Gestational Urinary Bpa Concentrations and Child Adiposity at Age 3 Years: The MIREC Study

Abstract

Background: Bisphenol A (BPA) is a high production volume chemical, and because of its use in numerous consumer products, exposure is ubiquitous. Prenatal BPA exposure has been associated with excess adiposity in rodent studies, but not consistently in human studies.Objectives: We investigated the relation between prenatal BPA exposure and early childhood adiposity in a prospective cohort study of 686 mother-child pairs.Methods: We used data from the Maternal Infant Research on Environmental Chemicals (MIREC) Study, a prospective pan-Canadian pregnancy and birth cohort study. We measured BPA in urine samples collected at an average of 13 weeks gestation. In six of the cities, we measured children’s weight, height, waist/hip circumference, and subscapular/triceps skinfold at an average of age 3.4 years. Using linear regression, we estimated covariate-adjusted associations between log2-transformed urinary BPA concentrations and adiposity measures.Results: Median urinary BPA concentrations were 0.8 ng/mL (IQR: 0.5-1.4). Among all children, there was no association between BPA and child adiposity. However, the association of BPA with waist circumference and subscapular skinfold thickness was modified by child sex (sex x BPA interaction p-values<0.2). Among girls, each 2-fold increase in urinary BPA concentrations was associated with a 0.3 cm (95% CI: 0, 0.5) and 0.2 mm (95% CI: 0, 0.3) increase in waist circumference and subscapular skinfold thickness, respectively. Among boys, BPA was weakly inversely associated with subscapular skinfold thickness (b: -0.1; 95% CI: -0.3, 0.1), but was not associated with waist circumference (b: 0.03; 95% CI: -0.19, 0.25).Conclusions: In this cohort, prenatal urinary BPA concentrations were associated with subtle increases in measures of central adiposity during early childhood among girls, but not boys. Future studies should confirm these associations and determine if they persist into later childhood.