Relationship between indices of insulin resistance and incident type 2 diabetes mellitus in Chinese adults

Background Insulin resistance (IR) is a pivotal pathogenesis characteristic of type 2 diabetes mellitus (T2DM). The current study aimed to explore the association between triglyceride/high-density lipoprotein cholesterol ratio (TG/HDL-c), triglyceride-glucose (TyG), and triglyceride glucose-body mass index (TyG-BMI), and T2DM incidence. Methods A total of 116,855 Chinese adults aged over 20 without diabetes were included. Multivariate Cox regression analysis and restricted cubic spine were utilized to investigate the association between IR indicators and T2DM. The T2DM risk across different quartiles of IR parameters was compared using Kaplan-Meier curves. The receiver operating characteristic analysis was used to investigate the predictive potential of each IR indicator for future T2DM. Results A total of 2685 participants developed T2DM during a median follow-up of 2.98 years. The adjusted hazard ratios (HR) of incident T2DM were 1.177, 2.766, and 1.1018 for TG/HDL-c, TyG, and TyG-BMI, respectively. There were significant increasing trends of T2DM across the quartiles of TG/HDL-c, TyG, and TyG-BMI. The HRs of new-onset T2DM in the highest quartiles versus the lowest quartile of TG/HDL-c, TyG, and TyG-BMI were 3.298, 8.402, and 8.468. RCS revealed the nonlinear relationship between IR and T2DM risk. The correlations between IR and T2DM were more pronounced in subjects aged <40. TyG-BMI had the highest predictive value for incident T2DM (AUC = 0.774), with a cut-off value of 213.289. Conclusion TG/HDL-c, TyG, and TyG-BMI index were all significantly positively associated with higher risk for future T2DM. Baseline TyG-BMI level had high predictive value for the identification of T2DM.