Differences in muscle quality have been proposed as a potential factor associated with metabolic disease, but population-level data in US adults have been limited. In the Journal of Diabetes & Metabolic Disorders, a cross-sectional observational study evaluated the relationship between the Muscle Quality Index (MQI) and type 2 diabetes in adults aged 20-60 years using data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. The analysis included 4,088 participants and assessed three MQI parameters: arm MQI (MQIarm), appendicular MQI (MQIapp), and total MQI (MQItotal).

Participants with type 2 diabetes had significantly lower MQI values compared with those without diabetes, including MQIarm (11.04 ± 2.07 vs 12.85 ± 2.39), MQIapp (1.53 ± 0.30 vs 1.77 ± 0.32), and MQItotal (2.97 ± 0.56 vs 3.44 ± 0.60), with all comparisons reaching statistical significance (p<0.001). Logistic regression and restricted cubic spline analyses showed a linear inverse association between MQI and diabetes prevalence (p for overall <0.001; p for nonlinear = 0.458), with consistent findings across demographic and clinical subgroups.

Mediation analysis identified high-density lipoprotein cholesterol (HDL) and body mass index (BMI) as mediators of the association between MQI and diabetes. Machine learning and Boruta analyses highlighted MQI parameters among key predictors, and receiver operating characteristic analysis showed higher area under the curve values for MQI compared with muscle mass and BMI.