Joint effect of ambient PM exposure and vitamin B during pregnancy on the risk of gestational diabetes mellitus.

BACKGROUND

Evidence has indicated that the risk of gestational diabetes mellitus (GDM) was linked to PM exposure during pregnancy, but findings on susceptible exposure windows are inconsistent. Further, previous studies have not paid attention to B intake in the relationship between PM exposure and GDM. The study is aimed to identify the strength and exposure periods for associations of PM exposure with GDM, followed by exploring the potential interplay of gestational B levels and PM exposure on the risk of GDM.

METHODS

The participants were recruited in a birth cohort between 2017 and 2018, and 1396 eligible pregnant women who completed a 75-g oral glucose tolerance test (OGTT) were included. Prenatal PM concentrations were estimated using an established spatiotemporal model. Logistic and linear regression analyses were used to test associations of gestational PM exposure with GDM and OGTT-glucose levels, respectively. The joint associations of gestational PM exposure and B level on GDM were examined under crossed exposure combinations of PM (high versus low) and B (insufficient versus sufficient).

RESULTS

In the 1396 pregnant women, the median levels of PM exposure during the 12 weeks before pregnancy, the 1st trimester, and the 2nd trimesters were 59.33 μg/m, 63.44 μg/m, and 64.39 μg/m, respectively. The risk of GDM was significantly associated with a 10 μg/m increase of PM during the 2nd trimester (RR = 1.44, 95 % CI: 1.01, 2.04). The percentage change in fasting glucose was also associated with PM exposure during the 2nd trimester. A higher risk of GDM was observed among women with high PM exposure and insufficient B levels than those with low PM and sufficient B.

CONCLUSION

The study supported higher PM exposure during the 2nd trimester is significantly associated with GDM risk. It first highlighted insufficient B status might enhance adverse effects of air pollution on GDM.