Air Pollution and the Risk of Cardiac Defects: A Population-Based Case-Control Study

Previous epidemiologic studies have assessed the role of the exposure to ambient air pollution in the development of cardiac birth defects, but they have provided somewhat inconsistent results. To assess the associations between exposure to ambient air pollutants and the risk of cardiac defects, a population-based case-control study was conducted using 1087 cases of cardiac defects and a random sample of 10,870 controls from 1,533,748 Taiwanese newborns in 2001 to 2007.Logistic regression was performed to calculate odds ratios for 10 ppb increases in O₃ and 10 μg/m³ increases in PM₁₀. In addition, we compared the risk of cardiac defects in 4 categories-high exposure (>75th percentile); medium exposure (75th to 50th percentile); low exposure (<50th–25th percentile); reference (<25th percentile) based on the distribution of each pollutant. The risks of ventricular septal defects (VSD), atrial septal defects (ASD), and patent ductus arteriosus (PDA) were associated with 10 ppb increases in O₃ exposure during the first 3 gestational months among term and preterm babies. In comparison between high PM₁₀ exposure and reference category, there were statistically significant elevations in the effect estimates of ASD for all and terms births. In addition, there was a negative or weak association between SO_2, NO₂, CO, and cardiac defects_.The study proved that exposure to outdoor air O₃ and PM₁₀ during the first trimester of gestation may increase the risk of VSD, ASD, and PDA.