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September 12, 2001

Sarcopenia—Understanding the Dynamics of Aging Muscle

Author Affiliations

Author Affiliation: Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, Mass.

JAMA. 2001;286(10):1230-1231. doi:10.1001/jama.286.10.1230

Sarcopenia is not a disease but rather refers specifically to the universal, involuntary decline in lean body mass that occurs with age, primarily due to the loss of skeletal muscle.1 Sarcopenia has important consequences. The loss of lean body mass reduces function, and loss of approximately 40% of lean body mass is fatal.25 Sarcopenia is distinct from wasting—involuntary weight loss due to inadequate intake, which is seen in starvation, advanced cancer, or acquired immunodeficiency syndrome. Sarcopenia also differs from cachexia, a cytokine-driven loss of lean body mass that occurs despite maintenance of weight, which is seen in patients with rheumatoid arthritis, congestive heart failure, or renal failure.6 However, sarcopenia is the backdrop against which the drama of disease is played out: a body already depleted of protein because of aging is less able to withstand the protein catabolism that comes with acute illness or inadequate protein intake.7

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