Abstract
INTRODUCTION: Although studies had shown that Insulin resistance (IR) was correlated with the occurrence of sarcopenia, there were still many controversial conclusions. Therefore, we conducted a more comprehensive study on the relationship between the estimated glucose disposal rate (eGDR), an alternative indicator of IR, and the risk of sarcopenia, muscle mass, and muscle strength to clarify their interactions. METHODS: The Study included individuals from The China Health and Retirement Longitudinal Study (CHARLS) who had complete eGDR data at baseline and did not develop low muscle mass and low muscle strength. The individuals were divided into four subgroups based on the quartile (Q) of the eGDR. The lowest quartile (Q1) of the eGDR was used as a reference. Logistic regression and linear regression were used to evaluate the relationship between eGDR and sarcopenia (low muscle mass, low muscle strength, possible sarcopenia, and sarcopenia) and sarcopenia related features (ASM/Ht2, grip, and RMS), respectively. In addition, we further evaluated the nonlinear relationship using smooth curve fitting and threshold effect analysis. RESULTS: The results showed that after adjusting for confounders, eGDR was negatively associated with the risk of sarcopenia and positively associated with sarcopenia related characteristics. In addition, men showed a more significant reduction in the likelihood of low muscle mass compared to women. But as eGDR levels rise, women gain more ASM/Ht(2). Further nonlinear analysis revealed an inverse correlation between eGDR and ASM/Ht(2) at the inflection point of 15.3893. Besides that, eGDR was positively correlated with grip (7.1862) and RMS (11.1042) before the inflection point. CONCLUSIONS: The study found that higher levels of eGDR were associated with a lower risk of developing sarcopenia. However, the effects of eGDR on muscle mass and muscle strength need to be considered comprehensively. For muscle mass, it is recommended to maintain eGDR below 15.3893, and for muscle strength, it is recommended to maintain eGDR below 7.1862, with more potential benefits for early warning of sarcopenia.