Decreased β-cell function is associated with reduced skeletal muscle mass in Japanese subjects without diabetes

Abstract

Background Decreased insulin secretion has a great impact on the incidence of type 2 diabetes in Japanese subjects. It is not clear whether β-cell function is related to muscle mass in subjects without diabetes.We investigated the relationship between β-cell function and skeletal muscle mass in Japanese subjects without diabetes. Methods The study included 1098 subjects (538 men and 560 women) aged 40 to 79 years, without diabetes (fasting glucose lower than 126 mg/dL and glycosylated hemoglobin lower than 6.5%), who consulted Osaka Medical College Health Science Clinic for a medical examination. Appendicularmuscle mass was measured by bioelectrical impedance analysis. Appendicularmuscle mass index was calculated as appendicularmuscle mass divided by height squared (kg/m2). The homeostatic model assessment of β-cell function was used to assess β-cell function. The homeostatic model assessment of insulin resistance was used as a measure of insulin resistance. The association between appendicularmuscle mass index and clinical parameters of β-cell function and insulin resistance was examined. Results Log-transformedhomeostatic model assessment of β-cell function and Log-transformed homeostatic model assessment of insulin resistance showed a normal distribution. In both men and women, there was a significant positive correlation between appendicularmuscle mass index and clinical parameters of β-cell function and insulin resistance. Tertile analysis, following stratification according to appendicularmuscle mass index, found that low appendicularmuscle mass index was significantly associated with the Log homeostatic model assessment of β-cell function and Log-transformedhomeostatic model assessment of insulin resistance. Conclusion This study shows that decreased β cell function is associated with reduced skeletal muscle mass in Japanese subjects without diabetes.