title: The association of plasma IL-6 levels with functional disability in community-dwelling elderly.
abstract: BACKGROUND
  IL-6 is a multifunctional cytokine that has been shown to increase with age.
  
  
  METHODS
  Plasma IL-6 was measured by ELISA in 1,727 community-dwelling elderly subjects whose blood was drawn during the third in-person survey of the Duke Established Populations for Epidemiologic Studies of the Elderly (EPESE). Demographics, functional status (disability), and disease states were determined. Correlations of these factors with IL-6 were analyzed with Spearman's Rho while differences between groups were assessed by Wilcoxon test.
  
  
  RESULTS
  IL-6 levels were higher with age (p = .0001) even in this older population (> 70 years). There was a positive correlation between IL-6 and functional disability for each of the functional status measures (p = .0001), as well as a correlation between self-rated health and IL-6. Significantly higher median levels of IL-6 were found in subjects reporting prevalent cancer, heart attack, and high blood pressure, but not diabetes or arthritis. The association between age and functional status with high IL-6 remained when all other variables were controlled, in multivariable analysis.
  
  
  CONCLUSIONS
  This association between increased plasma IL-6 levels and functional status suggests that dysregulation of IL-6 may be related to the functional disability seen with aging, and that IL-6 may be useful as a component of an overall marker of health.
authors.affiliation: Center for the Study of Aging and Human Development, Claude D. Pepper Older Americans Independence Center, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: H J
authors.initials: HJ
authors.lastname: Cohen
authors.forename: C F
authors.initials: CF
authors.lastname: Pieper
authors.forename: T
authors.initials: T
authors.lastname: Harris
authors.forename: K M
authors.initials: KM
authors.lastname: Rao
authors.forename: M S
authors.initials: MS
authors.lastname: Currie
mesh_terms: D000368:Aged; D000375:Aging / Q000097:blood; D003154:Community Medicine / Q000379:methods*; D006233:Persons with Disabilities; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006304:Health Status; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D015999:Multivariate Analysis; D012647:Self-Assessment
chemical_list: D015850:Interleukin-6