Brain (Alzheimer’s) worked better with Vitamin D intervention – meta-analysis

Created July 2013

Meta-Analysis of Memory and Executive Dysfunctions in Relation to Vitamin D

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

  • “Memory”

  • 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.

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See also VitaminDWiki

Tags: Cognitive Meta-analysis