Journal of Alzheimer's Disease, Online Date Wednesday, July 03, 2013
Cedric Annweiler 1, 2, 3, Manuel Montero-Odasso2, David J. Llewellyn4, Stéphane Richard-Devantoy5, Gustavo Duque, Olivier Beauchet1
- 1 Department of Neuroscience, Division of Geriatric Medicine and Memory Clinic, UPRES EA, UNAM, Angers University Hospital, Angers, France
- 2 Department of Medicine, Division of Geriatric Medicine, Parkwood Hospital, St. Joseph's Health Care London; Gait and Brain Lab, Lawson Health Research Institute, the University of Western Ontario, London, ON, Canada
- 3 Robarts Research Institute, Department of Medical Biophysics, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
- 4 Epidemiology and Public Health Group, University of Exeter Medical School, Exeter, United Kingdom
- 5 McGill University, Montréal, QC, Canada; 6: Ageing Bone Research Program, Sydney Medical School-Nepean Campus, University of Sydney, Penrith, NSW, Australia
Background: Hypovitaminosis D is associated with global cognitive impairment in adults. It remains unclear which domain-specific cognitive functions are affected with hypovitaminosis D.
Objective. To systematically review and quantitatively synthesize the association of serum 25-hydroxyvitamin D (25OHD) concentrations with episodic memory and executive functions in adults.
Methods: A Medline and PsycINFO® libraries search was conducted on May 2012, with no limit of date, using the Medical Subject Headings (MeSH) terms
- “Vitamin D” OR “Hydroxycholecalciferols” combined with the MeSH terms
- OR “Memory Disorders”
- OR “Executive Function”
- OR “Attention”
- OR “Cognition”
- OR “Cognition disorders”
- OR “Dementia”
- OR “Alzheimer disease”
- OR “Neuropsychological Tests”.
Fixed-effects meta-analysis was performed from 12 eligible studies using an inverse-variance method.
Results: Of the 285 selected studies, 14 observational studies (including 3 prospective cohort studies) and 3 interventional studies met the selection criteria. All were of good quality. The number of participants ranged from 44–5,692 community-dwellers (0–100% women).
In the pooled analysis, although episodic memory disorders showed only modest association with lower 25OHD concentrations (summary effect size of the difference (ES) = −0.09 [95%CI:−0.16;−0.03]),
associations of greater magnitude were found with executive dysfunctions (processing speed:
- mean difference of Trail Making Test (TMT)-A score = 4.0 [95%CI:1.20;6.83];
- mental shifting: mean difference of TMT-B score = 12.47 [95%CI:6.78;18.16];
- information updating tests: ES = −0.31 [95%CI:−0.5;−0.09]).
The pooled risk of incident decline of TMT-B score was OR = 1.25 [95%CI:1.05;1.48] in case of initial lower 25OHD concentrations. Vitamin D repletion resulted in improved executive functions (ES = −0.50 [95%CI:−0.69;−0.32] for before-and-after comparison), but exhibited no difference with control groups (ES = 0.14 [95%CI:−0.04;0.32] for between-group comparison after intervention).
Conclusion: Lower serum 25OHD concentrations predict executive dysfunctions, especially on mental shifting, information updating and processing speed.
The association with episodic memory remains uncertain.
- Alzheimers-Cognition - Overview
- Alzheimer’s and Vitamins D, B, C, E, as well as Omega-3, metals, etc. – June 2013
- Alzheimer's disease most likely will need more than monotherapy such as vitamin D – May 2013
- Alzheimer’s and Parkinson’s diseases associated with low vitamin D – meta-analysis June 2013
- Dementia less likely with increased levels of Magnesium etc.