Effects of Type II Diabetes on upper extremity muscle characteristics in older adults

Abstract

With one in every four older adults living with T2D and one in every two older adults meeting the criteria for prediabetes, neuromuscular changes due to T2D are likely to impact functional activities in this population. Limited work in evaluating motor unit number and size across muscles in the upper extremity in persons with Type II Diabetes (T2D) exists, mostly due to the traditional belief bias that the upper extremity is relatively spared in T2D as compared to the lower extremities. The purpose of the current study was to evaluate motor unit number and size (using electrophysiological motor unit number index (MUNIX) and motor unit size index (MUSIX)) across the upper extremity in older adults with T2D (n = 13) as compared to healthy age- and sex-matched controls (n = 12). Persons with T2D presented with more motor units and larger motor unit sizes (p < 0.05) as compared to age- and sex-matched control participants. These changes were not dependent upon muscle location within a limb, indicating systemic neuromuscular changes associated with T2D. These group effects were clarified when health state covariates (e.g., blood pressure) were accounted for. Findings are consistent with emerging data that show altered neuromuscular characteristics with health state considerations in persons with T2D.