Per- and Polyfluoroalkyl Substance Plasma Concentrations and Bone Mineral Density in Midchildhood: A Cross-Sectional Study (Project Viva, United States)

BACKGROUND: Identifying factors that impair bone accrual during childhood is a critical step toward osteoporosis prevention. Exposure to per- and polyfluoroalkyl substances (PFASs) has been associated with lower bone mineral density, but data are limited, particularly in children. METHODS: We studied 576 children in Project Viva, a Boston-area cohort of mother/child pairs recruited prenatally from 1999 to 2002. We quantified plasma concentrations of several PFASs and measured areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) in midchildhood. We used linear regression to examine associations between plasma concentrations of individual PFASs and aBMD z-score. We used weighted quantile sum (WQS) regression to examine the association of the PFAS mixture with aBMD z-score. All models were adjusted for maternal age, education, annual household income, census tract median household income, and child age, sex, race/ethnicity, dairy intake, physical activity, and year of blood draw. RESULTS: Children were [mean +/- standard deviation (SD)] 7.9 +/- 0.8 years of age. The highest PFAS plasma concentrations were of perfluorooctane-sulfonic acid (PFOS) (median [interquartile range (IQR)]: 6.4 (5.6) ng/mL} and perfluorooctanoic acid (PFOA) [median (IQR): 4.4 (3.2) ng/mL]. Using linear regression, children with higher plasma concentrations of PFOA, PFOS, and perfluorodecanoate (PFDA) had lower aBMD z-scores [e.g., beta: -0.16; 95% confidence interval (CI): -0.25, -0.06 per doubling of PFOA]. The PFAS mixture was negatively associated with aBMD z-score (beta: -0.16; 95% CI: -0.28, -0.04 per IQR increment of the mixture index). CONCLUSIONS: PFAS exposure may impair bone accrual in childhood and peak bone mass, an important determinant of lifelong skeletal health.