Hyperglycemia Is Associated with Impaired Muscle Quality in Older Men with Diabetes: The Korean Longitudinal Study on Health and Aging

Background: The study aimed to investigate the influence of hyperglycemia on muscle quality in older men with type 2 diabetes. Methods: This was a subsidiary study of the Korean Longitudinal Study of Health and Aging. Among 326 older men consenting to tests of body composition and muscle strength, 269 men were ultimately analyzed after the exclusion because of stroke (n=30) and uncertainty about the diagnosis of diabetes (n=27). Body composition was measured using dual-energy X-ray absorptiometry and computed tomography. Muscle strength for knee extension was measured using an isokinetic dynamometer. Muscle quality was assessed from the ratio of leg strength to the entire corresponding leg muscle mass. Results: The muscle mass, strength, and quality in patients with type 2 diabetes did not differ significantly from controls. However, when patients with diabetes were subdivided according to their glycemic control status, patients with a glycosylated hemoglobin (HbA1c) level of >= 8.5% showed significantly decreased leg muscle quality by multivariate analysis (odds ratio, 4.510; P=0.045) after adjustment for age, body mass index, smoking amount, alcohol consumption, physical activity, and duration of diabetes. Physical performance status was also impaired in subjects with an HbA1c of >= 8.5%. Conclusion: Poor glycemic control in these older patients with diabetes was associated with significant risk of decreased muscle quality and performance status. Glycemic control with an HbA1c of <8.5% might be needed to reduce the risk of adverse skeletal and functional outcomes in this population.