Background: Previous studies have examined the relationships between prenatal fine particulate matter (PM2.5) exposure and gestational diabetes mellitus (GDM), but the results were inconsistent. Furthermore, the possible effect modification by ABO blood group has not been explored.
Objectives: To assess the associations of PM2.5 exposures during pregnancy with maternal glucose levels as well as GDM, and further to evaluate the potential effect modification by ABO blood group.
Methods: Between January 2013 and January 2015, 4783 pregnant women were enrolled in our study based on a birth cohort in Wuhan. Daily PM2.5 exposure levels for each woman during pregnancy were estimated using a spatial-temporal land-use regression model. Linear regressions with general estimating equations (GEE) were performed to assess the associations between trimester-specific PM2.5 exposures and maternal glucose levels. Modified Poisson regressions with GEE analyses were used to evaluate the impacts of PM2.5 exposures during each trimester on the risk of GDM. The associations of PM2.5 exposure during the whole study period with glucose levels and GDM were estimated using multiple linear regression model and modified Poisson regression model, respectively. We conducted a stratified analysis to explore the potential effect modification by ABO blood group.
Results: Among all the 4783 participants, 394 (8.24%) had GDM. Exposure to PM2.5 was found to be positively associated with elevated fasting glucose level during the whole study period [0.382 mg/dL, 95% confidence interval (CI): 0.179-0.586, per 10 μg/m3 increase in PM2.5], the first trimester (0.154 mg/dL ,95% CI: 0.017-0.291) and the second trimester (0.541 mg/dL, 95% CI: 0.390-0.692). No statistically significant results were observed between PM2.5 and 1-h and 2-h glucose levels during any study period. Increased risks of GDM for each 10 μg/m3 increase in PM2.5 levels were observed during the whole study period [relative risk (RR): 1.120, 95% CI: 1.021-1.228] and the first trimester (RR: 1.074, 95% CI: 1.012-1.141), but not the second trimester (RR: 1.035, 95% CI: 0.969-1.106). Stratified analysis indicated that the associations of PM2.5 exposures with GDM were more pronounced among pregnant women with blood group A, but no significant effect modifications were observed.
Conclusion: Our study enriched epidemiological evidence linking PM2.5 exposures during pregnancy to elevated maternal glucose levels and increased risk of GDM. More importantly, we first highlighted that the impact of PM2.5 on GDM might be greater among pregnant women with blood group A.
Keywords: ABO blood Group; Blood glucose; Fine particulate matter; Gestational diabetes mellitus; Pregnancy.
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