Vitamin D supplementation and cognition—Results from analyses of the D-Health trial

Hai Pham, Mary Waterhouse, Sabbir Rahman, Catherine Baxter, Briony Duarte Romero, Donald S.A. McLeod, Bruce K. Armstrong, Peter R. Ebeling, Dallas R. English, Gunter Hartel, Michael G. Kimlin, Rachel L. O'Connell, Jolieke C. van der Pols, Alison J. Venn, Penelope M. Webb, David C. Whiteman, Osvaldo P. Almeida, Rachel E. Neale*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

1 Citation (Scopus)

Abstract

Background:

Observational studies have consistently found a link between low serum 25-hydroxyvitamin D concentration and higher risk of cognitive impairment. Results from randomized controlled trials have been mixed, and few have been conducted in the general population. 

Methods: 

We recruited 21,315 community-dwelling Australians aged between 60 and 84 years to participate in the D-Health Trial, a randomized, double-blind, placebo-controlled trial. The intervention was monthly oral doses of 60,000 international units of vitamin D or placebo for 5 years. We assessed cognitive function in a randomly sampled group of participants aged ≥70 years using the Telephone Interview for Cognitive Status (TICS) at 2 and 5 years after randomization. The primary outcome for this analysis was TICS score; the secondary outcome was the proportion of people who had cognitive impairment (defined as TICS score ≤25). We analyzed data using mixed models (linear and logistic). 

Results:

We interviewed 3887 participants at year 2 and 3614 participants at year 5. The mean TICS score at these time points was 32.3 and 32.2, respectively. Vitamin D supplementation did not affect cognitive function as measured by TICS score (mean difference between vitamin D and placebo groups 0.04; 95% CI −0.14 to 0.23), or alter risk of cognitive impairment (odds ratio 1.00; 95% CI 0.75 to 1.33). 

Conclusions:

Monthly bolus doses of vitamin D supplementation neither enhanced nor hindered cognitive function among older adults. Population-wide vitamin D supplementation of older adults that are largely vitamin D replete is unlikely to substantially benefit cognition.

Original languageEnglish
Pages (from-to)1773-1784
Number of pages12
JournalJournal of the American Geriatrics Society
Volume71
Issue number6
DOIs
Publication statusPublished - Jun 2023
Externally publishedYes

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