Joint association of triglyceride-glucose index and obesity indicators with stroke risk: a nationwide prospective cohort study

The triglyceride-glucose (TyG) index has been identified as an independent predictor of stroke risk. However, the comprehensive impact of combined indices, integrating TyG with obesity indicators such as body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR), on stroke risk remains insufficiently explored. Furthermore, there is a paucity of research on combined indices involving TyG and other obesity indicators like the weight-adjusted waist index (WWI), body roundness index (BRI), and a body shape index (ABSI). This study aimed to comprehensively evaluate the combined impact of TyG with various obesity indicators on stroke risk and to investigate their potential associations. This observational cohort study included 8,730 participants from the China Health and Retirement Longitudinal Study (CHARLS). Cox proportional hazards models, smooth curve fitting, and threshold effect analysis were employed to explore the potential relationships between the combined indices and stroke risk. The predictive value of TyG alone, obesity indicators, and the combined indices for stroke risk was compared using the area under the receiver operating characteristic (ROC) curve (AUC), and was validated by Delong test. Kaplan-Meier curves were used to illustrate the cumulative incidence of stroke events. Over a median follow-up of 7 years, 456 (5.20%) incident stroke cases were identified. After adjusting for confounding factors, non-linear relationships were observed between TyG-WC, TyG-WHtR, TyG-WWI, TyG-ABSI and stroke risk, demonstrating significant dose-response relationships (all P < 0.05 for the log-likelihood ratio test); conversely, TyG, TyG-BMI, and TyG-BRI exhibited linear relationships with stroke risk (The p values respectively: p < 0.001, p = 0.004, p = 0.019). The highest stroke risk incidence (7.55%) was observed in the Q4 group of TyG-WC. Furthermore, the combined indices showed higher AUC values for stroke risk compared to TyG or obesity indicators alone. Combined indices of TyG and obesity indicators are significantly associated with stroke risk. Combined obesity indicators with the TyG index may provide additional predictive utility for stroke risk compared to the TyG index alone. The combined assessment of the TyG index and obesity indicators could be considered in stroke risk assessment and primary prevention.