Rachel M. Shaffer

Project title: Maternal Urinary Phthalates in Relation to Gestational Diabetes and Glucose Intolerance During Pregnancy

Degree: MPH | Program: Environmental and Occupational Health (EOH) | Project type: Thesis/Dissertation
Completed in: 2018 | Faculty advisor: Sheela Sathyanarayana


Recent studies have linked phthalates with type 2 diabetes, but limited research exists on the potential association between phthalates and gestational diabetes (GDM), impaired glucose tolerance (IGT), and continuous glucose tolerance measures during pregnancy. We evaluated 11 urinary phthalate metabolites from the first (T1) and third (T3) trimesters of pregnancy and medical record abstraction data in 705 women from The Infant Development and Environment Study. We used logistic regression to examine the associations between log-transformed, specific gravity adjusted T1-only and average phthalate metabolite concentrations across pregnancy (average of T1 and T3) with GDM and IGT, and linear regression to examine the associations of T1 and pregnancy average phthalates with continuous glucose concentration. In sensitivity analyses, we examined interactions between exposure and race. We adjusted for maternal age, maternal body mass index, study center, race/ethnicity, and parity. We observed 60 cases of GDM, 90 cases of IGT, and an average (SD) GLT blood glucose of 113.6 (27.7) mg/dL. Average log MEP across pregnancy was associated with increased odds of GDM (OR: 1.88; 95% CI: 1.14, 3.10). Log MCOP was associated with increased blood glucose concentration (mg/dL) (T1: 6.19, 95% CI: 0.75, 11.63), T1T3: 6.98, 95% CI: 0.13, 13.82). There were suggestive associations of race-specific effects in Asians. Given the prevalence of phthalate exposures and the growing evidence of their potential metabolic effects, future studies should examine this question in larger cohorts of pregnant women, particularly in those who may be at higher risk for GDM and IGT. URI