Joint Associations of Cumulative Triglyceride‐Glucose—A Body Shape Index and Frailty Trajectories With Incident Cardiovascular Disease in Middle‐Aged and Older Chinese Adults
Lirong Lei, Shuaifeng Xiao, Sujuan Sun, Huilei HouABSTRACT
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.