An epidemiologic study of the impact of air pollution on birth weight in Georgia

Background & Objective: Low birth weight (LBW) has been an increasing health problem in the US. The effect of environmental pollution on birth weight remains to be determined. This research evaluated the relationship between LBW and air pollution in Georgia. Methods: The study population consisted of 70,465 full term (36-44 weeks) births delivered by mothers who lived in 14 urban counties of Georgia in 2004. Individual birth data was obtained from the National Center for Health and Statistics Natality Data Sets and the air pollutant emission data was from the US Environmental Protection Agency. Based on the total emission from point and non-point sources, counties were classified into three groups: low (LE), medium (ME), and high (HE) emission. Logistic regression and the analysis of variance were used to analyze birth weight outcome between the three groups. Results: Gestational exposure to carbon monoxide (CO), nitrogen oxides (NOx), and volatile organic compounds (VOC) in ME counties significantly decreased birth weight by 51.8 g (95% CI: 39.9, 63.8), 24.1 g (95% CI: 11.4, 36.7), and 60.8 g (95% CI: 49.0, 72.6), respectively, as compared to that in LE counties. Logistic regression analysis showed that LBW was positively associated with CO and VOC emissions with odds ratio of 1.2 (95% CI: 1.1, 1.3) and 1.3 (95% CI: 1.2, 1.5), respectively. Geographic Information System was used to map out the distribution by birth weight and air pollution. Conclusion: The results suggest that high levels of emission of CO and VOC might adversely affect birth weight.