PFAS Exposure and Postoperative Weight Regain in Adolescents After Bariatric Surgery: Findings From the Teen-LABS Study

Objective: Weight regain following bariatric surgery remains a clinical challenge, with limited understanding of contributing environmental factors. Per- and polyfluoroalkyl substances (PFAS), persistent chemicals linked to metabolic dysfunction, may influence long-term weight trajectories. This study aimed to evaluate associations between PFAS exposure and changes in BMI, percent weight loss, and waist circumference among adolescents after bariatric surgery. Methods: We included 186 adolescents (mean age: 17.1 years; 76.3% female; 72.0% White) from the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) cohort who underwent surgery between 2007 and 2012. Anthropometric measurements were collected at baseline and 6, 12, 36, and 60 months post surgery. Presurgical plasma concentrations of seven PFAS were measured using liquid chromatography–tandem mass spectrometry. Associations were estimated using linear mixed-effects models and quantile g-computation. Results: Higher concentrations of PFOS, PFHxS, and PFHpS were associated with greater BMI regain, reduced percent weight loss, and increased waist circumference from 1 to 5 years post surgery. At PFOS concentrations of 1.45 to 2.94 log₂ ng/mL, annual BMI regain increased from 1.34 to 1.84 kg/m² (p = 0.0497). Mixture analyses confirmed cumulative PFAS effects, with sulfonic acids showing the strongest associations. Conclusions: PFAS exposure was associated with weight regain after bariatric surgery in adolescents, potentially undermining long-term metabolic benefits. Trial Registration: ClinicalTrials.gov identifier NCT00474318. (Figure presented.).