Prenatal exposure to air pollution and the risk of preterm birth in rural population of Henan Province.

Due to the poor living and healthcare conditions, preterm birth (PTB) in rural population is a pressing health issue. However, PTB studies in rural population are rare. To explore the effects of air pollutants on PTB in rural population, we collected 697,316 medical records during 2014–2016 based on the National Free Preconception Health Examination Project. Logistic regression models were used to estimate the association between air pollutants and PTB and the modifying effects of demographic characteristics. Relative contribution and principal component analysis-generalized linear model (PCA-GLM) analysis were used to explore the most significant air pollutant and gestational period. Our results demonstrated that PTB risk is positively associated with exposure to air pollutants including PM 10 , PM 2.5 , SO 2 , NO 2 , and CO, while negatively associated with O 3 exposure (P < 0.05). In addition, we found that NO 2 was the largest contributor to the risk of PTB caused by air pollutants (26.5%). The third trimester of pregnancy was the most sensitive exposure window. PCA-GLM analysis showed that the first component (a combination of PM, SO 2 , NO 2 , and CO) increased the risk of PTB. Moreover, we found that rural women who are younger, had higher educated, multi-parity, or smoke appeared to be more sensitive to the association between air pollutants exposure and PTB (P -interaction <0.05). Our findings suggested that increased air pollutants except O 3 were associated with elevated PTB risk, especially among vulnerable mothers. Therefore, the effects of air pollutants exposure on PTB should be mitigated by restricting emission sources of NO 2 and SO 2 in rural population, especially during the third trimester. [Display omitted] • PTB risk was positively associated with prenatal exposure to PM, SO 2 , NO 2 and CO. • Exposure to relatively low concentrations of O 3 can decrease the risk of PTB. • Among pollutants explored, exposure to NO 2 and SO 2 was the major risk factor for PTB. • The third trimester is the most sensitive window for PTB caused by air pollution. • The effect of air pollution on PTB risks varies with an individual's characteristics. [ABSTRACT FROM AUTHOR]