%0 Journal Article %J J Alzheimers Dis %D 2020 %T Circulating Vitamin D Levels and Alzheimer's Disease: A Mendelian Randomization Study in the IGAP and UK Biobank. %A Wang, Longcai %A Qiao, Yanchun %A Zhang, Haihua %A Zhang, Yan %A Hua, Jiao %A Jin, Shuilin %A Liu, Guiyou %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Biological Specimen Banks %K Cognition Disorders %K Databases, Factual %K Female %K Genome-Wide Association Study %K Humans %K Hydroxycholecalciferols %K Male %K Mendelian Randomization Analysis %K Middle Aged %K Nutritional Status %K United Kingdom %K Vitamin D %K Vitamin D Deficiency %X

Observational studies strongly supported the association of low levels of circulating 25-hydroxyvitamin D (25OHD) and cognitive impairment or dementia in aging populations. However, randomized controlled trials have not shown clear evidence that vitamin D supplementation could improve cognitive outcomes. In fact, some studies reported the association between vitamin D and cognitive impairment based on individuals aged 60 years and over. However, it is still unclear that whether vitamin D levels are causally associated with Alzheimer's disease (AD) risk in individuals aged 60 years and over. Here, we performed a Mendelian randomization (MR) study to investigate the causal association between vitamin D levels and AD using a large-scale vitamin D genome-wide association study (GWAS) dataset and two large-scale AD GWAS datasets from the IGAP and UK Biobank with individuals aged 60 years and over. Our results showed that genetically increased 25OHD levels were significantly associated with reduced AD risk in individuals aged 60 years and over. Hence, our findings in combination with previous literature indicate that maintaining adequate vitamin D status in older people especially aged 60 years and over, may contribute to slow down cognitive decline and forestall AD. Long-term randomized controlled trials are required to test whether vitamin D supplementation may prevent AD in older people especially those aged 60 years and may be recommended as preventive agents.

%B J Alzheimers Dis %V 73 %P 609-618 %8 2020 %G eng %N 2 %1 https://www.ncbi.nlm.nih.gov/pubmed/31815694?dopt=Abstract %R 10.3233/JAD-190713 %0 Journal Article %J J Alzheimers Dis %D 2018 %T Alzheimer's Disease rs11767557 Variant Regulates EPHA1 Gene Expression Specifically in Human Whole Blood. %A Liu, Guiyou %A Zhang, Yan %A Wang, Longcai %A Xu, Jianyong %A Chen, Xiaoyun %A Bao, Yunjuan %A Hu, Yang %A Jin, Shuilin %A Tian, Rui %A Bai, Weiyang %A Zhou, Wenyang %A Wang, Tao %A Han, Zhifa %A Zong, Jian %A Jiang, Qinghua %K Alzheimer Disease %K Case-Control Studies %K China %K Gene Expression %K Genetic Predisposition to Disease %K Genome-Wide Association Study %K Humans %K Linkage Disequilibrium %K Polymorphism, Single Nucleotide %K Receptor, EphA1 %K Risk Assessment %X

Large-scale genome-wide association studies have reported EPHA1 rs11767557 variant to be associated with Alzheimer's disease (AD) risk in the European population. However, it is still unclear how this variant functionally contributes to the underlying disease pathogenesis. The rs11767557 variant is located approximately 3 kb upstream of EPHA1 gene. We think that rs11767557 may modify the expression of nearby genes such as EPHA1 and further cause AD risk. Until now, the potential association between rs11767557 and the expression of nearby genes has not been reported in previous studies. Here, we evaluate the potential expression association between rs11767557 and EPHA1 using multiple large-scale eQTLs datasets in human brain tissues and the whole blood. The results show that rs11767557 variant could significantly regulate EPHA1 gene expression specifically in human whole blood. These findings may further provide important supplementary information about the regulating mechanisms of rs11767557 variant in AD risk.

%B J Alzheimers Dis %V 61 %P 1077-1088 %8 2018 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/29332039?dopt=Abstract %R 10.3233/JAD-170468