Association between Triglyceride-glucose index and sarcopenia in China: A nationally representative cohort study

Background: The relationship between sarcopenia and insulin resistance (IR) has seldom been reported. Triglyceride-glucose (TyG) index, a new IR indicator, has gained traction as a prognostic tool for many diseases. We aimed to investigate whether the level of TyG index was related to the incidence of sarcopenia. Method: A total of 1819 participants above 60 without sarcopenia at baseline were included from the China Health and Retirement Longitudinal Study (CHARLS). Cox models were applied to evaluate the association between TyG and incident sarcopenia. Mediation analyses were performed to evaluate the contribution of the level of BMI to observed associations. Results: During a median follow-up of 4.0 years, 217 (11.9 %) participants developed sarcopenia. The multivariable-adjusted hazard ratios of total sarcopenia in higher quartiles of TyG index versus the lowest quartiles were 0.59, 0.61, and 0.46, respectively. There were significant trends toward a decreasing risk of sarcopenia across the quartiles of TyG index before adjusting for BMI, but no significant association was observed after accounting for BMI. The area under the ROC curve was 0.6281 (0.597–0.660). In subgroup analysis, there was an inverse significant association between TyG index and sarcopenia among male participants. In mediation analyses, BMI explained 88.7 % of the association of TyG index and sarcopenia. Conclusions: Our findings indicated that TyG index was negatively associated with incident sarcopenia in older Chinese without considering BMI adjustment. The association was not more significant after adjusting for BMI. BMI mediated the relationship between sarcopenia and TyG index among older Chinese population. Future study should validate our findings in a larger population.