Joint association of triglyceride-glucose index and body roundness index for sarcopenia risk: A national cohort study.

High TyG index was independently associated with reduced sarcopenia risk over a 4-year follow-up.

• HR: 0.74; 95% CI: 0.56-0.99
• Analysis conducted using Cox proportional hazards regression models
• Study included 4367 middle-aged and older participants from a national cohort
• Sarcopenia was assessed based on the 2019 Asian Working Group for Sarcopenia (AWGS 2019) criteria

High Body Roundness Index (BRI) was independently associated with reduced sarcopenia risk over a 4-year follow-up.

• HR: 0.27; 95% CI: 0.19-0.37
• The protective association of high BRI was stronger than that of high TyG alone
• Analysis conducted using Cox proportional hazards regression models
• Findings remained consistent across sensitivity analyses

The combination of high TyG and high BRI showed the strongest protective effect against sarcopenia risk.

• High TyG/high BRI group: HR: 0.22; 95% CI: 0.14-0.35
• Joint association was stronger than either measure independently
• Combined assessment of TyG and BRI enhanced the predictive capacity for sarcopenia
• Four groups were compared based on high/low TyG and high/low BRI combinations

TyG and BRI demonstrated a synergistic additive interaction in their association with sarcopenia risk.

• Relative Excess Risk due to Interaction (RERI): 0.32; 95% CI: 0.10-0.54
• The positive RERI with a confidence interval excluding zero indicates a statistically significant synergistic effect
• Additive interaction analysis was used to assess the interaction effects
• These associations remained consistent across sensitivity and subgroup analyses

The study population consisted of middle-aged and older adults assessed over a 4-year follow-up period using national cohort data.

• Total sample size: 4367 participants
• Follow-up duration: 4 years
• Sarcopenia diagnosis based on AWGS 2019 criteria
• Cox proportional hazards regression models were employed to examine independent and joint associations
• Sensitivity analyses and subgroup analyses were conducted to evaluate robustness and consistency