Life in Plastic: Prenatal Phthalate Exposure and Early Childhood Executive Function in the UPSIDE Cohort

Abstract

Phthalates are synthetic chemicals widely used as plasticizers in consumer products, resulting in pervasive human exposure. Many studies have examined associations between prenatal phthalate exposure and neurodevelopment with some evidence of sex-specific impacts on cognition; associations with childhood executive function (EF) remain understudied. This thesis examines: (1) sociodemographic factors associated with phthalate exposure in early pregnancy; and (2) associations between prenatal phthalate exposure and children’s EF. As part of the Understanding Pregnancy Signals and Infant Development (UPSIDE) cohort, first trimester maternal urine samples were collected and analyzed for a panel of phthalate metabolites. Children’s inhibitory control, one component of EF, was assessed using the Snack Delay task at follow up visits at 24 months of age. Poisson generalized linear models (n= 115) were fitted and adjusted for marital status, maternal education, and race, and stratified by sex. Higher parity and identifying as Black or Other race were associated with higher levels of ΣDiBP metabolites (p<0.05), while no associations were observed for other sociodemographic factors. No notable associations were found between phthalate exposure and Snack Delay performance in the full cohort or in either sex, suggesting no association between prenatal phthalate exposure and EF at 24 months, although larger studies with longer follow-up are needed to draw more definitive conclusions. The larger body of work on phthalates and child health outcomes supports the need for policies to reduce exposure and longitudinal studies evaluating long-term neurodevelopmental impact.