Maternal exposure to polycyclic aromatic hydrocarbons and visual developmental outcomes in early childhood

Visual impairment in early childhood is a critical developmental and public health concern. Limited epidemiological evidence exists on the role of prenatal polycyclic aromatic hydrocarbons (PAHs) in ocular development. This study investigated associations between maternal PAH exposure during pregnancy and visual outcomes in children. A total of 5330 mother-child pairs were recruited between 2022 and 2024. Maternal urinary concentrations of 11 hydroxylated PAH (OH-PAH) metabolites were measured in the third trimester. Children underwent standardized ophthalmic assessments, including uncorrected visual acuity, autorefraction, and axial length. Multivariable logistic regression and mixture models [generalized quantile g-computation (g-comp) and generalized weighted quantile sum (gWQS)] were applied. Elevated 2-OH Nap was associated with a 1.42-fold higher risk of right-eye visual acuity impairment (95 % CI: 1.18-1.72). Both 2-OH Nap and 1-OH Nap were linked to increased risk of refractive errors in both eyes [odds ratios (ORs) = 1.31-1.47]. Strong associations were observed between 9-OH Phe (OR = 1.55, 95 % CI: 1.22-1.96) and 3-OH Chr (OR = 1.44, 95 % CI: 1.15-1.81) with left-eye refractive impairment. Axial elongation showed significant associations with 2-OH Nap, 1-OH Nap, and 9-OH Phe (β range = 0.18-0.24 mm per unit increase in log-transformed exposure). Mixture analyses confirmed cumulative effects of OH-PAHs on refractive outcomes and axial length. This large-scale epidemiological study provides novel evidence that prenatal PAH exposure is associated with visual impairment in early childhood. Our findings highlight the susceptibility of the developing eye to environmental pollutants and emphasize the importance of public health and regulatory strategies aimed at reducing maternal exposure during pregnancy.