approaches frequently proposed to eliminate the HWE. Although the HWE is frequently addressed in the context of selection bias, our review suggests that the selection of occupational cohorts with advantageous health status would preferably be addressed as a source of confounding biases. The authors also conclude that the exclusion of unhealthy workers at employment and the study of active workers are the two main sources of HWE, and that the use of the general population as a comparison group in occupational epidemiology should be avoided if possible. The authors encourage investigators to make distinctions between the underlying factors related to the use of the general population as the comparison group in occupational epidemiology.