Sex-specific associations of prenatal and postnatal exposure to 15 endocrine-disrupting chemical exposures with visual impairment at age three: the Korean Children's Environmental Health Study (Ko-CHENS).

BACKGROUND

Endocrine-disrupting chemicals (EDCs) have been linked to pediatric outcomes, but evidence on visual development and sex differences is scarce. We examined whether prenatal and postnatal EDC exposures were associated with visual impairment at age 3.

METHODS

Participants were drawn from the Korean Children's Environmental Health Study, with urinary biomarkers measured at early pregnancy (n = 340), late pregnancy (n = 454), 24 months (n = 344), and 36 months (n = 713). A subset with complete data at all windows (n = 115) was analyzed using generalized estimating equations. Fifteen biomarkers (phthalate metabolites, bisphenols, parabens, triclosan) were assessed, and logistic regression models with inverse probability weighting estimated window-specific and population-averaged effects. Mixture effects were evaluated using weighted quantile sum regression and quantile g-computation. Visual acuity at 36 months was measured on the decimal scale, with impairment primarily defined as <0.5 in either eye, alongside alternative definitions for robustness.

RESULTS

Girls showed more consistent adverse associations between higher EDC concentrations and increased impairment risk. Each unit increase in mono-(3-carboxypropyl) phthalate was associated with higher odds of impairment during late pregnancy (OR = 2.47, 95% CI: 1.97, 3.12), at 24 months (OR = 1.64, 95% CI: 1.38, 1.95), and at 36 months (OR = 1.36, 95% CI: 1.14, 1.61), while bisphenol A at 36 months also conferred elevated risk (OR = 1.48, 95% CI: 1.32, 1.67). Boys generally exhibited weaker or inverse associations, except for mono-(carboxyoctyl) phthalate at 24 months (OR = 1.34, 95% CI: 1.19, 1.52). Mixture models were largely null, though weights consistently highlighted phthalates.

CONCLUSIONS

Early-life EDC exposures were associated with visual impairment at age 3 in a sex-specific manner, with stronger and more consistent effects in girls.