BACKGROUND: Previous studies suggest associations between air pollution exposures during pregnancy and reduced mean birth weight.
OBJECTIVE: To investigate air pollution exposure and changes in birth weight quantiles, as well as whether the associations vary across quantiles.
METHODS: Birth certificates of singleton births >= 27 weeks of gestation in the five-county Atlanta metropolitan area were obtained from the Office of Health Indicators for Planning, Georgia Department of Public Health. This study included births with estimated dates of conception between 1 January 2002 and 28 February 2006 (N=189,900 births). Daily pollutant concentrations at 12 km resolution were estimated for 12 ambient air pollutants by combining monitoring measurements and simulations from chemical transport models. We used daily 1-hour maximum, 24-hour average, or maximum 8-hour average for different pollutants following previous studies in Atlanta. We used quantile regression to estimate associations between birth weights quantiles (5th, 25th, 50th, 75th and 95th) and average pollutant concentrations during the first, second, third trimester and over the entire pregnancy. Analyses were also stratified by preterm and full-term births.
RESULTS: Among all births, we observed consistent associations between reduced birth weight quantiles and carbon monoxide (CO), elemental carbon (EC), nitrogen dioxide (NO2), nitrogen oxide (NOx), organic carbon (OC), sulfur dioxide (SO2), and fine particulate matter (PM2.5). Generally, we also observed stronger negative associations during the first and second trimesters compared to the third trimester among these pollutants. Pollutants CO, EC, NO2 and NOx showed stronger negative associations at increasing quantile levels. These associations were similar for full-term births. Among preterm births, CO, EC, NO2, NOx and OC exposures during the first and second trimesters had the most consistent negative associations with birth weight quantiles. Moreover, the decrease in birth weight quantiles among preterm births were larger compared to full-term births.
CONCLUSION: Ambient air pollutants, particularly those associated with traffic, were negatively associated with birth weight quantiles. There is evidence that their associations vary from across trimesters and across different quantiles.
Table of Contents
Data and Outcome Assessment 3
Ambient Air Pollutant Concentrations 4
Statistical Models 4
SUPPLEMENTAL MATERIALS 27
About this Master's Thesis
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|Ambient Air Pollution and Birth Weight Quantiles in Atlanta ()||2018-08-28 14:18:46 -0400||