Circulating Vitamin D Levels and Alzheimer’s Disease: A Mendelian Randomization Study in the IGAP and UK Biobank

2020 ◽  
Vol 73 (2) ◽  
pp. 609-618 ◽  
Author(s):  
Longcai Wang ◽  
Yanchun Qiao ◽  
Haihua Zhang ◽  
Yan Zhang ◽  
Jiao Hua ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Vitamin D ◽  
Mendelian Randomization ◽  
Uk Biobank ◽  
Vitamin D Levels

scholarly journals Mendelian randomization to evaluate the effect of plasma vitamin C levels on the risk of Alzheimer’s disease

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Haijie Liu ◽  
Yan Zhang ◽  
Yang Hu ◽  
Haihua Zhang ◽  
Tao Wang ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Vitamin C ◽  
Cognitive Performance ◽  
Large Scale ◽  
Mendelian Randomization ◽  
Plasma Vitamin ◽  
Causal Association ◽  
Uk Biobank ◽  
Gwas Dataset

Abstract Objective Until now, observational studies have explored the impact of vitamin C intake on Alzheimer’s disease (AD) risk, however, reported ambiguous findings. To develop effective therapies or prevention, the causal link between vitamin C levels and AD should be established. Methods Here, we selected 11 plasma vitamin C genetic variants from a large-scale plasma vitamin C GWAS dataset (N = 52,018) as the potential instrumental variables. We extracted their corresponding summary statistics from large-scale IGAP clinically diagnosed AD GWAS dataset (N = 63,926) and UK Biobank AD proxy phenotype GWAS dataset (N = 314,278), as well as two UK Biobank subgroups including the maternal AD group (27,696 cases of maternal AD and 260,980 controls) and paternal AD group (14,338 cases of paternal AD and 245,941 controls). We then performed a Mendelian randomization (MR) study to evaluate the causal association between plasma vitamin C levels and the risk of AD and AD proxy phenotype. Meanwhile, we further verified these findings using a large-scale cognitive performance GWAS dataset (N = 257,841). Results In IGAP, we found no significant causal association between plasma vitamin C levels and the risk of AD. In UK Biobank, we found that per 1 SD increase in plasma vitamin C levels (about 20.2 μmol/l) was significantly associated with the reduced risk of AD proxy phenotype (OR = 0.93, 95% CI 0.88–0.98, P = 7.00E−03). A subgroup MR analysis in UK Biobank indicated that per 1 SD increase in plasma vitamin C levels could significantly reduce the risk of AD proxy phenotype in the maternal AD group (OR = 0.89, 95% CI 0.84–0.94, P = 7.29E−05), but not in the paternal AD group (OR = 1.02, 95% CI 0.92–1.12, P = 7.59E−01). The leave-one-out permutation further showed that the SLC23A1 rs33972313 variant largely changed the precision of the overall MR estimates in all these four GWAS datasets. Meanwhile, we did not observe any significant causal effect of plasma vitamin C levels on the cognitive performance. Conclusion We demonstrated that there may be no causal association between plasma vitamin C levels and the risk of AD in people of European descent. The insistent findings in clinically diagnosed AD and AD proxy phenotype may be caused by the phenotypic heterogeneity.

scholarly journals Effect of Vitamin D Supplementation on the Progression of Alzheimer’s Disease in Rats: A Mechanistic Approach

2021 ◽  
Author(s):  
Parmi Patel ◽  
Jigna Samir Shah
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Vitamin D ◽  
Vitamin D Supplementation ◽  
Cognitive Status ◽  
Tau Proteins ◽  
Biochemical Alterations ◽  
Vitamin D Levels ◽  
The Brain

