Insulin-like growth factor-1 and interleukin 6 predict sarcopenia in very old community-living men and women: the Framingham Heart Study.
OBJECTIVE
To assess the prognostic role of the inflammatory cytokine, interleukin 6 (IL-6), and insulin-like growth factor-1 (IGF-1) in predicting 2-year changes in fat-free mass (FFM) while controlling for potential confounders.


METHODS
Population-based cohort, the Framingham Heart Study, examined in 1992-93 and 1994-95.


METHODS
General community.


METHODS
Two hundred thirty-two men and 326 women aged 72 to 92.


METHODS
IGF-1 was measured using radio-immunoassay and cellular IL-6 production using non-cross-reacting radioimmunoassays. FFM was estimated using population-specific equations for predicting FFM from bioelectrical impedance analysis developed separately for men and women.


RESULTS
Higher IGF-1 predicted smaller loss of FFM in men than lower IGF-1 did (P=.002), after adjusting for age, baseline FFM, fat mass, and 2-year weight changes, whereas cellular IL-6 was a significant predictor of sarcopenia in women (P=.02). Weight change was a strong determinant of change in FFM in both sexes (P<.0001).


CONCLUSIONS
Predictors of sarcopenia include body composition characteristics that are common to men and women and sex-specific metabolic predictors. Sarcopenia appears to reflect a withdrawal of anabolic stimuli, such as growth hormone, in men but an increase in catabolic stimuli, such as cellular IL-6, in women.
Payette
Hélène
H
Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Tufts University, Boston, Massachusetts, USA. helene.payette@usherbrooke.ca
Roubenoff
Ronenn
R
Jacques
Paul F
PF
Dinarello
Charles A
CA
Wilson
Peter W F
PW
Abad
Leslie W
LW
Harris
Tamara
T
D000273:Adipose Tissue / Q000378:metabolism; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight; D015331:Cohort Studies; D017097:Electric Impedance; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D015850:Interleukin-6 / Q000097:blood*; D016014:Linear Models; D008297:Male; D011379:Prognosis; D011863:Radioimmunoassay; D012111:Residence Characteristics; D012737:Sex Factors; D013997:Time Factors
D015850:Interleukin-6; D007334:Insulin-Like Growth Factor I