Table 4.
Association between sodium intake and executive function
| Studies | Quality Assessment | Salt categorization | Type of Cognitive assessment | Categorization of cognitive scores/function | Type of analysis | Results | Direction of association | ||
| Bojar et al. [35] | Poor | Sodium measured in mg/day, in continuous measures | Shifting Attention tests | Continuous | Pearson’s correlation | Cognition measure r p Shifting Attention tests 092 0.065 |
No association | ||
| Koh et al. [36] | Poor | Sodium measured in mg/day, in continuous measures | Verbal Fluency test (Letter Fluency) | Continuous | Spearman’s correlation | Cognition measure r p Letter Fluency -0.141 >0.05 |
No association | ||
| Sodium measured in mg/day, in continuous measures | Verbal Fluency test (Categorical Fluency) | Continuous | Spearman’s correlation | Cognition measure r p Categorical Fluency -0.055 >0.05 |
No association | ||||
| Sodium measured in mg/day, in continuous measures | Trail Making test | Continuous | Spearman’s correlation | Cognition measure r p Trailmaking -0.111 >0.05 |
No association | ||||
| Sodium measured in mg/day, in continuous measures | Digitspan backwards | Continuous | Spearman’s correlation | Cognition measure r p Digitspan backwards -0.016 >0.05 |
No association | ||||
| Hwang and Kim [37] | Fair | Sodium/potassium ratio, split into quartiles | Controlled Oral Word Association test | Continuous | ANOVA | Na/K quartile F p Q1 (M±SD) 17.22±9.04 1.98 0.12 Q2 (M±SD) 21.43±9.19 Q3 (M±SD) 24.78±11.65 Q4 (M±SD) 21.18±11.72 j-shaped but not statistically significant |
No association | ||
| Blumenthal et al. [27] | Good | Sodium measured in mg/day, in continuous measures | Composite score of: Trail Making Test, Stroop test, Digit span forward, Backward subtest from Weschler Adult Intelligence Scale, Digit symbol substitution test from Weschler Adult Intelligence Test, Ruff 2 & 7 test and Animal Naming Test |
Continuous | GLM | Dependent variable: composite score of cognitive tests For sodium b= 0.18, p=0.024 |
Lower sodium --> better cognition | ||
| Rush et al. [31] | Fair | Sodium measured in mg/day, in continuous measures | Verbal Fluency Test | Continuous | Linear regression | Dependent variable: Verbal Fluency Test score For sodium: β= 0.006, p=0.823 Adjusted for: Age, sex, education, total caloric intake, daily potassium intake, calcium intake, Mediterranean diet score |
No association | ||
| Sodium measured in mg/day, in quartiles | Verbal Fluency Test | Continuous | Linear test for trend | Mean test scores by caloric adjusted sodium intake quartiles p=0.897 Adjusted for: Age, sex, education level, total caloric intake *more like a inverted j-shaped relationship |
Null | ||||
| Sodium measured in mg/day, in continuous measures | Trailmaking Test (Trail B) | Continuous | Linear regression | Dependent variable: Trailmaking Test scores For sodium β= -0.079, p=0.005 Adjusted for: Age, sex, education, total caloric intake, daily potassium intake, calcium intake, Mediterranean diet score |
Higher sodium ->better cognition | ||||
| Sodium measured in mg/day, in continuous measures | Trailmaking Test (Trail B) | Continuous | Linear regression | Dependent variable: Trailmaking Test scores sodium intake predicting for Trails B score stratified by age <80 years old: standardized β=-0.04, p=0.365 ≥80 years old: standardized β=-0.15, p=0.014 Adjusted for: Sex, education, total caloric intake |
Higher sodium ->better cognition | ||||
| Sodium measured in mg/day, in quartiles | Trailmaking Test (Trail B) | Continuous | Linear test for trend | Mean test scores by caloric adjusted sodium intake quartiles p=0.073 Adjusted for: Age, sex, education level, total caloric intake |
Null | ||||
ANOVA, Analysis of Variance; CVD, cardiovascular diseases; FFQ, Food frequency questionnaire; GLM, generalized linear model; M, mean; MoCA, Montreal Cognitive Assessment; Na/K, sodium/potassium ratio; r, correlation coefficient; SD, standard deviation.