Statistical Analysis Of The Impact Of Air Pollutants On Adverse Pregnancy Outcomes

Along with the rapid economic development and a great improvement in the stan-dard of living conditions,people are taking air pollutions more and more seriously.Air pollutions has become one of the greatest environmental risks threatening human health due to its universal exposure,especially for the pregnant women who are more sensitive to air pollutants.Pregnant women are exposed to air pollutants,which can directly affect the fetus through the placenta,or indirectly affect the health of the fetus by affecting the mother's physiological changes.Therefore,it is important to investigate the effects of air pollutants on adverse pregnancy outcomes.Based on pre-pregnancy screening and post-pregnancy follow-up data provided by the ELEFANT(Environmental and lifestyle factors in metabolic health throughout life-course trajectories)project for 11,354 women living in Tianjin,this paper investigated the influence of air pollutants on two adverse pregnancy outcomes,preterm birth and low birth weight,from 24 weeks before preg-nancy to 40 weeks after pregnancy.We collected the dataset of six common air pollu-tants from 25 air quality monitoring stations in Tianjin during the period from January1,2014 to June 30,2016.Three interpolation methods for spatial data,namely in-verse distance weighted interpolation,ordinary kriging and cokriging,were adopted to interpolate the pollutant concentrations for each subject based on their residence infor-mation.With functional logistic regression,we analyzed the influence of air pollutants on adverse pregnancy outcomes in different period.The main results are presented as follows:The exposure levels of PM2.5and PM10 of pregnant women from four months after pregnancy to delivery,the exposure levels of NO2 during the peroid from four to six months before pregnancy and the three months after pregnancy to delivery are positively correlated with the odds ratio of low birth weight? the pregnant women's PM2.5exposure levels from one month after pregnancy to delivery,the exposure level of NO2 three to six months before pregnancy and four months after pregnancy to delivery,the exposure level of PM10 during the first four months of pregnancy to delivery are positively correlated with the odds ratio of preterm infants.The main contributions of this paper include: this is the first study using functional data analysis to investigate the impact of pollutants on adverse pregnancy outcomes?the seasonal trends of pollutant time series were removed before fitting the functional logistic model in order to control for the effect of seasonal factors? three spatial data interpolation methods were considered to obtain the air pollutants data for each study subject? the effects of six air pollutants on preterm birth and low birth weight before and after pregnancy were studied.