Lower limb muscle mass is associated with insulin resistance more than lower limb muscle strength in non-diabetic older adults.

Aim: We examined the association of muscle mass and muscle strength with insulin resistance, focusing on lower limb muscles. Methods: This was a cross-sectional study, and participants were registered in 2017 from the Tanno-Sobetsu Study, a population-based cohort study. After excluding individuals aged <64 years or with a history of diabetes mellitus, 272 non-diabetic older adults (116 men, 156 women) met the inclusion criteria. According to the homeostasis model assessment of insulin resistance, the participants were divided into two groups; that is, the insulin resistance group (homeostasis model assessment of insulin resistance >= 1.73) and non-insulin resistance group (homeostasis model assessment of insulin resistance <1.73). Muscle mass (lower limb, upper limb, appendicular and trunk) and muscle strength (grip strength and knee extension torque) were measured and divided by the weight, and then multiplied by 100 to calculate the weight ratio (%). The adjusted odds ratio (OR) of each muscle index for risk of insulin resistance was calculated separately for both men and women. Results: Lower limb muscle mass (OR 0.72, 95% CI 0.55-0.92 in men; OR 0.69, 95% CI 0.51-0.96 in women, respectively) and appendicular muscle mass (OR 0.75, 95% CI 0.61-0.94 in men; OR 0.72, 95% CI 0.54-0.95 in women, respectively), but not other muscle indexes, were associated with risk of insulin resistance, after adjusting for age, body mass index, highly sensitive C-reacting protein and smoking habits. Conclusions: Lower limb muscle mass of non-diabetic older adults is independently related to insulin resistance.