Associations of longitudinal trajectories of triglyceride-glucose index combined with classical and novel obesity indices and cardiovascular disease: evidence from a nationwide prospective cohort study in China.

BACKGROUND: The triglyceride glucose (TyG) index and various obesity indices have been proven to be cost-effective indicators of cardiovascular disease (CVD) risk. This study aims to systematically investigate and compare the associations between longitudinal trajectories of TyG index combined with classical and novel obesity indices (TyG-BMI, TyG-WC, TyG-WHtR, TyG-WWI, TyG-ABSI, TyG-BRI, TyG-CVAI) and CVD. METHODS: The study sample comprised 3505 non-CVD participants from the CHARLS national cohort. Longitudinal data from Waves 1 and 3 of the national surveys were used to quantify cumulative exposure and trajectories of TyG and its obesity derivatives. A multi-model analytical framework (including logistic regression, spline regression, and weighted quantile sum regression models) was constructed to systematically examine the strength of associations between trajectories of TyG and its obesity derivatives and CVD, and the contribution of each component. RESULTS: During 8-year median follow-up, 411 CVD cases occurred. The study demonstrated that compared to static baseline values, longitudinal assessment of cumulative exposure and trajectory of TyG and its obesity derivatives enhanced predictive capacity for CVD. Notably, combinations of TyG with classical obesity index WC and novel obesity index CVAI (TyG-WC and TyG-CVAI) exhibited superior performance for CVD risk assessment. Compared to participants with well-controlled trajectories and low exposure levels, those with poorly controlled or highest cumulative exposure to TyG index, TyG-BMI, TyG-WC, TyG-WHtR, TyG-WWI, TyG-ABSI, TyG-BRI, and TyG-CVAI had odds ratios of 1.61/1.40, 2.13/1.70, 2.00/1.78, 1.77/1.59, 1.31/1.36, 1.37/1.30, 1.76/1.56, and 2.00/1.72, respectively. Finally, weighted quantile sum regression results indicated that cumulative exposure to obesity and triglycerides contributed most to CVD risk among all metabolic indices, suggesting that simultaneous regulation of triglycerides and obesity may be critical for reducing CVD risk. CONCLUSION: In this cohort study, the longitudinal trajectories of TyG and its obesity derivatives were closely associated with CVD. Comparatively, the combinations of TyG with classical obesity index WC and novel obesity index CVAI (TyG-WC and TyG-CVAI) exhibited superior performance for CVD risk assessment, with this risk primarily driven by obesity and triglycerides.