Abstract Purpose: A multifaceted treatment approach can be effective for Alzheimer's disease (AD). However, currently, it involves only symptomatic treatment with cholinergic drugs. Beneficial effects of high vitamin D levels or its intake in the prevention and treatment of cognitive disorders have been reported. Thus, the present study examined the preventive effect of vitamin D supplementation on AD progression and evaluated its impact on the accumulation or degradation of Aβ plaques. Methods: A single intraperitoneal injection of scopolamine was used to induce AD in rats. Treatment of vitamin D was provided for 21 days after the injection. Various behavioral parameters like learning, spatial memory and exploratory behavior, biochemical alterations in the brain homogenate and histology of the hippocampus were investigated. Results: Our results indicated that scopolamine-induced rats depicted cognitive deficits with high Aβ levels and hyperphosphorylated tau proteins in the brain tissue, while vitamin D supplementation could significantly improve the cognitive status and lower these protein levels. These results were supported by the histopathological and immunohistochemical staining of the hippocampal brain region. Furthermore, mechanistic analysis depicted that vitamin D supplementation improved the Aβ protein clearance by increasing the neprilysin levels. It also reduced the accumulation of Aβ plaques by lowering neuroinflammation as well as oxidative stress. Conclusion: The present findings indicate that vitamin D supplementation can delay AD progression by an increase in Aβ plaques degradation or reducing inflammation and oxidative stress.

scholarly journals The non-genomic vitamin D pathway links β-amyloid to autophagic apoptosis in Alzheimer's disease

2021 ◽  
Author(s):  
Rai-Hua Lai ◽  
Yueh-Ying Hsu ◽  
Feng-Shiun Shie ◽  
Mei-Hsin Chen ◽  
Jyh-Lyh Juang
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Vitamin D ◽  
Cognitive Impairment ◽  
Vitamin D Deficiency ◽  
Epidemiological Studies ◽  
Vitamin D Supplementation ◽  
Adult Brain ◽  
Plasma Vitamin ◽  
Vitamin D Levels

Vitamin D is an important hormonal molecule, which exerts genomic and non-genomic actions in maintaining brain development and adult brain health. Many epidemiological studies have associated vitamin D deficiency with Alzheimer's disease (AD). Nevertheless, the underlying signaling pathway through which this occurs remains to be characterized. We were intrigued to find that although vitamin D levels are significantly low in AD patients, their hippocampal vitamin D receptor (VDR) levels are inversely increased in the cytosol of the brain cells, and colocalized with Aβ plaques, gliosis and autophagosomes, suggesting that a non-genomic form of VDR is implicated in AD. Mechanistically, Aβ induces the conversion of nuclear heterodimer of VDR/RXR heterodimer into a cytoplasmic VDR/p53 heterodimer. The cytosolic VDR/p53 complex mediates the Aβ induced autophagic apoptosis. Reduction of p53 activity in AD mice reverses the VDR/RXR formation and rescues AD brain pathologies and cognitive impairment. In line with the impaired genomic VDR pathway, the transgenic AD mice fed a vitamin D sufficient diet exhibit lower plasma vitamin D levels since early disease phases, raising the possibility that vitamin D deficiency may actually be an early manifestation of AD. Despite the deficiency of vitamin D in AD mice, vitamin D supplementation not only has no benefit but lead to exacerbated Aβ depositions and cognitive impairment. Together, these data indicate that the impaired genomic vitamin D pathway links Aβ to induce autophagic apoptosis, and suggest that VDR/p53 pathway could be targeted for the treatment of AD.

scholarly journals Low Vitamin D and Its Association with Cognitive Impairment and Dementia

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Sadia Sultan ◽  
Uzma Taimuri ◽  
Shatha Abdulrzzaq Basnan ◽  
Waad Khalid Ai-Orabi ◽  
Afaf Awadallah ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Vitamin D ◽  
Cognitive Impairment ◽  
Behavioral Problems ◽  
Small Sample Size ◽  
Vitamin D Supplementation ◽  
Small Sample ◽  
Vitamin D Levels ◽  
Prevention And Treatment

