Maternal particulate matter exposure and gestational diabetes mellitus: a population–based cohort study

Abstract

Gestational diabetes mellitus (GDM) prevalence is steadily increasing worldwide, posing a significant threat to the short- and long-term health of both mother and offspring. As particulate matter (PM) air pollution has been reported to affect glucose metabolism, it was suggested that maternal PM exposure may be associated with the development of GDM; however, evidence is limited and inconsistent. To study the association between maternal exposure to PM2.5 and PM10 and the risk of GDM, to identify critical windows of susceptibility and to evaluate effect modification by ethnicity. A retrospective cohort study was conducted including pregnancies of women who delivered at a large tertiary medical center in Israel between the years 2003 and 2015. Residential PM levels were estimated by a hybrid spatiotemporally resolved satellite-based model at 1-km spatial resolution. Multivariable logistic analyses were applied to study the association between maternal PM exposure in different pregnancy periods and GDM risk, while adjusting for background, obstetrical and pregnancy characteristics. Analyses were also stratified by ethnicity (Jewish / Bedouin). The study included 89,150 pregnancies, 3,245 (3.6%) were diagnosed with GDM. First trimester exposure to both PM2.5 (adj. OR per 5 μg/m3 = 1.09; 95%CI: 1.02, 1.17) and PM10 (adj. OR per 10 μg/m3 = 1.11; 95%CI: 1.06, 1.17) was significantly associated with increased risk for GDM. In the stratified analyses, the association with first trimester PM10 exposure was consistent among pregnancies of both Jewish and Bedouin women, while the association with first trimester PM2.5 exposure was significant among pregnancies of Jewish women only (adj. OR per 5 μg/m3 = 1.09; 95%CI: 1.00, 1.19), as well as association with preconception PM10 exposure (adj. OR per 10 μg/m3 = 1.07; 95%CI: 1.01, 1.14). No association was found between second trimester PM exposure and GDM risk. Maternal exposure to both PM2.5 and PM10 during the first trimester of pregnancy is associated with GDM, suggesting the first trimester as a particular window of susceptibility to the effect of PM exposure on GDM risk. The effects found in this study differed by ethnic group, emphasizing the importance of addressing ethnic disparities when assessing environmental impacts on health.