Oxidative Balance, Nutrition, and Cognitive Function in Older Adults: A Mediation Analysis Using NHANES 2011–2014 Data

Background The global rise in cognitive function impairment (CFI) parallels an aging population. While oxidative stress is considered a contributing factor, its role in CFI remains underexplored. This study examines the relationship between oxidative balance score (OBS) and CFI using 2011–2014 National Health and Nutrition Examination Survey (NHANES) data. Methods Data from 2,089 participants aged 60 and above were analyzed. OBS was calculated from 16 dietary and 4 lifestyle components. Cognitive function was evaluated using the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD), Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST). Multivariable weighted logistic regression, restricted cubic splines (RCS), subgroup, and mediation analyses assessed the association between OBS and CFI, adjusting for age, sex, and comorbidities. Sensitivity analysis tested result robustness. Results Higher OBS was significantly associated with a lower CFI risk after adjusting for confounders. RCS indicated a linear negative correlation between OBS and CFI. Subgroup analysis showed stronger associations in non-Hispanic Black and non-Hispanic White populations. Mediation analysis revealed the Geriatric Nutritional Risk Index (GNRI) and albumin/globulin ratio (AGR) had opposing mediating effects. Sensitivity analysis confirmed the stability of these findings in unweighted models. Conclusion Higher oxidative balance is significantly linked to reduced CFI risk in older adults. Enhancing oxidative balance through diet and lifestyle modifications could be a promising strategy to maintain cognitive health.