Associations between PFAS exposure and 25-hydroxyvitamin D levels among Hispanic children.

BACKGROUND: Perfluoroalkyl substances (PFAS) are persistent environmental chemicals that may affect vitamin D levels. Epidemiologic findings remain inconsistent, and have not explored associations in Hispanic populations, who experience disproportionate PFAS exposure and vitamin D insufficiency. OBJECTIVES: To quantify associations between plasma PFAS concentrations and serum 25-hydroxyvitamin D (25(OH)D) levels in Hispanic children. METHODS: Participants (n=106) were enrolled in the Vidas Activas Familias Saludables (VALE) study, a culturally tailored 10-week lifestyle intervention for Hispanic children aged 4-11 years. Plasma PFAS were measured at pre-intervention using liquid chromatography-tandem mass spectrometry, and serum 25(OH)D was assessed pre- and post-intervention using ELISA kits. Linear mixed regression models estimated associations between individual PFAS and 25(OH)D, adjusting for confounders. Principal component analysis (PCA) was used to identify co-exposure to PFAS mixtures. RESULTS: Higher plasma PFHxS concentrations were associated with higher serum 25(OH)D levels at pre- and post-intervention (mean difference (MD): 5.63 ng/mL per log increase, 95% CI: 1.81, 9.37). Four components were retained from the PCA. Greater co-exposure to PFOA, PFNA, and PFHpA (MD: 1.94 ng/mL, 95% CI: 0.37, 3.81), and co-exposure to PFOS and PFHxS (MD: 4.60 ng/mL, 95% CI: 2.75, 7.35), were associated with higher serum 25(OH)D. Associations were strongest among children <8 years old and males. CONCLUSIONS: PFAS exposure, individually and as mixtures, was associated with higher 25(OH)D in Hispanic children, particularly among younger children and males. Larger longitudinal studies of children with diverse racial and ethnic identities are needed to confirm age- and sex-specific PFAS-vitamin D associations.