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Few methods have been used to characterize repeatedly measured biomarkers of chemical mixtures. We applied latent profile analysis (LPA) to serum concentrations of 4 perfluoroalkyl and polyfluoroalkyl substances (PFAS) measured at 4 time points from gestation to age 12 years. We evaluated the relationships 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 receiver operating characteristic curve (AUC) for all PFAS. We identified 2 profiles: a higher PFAS profile (35% of sample) and a lower PFAS profile (relative to each other), based on their average PFAS concentrations at all time points. The higher PFAS profile had generally lower z scores for all outcomes, with somewhat larger effects for males, though all 95% CIs crossed the null. For example, the higher PFAS profile was associated with a 0.50-unit lower (β = −0.50; 95% CI, −1.07 to 0.08) BMI z score among males but not among females (β = 0.04; 95% CI, −0.45 to 0.54). We observed similar patterns with AUCs. We found that a higher childhood PFAS profile and higher cumulative PFAS mixtures may be associated with altered growth in early adolescence. This article is part of a Special Collection on Environmental Epidemiology. [ABSTRACT FROM AUTHOR]

Results of toxicological studies indicate that phthalates and per-/polyfluoroalkyl substances (PFAS), 2 classes of endocrine-disrupting chemicals, may alter the functioning of the hypothalamic-pituitary-adrenocortical (HPA) axis. We evaluated the associations of urinary phthalate metabolites and serum PFAS during gestation and childhood with adolescent hair cortisol concentrations (pg/mg hair) at age 12 years, an integrative marker of HPA axis activity (n  = 205 mother-child pairs; Cincinnati, Ohio; enrolled 2003–2006). We used quantile-based g-computation to estimate associations between mixtures of urinary phthalate metabolites or serum PFAS and hair cortisol. We also examined whether associations of individual phthalate metabolites or PFAS with cortisol varied by the timing of exposure. We found that a 1-quartile increase in all childhood phthalate metabolites was associated with 35% higher adolescent hair cortisol (phthalate mixture ψ = 0.13; 95% confidence interval: 0.03, 0.22); these associations were driven by monoethyl phthalate, monoisobutyl phthalate, and monobenzyl phthalate. We did not find evidence that phthalate metabolites during gestation or serum PFAS mixtures were related to adolescent hair cortisol concentrations. We found suggestive evidence that higher childhood concentrations of individual PFAS were related to higher and lower adolescent hair cortisol concentrations. Our results suggest that phthalate exposure during childhood may contribute to higher levels of chronic HPA axis activity. [ABSTRACT FROM AUTHOR]

Exposure to phthalates is associated with diminished cognition. It is unknown, however, if disproportionate exposure to phthalates among racial minorities contributes to racial disparities in children's intellectual abilities. Methods: We used data from 253 mother-child pairs in Cincinnati, OH (HOME Study, 2003-2006). We measured urinary concentrations of eleven phthalate metabolites twice during pregnancy and up to six times in childhood. We evaluated children's cognitive abilities at ages 5 and 8 years. Using causal mediation models, we quantified covariate-adjusted direct and indirect effects of race on children's Full Scale IQ scores for individual phthalate metabolite concentrations during gestation and childhood. Results: Average IQ scores among Black children (n = 90) were 7.0-points lower (95% CI: -12, -1.8) than White children (n = 145) after adjustment for socioeconomic factors. Urinary monobenzyl phthalate (MBzP) and monoethyl phthalate (MEP) concentrations during gestation and childhood were higher among Black children. We did not observe compelling evidence that phthalate mediated the race-IQ association, with the exception of MEP. Childhood MEP concentrations partially mediated the race- IQ association. For instance, the disparities in IQ scores between Black and White children would have been reduced by 1.9 points (95% CI: -4.7, 0.7) for each 10-fold reduction in urinary MEP concentrations at age 2 years. Other phthalate metabolite concentrations during pregnancy or childhood did not mediate the race-IQ association. Conclusions: We found that urinary MEP concentrations partly mediated IQ disparities among HOME Study children. Reducing exposure to some phthalates might help reduce IQ disparities among Black and White children. [ABSTRACT FROM AUTHOR]