A Study of the Relationship Between the Triglyceride-Glucose Index and Skeletal Muscle Mass in a General Chinese Population

Objective: There is no study on the relationship between triglyceride-glucose index (TyG index) and skeletal muscle mass in middle-aged and elderly C population. Therefore, the aim of the study is to investigate the relationship between the TyG index and weight-adjusted relative skeletal muscle index (RSMI) in middle-aged and elderly C population. Methods: We retrospectively studied 947 aged >= 40 years subjects who got a routine medical examination in the Department of Geriatrics of R Hospital from May 2021 to March 2023. The RSMI was designed to evaluate skeletal muscle mass and calculated based on lean mass of the limbs(kg)/body weight(kg) x 100%. Skeletal muscle mass reduction was defined as a RSMI of 1-2 standard deviations (SD) below of healthy adults aged 30-49 years old. Considering the quartile groups of the TyG index, the subjects were assigned to 4 groups: Q1 (less than or equal to 8.171), Q2 (from 8.172 to 8.569), Q3 (from 8.570 to 8.992), and Q4 (greater than or equal to 8.993). Results: With TyG index increased, RSMI levels significantly reduced(P < .001). Spearman's correlation analysis showed that the TyG index was negatively correlated with RSMI in males (r = -0.320) and females (r = -0.240). The TyG index was positively correlated with body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), fasting plasma glucose (FPG), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) (P < .05). Besides, binary logistic regression analysis showed that the risk of developing reduced skeletal muscle mass in the group Q4 was 2.131 (95%CI:1.118-4.064) in males; and was 2.472 (95%CI:1.581-3.867) in females compared to the Q1 group. Conclusion: TyG index was negatively correlated with relative skeletal muscle index, and a higher TyG index was associated with the development of reduced skeletal muscle mass independently of other influencing factors. Therefore, the TyG index promises to be a predictor of skeletal muscle mass loss.