Air Pollution Exposures During Adulthood and Risk of Endometriosis in the Nurses' Health Study II

BACKGROUND: Particulate matter and proximity to large roadways may promote disease mechanisms, including systemic inflammation, hormonal alteration, and vascular proliferation, that may contribute to the development and severity of endometriosis. OBJECTIVE: Our goal was to determine the association of air pollution exposures during adulthood, including distance to road, particulate matter < 2.5 mu m, between 2.5 and 10 mu m, and < 10 mu m, (PM2.5, PM10-2.5, PM10), and timing of exposure with risk of endometriosis in the Nurses' Health Study II. METHODS: Proximity to major roadways and outdoor levels of PM2.5, PM10-2.5, and PM10 were determined for all residential addresses from 1993 to 2007. Multivariable-adjusted time-varying Cox proportional hazard models were used to estimate the relation between these air pollution exposures and endometriosis risk. RESULTS: Among 84,060 women, 2,486 incident cases of surgically confirmed endometriosis were identified over 710,230 person-years of follow-up. There was no evidence of an association between endometriosis risk and distance to road or exposure to PM2.5, PM10-2.5, or PM10 averaged over follow-up or during the previous 2- or 4-year period. CONCLUSIONS: Traffic and air pollution exposures during adulthood were not associated with incident endometriosis in this cohort of women.