Higher inflammatory marker levels in older persons: associations with 5-year change in muscle mass and muscle strength.
BACKGROUND
There is growing evidence that higher levels of inflammatory markers are associated with physical decline in older persons, possibly through the catabolic effects of inflammatory markers on muscle. The aim of this study was to investigate the association between serum levels of inflammatory markers and loss of muscle mass and strength in older persons.


METHODS
Using data on 2,177 men and women in the Health, Aging, and Body Composition Study, we examined 5-year change in thigh muscle area estimated by computed tomography and grip and knee extensor strength in relation to serum levels of interleukin-6 (IL-6), C-reactive protein, tumor necrosis factor-alpha (TNF-alpha), and soluble receptors (measured in a subsample) at baseline.


RESULTS
Higher levels of inflammatory markers were generally associated with greater 5-year decline in thigh muscle area. Most associations, with the exception of soluble receptors, were attenuated by adjustment for 5-year change in weight. Higher TNF-alpha and interleukin-6 soluble receptor levels remained associated with greater decline in grip strength in men. Analyses in a subgroup of weight-stable persons showed that higher levels of TNF-alpha and its soluble receptors were associated with 5-year decline in thigh muscle area and that higher levels of TNF-alpha were associated with decline in grip strength.


CONCLUSIONS
TNF-alpha and its soluble receptors showed the most consistent associations with decline in muscle mass and strength. The results suggest a weight-associated pathway for inflammation in sarcopenia.
Schaap
Laura A
LA
Department of Epidemiology and Biostatistics, the EMGO Institute for Health and Care Research, VU University Medical Center, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands. l.schaap@vumc.nl
Pluijm
Saskia M F
SM
Deeg
Dorly J H
DJ
Harris
Tamara B
TB
Kritchevsky
Stephen B
SB
Newman
Anne B
AB
Colbert
Lisa H
LH
Pahor
Marco
M
Rubin
Susan M
SM
Tylavsky
Frances A
FA
Visser
Marjolein
M
D000368:Aged; D002097:C-Reactive Protein / Q000032:analysis*; D005260:Female; D018737:Hand Strength; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D016014:Linear Models; D008297:Male; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000473:pathology*; D019947:Receptors, Interleukin-6 / Q000097:blood; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000097:blood*
D015850:Interleukin-6; D019947:Receptors, Interleukin-6; D047888:Receptors, Tumor Necrosis Factor, Type I; D014409:Tumor Necrosis Factor-alpha; D002097:C-Reactive Protein