Association between the triglyceride-glucose-body mass index and the risk of early vascular aging in young and middle-aged Chinese adults: a cross-sectional study

Background Insulin resistance is closely associated with arterial stiffness and vascular aging. The triglyceride–glucose–body mass index (TyG-BMI) is a validated surrogate marker of insulin resistance. However, evidence regarding the association between TyG-BMI and early vascular aging (EVA) remains limited, particularly among young and middle-aged populations. Methods This cross-sectional study included 1,272 Chinese adults aged 30–59 years who underwent brachial–ankle pulse wave velocity (baPWV) assessment. EVA was defined using the Framingham vascular age score. Multivariable logistic and linear regression models, restricted cubic spline analyses, and threshold analyses were applied to evaluate the association between TyG-BMI and EVA. Receiver operating characteristic (ROC) curve analysis was conducted to assess the predictive value of TyG-BMI for EVA. Results Each one-unit increase in TyG-BMI was associated with a 2.9% higher risk of EVA (odds ratio 1.029, 95% confidence interval 1.024–1.034) after full adjustment. Restricted cubic spline analysis revealed a nonlinear association, with an inflection point at TyG-BMI of 220.90. Below this threshold, EVA risk increased modestly, whereas above the threshold, the risk increased substantially. TyG-BMI was also positively associated with baPWV and other vascular aging indicators. ROC analysis suggested a moderate discriminatory ability of TyG-BMI for identifying individuals with EVA.(area under the curve 0.812). Conclusions TyG-BMI is independently and nonlinearly associated with the risk of early vascular aging in young and middle-aged Chinese adults. TyG-BMI may serve as a practical biomarker for identifying individuals at high risk of vascular aging.