Transition of Hypertriglyceridemic-Waist Phenotypes and the Risk of Type 2 Diabetes Mellitus among Middle-Aged and Older Chinese: A National Cohort Study

The rapid economic growth and nutritional changes in China have brought an increased burden of type 2 diabetes mellitus (T2DM). This study aimed to assess the effects of hypertriglyceridemic-waist (HTW) and its dynamic transitions on incident T2DM among middle-aged and older Chinese. Data were extracted from the China Health and Retirement Longitudinal Study (CHARLS). Participants were classified into three HTW phenotypes, namely NTNW (normal triglyceride (TG) and waist circumference (WC)), NTEW/ETNW (normal TG and enlarged WC, or elevated TG and normal WC) and ETEW (elevated TG and enlarged WC). Multivariable Cox frailty models were used to assess the associations of HTW phenotypes and their transitions over time with the risk of T2DM. A total of 7397 subjects without T2DM were included, of which 849 developed T2DM during 2011–2018. Compared with individuals with NTNW, people in the NTEW/ETNW group and ETEW group were at a significantly higher risk of T2DM (HR(NTEW/ETNW) = 1.28, 95% CI: 1.06–1.54 and HR(ETEW) = 1.61, 95% CI: 1.26–2.06). For subjects with NTNW at baseline, the risk of developing T2DM increased by 38% and 83% if their metabolic status changed to NTEW/ETNW and ETEW, respectively. For subjects with NTEW/ETNW, the risk of T2DM decreased by 33% when their metabolic status changed to normal (NTNW); but the risk increased by 49% if the status became more serious (ETEW). NTEW/ETNW, ETEW and their transitions to adverse states were risk factors for T2DM.