Early PFAS Exposure Linked to Lower Bone Density in Adolescents

Early-life exposure to per- and polyfluoroalkyl substances (PFAS) was associated with reduced bone mineral density (BMD) in adolescents, according to research published in the Journal of the Endocrine Society.

The study, which followed 218 children from birth through age 12, adds to a growing body of evidence suggesting that these widely used synthetic chemicals may interfere with normal bone development during a critical window of growth.

Forever Chemicals and the Developing Skeleton

PFAS are a class of more than 4000 fluorinated compounds used in industrial and consumer products for their water- and stain-resistant properties. Human exposures occur through drinking water, food, indoor air, dust, and consumer products. Because many PFAS persist in the environment and in the human body for years, they have been dubbed "forever chemicals."

Adolescence represents a particularly important period for skeletal development. Nearly 40% of total body bone mineral is acquired during the 4 years surrounding peak mineral accretion rates, which occur at an average age of 12.5 years in females and 14.1 years in males. Achieving adequate bone mass during this window is considered essential for reducing the lifetime risk of fractures and osteoporosis.

Researchers from the Health Outcomes and Measures of the Environment Study (NCT00129324), a prospective pregnancy and birth cohort based in Cincinnati, Ohio, measured serum concentrations of 4 PFAS—perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA)—at delivery and at ages 3, 8, and 12 years.

At age 12, trained technicians used dual-energy x-ray absorptiometry to assess BMD at 6 skeletal sites, including the whole body, lumbar spine, hip, and forearm. Statistical models were adjusted for a range of maternal and child characteristics, including diet quality, physical activity, and pubertal stage.

Higher PFOA concentrations were associated with lower BMD at the 1/3 distal radius, a site reflecting cortical bone, at every time point examined from birth through age 12. Each interquartile range increase in PFOA was associated with BMD Z-score differences ranging from −0.36 to −0.54 at this site, depending on the time point.

For other PFAS, associations with BMD varied by when the exposure was measured and which skeletal site was assessed. Concentrations of PFHxS and PFOS measured at age 3 were associated with higher BMD at weight-bearing sites such as the whole body, total hip, and femoral neck, while concentrations measured at ages 8 and 12 tended to be associated with lower BMD at multiple sites. Higher PFNA concentrations at age 12 were significantly associated with lower BMD in the whole body, total hip, femoral neck, and ultradistal radius.

Girls Appeared More Vulnerable Than Boys

Sex differences were also observed. Among females, PFAS concentrations measured at age 12, including a mixture of all 4 compounds, were significantly associated with lower forearm BMD, while associations among males were generally weaker.

"Adolescence is a key period for building strong bones, and achieving optimal bone mass during this time can reduce lifelong risks of fractures and osteoporosis," said lead author Jessie P. Buckley, PhD, MPH, of the UNC Gillings School of Global Public Health.² "Our findings suggest reducing PFAS exposure during key developmental windows could support healthier bones throughout life."

The researchers noted that the observed BMD differences, ranging from 0.2 to 0.8 standard deviations per interquartile range increase in PFAS, could be clinically meaningful. Prior research has shown that a 1 standard deviation change in BMD is associated with 1.3 to 1.4 times greater odds of forearm fracture in children.

The authors also cautioned that BMD alone does not fully capture bone strength and that future studies should examine whether early PFAS exposure affects fracture risk and long-term skeletal outcomes into adulthood. The study was funded by the National Institute of Environmental Health Sciences.

References

1. Buckley JP, Marquess KM, Braun JM, et al. Per- and polyfluoroalkyl substances and adolescent bone mineral density: assessing periods of susceptibility. J Endocr Soc. 2026. doi:10.1210/jendso/bvag039

2. PFAS exposure may weaken teens’ bones. News release. The Endocrine Society. Published March 17, 2026. Accessed March 17, 2026. https://www.eurekalert.org/news-releases/1119498