Muscle dysfunction in type 2 diabetes: a major threat to patient's mobility and independence

Type 2 diabetes, a common metabolic disease in older people, is a major risk factor for functional limitation, impaired mobility, and loss of independence. In older people, the pathogenesis of functional limitation and disability is complex and multifactorial. A number of potential pathways are involved including cardiovascular disease, peripheral neuropathy, overweight, osteoarthritis, visual deficit, and cognitive impairment, conditions that are all more prevalent among patients with diabetes. Sarcopenia, a geriatric condition characterized by a progressive and generalized loss of skeletal muscle mass and strength, is also involved in the pathogenesis of functional limitations and disability. Recent research has shown that older patients with type 2 diabetes are often affected by skeletal muscle impairment, leading to reduced muscle strength and physical function. Insulin resistance, hyperglycemia, muscle fat infiltration, and peripheral neuropathies are hypothesized as the fundamental biological mechanisms leading to muscle impairment in people with diabetes. This review summarizes the current literature on the biological pathways responsible for skeletal muscle dysfunction in type 2 diabetes and analyzes the role of decline in muscle strength and quality on the association between diabetes and mobility disability.