Ambient Air Pollution and Preeclampsia Onset in Massachusetts, United States

Abstract

Background and Aim: Ambient particulate matter and gaseous air pollution have been linked to preeclampsia. However, despite the recognition that preeclampsia is likely a heterogenous syndrome with distinct pathogenic mechanisms, few studies have examined the association between air pollution and subtypes of preeclampsia. Our objective was to examine differential impacts of air pollution on early- vs. late-onset (i.e., diagnosed in or after 34th gestation week) preeclampsia among pregnant women in the Boston, Massachusetts based biorepository, LIFECODES. Methods: Preeclampsia was diagnosed according to the American College of Obstetrics and Gynecologists guidelines and each case was reviewed by a panel Maternal–Fetal Medicine–certified physicians. Women’s exposures to ozone and fine particulate matter (PM2.5) during pregnancy were estimated based on geocoded residential addresses using U.S. Environmental Protection Agency’s Fused Air Quality Surface Using Downscaling Files. Cox proportional hazards models and multinomial logistic regression were used to examine the associations of ozone and PM2.5 with preeclampsia and its onsets. Hazard ratio (HR), odds ratio (OR), and 95% confidence interval (95% CI) for each interquartile range increase in exposures were reported. Results: A total of 3,316 pregnant women were included. In the cox model, higher exposures to ozone during pregnancy were associated with higher hazard being diagnosed with preeclampsia (HR: 1.67, 95% CI: 1.16, 2.40). In the multinomial logistic regression model, ozone was significantly associated with early-onset preeclampsia (OR: 2.50, 95% CI: 1.48, 4.21) but not late-onset preeclampsia (OR: 1.34, 95% CI: 0.96, 1.88), and PM2.5 was significantly associated with both early- (OR: 1.62, 95% CI: 1.07, 2.45) and late-onset preeclampsia (OR: 1.32, 95% CI: 1.02, 1.71). Conclusions: Exposures to ozone and PM2.5 were significantly associated preeclampsia. This association was significant with respect to ozone exposure in the earlier onset, but not later onset, preeclampsia. This study highlights the importance of assessing the heterogeneity in preeclampsia.