Prenatal phthalate exposures and anthropometryduring adolescence: The HOME Study

Abstract

Background/Aim: Phthalate exposures are ubiquitous in pregnant women and may be obesogenic. Although excess adolescent adiposity predicts obesity and cardiometabolic diseases during adulthood, few studies have examined associations between prenatal phthalate exposures and anthropometric outcomes during adolescence. We investigated the relationships between prenatal phthalate exposures and anthropometry at age 12 years.Methods: We used data from 219 mother-child pairs enrolled in the Health Outcomes and Measures of the Environment (HOME) Study, a prospective pregnancy and birth cohort enrolled in Cincinnati, OH from 2003-2006. We measured monobutyl phthalate (MnBP), monobenzyl phthalate (MBzP), mono-(3-carboxypropyl) phthalate (MCPP), monoethyl phthalate (MEP), monoisobutyl phthalate (MiBP), and four metabolites of di-2-ethylhexyl phthalate (DEHP) in maternal urine samples collected at 16 and 26 weeks of pregnancy. At age 12 years, we measured child weight and height. We used multivariable linear regression to estimate covariate-adjusted associations of a 10-fold increase in average maternal urinary phthalate metabolite concentrations with age- and sex- standardized height, weight, and BMI z-scores. We assessed effect measure modification (EMM) by child sex using stratified models.Results: In adjusted analyses, maternal urinary phthalate metabolite concentrations were not associated with height, weight, or BMI z-scores in the overall sample. However, associations of MBzP concentrations with all anthropometry z-scores were modified by child sex, with lower z-scores among girls, but not boys. For example, a 10-fold increase in MBzP concentrations was associated with lower BMI z-scores in girls (β=-0.4; 95% CI: -0.9, 0.0) but not boys (β=0.2; 95% CI: -0.3, 0.7; EMM p-value=0.09). Additionally, a 10-fold increase in MiBP was associated with increased height z-scores among boys (β=0.7; 95% CI: 0.1, 1.3), but not girls (β=0.0; 95% CI: -0.6, 0.5; EMM p-value=0.09).Conclusions: In this prospective cohort study, higher prenatal phthalate exposures were not associated with adolescent anthropometry, but there may be sex-specific effects.