Non-monotonic association between chlorinated polyfluorinated ether sulfonic acids exposure and the risk of overweight/obesity status in adults

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Background Chlorinated polyfluorinated ether sulfonic acids (Cl-PFESA 6:2 and 8:2), used as perfluorooctane sulfonate (PFOS) alternatives, affect lipid metabolism in vivo and in vitro studies. The association between Cl-PFESAs exposure and the prevalence of overweight /obesity in human is unknown. Objectives We investigated associations of serum 6:2 Cl-PFESA and 8:2 Cl-PFESA with overweight/obesity status in adults. Methods We quantified four perfluoroalkyl substances (PFAS), including 6:2 Cl-PFESA, 8:2 Cl-PFESA, PFOS, and perfluorooctanoic acid (PFOA) in 1275 Chinese adults from the Isomers of C8 Health Project in China study. Participants were categorized into normal weight group [body mass index (BMI) < 25 kg/m 2 ] and overweight/obesity group (BMI ≥ 25 kg/m 2 ). Results Adjusted for potential confounders, BMI in the second quartile of each ln-ng/mL greater concentration of 6:2 Cl-PFESA and 8:2 Cl-PFESA were 0.45 [95% confidence interval (CI): 0.08, 0.82], and 0.39 (95% CI:0.03, 0.76) significantly higher than the lowest quartile, respectively. Cl-PFESAs displayed inverted U-shaped associations with the risk of overweight/obesity, and the inflection point of 6:2 Cl-PFESA and 8:2 Cl-PFESA were 1.80 ng/mL, 0.01 ng/mL, respectively. PFOS was associated with waist circumference (WC) but not BMI in each quartile. For PFOA, the associations with outcomes were linearly positive ( P for trend < 0.05). Conclusions This study reports the first observations on non-monotonic associations between serum 6:2 Cl-PFESA and 8:2 Cl-PFESA concentrations and the prevalence of overweight/obesity in adults. More epidemiological investigations are required to confirm the observed associations.