Oxidative protein damage is associated with elevated serum interleukin-6 levels among older moderately to severely disabled women living in the community

Abstract

Background. Elevated interleukin (IL)-6 is associated with adverse outcomes. Our objective was to determine whether serum protein carbonyls, an indicator of oxidative protein damage and oxidative stress, were associated with IL-6. Methods. Serum protein carbonyls and IL-6 were measured in 739 women, age ≥65 years, in the Women's Health and Aging Study I. Results. Geometric mean of protein carbonyls was 0.082 nmol/mg. After adjusting for age and smoking status, loge serum protein carbonyls were associated with loge IL-6 (β = 0.143, standard error [SE] = 0.048, p = .003) in linear regression analyses and with elevated IL-6 (≥2.5 pg/mL) (odds ratio = 1.38, 95% confidence interval, 1.02-1.86, p = .037) in logistic regression analyses. Conclusion. Oxidative damage to proteins is independently associated with serum IL-6 among older women living in the community. Increased oxidative stress may be a factor involved in the pathogenesis of the proinflammatory state that occurs in older adults. Copyright 2008 by The Gerontological Society of America.