Associations of the triglyceride-glucose index and triglyceride-glucose/body mass index with all-cause mortality in Chinese centenarians

Background The triglyceride-glucose (TyG) index and triglyceride-glucose/body mass index (TyG-BMI) have been shown to be associated with cardiovascular and cerebrovascular disorders and the risk of death. The aim of this study was to explore the relationships of the TyG index and TyG-BMI with all-cause mortality among Chinese centenarians. Methods Data from the China Hainan Centenarian Cohort Study (CHCCS) were analyzed. Eligible centenarians were divided into quartiles on the basis of their TyG and TyG-BMI indices. Kaplan-Meier analysis was used to compare survival times across groups. The associations of the TyG index and TyG-BMI with all-cause mortality were investigated using restricted cubic splines (RCSs) and Cox proportional hazards regression models. Moreover, the concordance of the associations of the TyG index and TyG-BMI with all-cause mortality in different subgroups was further explored by subgroup analysis. Results A total of 921 centenarian participants were included in this study. During a median follow-up of 29.70 months, 852 (92.5%) centenarians died. The results of the RCS analysis demonstrated that the TyG index and TyG-BMI were both linearly and negatively associated with all-cause mortality. Compared with that for the highest the TyG index and TyG-BMI quartile groups, higher risks of death were found for the lowest quartile groups (TyG Q1 vs. Q4, HR 1.27, 95% CI 1.03-1.56, P = 0.024; TyG-BMI Q1 vs. Q4, HR 1.60, 95% CI 1.30-1.96, P < 0.001). Centenarians with lower TyG index and TyG-BMI values had significantly greater mortality risks according to the Kaplan-Meier analysis (log-rank P = 0.020, log-rank P < 0.001, respectively). Subgroup analysis demonstrated that blood pressure could influence the linear negative correlation between the TyG-BMI and all-cause mortality. Conclusion Both lower TyG and TyG-BMI indices were significantly associated with higher all-cause mortality in Chinese centenarians, whereas the TyG-BMI was superior to the TyG index in predicting the mortality risk of centenarians.