Associations of urinary phenolic environmental estrogens exposure with blood glucose levels and gestational diabetes mellitus in Chinese pregnant women

Background: Endocrine-disrupting chemicals (EDCs) are considered to be related to diabetes, but studies of the association between phenolic EDCs and gestational diabetes mellitus (GDM) are limited. Objectives: To assess associations of maternal urinary bisphenol A (BPA), nonylphenol (NP), and 2-tertoctylphenol (2-t-OP) with GDM occurrence. Methods: A cross-sectional study was performed among 390 Chinese women at 24-28 weeks of gestation. GDM was diagnosed with a 2-h 75-g oral glucose tolerance test (OGTT). BPA, NP, and 2-t-OP concentrations were determined in urine samples. Linear and logistic regression tests evaluated associations of BPA, NP, and 2-t-OP with blood glucose levels and GDM prevalence. Results: The 2-t-OP concentrations in GDM patients were significantly higher than in non-GDM women with me-dian values of 2.23 mu g/g Cr and 1.79 mu g/g Cr, respectively. No significant difference was observed in BPA and NP. Urinary 2-t-OP was positively associated with blood glucose levels after adjustment for several confounding fac-tors and urinary BPA and NP. Higher 2-t-OP levels were associated with higher odds of GDM (OR: 5.78; 95% CI: 2.04, 16.37), whereas higher NP levels were associated with lower odds (OR: 0.22; 95% CI: 0.05, 0.85) in the ad-justed models. In addition, compared to the first quartile of 2-t-OP, the adjusted odds ratios (ORs) and 95% con-fidence intervals (95% CIs) for GDM in the second, third, and fourth quartiles were 2.81 (1.23, 6.42), 3.01 (1.30, 6.93), and 5.49 (2.24, 13.46), respectively. Conclusion: Our study indicates that, for the first time to our knowledge, exposure to 2-t-OP is associated with a higher risk of GDM. However, higher NP exposure is associated with lower GDM risk. Further studies are neces-sary to affirm the associations of 2-t-OP and NP with GDM, and to elucidate the causality of these findings. (C) 2020 Elsevier B.V. All rights reserved.