Sarcopenia Causes, Definition And Prevalence

Sarcopenia is the age associated degenerative loss of muscle tissue. Sarcopenia is estimated to affect 30% of people over the age of 60, and over 50% of people over the age of 80. Narici and Maffulli (2010) state that whilst sarcopenia is associated with loss of muscle function, the two are not proportional. Therefore, it is important to recognize that sarcopenia may not directly lead to impaired muscle function. The European Society for Clinical Nutrition and Metabolism Special Interest Groups define sarcopenia as the presence of low skeletal muscle mass and low muscle strength. Similarly, Evans (2010) states that sarcopenia is most prevalent in older adults who have an appendicular lean/fat mass 2 SD less than that of young adult. This is consistent with older adults whom are bedridden, unable to stand up from a chair, or have a gait speed less than 1 meter per second. Evans’ definition of sarcopenia outlines clear criteria, which can be the subject of future intervention, such as aiming to increase gait speed or increase lean mass.Sarcopenia Causes, Definition And Prevalence

Causes

An array of environmental and genetic factors are thought to cause sarcopenia. A review conducted by Walston (2012) presents a conceptual framework which outlines the multifactorial cause of sarcopenia. Endocrinal changes, namely the age-related decline in anabolic hormones, such as testosterone, likely cause sarcopenia. Testosterone increases muscle protein synthesis. In adult males, testosterone decreases by 1% every year, whist females experience a sharp decline between the ages of 20-45. It is suggested that decreased testosterone leading to decreased muscle protein synthesis causes muscle tissue loss.