Vitamin D is a neurosteroid hormone that regulates neurotransmitters and neurotrophins. It has anti-inflammatory, antioxidant, and neuroprotective properties. It increases neurotrophic factors such as nerve growth factor which further promotes brain health. Moreover, it is also helpful in the prevention of amyloid accumulation and promotes amyloid clearance. Emerging evidence suggests its role in the reduction of Alzheimer’s disease hallmarks such as amyloid-beta and phosphorylated tau. Many preclinical studies have supported the hypothesis that vitamin D leads to attentional, behavioral problems and cognitive impairment. Cross-sectional studies have consistently found that vitamin D levels are significantly low in individuals with Alzheimer’s disease and cognitive impairment compared to healthy adults. Longitudinal studies and meta-analysis have also exhibited an association of low vitamin D with cognitive impairment and Alzheimer’s disease. Despite such evidence, the causal association cannot be sufficiently answered. In contrast to observational studies, findings from interventional studies have produced mixed results on the role of vitamin D supplementation in the prevention and treatment of cognitive impairment and dementia. The biggest issue of the existing RCTs is their small sample size, lack of consensus over the dose, and age of initiation of vitamin D supplements to prevent cognitive impairment. Therefore, there is a need for large double-blind randomized control trials to assess the benefits of vitamin D supplementation in the prevention and treatment of cognitive impairment.

Vitamin-D-Free Regimen Intensifies the Spatial Learning Deficit in Alzheimer's Disease

2011 ◽  
Vol 121 (1) ◽  
pp. 16-24 ◽  
Author(s):  
Mohsen Taghizadeh ◽  
Abolghassem Djazayery ◽  
Mahmoud Salami ◽  
Mohammad Reza Eshraghian ◽  
Sayyed Alireza Talaei Zavareh
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Vitamin D ◽  
Spatial Learning ◽  
Learning Deficit

Life Course Adiposity and Alzheimer’s Disease: A Mendelian Randomization Study

2021 ◽  
pp. 1-10
Author(s):  
Xian Li ◽  
Yan Tian ◽  
Yu-Xiang Yang ◽  
Ya-Hui Ma ◽  
Xue-Ning Shen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Life Course ◽  
Mendelian Randomization ◽  
Association Studies ◽  
Meta Analysis ◽  
Genome Wide Association Studies ◽  
Fat Percentage ◽  
Regression Methods ◽  
Weighted Median

Background: Several studies showed that life course adiposity was associated with Alzheimer’s disease (AD). However, the underlying causality remains unclear. Objective: We aimed to examine the causal relationship between life course adiposity and AD using Mendelian randomization (MR) analysis. Methods: Instrumental variants were obtained from large genome-wide association studies (GWAS) for life course adiposity, including birth weight (BW), childhood body mass index (BMI), adult BMI, waist circumference (WC), waist-to-hip ratio (WHR), and body fat percentage (BFP). A meta-analysis of GWAS for AD including 71,880 cases and 383,378 controls was used in this study. MR analyses were performed using inverse variance weighted (IVW), weighted median, and MR-Egger regression methods. We calculated odds ratios (ORs) per genetically predicted standard deviation (1-SD) unit increase in each trait for AD. Results: Genetically predicted 1-SD increase in adult BMI was significantly associated with higher risk of AD (IVW: OR = 1.03, 95% confidence interval [CI] = 1.01–1.05, p = 2.7×10–3) after Bonferroni correction. The weighted median method indicated a significant association between BW and AD (OR = 0.94, 95% CI = 0.90–0.98, p = 1.8×10–3). We also found suggestive associations of AD with WC (IVW: OR = 1.03, 95% CI = 1.00–1.07, p = 0.048) and WHR (weighted median: OR = 1.04, 95% CI = 1.00–1.07, p = 0.029). No association was detected of AD with childhood BMI and BFP. Conclusion: Our study demonstrated that lower BW and higher adult BMI had causal effects on increased AD risk.

