Gestational and early childhood phthalate exposures and adolescent body composition: The HOME Study

Abstract

BACKGROUND AND AIM: Early life phthalate exposures may cause metabolic disruption. However, results from human studies are inconsistent and few have examined body composition during adolescence. We investigated associations of urinary phthalate metabolite concentrations during gestation and childhood with body composition at age 12 years to identify periods of heightened susceptibility. METHODS: We used data from 206 mother-child pairs in a prospective pregnancy and birth cohort enrolled in Cincinnati, OH from 2003-2006. We measured nine phthalate metabolites in spot urine samples collected twice from mothers during pregnancy and up to six times from children at 1, 2, 3, 4, 5 and 8 years. At age 12 years, we assessed whole body fat and lean mass, android, gynoid, and visceral fat mass with dual x-ray absorptiometry, and calculated android to gynoid %fat ratio and age- and sex-standardized fat and lean mass index Z-scores. Using a multiple informant model, we estimated the covariate-adjusted associations between urinary phthalate metabolite concentrations at each time period and adiposity Z-scores at age 12 years. We assessed effect measure modification by child sex using stratified models. RESULTS:Associations of urinary mono-n-butyl, mono-isobutyl, and mono-benzyl phthalate concentrations with 12-year body composition outcomes differed by time period, with stronger associations for exposures during gestation and later childhood. For example, each 10-fold increase in urinary mono-benzyl phthalate concentrations during gestation at ages 5 and 8 years was associated with a -0.34 (95%CI: -0.72,0.05), -0.44 (95%CI: -0.83,-0.05), and -0.35 (95%CI:-0.71,0.00) Z-score difference in whole body lean mass at age 12 years, respectively, but not for exposure in in early childhood. Slightly weaker but similar patterns of association were found with other body composition measures; associations did not differ by child sex. CONCLUSIONS:Exposure to certain phthalates during gestation and late childhood may be associated with adolescent body composition, particularly lean mass. KEYWORDS: Children’s environmental health, Endocrine disrupting chemicals, Obesity and metabolic disorders, Phthalates