Association between geriatric nutritional risk index and cognitive function in older adults with/without chronic kidney disease

Background: Cognitive impairment is highly prevalent among patients with chronic kidney disease, who face an increased risk of cognitive decline. The aim of this study was to investigate the relationship between the Geriatric Nutritional Risk Index (GNRI) and cognitive function in older individuals, both with and without chronic kidney disease (CKD). Methods: In this study, we analyzed data from 2728 participants in the 2011-2014 National Health and Nutrition Examination Survey (NHANES). Cognitive function was measured using the Consortium to Establish a Registry for the Alzheimer's Disease Word Learning subtest (CERAD W-L), the animal fluency test (AFT), the digit symbol substitution test (DSST), and the global cognitive z-score. The GNRI, representing whole-body nutritional status, was calculated based on serum albumin, body weight, and ideal body weight. We employed weighted multiple linear regression analyses and subgroup analyses to assess the independent association of GNRI with cognitive function in CKD and non-CKD populations. Smoothing techniques were used to fit curves, and interaction tests were used to assess the robustness and specificity of the findings. Results: Our analyses revealed a significant positive association between higher GNRI levels and cognitive function in the older US population (for global z-score: beta = 0.01; 95% confidence interval [CI] = 0.00, 0.01). This association remained consistent across various subgroup analyses, including those for different gender groups, age groups, smoking statuses, diabetes statuses, hypertension statuses, individuals with a BMI below 25, individuals who consumed alcohol, and non-Hispanic white individuals. Smoothed curve-fitting analyses indicated that the GNRI was linearly related to cognitive function. No statistically significant interactions were detected among these variables. Conclusion: Our findings emphasize the positive association between GNRI and cognitive health in individuals with or without CKD, especially when combined with other risk factors. Consequently, enhancing the nutritional status of the elderly may serve as a viable strategy to thwart the onset of cognitive decline.