Preconception air pollution exposure and glucose tolerance in healthy pregnant women in a middle-income country

Abstract

Background: Preconception exposure to air pollution has been associated with glucose tolerance during pregnancy. However, the evidence in low and middle-income countries (LMICs) is under debate yet. Therefore, this study aimed to assess the relationship between exposure to ambient particulate matter (PM) and traffic indicators with glucose tolerance in healthy pregnant women in Sabzevar, Iran (2019). Methods: Two-hundred and fifty healthy pregnant women with singleton pregnancies and 24-26 weeks of gestations participated in our study. Land use regression (LUR) models were applied to estimate the annual mean of PM1, PM2.5 and PM10 at the residential address. Traffic indicators, including proximity of women to major roads as well as total streets length in 100, 300 and 500m buffers around the home were calculated using the street map of Sabzevar. The oral glucose tolerance test (OGTT) was used to assess glucose tolerance during pregnancy. Multiple linear regression adjusted for relevant covariates was used to estimate the association of fasting blood glucose (FBG), 1-h and 2-h post-load glucose with PMs and traffic indicators. Results: Exposure to PM1, PM2.5 and PM10 was significantly associated with higher FBG concentration. Higher total streets length in a 100 m buffer was associated with higher FBG and 1-h glucose concentrations. An interquartile range (IQR) increase in proximity to major roads was associated with a decrease of -3.29 mg/dL (95% confidence interval (CI): -4.35, -2.23, P-value < 0.01) in FBG level and -3.65 mg/dL (95% CI: -7.01, -0.28, P-value = 0.03) decrease in 1-h post-load glucose. Conclusion: We found that higher preconception exposure to air pollution was associated with higher FBG and 1-h glucose concentrations during pregnancy.

Impact of polluting fuels for cooking on diabetes mellitus and glucose metabolism in south urban China

“…To the best of our knowledge, this study is one of the first studies which evaluates the association of exposure to polluting fuels for cooking with OGTT of urban areas in a developing country. Although we did not find a positive relationship, results were similar to the negative findings of ambient PM and glucose tolerance in healthy pregnant women in Iran 40 . In addition, we unexpectedly observed the negative associations between exposure to polluting fuels for cooking and HbA 1c .…”

“…Although we did not find a positive relationship, results were similar to the negative findings of ambient PM and glucose tolerance in healthy pregnant women in Iran. 40 In addition, we unexpectedly observed the negative associations between exposure to polluting fuels for cooking and HbA 1c . HbA 1c is a stable marker for the mean blood glucose level in an individual over the previous 30 to 120 days, which might be a more accurate indicator of the association with long-term exposure to air pollution.…”

Identifying pre-conception and pre-natal periods in which ambient air pollution exposure affects fetal growth in the predominately Hispanic MADRES cohort

“…Although our study examined exposure to air pollution three months prior to conception, no critical windows of exposure on fetal growth were identified during this preconception period. Emerging literature has shown that preconception air pollution exposure influences pregnancy outcomes, notably gestational diabetes mellitus [ 41 – 43 , 62 ]. The influence of preconception exposure to air pollution on fetal growth may be smaller than that of exposure during pregnancy, thus indicating more statistical power may be needed through larger sample sizes.…”

“…Averaging exposure across pregnancy lacks the ability to identify critical windows of exposure or capture the true variability of the exposures across gestation. Exposure time windows have also generally been limited to prenatal time points, with few studies exploring whether preconception exposures influence fetal growth, which has been shown to influence other pregnancy outcomes [ 41 – 43 ].…”

Identification of differential metabolites using untargeted metabolomics between gestational diabetes and normal pregnant women

“…[4][5][6] In addition to traditional risk factors, new data suggest that environmental and psychosocial factors are also risk factors for the development of GDM. 7,8 GDM may be harmful to both mother and fetus, for example, by increasing the risk of maternal pre-eclampsia 9 and of macrosomia 10 in the fetus. Therefore, it is most important to screen for potential diagnostic biomarkers of GDM and to promote the study of the pathologic mechanisms of GDM.…”