Table 1.

Sarcopenia categories by cause (Adapted from Dionyssiotis Y et al.[7] with permission).

Categories	Examples
Primary sarcopenia
Age-related sarcopenia	Without any known cause
Secondary sarcopenia
Activity-related sarcopenia	Can result from bed rest, sedentary lifestyle, deconditioning or zero-gravity conditions.
Disease-related sarcopenia	Associated with advanced organ failure (heart, lung, liver, kidney, and brain), inflammatory disease (such as Rheumatoid arthritis) malignancy or endocrine disease
Nutrition-related sarcopenia	Associated with inadequate caloric intake, malabsorption, gastrointestinal disorders, drug induced anorexia