Dietary sodium/potassium intake and cognitive impairment in elderly patients with hypertension: data from nhanes 2011-2014

Objective: Salt is a widely used condiment throughout the world. Sodium chloride is the main salt component. Sodium is an essential macronutrient that maintains fluid balance and cellular homeostasis. It is suggested that dietary sodium may influence cognition by cerebrovascular and cerebral blood flow. This study aimed to assess the relationship between dietary sodium/ potassium intake and cognition in elderly individuals with hypertension. Design and method: We designed a cross-sectional study based on the 2011–2014 National Health and Nutrition Examination Survey (NHANES). Cognitive performance was assessed using the Digit Symbol Substitution Test (DSST), Consortium to Establish a Registry for Alzheimer's Disease test (CERAD), and Animal Fluency Test (AFT). Multivariate logistic regression and restricted cubic spline (RCS) was used to assess the relationship between dietary sodium/ potassium intake and cognition. Results: After excluding participants with incomplete data, 1670 out of 2276 participants had confirmed hypertension. Compared with the lowest quartile of dietary sodium, the lowest weighted odds ratio (OR) of cognitive impairment in DSST was observed in Q4 (OR=0.45, 0.29–0.70), and a similar trend was observed in AFT (OR=0.34, 0.18–0.65). After adjusting the covariates, the lowest weighted multivariate adjusted OR of cognitive impairment in DSST were also observed in Q4 (OR=0.47, 0.26–0.84) compared with the lowest quartile of dietary sodium. The RCS results showed that dietary sodium was U-shaped and associated with the risk of cognitive impairment in the DSST (Pnon–linearity=0.0067). No significant association was observed between dietary potassium and cognitive performance. Conclusions: Too high and too low dietary sodium levels were associated with impairment of specific processing speed, sustained attention, and working memory for hypertension among the elderly in the United States. However, no association was observed between the dietary potassium intake and cognition.