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

Background: A low‐grade proinflammatory state is common in older adults and is associated with poor outcomes such as cardiovascular disease, disability, and increased mortality. Protein carbonyls are a useful biomarker of oxidative stress. The proinflammatory cytokine interleukin (IL)‐6 can be upregulated by increased oxidative stress. Specific Aims: To determine whether serum protein carbonyls were independently associated with IL‐6. Methods: We characterized the relationship between serum protein carbonyls and IL‐6 in a cross‐sectional study involving 739 women, age 65 and older, in the Women’s Health and Aging Study I. Results: Geometric mean serum protein carbonyls were 0.082 nmol/mg. After adjusting for age and smoking, serum protein carbonyls were associated with elevated IL‐6 (≥ 2.5 pg/mL) (Odds Ratio: 1.38, 95% CI: 1.02–1.86, P = 0.037) in a logistic regression analysis. In linear regression analyses, serum protein carbonyls were associated with increased IL‐6 (beta = 0.95, P = 0.0008) after adjusting for age and smoking. Conclusion: These results suggest that serum protein carbonyl concentrations are independently associated with serum IL‐6 levels among older women living in the community. Increased oxidative stress may be a factor involved in the pathogenesis of the mild proinflammatory state that occurs in older adults. This research was supported by NIH R01 AG027012.