The Relationship Between Atmospheric Particulate Matter And Adverse Birth Outcomes,Health Risk Assessment

Background:Air pollution is a global public health problem,which is especially serious in fast developing China.Studies have investigated the relationship between air pollution and preterm birth,however,the results have been inconclusive.Majority of earlier studies have been conducted in areas with much lower air pollution levels.Building upon the Lanzhou birth cohort study,we aim to examine the relationship between air pollution and preterm birth in Lanzhou and to identify key exposure windows influencing the risk of preterm birth..We then conduct sampling on indoor PM_2.5 to evaluate metal compositions based on different types of cooking fuels in different seasons.By assessing potential health risk through inhalation exposure pathways,we examine the relationship between indoor heavy metal pollution and birth outcomes.This study will comprehensively evaluate the health effects on birth outcomes caused by both ambient and indoor air pollution,particularly particulate matters in Lanzhou city.Goal:The goal of the study is to use logistic regression model to examine the relationship between exposure to air pollutants(SO₂?NO₂ and PM₁₀)during pregnancy and preterm birth.risk,and to understand the impact caused by different types of air pollutants on preterm birth during different gestational time windows.The study results will provide scientific evidence to government who enact air pollution controlling policies and eventurally reduce preterm births.We will also explore the goodness of fit of different models by incorporating multiple pollutants,which could lead meaningful methodology references for environmental epidemiology study in China.Finally,we conduct health risk assessment caused by heavy mental contained in indoor PM_2.5 through inhalation pathways to predict the acceptable level of health risks among population.The results will provide evidence for policy makers to make decisions about risk management and enacting relevant strategies.Method:?1?Conducting summary statistical analysis to describe and analyze air pollutants collected through the air monitoring stations operated by the Gansu Provincial Environmental Monitoring Central Station in Lanzhou during 2009 to 2012.?2?Using data collected in the Lanzhou birth cohort study between 2010 to 2012,we selected information on home and work addresses and other confounding variables,which were collected through questionnaires by in-person interviews,and birth outcomes and maternal complications during pregnancy,which were abstracted from hospital records,for the current study.?3?Combing with air pollution monitoring data,individual exposures during pregnancy were calculated using inverse-distance weighting approach based on home and working addresses.?4?Using logistic regression model adjusting potential confoundingfactors,including age,education,family income,smoking,season of conception,parity and type of cooking fuels,to examine the relationship between preterm birth and air pollutants by different exposure time windows.?5?Useing Health Risk Assessment Model recommended by American EPA to conduct quantitative analysis on health risks caused by heavy metal contained in indoor PM _2.5.Result:?1?The annual PM₁₀ level in Lanzhou was relatively high.The PM₁₀ level in winter and spring was significantly higher than it in summer and autumn.It was also significantly higher in heating season compared to non-heating season.There were two major peaks from December through March and April of next year.In November,Lanzhou enters heating season while coal was the major component of Lanzhou's energy structure.Therefore,the amount of coal used for heating increased dramatically during this period.Moreover,the frequency of calm wind and temperature inversion was high in winter,which hinderred the spread of pollutants.In spring,the sandstorm weather appeared at a high frequency as well.Therefore,the coal burning and dust became the two largest contributors to PM₁₀ pollution in Lanzhou.?2?The results of Single Pollutant Logistic Regression Model showed:during four,six and eight weeks before delivery,exposure to high concentration of PM₁₀ was associated with an increased risk of extreme preterm birth,the OR was 1.07?95%CI:1.02-1.13?,1.09?95%CI:1.02-1.15?,1.10?95%CI:1.03-1.17?;during the entire pregnancy,the 1^st trimester,four or six weeks before delivery,exposure to high concentration of PM₁₀ was associated with an increased risk of medically-indicated preterm birth,the OR was 1.14?95%CI:1.02-1.28?,1.07?95%CI:1.01-1.14?,1.04?95%CI:1.00-1.09?,1.04?95%CI:1.00-1.09?.?3?The results of Multiple Pollutants Logistic Regression Model showed:after including different pollutants PM₁₀0 and SO₂ in the regression model at the same time,during four,six and eight weeks before delivery,exposure to high concentration of PM₁₀ was associated with an increased risk of extreme preterm birth,the OR was 1.08?95%CI:1.02-1.14?,1.09?95%CI:1.03-1.16?,1.10?95%CI:1.03-1.18?,during the entire pregnancy,the 1^st trimester,four weeks before delivery,the exposure to high concentration of PM₁₀ was associated with an increased risk of medically-indicated preterm birth,the OR is 1.13?95%CI:1.00–1.27?,1.07?95%CI:1.00-1.14?,1.04?95%CI:1.00-1.09?.After including pollutants PM₁₀ and NO₂ in the regression model at the same time,during four,six and eight weeks before delivery and the 3^rdd trimester,exposure to high concentration of PM₁₀ was associated with an increased risk of extreme preterm birth,the OR was 1.11?95%CI:1.00-1.22?,1.09?95%CI:1.03-1.15?,1.11?95%CI:1.04-1.18?,1.13?95%CI:1.05–1.21?;during the entire pregnancy,the 1^st trimester,and four weeks before delivery,exposure to high concentration of PM₁₀ was associated with an increased risk of medically-indicated preterm birth,the OR was 1.15?95%CI:1.02-1.31?,1.08?95%CI:1.01-1.16?,1.04?95%CI:1.00-1.09?.After including pollutants PM₁₀,NO₂ and SO₂ in the regression model at the same time,during four,six and eight weeks before delivery and the 3^rd trimester,exposure to high concentration of PM₁₀ was associated with an increased risk of extreme preterm birth,the OR was 1.11?95%CI:1.01-1.23?,1.09?95%CI:1.03-1.15?,1.11?95%CI:1.04–1.18?,1.13?95%CI:1.05–1.21?;during the entire pregnancy,the 1^st trimester,four weeks before delivery,exposure to high concentration of PM₁₀ was associated with an increased risk of medically-indicated preterm birth,the OR is 1.14?95%CI:1.01-1.30?,1.08?95%CI:1.01-1.15?,1.04?95%CI:1.00-1.09?.?4?The results of health risks resulted from heavy metals contained in indoor PM_2.5.5 through inhalation showed that different types of cooking fuels were associated with significantly different carcinogenic and non-carcinogenic risks on adults and children.The carcinogenic and non-carcinogenic risks caused by heavy metal were the highest while using coal as cooking fuels.The carcinogenic risks and non-carcinogenic risks were almost the same while using clean energy and electricity as cooking fuels.?5?There was a linear relationship between heavy metals such as As,Cd and Ba in indoor PM_2.5.5 and adverse birth outcomes?low birth weight,which is<2500 g?During heating seasons,there was an inverse association between concentrations of As and;Cd and birth weight;as well as between concentration of As and,Cd and gestational week.During non-heating seasons,there was a positive association between concentration of Ba,Fe and Tl and birth weight,as well as between concentrations of Fe and gestational week.Conclusion:Exposure to high level of PM₁₀0 during pregnancy was associated with an increased risk of preterm birth,and the risk varied clinical subtypes and exposure windows.The sensitive period of preterm birth is at four weeks before delivery,six weeks before delivery,and eight weeks before delivery.The exposure to high concentration of PM₁₀ has a more significant negative impact on medically-indicated and extreme preterm birth.