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

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.

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.

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.

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.