Perfluoroalkyl and Polyfluoroalkyl Substances and Body Size and Composition Trajectories in Midlife Women: The Study of Women’s Health Across the Nation 1999–2018

BACKGROUND/OBJECTIVES: Perfluoroalkyl and polyfluoroalkyl substances (PFAS) have been suggested as obesogens but epidemiologic evidence is limited. We examined associations of serum PFAS concentrations with longitudinal trajectories of weight, waist circumference (WC), fat mass and proportion fat in midlife women. SUBJECTS/METHODS: This study included 1,381 midlife women, with a total of 15,000 repeated measures from the multi-racial/ethnic Study of Women’s Health Across the Nation between 1999 and 2018. The average follow-up was 14.9 (range: 0–18.6) years. Body size (objectively measured weight and WC) and body composition from dual-energy X-ray absorptiometry were assessed at near-annual visits. Linear mixed models with piecewise linear splines were utilized to model non-linear trajectories of body size and composition. RESULTS: After multivariable adjustment, PFAS concentrations were positively associated with weight, WC, fat mass, and proportion fat at baseline and during follow-up. Comparing the highest to the lowest tertiles of PFAS concentrations, adjusted geometric mean weight was 73.9 kg vs. 69.6 kg for PFOS (P<0.0001), and 74.0 vs. 69.4 kg for linear PFOA (P<0.0001) at baseline. Women with the highest tertile of PFOS had an annual increase rate of 0.33% (95% CI: 0.27%, 0.40%) in weight, compared to the lowest tertile with 0.10% (95% CI: 0.04%, 0.17%) (P<0.0001). PFOS was also significantly related to higher increase rates in WC (difference=0.12% per year, P=0.002) and fat mass (difference=0.25% per year, P=0.0002). EtFOSAA and MeFOSAA showed similar effects to PFOS. Although PFHxS was not related to body size or fat at baseline, PFHxS was significantly associated with accelerated increases in weight (P<0.0001), WC (P=0.003), fat mass (P<0.0001), and proportion fat (P=0.0009). No significant results were found for PFNA. CONCLUSIONS: Certain PFAS were positively associated with greater body size and body fat, and higher rates of change over time. PFAS may be an underappreciated contributing factor to obesity risk.