Urinary phenols in early to mid-pregnancy and risk of gestational diabetes: A longitudinal study in a multiracial cohort

Environmental phenols are ubiquitous endocrine disruptors and putatively diabetogenic. However, data during pregnancy are scant. We investigated the prospective associations between pregnancy phenols concentrations and gestational diabetes (GDM) risk. In a nested matched case-control study of 111 individuals with GDM and 222 non-GDM controls within the prospective PETALS cohort, urinary bisphenol A (BPA), BPA substitutes (bisphenol F, bisphenol S [BPS]), benzophenone-3, and triclosan were quantified during the first and second trimesters. Cumulative concentrations across the two times were calculated using the area under the curve (AUC). Multivariable conditional logistic regression examined the associations of individual phenols with GDM risk. We conducted mixture analysis using Bayesian kernel machine regression. We a priori examined effect modification by Asians/Pacific Islanders (A/PI) race/ethnicity due to the case-control matching and highest GDM prevalence among A/PI. Overall, first-trimester urinary BPS was positively associated with an increased risk of GDM [adjusted odds ratio comparing the highest versus lowest tertile aORT3 vs. T1 (95% CI)=2.12 (1.00-4.50)]. We identified associations among non-A/P, who had higher phenols concentrations than A/PI. Among non-A/PI, first-trimester BPA, BPS, and triclosan were positively associated with GDM risk [aORT3 vs. T1 (95% CI)=2.91 (1.05-8.02), 4.60 (1.55-13.70), 2.88 (1.11-7.45), respectively]. Triclosan in the second trimester and AUC were positively associated with GDM risk among non-A/PI (P <0.05). In mixture analysis, triclosan was significantly associated with GDM risk. Urinary BPS among all and BPA, BPS, and triclosan among non-A/PI were associated with GDM risk. Pregnant individuals should be aware of these phenols’ potential adverse health effects.