Increased risk of gestational diabetes mellitus in women with higher prepregnancy ambient PM2.5 exposure.

BACKGROUND:Air pollution is a serious environmental problem in China. This study was designed to investigate whether exposure to particulate matter with an aerodynamic diameter ≤ 2.5 μm (PM2.5) before pregnancy is associated with gestational diabetes mellitus (GDM) and fasting glucose in China. METHODS:We recruited subjects and collected clinical data from the Nanjing Maternity and Child Health Care Hospital from July 2016 to October 2017. A series of validated land-use regression (LUR) models were built to assess individual exposure to PM2.5 in a 1 × 1 km area at both work and home addresses following a time-weighted pattern. Multiple linear regression and logistic regression analyses were performed to examine the association between PM2.5 exposure and GDM and fasting glucose. RESULTS:In total, 11,639 of 16,995 women were included in the final analysis. Among the 11,639 women, 2776 (23.85%) had GDM. Individual exposure to PM2.5 within three months before pregnancy ranged from 21.58 to 85.92 μg/m3. Positive associations were observed among the interquartile ranges (IQRs) of exposure to PM2.5 within three months before pregnancy and GDM (OR = 2.61, 95% CI: 1.40-4.93, p < .01) as well as fasting glucose levels (β = 0.57, 95% CI: 0.45-0.68, p < .01). The diabetogenic effects of PM2.5 gradually increased from the first month before pregnancy, peaked in the second month and then gradually decreased until the third month when the week-specific exposure were analyzed to identify the sensitive time window. CONCLUSION:Our study confirmed that higher exposure to PM2.5 within three months before pregnancy is significantly associated with increased risk of GDM and elevated fasting glucose levels, reflecting the importance of preconceptional environmental exposure in the development of maternal GDM.