Associations of Gestational Perfluoroalkyl Substances Exposure with Early Childhood BMI z -Scores and Risk of Overweight/Obesity: Results from the ECHO Cohorts.

Background: Gestational per- and polyfluoroalkyl substances (PFAS) exposure may be associated with adiposity and increased risk of obesity among children and adolescents. However, results from epidemiological studies evaluating these associations are inconsistent.
Objectives: We estimated the associations of pregnancy PFAS concentrations with child body mass index (BMI) z -scores and risk of overweight/obesity in eight U.S. cohorts.
Methods: We used data from 1,391 mother-child pairs who enrolled in eight Environmental influences on Child Health Outcomes (ECHO) cohorts (enrolled: 1999-2019). We quantified concentrations of seven PFAS in maternal plasma or serum in pregnancy. We measured child weight and height between the ages of 2 and 5 y and calculated age- and sex-specific BMI z -scores; 19.6% children had more than one BMI measurement. We estimated covariate-adjusted associations of individual PFAS and their mixture with child BMI z -scores and risk of overweight/obesity using linear mixed models, modified Poisson regression models, and Bayesian approaches for mixtures. We explored whether child sex modified these associations.
Results: We observed a pattern of subtle positive associations of PFAS concentrations in pregnancy with BMI z -scores and risk of overweight/obesity. For instance, each doubling in perfluorohexane sulfonic acid concentrations was associated with higher BMI z -scores ( β = 0.07 ; 95% CI: 0.01, 0.12). Each doubling in perfluroundecanoic acid [ relative risk  ( RR ) = 1.10 ; 95% CI: 1.04, 1.16] and N -methyl perfluorooctane sulfonamido acetic acid ( RR = 1.06 ; 95% CI: 1.00, 1.12) was associated with increased risk of overweight/obesity, with some evidence of a monotonic dose-response relation. We observed weaker and more imprecise associations of the PFAS mixture with BMI or risk of overweight/obesity. Associations did not differ by child sex.
Discussion: In eight U.S.-based prospective cohorts, gestational exposure to higher levels of PFAS were associated with slightly higher childhood BMI z -score and risk of overweight or obesity. Future studies should examine associations of gestational exposure to PFAS with adiposity and related cardiometabolic consequences in older children. https://doi.org/10.1289/EHP11545.