Associations between Per- and Polyfluoroalkyl Substances Exposures and Bone Mineral: A Systematic Review and Best Evidence Synthesis

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental pollutants known for their bioaccumulative nature. Reduced bone mineral density (BMD) is associated with an increased risk of developing osteoporosis. This pioneering study aims to assess the effects of different PFAS compounds on bone mineral. We conducted searches on online databases. Inclusion criteria included the presence of associations between perfluorooctanoic acid (PFOA), perfluorooctanesulfonate (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) and BMD, BMD z-score, and bone mineral content (BMC). Meta-analyses were performed. Best evidence synthesis (BES) was performed to summarize the results. The results of BES showed that the evidence of PFOS, PFOA and PFNA with reduced bone mineral were moderate. The variability in methods for assessing bone mineral and sex differences are potential sources of heterogeneity in the results. Meta analysis showed that PFOA was associated with BMD (β −0.01, 95% CI −0.01 to −0.00; I² = 0%). Subgroup analysis by sex showed that PFOS (β −0.01, 95% CI −0.01 to −0.00; I² = 50%), PFOA (β −0.01, 95% CI −0.01 to +0.00; I² = 29%) were negatively correlated with BMD. This systematic review and BES revealed negative correlations between exposure to PFOS, PFOA, PFNA and bone mineral. Sex emerged as a potential factor affecting the negative effects of PFAS on bone mineral. The damage of PFAS to bone mineral still requires further exploration.