Estimating effects of longitudinal and cumulative exposure to PFAS mixtures on early adolescent body composition

Few methods have been used to characterize repeatedly measured biomarkers of chemical mixtures. We applied latent profile analysis (LPA) to serum concentrations of four perfluoroalkyl and polyfluoroalkyl substances (PFAS) at four timepoints from gestation to age 12 years. We evaluated the relations between profiles and z-scores of height, body mass index, fat mass index, and lean body mass index at age 12 years (n = 218). We compared LPA findings with an alternative approach for cumulative PFAS mixtures using g-computation to estimate the effect of simultaneously increasing the area under the curve (AUC) for all PFAS. We identified two profiles: a higher (35% of sample) and lower PFAS profile (relative to each other), based on their average PFAS concentrations at all timepoints. The higher PFAS profile had generally lower z-scores for all outcomes, with somewhat larger effects for males, though all CIs crossed the null. For example, the higher PFAS profile was associated with a -0.50 (95% CI: -1.07, 0.08) lower BMI z-score among males but not females (0.04; 95% CI: -0.45, 0.54). We observed similar patterns with AUCs. We found that higher childhood PFAS profile and higher cumulative PFAS mixtures may be associated with altered growth in early adolescence.