Associations between perfluoroalkyl substance exposure and lean body mass in US adults: evidence from the NHANES 2015-2018

Perfluoroalkyl substances (PFAS) are widely used in consumer and industrial products, and their adverse effects have been studied extensively. However, associations between PFAS and lean body mass (LBM) remain unclear. We examined cross-sectional associations among 1340 adults, aged 20-60 years, who participated in the 2015-2018 National Health and Nutrition Examination Survey (NHANES). Serum concentrations of perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFDA), perfluorooctane sulfonic acid (PFOS), and perfluorohexane sulfonic acid (PFHxS) had higher detection rates. They were used to correlate with LBM in humans. Effect modifications by sex and body mass index (BMI) were also evaluated. Restricted cubic spline (RCS) modeling was used to examine dose-response associations between PFAS and outcomes. We found that LBM decreased by 5.87 kg (95% CI: -7.58, -4.16), 3.14 kg (95% CI: -4.02, -2.25), and 2.60 kg (95% CI: -3.42, -1.78) in the highest quartile of PFDA serum concentration, respectively, relative to the weight of the lowest quartile (trend p < 0.001). LBM decreased by 2.27 kg (95% CI: -3.89, -0.65), 1.42 kg (95% CI: -2.26, -0.58), and 0.79 kg (95% CI: -1.57, -0.02) in the highest quartile of PFOS serum concentration groups, respectively (all trend p < 0.05). The association was consistently stronger in females than in males. RCS modeling further confirmed that serum PFOS and PFDA were negatively associated with LBM.