Preserved Lower Limb Muscle Mass Prevents Insulin Resistance Development in Nondiabetic Older Adults

Objective: To investigate roles of sarcopenia indexes in prediction of development of insulin resistance in nondiabetic older adults. Design: A 2-year follow-up cohort. Setting and participants: The Tanno-Sobetsu study, a prospective observational cohort, included 194 community-dwelling nondiabetic older adults during 2017-2019. Methods: Lower limb, upper limb, appendicular, and trunk muscle masses by a bioelectrical impedance analysis, grip strength, knee extension torque, and walking speed were measured in study participants aged >65 years (79 men and 115 women) at baseline. Muscle mass and strength were divided by the weight, and then multiplied by 100 to calculate the weight ratio (%). Insulin resistance was assessed by homeostasis model (HOMA-IR) at baseline, and the study participants whose HOMA-IR was less than 1.73 at baseline were followed for a maximum of 2 years. The study endpoint was development of insulin resistance defined as HOMA-IR >1.73. The adjusted hazard ratio (HR) of each sarcopenia component for development of insulin resistance was calculated. Results: Lower limb muscle mass (HR 0.88, 95% CI 0.79-0.98) and appendicular muscle mass (HR 0.89, 95% CI 0.81-0.99), but not other sarcopenia components, were associated with the development of in-sulin resistance, independently of sex and age, HOMA-IR, and waist circumference at baseline. Conclusions and Implications: The loss of lower limb muscle mass is a significant risk factor for devel-opment of insulin resistance independently of obesity in nondiabetic older adults. The lower limb muscle mass may be a novel target of interventions for the prevention of diabetes in older adults. (c) 2022 The Authors. Published by Elsevier Inc. on behalf of AMDA -The Society for Post-Acute and Long-Term Care Medicine. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

In older adults without diabetes, the loss of lower limb muscle mass is a significant risk factor for the development of insulin resistance, independent of obesity.