THE ASSOCIATION OF PLASMA IL-6 LEVELS WITH FUNCTIONAL DISABILITY IN COMMUNITY-DWELLING ELDERLY

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 Epidemi ologic Studies of the Elderly (EPESE). Demographics, functional status (disability), and disease states were determined. Correlations of the se factors with IL-6 were analyzed with Spearman's Rho while differenc es between groups were assessed by Wilcoxon test. Results. IL-6 levels were higher with age (p = .0001) even in this older population (>70 y ears). There was a positive correlation between IL-6 and functional di sability for each of the functional status measures (p = .0001), as we ll as a correlation between self-rated health and IL-6. Significantly higher median levels of IL-6 were found in subjects reporting prevalen t cancer, heart attack, and high blood pressure, but not diabetes or a rthritis. The association between age and functional status with high IL-6 remained when all other variables were controlled, in multivariab le analysis. Conclusions. This association between increased plasma IL -6 levels and functional status suggests that dysregulation of IL-6 ma y 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.