Joint Associations of Cumulative Triglyceride-Glucose-A Body Shape Index and Frailty Trajectories With Incident Cardiovascular Disease in Middle-Aged and Older Chinese Adults.

Aim

To examine the independent and joint associations of cumulative triglyceride-glucose-a body shape index (TyG-ABSI) and frailty trajectories with incident cardiovascular disease (CVD) in middle-aged and older Chinese adults.

Methods

We analyzed data from the China Health and Retirement Longitudinal Study. We calculated cumulative TyG-ABSI as the mean of fasting measurements in 2011 and 2015; we identified frailty trajectories from frailty-index measurements in 2011, 2013, and 2015 using latent class linear mixed models. Survey-ascertained incident CVD was a newly reported physician diagnosis of heart disease or stroke in 2018 or 2020. We used complementary log-log discrete-time survival models with cluster-robust standard errors because exact onset dates were unavailable.

Results

Among 3026 participants, 606 met the study definition of incident CVD. Each 1-SD increase in cumulative TyG-ABSI was associated with higher CVD risk (HR 1.16, 95% CI 1.06-1.26), and the higher frailty trajectory was associated with greater risk (HR 1.91, 95% CI 1.53-2.39). Relative to low TyG-ABSI/lower frailty, HRs were 1.26 (95% CI 1.04-1.53), 1.87 (1.34-2.61), and 2.43 (1.79-3.29) for high/lower, low/higher, and high/higher groups. Multiplicative and additive interactions were not significant.

Conclusions

Cumulative TyG-ABSI and frailty trajectory were independently associated with survey-ascertained incident CVD. Their joint distribution showed a cumulative risk gradient without statistical synergy. These observational findings support complementary risk stratification, not a validated clinical threshold or causal effect.