RT Journal
A1 Roubenoff R, Castaneda C
T1 SArcopenia—understanding the dynamics of aging muscle
JF JAMA
JO JAMA
YR 2001
FD September 12
VO 286
IS 10
SP 1230
OP 1231
DO 10.1001/jama.286.10.1230
UL http://dx.doi.org/10.1001/jama.286.10.1230
AB 
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.2- 5
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