Prenatal and postnatal bisphenol A exposure and body mass index in childhood in the CHAMACOS cohort.

Background: Bisphenol A (BPA), a widely used endocrine-disrupting chemical, has been associated with increased body weight and fat deposition in rodents.

Objectives: We examined whether prenatal and postnatal urinary BPA concentrations were associated with body mass index (BMI), waist circumference, percent body fat, and obesity in 9-year-old children (n = 311) in the CHAMACOS longitudinal cohort study.

Methods: BPA was measured in spot urine samples collected from mothers twice during pregnancy and from children at 5 and 9 years of age.

Results: Prenatal urinary BPA concentrations were associated with decreased BMI at 9 years of age in girls but not boys. Among girls, being in the highest tertile of prenatal BPA concentrations was associated with decreased BMI z-score (β = -0.47, 95% CI: -0.87, -0.07) and percent body fat (β = -4.36, 95% CI: -8.37, -0.34) and decreased odds of overweight/obesity [odds ratio (OR) = 0.37, 95% CI: 0.16, 0.91] compared with girls in the lowest tertile. These findings were strongest in prepubertal girls. Urinary BPA concentrations at 5 years of age were not associated with any anthropometric parameters at 5 or 9 years, but BPA concentrations at 9 years were positively associated with BMI, waist circumference, fat mass, and overweight/obesity at 9 years in boys and girls.

Conclusions: Consistent with other cross-sectional studies, higher urinary BPA concentrations at 9 years of age were associated with increased adiposity at 9 years. However, increasing BPA concentrations in mothers during pregnancy were associated with decreased BMI, body fat, and overweight/obesity among their daughters at 9 years of age.