Lipid–Glucose Metabolic Index (TyG) as an Early Indicator of Vascular Aging: Evidence of Body Mass Index Modification in a Chinese Community Cohort

Background and Aims: Cardiovascular disease remains a leading global health concern, with atherosclerosis being a major contributor to mortality. This study examines the association between the triglyceride–glucose (TyG) index—a novel surrogate marker of insulin resistance—and atherosclerosis in Chinese adults, and evaluates the modifying effect of body mass index (BMI) on this relationship. Methods and Results: A total of 4729 healthy Chinese adults were included from a community-based health survey. The TyG index was calculated as ln[fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2]. Arterial stiffness was assessed via carotid-femoral (cfPWV), carotid-radial (crPWV), and carotid-dorsalis pedis (cdPWV) pulse wave velocities. After adjustment for conventional risk factors, the TyG index showed a significant association with peripheral arterial stiffness (cdPWV >10.57 cm/s or crPWV >11.12 cm/s), but not with cfPWV. A significant interaction between TyG index and BMI was observed for both crPWV and cdPWV. The risk of elevated crPWV and cdPWV increased across TyG index quartiles at varying BMI levels (P< 0.001). A dose-response relationship between TyG index and crPWV/cdPWV was evident in participants with normal weight and overweight, particularly among normal-weight adults, but was absent in participants with obesity. Conclusion: The TyG index independently predicts peripheral arterial stiffness, particularly in normal-weight adults. These findings highlight the lipid–glucose metabolic imbalance as a driver of early vascular aging and suggest that TyG assessment may refine cardiometabolic risk stratification beyond BMI.