Higher inflammatory marker levels in older persons: associations with 5-year change in muscle mass and muscle strength

Abstract

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.

Figure 1.

Association between inflammatory markers and 5-year change in thigh muscle area (cm²) and grip strength in weight-stable (within 3% change in weight) persons per standard deviation change in marker. Notes: Adjusted for baseline measures of the outcome, age, sex, race, study site, chronic diseases, physical activity, anti-inflammatory drug use, statin use, estrogen use, and steroid use. Number of persons in the analyses: 5-year change in thigh muscle area: n = 617 for IL-6; n = 605 for CRP; n = 601 for TNF-α; n = 85 for IL-2sR, IL-6sR, and TNFsR1; n = 84 for TNFsR2. 5-year change in grip strength: n = 760 for IL-6, n = 779 for CRP, n = 739 for TNF-α, n = 117 for IL-2sR and IL-6sR, n = 115 for TNFsr1, n = 116 for TNFsR2. 5-year change in knee extensor strength: n = 685 for IL-6, n = 702 for CRP, n = 667 for TNF-α, n = 101 for IL-2sR and IL-6sR, n = 100 for TNFsR1 and TNFsR2. CRP = C-reactive protein; IL-6 = interleukin-6; IL-2sR = interleukin-2 soluble receptor; IL-6sR = interleukin-6 soluble receptor; TNF-α = tumor necrosis factor-alpha; TNFsR1 = tumor necrosis factor soluble receptor 1; TNFsR2 = tumor necrosis factor soluble receptor 2.