Vitamin D insufficiency and cognitive impairment in Asians: a multi-ethnic population-based study and meta-analysis

C. Annweiler, D. Milea, H. E. Whitson, C. Y. Cheng, T. Y. Wong, M. K. Ikram, E. L. Lamoureux, C. Sabanayagam*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

33 Citations (Scopus)

Abstract

Background: The relationship between vitamin D insufficiency and cognitive impairment remains equivocal in Asians. We examined the association between circulating 25-hydroxyvitamin D (25OHD) concentration and cognitive performance in a large multi-ethnic Singaporean population-based study. We also conducted a meta-analysis of 25OHD concentrations amongst cognitively impaired older adults in Asia. Methods: Our population-based cross-sectional study included 2273 persons ≥60 years of age from the Singapore Epidemiology of Eye Diseases (SEED) study (mean ± SD age 70.4 ± 6.2 years; 44.7% female), who were categorized according to 25OHD concentration (i.e. ≤10, 10.1–20 and >20 ng mL−1). The 25OHD concentration was measured and adjusted to reflect a deseasonalized value. Cognition was assessed using the total and domain scores of the Abbreviated Mental Test (AMT). Global cognitive impairment was defined as AMT score of ≤6 if 0–6 years of education and AMT score of ≤8 if >7 years of education. Fully adjusted multivariate models were used. We included seven studies in a meta-analysis of 25OHD and cognition in Asia (6068 participants; 1179 cognitively impaired cases). Results: Participants with 25OHD levels >20 ng mL−1 (n = 1302) had higher AMT total scores (mean ± SD 8.5 ± 1.9) and were less likely to have cognitive impairment (14.1%) than participants with lower 25OHD levels (overall P < 0.001, P-trend < 0.001). Deseasonalized 25OHD concentration was associated with AMT score (β = 0.10 per 10 ng mL−1, P = 0.035). Vitamin D insufficiency (25OHD ≤20 ng mL−1) was associated with global cognitive impairment (OR 1.56, P = 0.028). Specifically, 25OHD concentration correlated with semantic memory (r = 0.08, P = 0.009) and orientation in time (r = 0.09, P = 0.003). In the meta-analysis, the pooled mean 25OHD difference was −6.83 ng mL−1 (95% confidence interval −11.36; −2.30), indicating lower 25OHD concentrations amongst cognitively impaired compared to cognitively healthy participants in Asia. Conclusion: Vitamin D insufficiency is associated with a greater likelihood of and more severe cognitive impairment in Asian populations.

Original languageEnglish
Pages (from-to)300-311
Number of pages12
JournalJournal of Internal Medicine
Volume280
Issue number3
DOIs
Publication statusPublished - Sept 2016
Externally publishedYes

Bibliographical note

Funding:
The Singapore Epidemiology of Eye Diseases
(SEED) studies were funded by the Singapore
National Medical Research Council (NMRC)
NMRC/STaR/0003/2008) and the Singapore Kidney Eye Study by NMRC/TA/0008/2012.

Publisher Copyright:
© 2016 The Association for the Publication of the Journal of Internal Medicine

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