Prenatal exposure to persistent organic pollutants and childhood adiposity: Findings from the MIREC cohort

BACKGROUND: The rising prevalence of childhood adiposity raises concerns about the role of early-life environmental exposures. We examined associations between prenatal exposure to per- and polyfluoroalkyl substances (PFAS), polybrominated diphenyl ethers (PBDEs), and dichlorodiphenyldichloroethylene (DDE) and measures of adiposity in children up to age ∼10 years. METHODS: First-trimester maternal plasma concentrations of target chemicals were measured in the Maternal-Infant Research on Environmental Chemicals (MIREC) cohort. Children were followed longitudinally from birth through early (∼4 years) and later childhood (∼10 years). Adiposity was assessed using body mass index (BMI), waist circumference, and waist-to-height ratio (WHtR). Associations were estimated using generalized estimating equations, linear regressions, and Bayesian Kernel Machine Regression (BKMR) for chemical mixtures, adjusting for relevant confounders. RESULTS: Longitudinal analyses showed largely null associations, except for PFOS, which was associated with larger waist circumference in males (β per 10-fold increase: 0.55; 95% CI: 0.06, 1.04). Analyses at each age of assessment showed that maternal DDE was associated to lower BMI at birth (β: -0.19; 95% CI: -0.37, -0.02) and ΣPBDE was associated with larger waist circumference and WHtR at ∼4 years (β: 0.22; 95% CI: 0.06, 0.38 and β: 0.26; 95% CI: 0.11, 0.42, respectively). In sex-stratified analyses at ∼4 years, maternal BDE-47 and PFOS were associated with higher BMI and waist circumference in males (β: 0.24; 95% CI: 0.02, 0.46 and β: 0.51; 95% CI: 0.11, 0.90, respectively), while BDE-153 was inversely associated with BMI in females (β: -0.17; 95% CI: -0.32, -0.01). Mixture analyses suggested associations with larger waist circumference and WHtR at ∼4 years, with sex-specific, non-linear patterns. CONCLUSIONS: In this large prospective cohort, prenatal exposure to persistent organic pollutants showed limited and sex-specific associations with adiposity, particularly at ∼4 years of age. These findings underscore the importance of considering developmental windows and mixture effects in studies of early metabolic health.