scholarly journals Genetically Determined Blood Pressure, Antihypertensive Medications, and Risk of Alzheimer’s Disease: A Mendelian Randomization Study

2020 ◽  
Author(s):  
Ya-Nan Ou ◽  
Yu-Xiang Yang ◽  
Xue-Ning Shen ◽  
Ya-Hui Ma ◽  
Shi-Dong Chen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Blood Pressure ◽  
Alzheimer's Disease ◽  
Lower Risk ◽  
Mendelian Randomization ◽  
Angiotensin Receptor Blockers ◽  
Genome Wide Association Studies ◽  
Reverse Causality ◽  
Antihypertensive Medications ◽  
Genetically Determined

Abstract BackgroundObservational studies suggest that the use of antihypertensive medications (AHMs) is associated with a reduced risk of Alzheimer’s disease (AD); however, these findings may be biased by confounding and reverse causality. We aimed to explore the effects of blood pressure (BP) and lowering systolic BP (SBP) via the protein targets of different AHMs on AD through a two-sample Mendelian randomization (MR) approach.MethodsGenetic proxies from genome-wide association studies of BP traits and BP-lowering variants in genes encoding AHM targets were extracted. Estimates were calculated by inverse-variance weighted method as the main model. MR Egger regression and leave-one-out analysis were performed to identify potential violations. ResultsThere was limited evidence that genetically predicted SBP/diastolic BP level affected AD risk based on 400/398 single nucleotide polymorphisms (SNPs), respectively (all P>0.05). Suitable genetic variants for β-blockers (1 SNP), angiotensin receptor blockers (1 SNP), calcium channel blockers (CCBs, 45 SNPs) and thiazide diuretics (5 SNPs) were identified. Genetic proxies for CCB [odds ratio (OR)=0.959, 95% confidence interval (CI)=0.941-0.977, P<0.001], and overall use of AHMs (OR=0.961, 95% CI=0.944-0.978, P<0.001, SNPs=52) were associated with a lower risk of AD. No notable heterogeneity and directional pleiotropy were identified (all P>0.05). No single SNP was driving the observed effects. ConclusionsThis MR analysis found robust evidence that genetically determined lowering BP was associated with a lower risk of AD and CCB was identified as a promising strategy for AD prevention.

scholarly journals Genetically determined blood pressure, antihypertensive medications, and risk of Alzheimer’s disease: a Mendelian randomization study

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Ya-Nan Ou ◽  
Yu-Xiang Yang ◽  
Xue-Ning Shen ◽  
Ya-Hui Ma ◽  
Shi-Dong Chen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Blood Pressure ◽  
Alzheimer's Disease ◽  
Lower Risk ◽  
Mendelian Randomization ◽  
Angiotensin Receptor Blockers ◽  
Genome Wide Association Studies ◽  
Reverse Causality ◽  
Antihypertensive Medications ◽  
Genetically Determined

Abstract Background Observational studies suggest that the use of antihypertensive medications (AHMs) is associated with a reduced risk of Alzheimer’s disease (AD); however, these findings may be biased by confounding and reverse causality. We aimed to explore the effects of blood pressure (BP) and lowering systolic BP (SBP) via the protein targets of different AHMs on AD through a two-sample Mendelian randomization (MR) approach. Methods Genetic proxies from genome-wide association studies of BP traits and BP-lowering variants in genes encoding AHM targets were extracted. Estimates were calculated by inverse-variance weighted method as the main model. MR Egger regression and leave-one-out analysis were performed to identify potential violations. Results There was limited evidence that genetically predicted SBP/diastolic BP level affected AD risk based on 400/398 single nucleotide polymorphisms (SNPs), respectively (all P > 0.05). Suitable genetic variants for β-blockers (1 SNP), angiotensin receptor blockers (1 SNP), calcium channel blockers (CCBs, 45 SNPs), and thiazide diuretics (5 SNPs) were identified. Genetic proxies for CCB [odds ratio (OR) = 0.959, 95% confidence interval (CI) = 0.941–0.977, P = 3.92 × 10−6] and overall use of AHMs (OR = 0.961, 95% CI = 0.944–0.978, P = 5.74 × 10−6, SNPs = 52) were associated with a lower risk of AD. No notable heterogeneity and directional pleiotropy were identified (all P > 0.05). Additional analyses partly support these results. No single SNP was driving the observed effects. Conclusions This MR analysis found evidence that genetically determined lowering BP was associated with a lower risk of AD and CCB was identified as a promising strategy for AD prevention.

