title: Longitudinal evidence on the association between interleukin-6 and C-reactive protein with the loss of total appendicular skeletal muscle in free-living older men and women.
abstract: BACKGROUND
  there is no longitudinal evidence about the association between the loss of total appendicular skeletal muscle (TASM) and cytokines.
  
  
  OBJECTIVE
  to investigate whether high levels of the inflammatory markers such as interleukin-6 (IL-6) and C-reactive protein (CRP) are associated with the loss of TASM in free-living non-sarcopenic older people.
  
  
  METHODS
  five-year prospective cohort study.
  
  
  METHODS
  one hundred and fifteen free-living non-sarcopenic older men and women aged 60-84 years at baseline and 5-year follow-up were included.
  
  
  METHODS
  TASM was measured by dual-energy X-ray absorptiometry, and the relative change in TASM was calculated. The response variable was the loss of TASM defined as the lowest sex-specific 15th percentile of the cohort distribution of percentage of change in TASM. The exposure variables were the baseline serum IL-6 and CRP levels measured by ELISA.
  
  
  RESULTS
  sixteen subjects were below the sex-specific 15th percentile of the cohort. The mean absolute loss of TASM in these men and women subjects was 1.9 and 1.3 kg, respectively. The risk of loss TASM was 1.29 times higher (95% confidence interval [CI], 1.01-1.64) (P = 0.03) per unit of increase in IL-6 (pg/ml) and 1.28 times higher (95% CI, 1.04-1.58) (P = 0.01) per unit of increase in CRP (mg/l). As a categorical variable, the risk of loss TASM was 4.85 times higher (95% CI, 1.24-18.97) among subjects with serum IL-6 >2.71 pg/ml and 3.97 times higher (CI 95%, 1.09-14.39) among subjects with serum CRP >3.74 mg/l. These findings remained after adjusting for age, sex and 5-year weight change.
  
  
  CONCLUSIONS
  inflammation is associated with the loss of TASM in free-living non-sarcopenic older men and women.
authors.affiliation: Coordinación de Nutrición, Centro de Investigación en Alimentación y Desarrollo, Hermosillo, Sonora, México. helio@ciad.mx
authors.forename: Heliodoro
authors.initials: H
authors.lastname: Alemán
authors.forename: Julian
authors.initials: J
authors.lastname: Esparza
authors.forename: Fatima Araceli
authors.initials: FA
authors.lastname: Ramirez
authors.forename: Humberto
authors.initials: H
authors.lastname: Astiazaran
authors.forename: Hélène
authors.initials: H
authors.lastname: Payette
mesh_terms: D015502:Absorptiometry, Photon; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology* / Q000473:pathology; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D016009:Chi-Square Distribution; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D057187:Independent Living; D007249:Inflammation / Q000000981:diagnostic imaging / Q000276:immunology* / Q000473:pathology; D018836:Inflammation Mediators / Q000097:blood*; D015850:Interleukin-6 / Q000097:blood*; D016015:Logistic Models; D008297:Male; D008800:Mexico; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000473:pathology*; D009929:Organ Size; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D015415:Biomarkers; C508600:IL6 protein, human; D018836:Inflammation Mediators; D015850:Interleukin-6; D002097:C-Reactive Protein