Vitamin D in the Development and Progression of Alzheimer’s Disease: Implications for Clinical Management

2021 ◽  
Author(s):  
Francesco Panza ◽  
Maddalena La Montagna ◽  
Luisa Lampignano ◽  
Roberta Zupo ◽  
Ilaria Bortone ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Vitamin D ◽  
Clinical Management

scholarly journals Circulating biomarkers of immunity and inflammation, risk of Alzheimer’s disease, and hippocampal volume: a Mendelian randomization study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lana Fani ◽  
Marios K. Georgakis ◽  
M. Arfan Ikram ◽  
M. Kamran Ikram ◽  
Rainer Malik ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mendelian Randomization ◽  
Hippocampal Volume ◽  
Cd4 Count ◽  
European Ancestry ◽  
Monocyte Count ◽  
Circulating Biomarkers ◽  
Lymphocyte Ratio ◽  
Immune Biomarkers

AbstractThe aim of this study was to explore the association between genetically predicted circulating levels of immunity and inflammation, and the risk of Alzheimer’s disease (AD) and hippocampal volume, by conducting a two-sample Mendelian Randomization Study. We identified 12 markers of immune cells and derived ratios (platelet count, eosinophil count, neutrophil count, basophil count, monocyte count, lymphocyte count, platelet-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, CD4 count, CD8 count, CD4-to-CD8 ratio, and CD56) and 5 signaling molecules (IL-6, fibrinogen, CRP, and Lp-PLA2 activity and mass) as primary exposures of interest. Other genetically available immune biomarkers with a weaker a priori link to AD were considered secondary exposures. Associations with AD were evaluated in The International Genomics of Alzheimer’s Project (IGAP) GWAS dataset (21,982 cases; 41,944 controls of European ancestry). For hippocampal volume, we extracted data from a GWAS meta-analysis on 33,536 participants of European ancestry. None of the primary or secondary exposures showed statistically significant associations with AD or with hippocampal volume following P-value correction for multiple comparisons using false discovery rate < 5% (Q-value < 0.05). CD4 count showed the strongest suggestive association with AD (odds ratio 1.32, P < 0.01, Q > 0.05). There was evidence for heterogeneity in the MR inverse variance-weighted meta-analyses as measured by Cochran Q, and weighted median and weighted mode for multiple exposures. Further cluster analyses did not reveal clusters of variants that could influence the risk factor in distinct ways. This study suggests that genetically predicted circulating biomarkers of immunity and inflammation are not associated with AD risk or hippocampal volume. Future studies should assess competing risk, explore in more depth the role of adaptive immunity in AD, in particular T cells and the CD4 subtype, and confirm these findings in other ethnicities.

scholarly journals Breast Cancer, Alzheimer’s Disease, and APOE4 Allele in the UK Biobank Cohort

2021 ◽  
Vol 5 (1) ◽  
pp. 49-53
Author(s):  
Steven Lehrer ◽  
Peter H. Rheinstein
Keyword(s):  
Breast Cancer ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Apoe Genotype ◽  
Uk Biobank ◽  
Breast Cancer Patients ◽  
Apoe4 Allele ◽  
Significant Difference ◽  
The Uk ◽  
Cognitive Problems

Background: Cognitive problems are common in breast cancer patients. The apolipoprotein E4 (APOE4) gene, a risk factor for Alzheimer’s disease (AD), may be associated with cancer-related cognitive decline. Objective: To further evaluate the effects of the APOE4 allele, we studied a cohort of patients from the UK Biobank (UKB) who had breast cancer; some also had AD. Methods: Our analysis included all subjects with invasive breast cancer. Single nucleotide polymorphism (SNP) data for rs 429358 and rs 7412 was used to determine APOE genotypes. Cognitive function as numeric memory was assessed with an online test (UKB data field 20240). Results: We analyzed data from 2,876 women with breast cancer. Of the breast cancer subjects, 585 (20%) carried the APOE4 allele. Numeric memory scores were significantly lower in APOE4 carriers and APOE4 homozygotes than non-carriers (p = 0.046). 34 breast cancer subjects (1.1%) had AD. There was no significant difference in survival among genotypes ɛ3/ɛ3, ɛ3/ɛ4, and ɛ4/ɛ4. Conclusion: UKB data suggest that cognitive problems in women with breast cancer are, for the most part, mild, compared with other sequelae of the disease. AD, the worst cognitive problem, is relatively rare (1.1%) and, when it occurs, APOE genotype has little impact on survival.

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