Association Between the Prognostic Nutritional Index and Cognitive Function Among Older Adults in the United States: A Population-Based Study

Background: Nutritional status has been recognized as an important factor influencing cognitive function-related diseases, but few comprehensive nutrition indicators are available to assess the risk of cognitive decline. Objective: This study aimed to investigate the relationship between the prognostic nutritional index (PNI) and cognitive function in an elderly population, and the differences in nutrient intake between different levels of nutritional risk. Methods: Based on cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014, we included 2,564 older participants. The lower quartile of each of the four cognitive tests was considered to have cognitive function impairment (CFI). Binary and multivariate logistic regression models were used to estimate the relationship between the PNI and the odds ratio of CFI. Results: After adjustment for confounding variables, we found that the odds of CFI were significantly lower for participants with normal PNI levels than for those with lowPNI levels. In a comparison of global cognitive impairment scores, participants with a normal PNI had lower ratios of poor cognitive performance than those with a low PNI. By comparing the nutrient intake at different PNI levels, we found a reduction in the intake of protein, dietary fiber, total saturated fatty acids, and multiple micronutrients in the low PNI group. Conclusion: Our study shows that the PNI can be a good predictor of the odds of CFI in the elderly population and that it is a convenient indicator of reduced intake of nutrients which may be important to brain health.