Fig. 1Changes of appendicular skeletal muscle mass (ASM), and ASM indices according to age trends in Korean (A) men and (B) women using data from Korea National Health and Nutrition Examination Study 2008 to 2010. ht2, height squared (m). Modified from Kim et al. [4].
Table 1Major causes or mechanisms of sarcopenia in older adults
Primary |
Age related: sex hormones, muscle apoptosis, mitochondrial dysfunction |
Secondary |
Activity related: physical inactivity, disuse, decon ditioning, zero gravity |
Nutrition related: inadequate dietary intake, malabsorption, gastrointestinal disorders or medications that cause anorexia |
Endocrine disorder related: obesity, insulin resistance, inflammatory cytokine, steroid treatment, abnormal thyroid function |
Neurodegenerative disorder related: stroke, parkinsonism, diabetic neuropathy |
Chronic disease related: malignancy, advanced organ failure |
Table 2Clinical phenotype of frailty proposed by Fried et al.
Weight loss |
Unintentional loss of ≥4.5 kg in the past year |
Weakness |
Hand-grip strength in the lowest 20% quintile adjusted for sex and body mass index |
Exhaustion |
Poor endurance and energy, self-reported from the Center for Epidemiologic Studies Depression Scale |
Slowness |
Walking speed under the lowest quintile adjusted for sex and height |
Low physical activity level |
Lowest quintile of kilocalories of physical activity during the past week, measured by the Minnesota Leisure Activity Scale |