scholarly journals Genetically determined blood pressure, antihypertensive medications, and risk of Alzheimer’s disease: a Mendelian randomization study

2021 ◽  
Author(s):  
Ya-Nan Ou ◽  
Yu-Xiang Yang ◽  
Xue-Ning Shen ◽  
Ya-Hui Ma ◽  
Shi-Dong Chen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Blood Pressure ◽  
Alzheimer's Disease ◽  
Lower Risk ◽  
Mendelian Randomization ◽  
Angiotensin Receptor Blockers ◽  
Genome Wide Association Studies ◽  
Reverse Causality ◽  
Antihypertensive Medications ◽  
Genetically Determined

Abstract Background: Observational studies suggest that the use of antihypertensive medications (AHMs) is associated with a reduced risk of Alzheimer’s disease (AD); however, these findings may be biased by confounding and reverse causality. We aimed to explore the effects of blood pressure (BP) and lowering systolic BP (SBP) via the protein targets of different AHMs on AD through a two-sample Mendelian randomization (MR) approach. Methods: Genetic proxies from genome-wide association studies of BP traits and BP-lowering variants in genes encoding AHM targets were extracted. Estimates were calculated by inverse-variance weighted method as the main model. MR Egger regression and leave-one-out analysis were performed to identify potential violations. Results: There was limited evidence that genetically predicted SBP/diastolic BP level affected AD risk based on 400/398 single nucleotide polymorphisms (SNPs), respectively (all P>0.05). Suitable genetic variants for β-blockers (1 SNP), angiotensin receptor blockers (1 SNP), calcium channel blockers (CCBs, 45 SNPs) and thiazide diuretics (5 SNPs) were identified. Genetic proxies for CCB [odds ratio (OR)=0.959, 95% confidence interval (CI)=0.941-0.977, P=3.92×10-6], and overall use of AHMs (OR=0.961, 95% CI=0.944-0.978, P=5.74×10-6, SNPs=52) were associated with a lower risk of AD. No notable heterogeneity and directional pleiotropy were identified (all P>0.05). Additional analyses partly support these results. No single SNP was driving the observed effects. Conclusions: This MR analysis found evidence that genetically determined lowering BP was associated with a lower risk of AD and CCB was identified as a promising strategy for AD prevention.

scholarly journals Genetically determined TSH level within reference range is inversely associated with Alzheimer’s disease

2021 ◽  
Author(s):  
Gloria Hoi-Yee Li ◽  
Ching-Lung Cheung ◽  
Elaine Yun-Ning Cheung ◽  
Wai-Chi Chan ◽  
Kathryn Choon-Beng Tan
Keyword(s):  
Atrial Fibrillation ◽  
Alzheimer’S Disease ◽  
Blood Pressure ◽  
Alzheimer's Disease ◽  
Reference Range ◽  
Genome Wide Association Studies ◽  
Inverse Association ◽  
Rotterdam Study ◽  
Genetically Determined ◽  
Mr Study

