Periconceptional polycyclic aromatic hydrocarbon levels in maternal hair and fetal risk for congenital heart defects

Background: Congenital heart defects (CHDs) have a complex etiology, and environmental factors play an important role in their occurrence. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous chemicals, and some have teratogenic potential. However, few studies have examined PAHs exposure and CHD risk. We investigated the association between PAHs in maternal scalp hair and CHD risk. Methods: A case-control study involving 170 severe CHD cases and 170 healthy controls was conducted, and the concentrations of 11 PAHs in maternal hair grown during the periconceptional period were quantified. A generalized linear mixed model (GLMM) was used to determine the effects of each PAHs on the risk for CHDs. Weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were used to assess the overall effects of the 11-PAHs mixture on the risk for CHDs. Results: The median concentration of chrysene (CHR) was higher in CHD cases (9.75 ng/g) than in controls (6.50 ng/g). In GLMM, higher levels of CHR were associated with a 4.88-fold greater risk for CHDs (95 % confidence interval [CI]: 2.69-8.89). In WQS regression, higher levels of PAHs mixture were associated with a 2.03-fold greater CHD risk (95 % CI: 1.75-2.31), and CHR had the highest weighting (weighted 0.9346). In BKMR, CHD risks increased steadily with the levels of the PAHs mixture. CHR showed a toxic effect when the other PAHs were fixed at their 25(th), 50(th), or 75(th) percentile. No interactions among PAHs were found. Conclusions: When examined individually, a high concentration of CHR in periconceptional maternal hair was associated with an increased risk for CHDs. When considering the 11 PAHs together, higher levels of the PAHs mixture were associated with increased odds of CHD occurrence.