A prospective study of early-pregnancy thyroid markers, lipid species, and risk of gestational diabetes mellitus - 环境暴露与健康实验室

Abstract Context While the associations between thyroid markers and gestational diabetes mellitus (GDM) have been extensively studied, the results are inconclusive and the mechanisms remain unclear. Objective We aimed to investigate the prospective associations of thyroid markers in early gestation with GDM risk, and examine the mediating effects through lipid species. Methods This study included 6068 pregnant women from the Tongji-Shuangliu Birth Cohort. Maternal serum thyroid markers (free triiodothyronine (fT3), free thyroxine (fT4), thyroid-stimulating hormone, thyroid peroxidase antibody, and thyroglobulin antibody) were measured before 15 weeks. Deiodinase activity was assessed by fT3/fT4 ratio. Plasma lipidome were quantified in a subset of 883 participants. Results Mean age of the participants was 26.6 ± 3.7 years, and mean gestational age was 10.3 ± 2.0 weeks. Higher levels of fT4 were associated with a decreased risk of GDM (OR=0.73 comparing the extreme quartiles; 95% CI 0.54, 0.98, Ptrend =0.043), while higher fT3/fT4 ratio was associated with an increased risk of GDM (OR=1.43 comparing the extreme quartiles; 95% CI 1.06, 1.93, Ptrend =0.010) after adjusting for potential confounders. Multiple linear regression suggested that fT3/fT4 ratio was positively associated with alkylphosphatidylcholine 36:1, phosphatidylethanolamine plasmalogen 38:6, diacylglyceride 18:0/18:1, sphingomyelin 34:1, and phosphatidylcholine 40:7 (false discovery rate adjusted P