Objective: Identify most likely health effects of occupational exposure to engineered nanoparticles (ENP). Recommend analytic approaches to address epidemiologic challenges.
Methods: Review air pollution and occupational literature on health effects of fine particulate matter (PM). Provide example of mortality study of exposure to PM composed of metalworking fluid. Apply standard Cox models and g-estimation to adjust for potential healthy worker survival effect (HWSE).
Results: In contrast with standard methods, g-estimation suggests that exposure to PM may cause chronic heart and lung disease; longer exposure reduces survival. HWSE appears stronger for chronic disease than for cancer.
Conclusions: We recommend hazard surveillance, short-term panel studies of biomarkers, and prospective cohort studies of cardiovascular and respiratory diseases. Building research capacity in g-estimation methods to reduce HWSE is necessary for future studies of chronic disease and ENP.