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AMBIENT AIR QUALITY AND SELECTED BIRTH DEFECTS, SEVEN COUNTY STUDY, TEXAS, 1997-2000
Citation:
GILBOA, S., P. MENDOLA, A. F. OLSHAN, P. LANGLOIS, D. SAVITZ, D. P. LOOMIS, A. H. HERRING, AND D. E. FIXLER. AMBIENT AIR QUALITY AND SELECTED BIRTH DEFECTS, SEVEN COUNTY STUDY, TEXAS, 1997-2000. Presented at UNC Women's Health Research Day, Chapel Hill, NC, March 23, 2005.
Description:
Background: A number of epidemiologic investigations have shown adverse effects of ambient air pollution on reproductive outcomes. A recent case-control study found associations between
second gestational month carbon monoxide and ozone exposure and elevated risks of selected cardiac birth defects.
Objective: Our population-based, case-control study investigated the association between maternal exposures to carbon monoxide, nitrogen dioxide, ozone, sulfur dioxide, and PMIo during weeks three through eight of pregnancy and the risk of selected cardiac birth defects and oral clefts among live births and fetal deaths between 1997 and 2000 in seven Texas counties. Methods: Cases were selected from the Texas Birth Defects Registry (n=4570). Non-malformed controls were sampled from vital records and frequency matched to cases on year of birth, vital status, and maternal county of residence at delivery (n=3667). Data from United States Environmental Protection Agency (EPA) stationary monitors were used to estimate air pollution exposures. The risk of eight clinical diagnostic groupings and nine individual birth defects in
relation to each of the five pollutants were analyzed. Unconditional binary and polytomous logistic regression models were used to adjust for covariates available in the vital record. Results: Comparing the highest quartile of exposure to the lowest, there were positive associations between carbon monoxide and tetralogy of Fallot (odds ratio (OR) = 2.04; 95% confidence interval (CI) 1.26, 3.29), PMI0 and isolated atrial septal defects (OR = 2.27; 95% CI: 1.43, 3.60), and sulfur dioxide and isolated ventricular septal defects (OR = 2.16; 95% CI: 1.51, 3.09). Inverse associations were found between nitrogen dioxide and ventricular septal defects and between sulfur dioxide and isolated atrial septal defects. The study provides limited evidence that air pollution exposure influences the risk of oral clefts.
Conclusions. This study contributes to a growing body of epidemiologic literature on the adverse reproductive effects of ambient air pollution exposure. These results support a previously reported finding of an association between ozone exposure and pulmonary artery and valve defects. There are a number of suggested associations with sulfur dioxide and PM10. This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.