Association between the triglyceride glucose-body roundness index and the incidence of cardiovascular disease among Chinese middle and old-aged adults: a nationwide prospective cohort study.

Aim: Previous studies have suggested that the triglyceride glucose (TyG) index and body roundness index (BRI) are indicators of insulin resistance (IR) and are associated with the incidence of cardiovascular disease (CVD) among middle and old-aged adults. BRI is considered a more accurate indicator of the proportion of body fat and visceral fat than body mass index (BMI). However, it remains unclear whether the combined use of the TyG index and BRI, specifically the triglyceride glucose-body roundness index (TyG-BRI), is associated with the incidence of CVD among Chinese middle and old-aged adults.

Methods: Data were obtained from the China Health and Retirement Longitudinal Study (CHARLS). The TyG-BRI index was computed using baseline measurements of triglycerides, fasting blood glucose, waist circumference, and height. Cox proportional hazards regression and restricted cubic spline (RCS) regression analyses were applied to assess the association between the TyG-BRI index and incident CVD (defined as cardiac events or stroke).

Results: A total of 8,113 Chinese adults participated in this study, with a median age of 58 years, including 56.3% males. The fully adjusted Cox regression analysis revealed that individuals in the highest quartile (Q4) of the TyG-BRI index had a 59.1% increased risk of developing incident CVD compared to those in the lowest quartile (HR, 1.591 [95% CI, 1.330-1.902]). The TyG-BRI index showed a significant linear association with CVD incidence (P for nonlinearity = 0.447, P < 0.001). This association persisted after conducting subgroup and sensitivity analyses.

Conclusions: This study introduced a novel TyG-BRI index, which integrated IR and body roundness as a comprehensive indicator, demonstrating its strong and independent association with increased CVD risk in a Chinese nationwide cohort. Our findings provide new insights into the interaction between metabolic dysfunction and cardiovascular risk, suggesting that the TyG-BRI index could serve as a practical tool for targeted preventive interventions.