A novel nutritional index based on triglyceride, cholesterol, and body weight as a protective factor against sarcopenia: evidence from CHARLS and NHANES

BACKGROUND: sarcopenia, characterized by low muscle mass and function, significantly impacts health outcomes in aging populations. This study investigated the association between triglyceride cholesterol body weight index (TCBI) and sarcopenia risk among middle-aged and elderly Chinese individuals and American adults. METHODS: we analyzed data from CHARLS (2011) and NHANES (2015-2018) to investigate TCBI-sarcopenia associations. TCBI was categorized into quartiles. Multiple logistic regression models examined associations between TCBI and sarcopenia risk. Dose-response relationships were evaluated using restricted cubic spline models, while ROC analyses assessed predictive performance. Subgroup and sensitivity analyses were performed. RESULTS: both studies showed strong inverse associations between TCBI and sarcopenia risk. After adjustment, CHARLS demonstrated that compared with the lowest TCBI quartile, sarcopenia risk decreased progressively in the second (OR = 0.486, 95 % CI = 0.407-0.578), third (OR = 0.226, 95 % CI = 0.182-0.281), and highest (OR = 0.113, 95 % CI = 0.084-0.151) quartiles. NHANES showed significantly lower sarcopenia risk in the second (OR = 0.470, 95 % CI = 0.271-0.815), third (OR = 0.264, 95 % CI = 0.122-0.572), and highest (OR = 0.074, 95 % CI = 0.024-0.225) quartiles. Restricted cubic spline analysis revealed significant non-linear relationships, with protective associations most pronounced at lower TCBI levels. Subgroup analyses showed consistent associations. CONCLUSIONS: higher TCBI levels were significantly associated with reduced sarcopenia risk in both populations. TCBI may serve as a valuable tool for sarcopenia risk assessment.