Investing in Prospective Cohorts for Etiologic Study of Occupational Exposures

Prospective cohorts have played a major role in understanding the contribution of diet, physical activity,medical conditions, and genes to the development ofmany diseases, but have not been widely used for occupational exposures. Studies in agriculture are an exception. We draw upon ourexperience using this design to study agriculturalworkers to identify conditions that might foster use of prospective cohorts to study other occupational settings. Prospective cohort studies are perceived by many as the strongest epidemiologic design. It allows updating of information on exposure and other factors, collection of biologic samples before disease diagnosis for biomarker studies, assessment of effect modification by genes, lifestyle, and otheroccupational exposures, and evaluation of a wide range of health outcomes. Increased use of prospective cohorts would be beneficial in identifying hazardous exposures in the workplace. Occupational epidemiologists should seek opportunities to initiate prospective cohorts to investigate high priority, occupational exposure