The association between maternal air pollution exposure and the incidence of congenital heart diseases in children: A systematic review and meta-analysis.

Congenital heart diseases (CHDs) are a prevalent form of congenital malformations in newborns. Although previous studies have explored the association between maternal exposure to ambient air pollution and congenital anomalies in offspring, the results still remain ambiguous. To fill the knowledge gap, we performed a systematic review and meta-analysis of existing literature. A comprehensive search of the literature was conducted in PubMed, Embase, and Web of Science until August 12, 2022. We analyzed the relationship between air pollution and multiple CHDs using either a fixed-effect model or a random-effects model. Summary risk estimates of pollution-outcome pairs were calculated based on (i) risk per increment of concentration and (ii) risk at high versus low exposure levels. Additionally, we performed leave-one-out analyses and used funnel plots to assess the potential publication bias. A total of 32 studies were included and four studies utilizing distributed lag nonlinear models (DLNM) models were added to our retrospective review. In the continuous exposure meta-analysis, there were statistically significant negative associations between sulfur dioxide (SO) and transposition of the great arteries (OR = 0.96; 95 % CI: 0.93-0.99), pulmonary artery and valve defect (OR = 0.90; 95 % CI: 0.83-0.97), and ventricular septal defect (OR = 0.95; 95 % CI: 0.91-0.99). High versus low SO exposure was associated with a decreased risk of tetralogy of Fallot [OR = 0.83; 95 % CI: 0.69-0.99]. However, carbon monoxide (CO) increased risk estimates for tetralogy of Fallot in both continuous exposure (OR = 2.25; 95 % CI: 1.42-3.56) and high-low exposure (OR = 1.24; 95 % CI: 1.01-1.54). Particulate matter 10 (PM) statistically significant increased in the risk of overall CHD with odds ratios of 1.03 (95 % CI: 1.01-1.05) and 1.04 (95 % CI: 1.00-1.09) in continuous and categorical exposure analysis, respectively. These findings provide potential evidence for the association between maternal air pollution exposure and CHDs.