Table 1.
Observational studies examining serum 25(OH)D and cognitive function.
| Citation | Sample (size, key characteristics) | Study Design | Cognition Aspect/Measures | Covariates | Outcomes | |
|---|---|---|---|---|---|---|
| Brouwer-Brolsma et al. (2013) [12] | 127 frail or prefrail Dutch elderly, mean age 79 years, SD 7.6 | Cross-sectional | Global Cognition | MMSE | Age, sex, BMI, education, smoking, alcohol consumption, habitual physical activity, and season of blood sampling | Significant positive association between executive functioning and serum 25(OH)D (β = 0.007, p = 0.01). For every 11 nmol increase in serum 25(OH)D, 1 more work was memorized on the Word Learning Test. |
| Episodic Memory | Word Learning Test direct recall, delayed recall, and recognition | |||||
| Attention and working memory | Digit Span forward and backward test | |||||
| Information processing speed and concept shifting interference | Trail Making Test A and B | |||||
| Selective attention | Stroop Color–Word Test | |||||
| Executive Functioning | Verbal fluency and Reaction Test | |||||
| Brouwer-Brolsma et al. (2015) [13] | 2857 Dutch participants, 59% male with an average age of 72.5 years. | Cross-sectional | Global Cognition | MMSE | Age, sex, BMI, education, smoking, alcohol consumption, habitual physical activity, and season of blood sampling | Significant association between higher serum 25(OH)D and attention and working memory (PR: 0.50, 95% CI 0.29–0.84) |
| Immediate and delayed recall | Rey Auditory Verbal Learning Test | |||||
| Attention and working memory | Digit span forward and backward | |||||
| Information processing speed | Trail Making Test part A and Symbol Digit Modalities | |||||
| Executive functioning (concept shifting interference | Trailing Making Test part B | |||||
| Executive functioning (selective attention) | Stroop Color–Word test | |||||
| Executive functioning | Letter fluency | |||||
| Milman et al. (2014) [14] | 253 Ashkenazi Jewish with exceptional longevity, median age 97 years | Cross-sectional | Global Cognition | MMSE | Age, sex, BMI, education, history of tobacco use, depression, HDL cholesterol levels, and presence of ≥2 medical comorbidities | Insufficient serum 25(OH)D levels significantly associated with lower global cognition (OR 3.2, 95% CI 1.1–9.29, p = 0.03) and CDT (OR 8.96, 95% CI 1.08–74.69, p = 0.04) |
| Executive functioning | Clock-drawing test | |||||
Abbreviations: MMSE (Mini-Mental State Exam); BMI (Body Mass Index); HDL (High-density lipoprotein).