Muscle Quality in Relation to Prediabetes Phenotypes: A Population-Based Study With Mediation Analysis

Area of Science:

• Endocrinology
• Metabolic Health
• Musculoskeletal Health

Background:

• Prediabetes increases physical disability risk.
• Muscle quality, a key functional measure, has not been thoroughly studied in prediabetes phenotypes.
• Understanding muscle quality alterations is crucial for managing prediabetes complications.

Purpose of the Study:

• To assess muscle quality in prediabetes and its specific phenotypes within a general US population.
• To investigate the associations between prediabetes, muscle quality, and potential mediators like insulin resistance.

Main Methods:

• Cross-sectional analysis of the National Health and Nutrition Examination Survey (2011-2014).
• Muscle quality calculated as grip strength divided by arm muscle mass (DXA).
• Participants categorized by prediabetes defects: isolated (IFG, IGT, IA1c), dual, or all three.

Main Results:

• Lower muscle quality observed in prediabetes overall and most phenotypes, despite higher grip strength/muscle mass.
• Decreased muscle quality and increased odds of low quality correlated with more glucometabolic defects.
• Insulin resistance was the primary mediator; HbA1c-defined prediabetes showed worse muscle quality than glucose-defined prediabetes.

Conclusions:

• Muscle quality is impaired in prediabetes and its specific phenotypes.
• Elevated HbA1c may be a stronger indicator of reduced muscle quality compared to blood glucose levels.
• Targeting insulin resistance and monitoring HbA1c could be important for preserving muscle function in prediabetes.