Ambient Air Pollution and Traffic Exposures and Congenital Heart Defects in the San Joaquin Valley of California

Background Congenital anomalies are a leading cause of infant morbidity and mortality. Studies suggest associations between environmental contaminants and some anomalies, although evidence is limited. Methods We used data from the California Center of the National Birth Defects Prevention Study and the Children's Health and Air Pollution Study to estimate the odds of 27 congenital heart defects with respect to quartiles of seven ambient air pollutant and traffic exposures in California during the first 2 months of pregnancy, 1997–2006 (n = 822 cases and n = 849 controls). Results Particulate matter