Sex-Specific associations between per- and polyfluoroalkyl substances (PFAS) exposure and spinal posture in Children: The mediating role of bile acid metabolism.

The spine is crucial for structural support, and its development in children is influenced by genetic and environmental factors, including PFAS, which may disrupt bone metabolism. This study examined prenatal PFAS exposure, bile acids, and spinal posture in 518 mother-child pairs from the Shanghai MCPC. PFAS levels were measured in cord serum, bile acids in stool at 6 months, and spinal posture (ages 3-5) using the Zebris Pointer system. Sex-specific associations were found: in females, PFOS, PFTrA, and PFHxS positively correlated with lumbar inclination, while in males, only PFHxS showed a significant association. Weighted quantile sum regression highlighted PFTrA, PFHxA, and PFHxS as key contributors. Mediation analysis suggested bile acids (e.g., HDCA, TCA, TDCA, GLCA) may suppress PFAS effects on spinal posture, particularly in females. These findings indicate PFAS may disrupt spinal development via bile acid metabolism, warranting further research into mechanisms and prevention strategies.