Background: Phthalate exposures are hypothesized to increase obesity; however, prior research has been largely cross-sectional.
Objective: To evaluate associations between prenatal phthalate exposures and body mass index (BMI) at child ages 5 and 7 years.
Methods: Nine metabolites of six phthalates: di-(2-ethylhexyl)phthalate (DEHP), di-n-octyl-, di-iso-butyl-, di-n-butyl-, butylbenzyl-, and diethyl phthalates, were measured in spot urine samples collected from pregnant African American and Dominican women during their third trimester, and from their children at ages 3 and 5 years. To reduce multiple comparison issues, we initially used Principal Component Analysis (PCA) to identify major patterns of (ln)- transformed metabolite concentrations. Height and weight were assessed at ages 5 and 7 years, and fat mass and waist circumference at age 7. Linearized generalized estimating equation analyses related maternal component scores to child anthropometric outcomes at ages 5 (n=326) and 7 (n=330).
Results: PCA identified a DEHP component and a non-DEHP component. In boys, higher maternal non-DEHP, but not DEHP, component scores were associated with lower BMI z-score (β=-2.02; 95% CI:-3.71, -0.32, n=124). No significant associations with anthropometric outcomes were seen in girls (For BMI z-score, β=0.07; 95% CI: -0.18, 0.31, n=181). Interactions between sex and non-DEHP component association with outcomes were statistically significant (p<0.01).
Conclusion: Contrary to hypotheses, prenatal non-DEHP phthalate exposures were associated with lower BMI z-score, waist circumference and fat mass in boys during early childhood.