Maternal exposure to air pollution and congenital heart diseases in Henan, China: A register-based case-control study

Association between ambient air pollution and congenital heart diseases (CHDs) remains inconclusive, and the critical exposure windows has not been well studied. This case-control study aimed to assess the effect of ambient air pollution exposure on the risk of CHDs and the subtypes in Henan, China, and further to explore potential susceptible windows. Daily average particulate matter with an aerodynamic diameter of ≤2.5 µm (PM2.5) and ≤10 µm (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO) and ozone (O3) were collected by Chinese Air Quality Reanalysis datasets. Binary logistic regression was used to examine trimester-specific associations between per 10 μg/m3 increase in air pollutants and CHDs as well as the major subtypes. Distributed lag models incorporating logistic regression were applied to explore weekly-specific associations. A total of 196,069 singleton live births were included during 2013–2018, 643 CHDs were identified (3.3‰). We found that first and second trimester CO exposure increased overall CHDs risk, the adjusted odds ratio (aOR) and 95% confidence interval (CI) were 1.066 (1.010–1.125) and 1.065 (1.012–1.122). For CHDs subtypes, we observed that NO2 and CO in first trimester, PM2.5 and PM10 in the second trimester exposure were associated with the risk of atrial septal defect (ASD), the susceptible windows of air pollutants and ASD mainly occurred in the 1st- 6th gestational weeks. No positive association was observed for air pollution and tetralogy of Fallot. Our findings suggest that ambient air pollution exposure is associated with the risk of CHDs especially for ASD, and the susceptible windows generally occurred in first trimester. Further well-designed longitudinal studies are warranted to confirm our findings.