Vitamin D and Alzheimer's disease

Discussion in 'General Discussion' started by Jason, May 31, 2017.

  1. Jason

    Jason Developer / Handyman Staff Member

    Genetically decreased vitamin D and risk of Alzheimer disease.
    Neurology. 2016 Dec 13;87(24):2567-2574. Epub 2016 Nov 16.

    OBJECTIVE:
    To test whether genetically decreased vitamin D levels are associated with Alzheimer disease (AD) using mendelian randomization (MR), a method that minimizes bias due to confounding or reverse causation.

    METHODS:
    We selected single nucleotide polymorphisms (SNPs) that are strongly associated with 25-hydroxyvitamin D (25OHD) levels (p < 5 × 10-8) from the Study of Underlying Genetic Determinants of Vitamin D and Highly Related Traits (SUNLIGHT) Consortium (N = 33,996) to act as instrumental variables for the MR study. We measured the effect of each of these SNPs on 25OHD levels in the Canadian Multicentre Osteoporosis Study (CaMos; N = 2,347) and obtained the corresponding effect estimates for each SNP on AD risk from the International Genomics of Alzheimer's Project (N = 17,008 AD cases and 37,154 controls). To produce MR estimates, we weighted the effect of each SNP on AD by its effect on 25OHD and meta-analyzed these estimates using a fixed-effects model to provide a summary effect estimate.

    RESULTS:
    The SUNLIGHT Consortium identified 4 SNPs to be genome-wide significant for 25OHD, which described 2.44% of the variance in 25OHD in CaMos. All 4 SNPs map to genes within the vitamin D metabolic pathway. MR analyses demonstrated that a 1-SD decrease in natural log-transformed 25OHD increased AD risk by 25% (odds ratio 1.25, 95% confidence interval 1.03-1.51, p = 0.021). After sensitivity analysis in which we removed SNPs possibly influenced by pleiotropy and population stratification, the results were largely unchanged.

    CONCLUSIONS:
    Our results provide evidence supporting 25OHD as a causal risk factor for AD. These findings provide further rationale to understand the effect of vitamin D supplementation on cognition and AD risk in randomized controlled trials.

    Genes which reduce blood-level vitamin D increase the risk of Alzheimer’s disease – Dec 2016
    source: https://www.vitamindwiki.com/tiki-index.php?page_id=8094
  2. Graham

    Graham Developer Staff Member

    Curious .. just had someone email who wants to embark on a long term trial of D3 for alzheimers.

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