Oxidative Stress Is Related to Frailty, Not to Age or Sex, in a Geriatric Population: Lipid and Protein Oxidation as Biomarkers of Frailty

OBJECTIVES: To ascertain whether indicators of oxidative damage to lipids (malondialdehyde (MDA)) and proteins (protein carbonylation) are biomarkers of frailty, after adjusting for age, sex, and other possible confounders. DESIGN: Cross-sectional cohort study. SETTING: Community. PARTICIPANTS: Toledo Study for Healthy Aging participants (N = 742, aged 65-95), classified as frail (n = 54), prefrail (n = 278) and nonfrail (n = 410) according to the Fried criteria. MEASUREMENTS: Blood plasma was obtained using centrifugation (1,500 G, 15 minutes) and immediately frozen at -80 degrees C. Plasma lipid peroxidation was determined by measuring the MDA formed from lipoperoxides using high-performance liquid chromatography and protein carbonylation was measured using Western blot. RESULTS: Age-and sex-adjusted levels of lipoperoxides (measured as MDA) and protein carbonylation in plasma proved to be related to frailty, even after including possible independent confounders. CONCLUSION: Circulating oxidative damage biomarkers, such as MDA and protein carbonylation, are related to frailty and not to age or sex. These parameters may be considered as potential biomarkers of frailty in the context of a multidisciplinary health-promoting approach for older adults.