"Availability and standards on techniques to estimate muscle mass (or lean body mass) in epidemiological studies were becoming available. Based on these parameters, sarcopenia was operationally defined as a gradual loss of muscle mass. For instance, Baumgartner used a definition based on appendicular skeletal muscle mass estimated by DXA, corrected for height, and defined sarcopenia as being two standard deviations below sex specific means of healthy young persons (18-40 years) of a reference population 2. Longitudinal studies confirmed that a progressive reduction in muscle mass was present in both males and females 3. Muscle mass declines at approximately 1-2% per year after the age of 50 years. Sarcopenia, when defined as a severe muscle mass loss (two standard deviations below healthy young populations) is present in 5 to 13% of persons 60 to 70 years old and 11 to 50% of those over 80 years 4"--