Abstract
BACKGROUND: Type 2 diabetes mellitus (T2DM) and sarcopenia have emerged as significant public health challenges that disproportionately affect middle-aged adults. However, the relationship between T2DM and muscle parameters in this critical age remains inadequately elucidated. METHODS: We conducted a comprehensive analysis of cross-sectional data derived from 2,446 middle-aged participants (aged 40-59 years; 1,230 men and 1,216 women) enrolled in the National Health and Nutrition Examination Survey (NHANES) 2011-2014. T2DM was defined by physician-confirmed diagnosis and/or glycohemoglobin (HbA1c) ≥ 6.5%. We systematically evaluated appendicular lean mass index (ALMI) and grip strength in relation to T2DM status, employing multiple linear regression models with hierarchical adjustment for demographic, anthropometric, and clinical covariates. RESULTS: Following comprehensive covariate adjustment, T2DM exhibited a significant inverse association with combined grip strength (β=-3.14; 95% CI: -4.55, -1.73) but showed no significant association with ALMI (β=-0.05; 95% CI: -0.13, 0.02). Sex-stratified analyses revealed significant reductions in both muscle mass and strength exclusively among men with T2DM, whereas no significant associations were observed in women. The adverse impact of T2DM on grip strength was particularly pronounced among individuals with BMI < 25 kg/m² (β=-6.72; 95% CI: -10.38, -3.06). Furthermore, glycohemoglobin demonstrated positive associations with ALMI in non-diabetic individuals, while serum glucose levels exhibited inverse associations with ALMI across the total study population. CONCLUSIONS: Our findings demonstrated negative associations between T2DM and muscle mass and strength in middle-aged men, but not in women. These observations underscore the critical importance of early muscle health surveillance and targeted therapeutic interventions in T2DM patients, particularly among men and those with BMI < 25 kg/m².