Sarcopenia has recently attracted widespread attention, because it increases risks of fall and bedridden. Although patients with type 2 diabetes mellitus (T2DM) are known to have lower muscle mass of limbs than healthy people, the mechanism is still unclear. We thus examined the association of muscle mass with parameters of endogenous insulin secretion such as fasting immunoreactive insulin, fasting C-peptide immunoreactivity (CPR), and daily urine CPR in 191 men with T2DM. Muscle mass of arms and legs was evaluated by dual-energy X-ray absorptiometry, and we calculated relative skeletal muscle index (RSMI), which is useful for the diagnosis of sarcopenia. Multiple regression analyses adjusted for age, duration of T2DM, serum creatinine, HbA1c, and insulin-like growth factor-I showed that each parameter of endogenous insulin was significantly and positively correlated with muscle mass of arms and legs as well as RSMI (p < 0.05). Moreover, logistic regression analyses adjusted for confounding factors mentioned above showed that each parameter of endogenous insulin was significantly lower in subjects with sarcopenia than those without it (p < 0.05). In conclusion, reduction in endogenous insulin secretion is an independent risk factor of sarcopenia in men with T2DM.
Keywords: Diabetes mellitus; IGF-Ι; Insulin secretion; Sarcopenia; Skeletal muscle mass.