Relationship Between Temporal Distribution Of Air Pollution Exposure And Glucose Homeostasis During Pregnancy

ObjectiveTo investigate the effects of air pollutant exposure during pre-pregnancy and first trimester on the risk of gestational diabetes mellitus(GDM)and glucose homeostasis during pregnancy。MethodsFrom March 2015 to April 2019,6059 pregnant women were recruited from hefei first people’s hospital,the first affiliated hospital of anhui medical university and anhui provincial maternal and child health care hospital.Face-to-face questionnaire was used to collect the demographic data,the health status of pregnant women and lifestyle of pregnant women.All subjects underwent an oral glucose tolerance test from 24 to 28 weeks of pregnancy to obtain fasting blood glucose(FPG)and 1h plasma glucose(PG-1h)and 2h plasma glucose(PG-2h).GDM was diagnosed with reference to the IADPSG diagnostic criteria.The daily average concentrations of PM2.5,PM10,SO2 and O3 in fixed monitoring station in Hefei were obtained from the Hefei Environmental Protection Administration.The individual exposure of pregnant women is based on the concentration of air pollutants at monitoring points in the area where the home address of the pregnant woman is located.We used logistic regression to investigate the association of exposure to major air pollutants(PM2.5、PM10、SO2 and O3)during different periods of pregnancy(pre-pregnancy and first trimester)and duration of exposure to high levels of pollutants with GDM.The effects of exposure to air pollutants on glucose metabolism indexes(FPG,PG-1h and PG-2h)were analyzed by multivariate linear regression.Furthermore,quadratic polynomial fitting method was used to explore the maximum effect time of air pollutants on blood glucoseResultsOf the 6059 participants,1230(20.3%)had GDM.Chi-square test results showed that maternal age,education level,pre-pregnancy BMI,parity,frequency of physical activity of pregnant women,frequency of fruit and sweets intake,history of diabetes among immediate family members,season of OGTT,and meteorological factors are related to GDM risk.From the summer of 2014 to the winter of 2018,the seasonal variation of AQI in hefei was the highest in winter and the lowest in summer.The results of multivariate logistic regression analysis showed that after adjusting for confounding factors,the risk of GDM increased gradually with the prolonged exposure time of high-concentration pollutants compared with pregnant women who were not exposed to high pollution during pre-pregnancy(χ2=38.53,p for trend<0.001),the OR,95%CI values for exposure time 1,2,and 3 months were 1.21(0.94 to 1.56),1.29(1.01 to 1.65),and 1.72(1.29 to 2.29).The study found that in the single-pollutant model,exposure to air pollutants before pregnancy was significantly correlated with GDM risk.For each increase in PM2.5,PM10,SO2,and O3 during pre-pregnancy,the risk of GDM increased by 27%(OR=1.27,95%CI:1.10～1.47),39%(OR=1.39,95%CI:1.25～1.56),19%(OR=1.19,95%CI:1.10～1.30)and 19%(OR=1.19,95%CI:1.08～1.30).The results showed a positive effect of exposure to higher-concentration air pollutants 1 year before pregnancy on glucose homeostasis during pregnancy.For each IQR increase in PM2.5 and PM10,the risk of GDM increased by 18%(OR=1.18,95%CI:1.09～1.28)and 11%OR=1.11,95%CI:1.02～1.20)The time windows of the maximum effect of PM2.5,PM10,SO2,and O3 on GDM were different.The time windows of the maximum effect of PM2.5,PM10,and SO2 were 6 months,5 months,and 1 month before the last menstrual period(LMP)and 3 months after the LMP,respectively.Multivariate linear regression analysis of the effects of air pollutant exposure on glucose metabolism indicators.The results show the time windows of the maximum effect of PM2.5 exposure on FPG,PG-1h and PG-2h were 6 months before pregnancy,7 months before pregnancy and 6 months before pregnancy The time windows of the maximum effect of PM10 exposure on FPG,PG-1h and PG-2h were 5 months before pregnancy,6 months before pregnancy and 6 months before pregnancy.The time windows of the maximum effect of SO2 exposure on FPG,PG-1h and PG-2h were 3 months before pregnancy,3 months before pregnancy and 2 months before pregnancy.The maximum effect window of O3 exposure on FPG,PG-1h and PG-2h all appeared at 3 months after pregnancy.The effect of air pollutant exposure on glucose metabolism indicators is similar to the effect of air pollutants on GDMConclusionsThe exposure to air pollutants during pre-pregnancy and pregnancy has a significant impact on GDM risk and glucose metabolism indicators.The risk of GDM increased significantly with the increase of exposure time to high-concentration pollutants in the 3 months before pregnancy.The maximum effect time of different pollutants on glucose metabolism indicators was different.The maximum effect time of PM on GDM and glucose metabolism indicators appeared earlier than SO2 and O3 Considering the above-mentioned associations,the impact of pre-pregnancy air pollutant exposure on GDM risks should be emphasized,and high-quality intervention studies should be conducted to identify potential public health values.