Ambient PM2.5 exposure during pregnancy and the risk of preterm delivery in Georgia, 1999 to 2006 Open Access

Huang, Meilin (2013)

Permanent URL: https://etd.library.emory.edu/concern/etds/6h440t269?locale=en
Published

Abstract


Health effects of air pollution from vehicular emissions and other combustion sources on cardiovascular and respiratory outcomes have been well studied. But the relationship between air pollution and preterm birth is limited (Huynh, Woodruff el at, 2006). In this research, by using the Georgia statewide birth cohort, we investigated whether ambient air pollutant exposure during pregnancy was associated with the risk of preterm delivery. Our study included pregnant mothers in Georgia, whose home address at delivery were less than 5km or 10km from an Air Quality System (AQS) monitor and who conceived between January 1st 1999 and December 31st 2006. Associations between fine particulate matter air pollution (PM2.5) and preterm delivery were examined over different gestational exposure windows. Using a discrete-time frame survival model, we first estimated the odds ratio of preterm birth for each exposure window and for each county. We then used a meta-analysis approach to combine county-specific odds ratios to obtain estimated pooled odds ratios for each exposure window in Georgia.

Overall, we did not identify significant associations between gestational PM2.5 exposures and the risks of preterm birth. After controlling for race/ethnicity, maternal education, marital status, tobacco use during pregnancy, Medicaid status, conception date, conception season, maternal age and infant sex, we found that for mothers who lived within a 10-km buffer of an AQS monitor, an interquartile (3.542 µg/m3) increase in the cumulative average PM2.5 exposure was associated with a 3.4% increase in the risk of preterm birth (95% CI is [0.959, 1.115]); the adjusted odds ratio for the preterm birth per IQR range increase in trimester two average PM2.5 exposure was 1.04 (95% CI is [0.988, 1.095]). Additionally, controlling for fine-scale spatial effects in our models did not make a difference in the risk estimates.

Table of Contents

Contents
Introduction...8

Preterm delivery and fine particulate matter...8
Problem Statement...9
Significance Statement...9

Review of the Literature...10

Introductory...10
Literature Review...11

Methodology...13

Data resource and management...13
Models and analysis...15
Meta-analysis...17

Results...17
Discussion...20
References...21
Tables...24

Table1: Descriptive analysis for pregnant women...24
Table 2: Unadjusted odds ratio for preterm delivery...24
Table 3: Adjusted odds ratio for preterm delivery...25
Table 4: Interquartile Range (IQR) and Median values (μg/m3) for Exposure Metrics in a Study of PM2.5 Levels and Risk of Preterm Birth, Georgia, 1999-2006...26
Table5: Adjusted average odds ratio estimates in AQS buffer 5...27
Table 6: Adjusted average odds ratio estimates in AQS buffer 10...27

Appendix...29

Adjusted average odds ratio estimates in AQS buffer 5...29
Adjusted average odds ratio estimates in AQS buffer 10...30

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