Association of Vitamin D and Magnesium Status with Cognitive Function in Older Adults: Results from the National Health and Nutrition Examination Survey (NHANES) 2011 to 2014 (FS05-03-19)

Abstract

Abstract Objectives Vitamin D protects neuronal structure and aids in neuronal calcium regulation and may play a role in neurodegeneration and aging. Magnesium plays an important role in multiple neurological disorders including cognitive impairment, and is linked with the synthesis and metabolism of vitamin D. Whether vitamin D and magnesium status influence cognitive function in older adults is poorly studied. We examined potential associations of these nutrients with cognitive status in a population-based cross-sectional study. Methods Utilizing data from the National Health and Nutrition Survey (NHANES) 2011 to 2014, 2984 participants aged 60 years and older who completed the Digit Symbol Substitution Test (DSST) were analyzed. Cognitive function was assessed using DSST scores. Cases were defined as participants with a 25th percentile or lower score on the DSST. Total vitamin D and magnesium intake were determined from 24-hour dietary recalls and supplemental interviews. Serum 25-hydroxyvitamin D (25(OH)D) was used to define vitamin D status. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results After adjustment for confounders, total energy and magnesium intake, a higher serum 25(OH)D level was associated with decreased odds of having a low DSST score (OR: 0.66; 95% CI: 0.50, 0.87) comparing highest vs. lowest tertile (P trend < 0.01). A similar association was observed for total vitamin D intake, with a reduced risk of lower DSST score with higher vitamin D intake. An inverse association of higher serum 25(OH)D with cognitive function was observed primarily among participants with a daily total magnesium intake of <254 mg (OR: 0.50; 95% CI: 0.32, 0.78) or ≥375 mg (OR: 0.60; 95% CI: 0.38, 0.95). There were no clear associations for cognitive function with total magnesium intake overall. Conclusions We found that higher serum 25(OH)D levels were associated with reduced risk of low cognitive function in older adults, and this association appeared to be modified by the intake level of magnesium. These findings warrant further studies investigating magnesium and vitamin D and their combined effects on cognitive function. Funding Sources UNTHSC. Supporting Tables, Images and/or Graphs