Effects of PM constituents on gestational diabetes mellitus in Chinese pregnant women: The potential modifying role of vitamin B.

Associations of PM and its constituents with gestational diabetes mellitus (GDM) are still unclear, and little is known about the impact of vitamin B. The Gene-Environment-Nutrient-Epigenetics interaction on Maternal and Children health study (GENEMaC) cohort was conducted during 2017-2018 in Tianjin, China, and 1396 eligible women were included in the final analysis. Spatiotemporal models were used to estimate PM exposure levels and its constituents, including sulfate (SO), ammonium (NH), nitrate (NO), organic matter (OM), black carbon (BC). Logistic regression and distributed lag non-linear model (DLNM) were used to assess each pollutant-GDM association. Weighted quantile sum (WQS) regression was conducted to assess the extent of contributions of pollutants co-exposure to GDM. The logistic regression showed that exposures to PM, NO, and NH during the 2nd trimester of pregnancy increased the risk of GDM. DLNM analyses observed a lag exposure-response relationship for each constituent, while BC exposed in the 2nd trimester was displayed as the top contributor in the WQS model. The joint effects of constituents exposure (high versus low) and serum B (tertiles) on GDM were further evaluated, and the highest risks of GDM were consistently observed in the low B level and high pollution groups for SO, NO, and NH. These findings provide evidence of the impact of PM components on GDM and highlight the susceptibility of pregnant women with low B levels to air pollution.