Sarcopenia is defined by the loss of muscle mass, strength, and physical function, and its prevalence varies significantly depending on the definition used.

Sarcopenia is an age-related syndrome characterised by progressive and generalised loss of skeletal muscle mass and strength; it is a major contributor to the risk of physical frailty, functional impairment in older people, poor health-related quality of life and premature death... Prevalence estimates for sarcopenia vary widely in different clinical, research settings, reflecting divergence in the approaches used for definition.