Abstract Context Contradictory findings were reported in observational studies on the association of thyroid function [thyroid stimulating hormone (TSH) and free thyroxine (FT4) levels] with Alzheimer’s disease (AD). Objective To determine whether genetically determined TSH/FT4 levels within reference range are causally associated with AD. Design Bi-directional two-sample Mendelian randomization (MR) study. Setting and participants With summary statistics from the largest genome-wide association studies (GWAS)/GWAS meta-analysis of TSH level(n≥54,288), FT4 level(n=49,269) and AD(71,880 cases; 383,378 controls), we used MR approach to evaluate the bi-directional causal relationship between TSH/FT4 levels and AD. Inverse-variance weighted method was adopted as the main analysis. Results One standard deviation increase in genetically determined TSH level within reference range was causally associated with reduced risk of AD (Odds ratio:0.988; 95% CI:0.977-0.998). Similar inverse association was observed in sex-specific analysis. The causal association was attenuated after adjustment for atrial fibrillation and blood pressure, suggesting they may mediate the causal pathway. Positive causal effect of AD on TSH level was only detected in male. This male-specific feedback loop may explain why the largest cohort study to-date (Rotterdam study) demonstrated a null observational association in men. Null association was observed between FT4 level and AD in both directions. Conclusions Genetic predisposition to increased TSH level, even within reference range, may lower the risk of AD, with atrial fibrillation, systolic and diastolic blood pressure as possible mediators. Given the higher magnitude of risk reduction observed in Rotterdam study, whether the causal estimates derived from this MR study are underestimated warrants further investigations.

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.

Associations of Blood Pressure with Functional and Cognitive Changes in Patients with Alzheimer's Disease

2016 ◽  
Vol 41 (5-6) ◽  
pp. 314-323 ◽  
Author(s):  
Fabricio Ferreira de Oliveira ◽  
Elizabeth Suchi Chen ◽  
Marilia Cardoso Smith ◽  
Paulo Henrique Ferreira Bertolucci
Keyword(s):  
Alzheimer’S Disease ◽  
Blood Pressure ◽  
Alzheimer's Disease ◽  
Rating Scale ◽  
Late Onset ◽  
Angiotensin Receptor Blockers ◽  
Channel Blockers ◽  
Clinical Dementia Rating ◽  
Cognitive Changes ◽  
Converting Enzyme Inhibitors

Background: Midlife hypertension followed by late life hypotension resulting from neurodegeneration increases amyloidogenesis and tauopathy. Methods: Consecutive outpatients with late-onset Alzheimer's disease (AD) at various stages and their respective caregivers were assessed for score variations in 1 year of tests assessing caregiver burden, functionality and cognition according to blood pressure (BP) variations and APOE haplotypes, while also taking into account differential effects of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, β-blockers, calcium channel blockers, diuretics, or no antihypertensive medication on score changes. The diagnosis and treatment of arterial hypertension followed the JNC 7 report. Results: Variations in systolic BP (-11.76 ± 17.1 mm Hg), diastolic BP (-4.92 ± 10.3 mm Hg) and pulse pressure (-6.84 ± 12.6 mm Hg) were significant after 1 year (n = 191; ρ < 0.01). For APOE4+ carriers, rises in systolic or diastolic BP improved Clinical Dementia Rating Scale Sum of Boxes scores (ρ < 0.04), with marginally significant improvements in Mini-Mental State Examination scores resulting from risen systolic (ρ = 0.069) or diastolic BP (ρ = 0.079), and in basic independence only regarding risen diastolic BP (ρ = 0.055). APOE4- carriers resisted any functional or cognitive effects of BP variations. No differences were found regarding any antihypertensive class for variations in BP or any test scores, regardless of APOE haplotypes. Conclusions: Targeting mild BP elevations brings better functional and cognitive results for APOE4+ carriers with AD.

scholarly journals Growth Differentiation Factor 15 Is Associated With Alzheimer’s Disease Risk

2021 ◽  
Vol 12 ◽  
Author(s):  
Peng-Fei Wu ◽  
Xing-Hao Zhang ◽  
Ping Zhou ◽  
Rui Yin ◽  
Xiao-Ting Zhou ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mendelian Randomization ◽  
Association Studies ◽  
Sensitivity Analyses ◽  
European Ancestry ◽  
Reverse Direction ◽  
Genome Wide Association Studies ◽  
Growth Differentiation Factor 15 ◽  
Differentiation Factor

BackgroundPrevious observational studies have suggested that associations exist between growth differentiation factor 15 (GDF-15) and neurodegenerative diseases. We aimed to investigate the causal relationships between GDF-15 and Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS).MethodsUsing summary-level datasets from genome-wide association studies of European ancestry, we performed a two-sample Mendelian randomization (MR) study. Genetic variants significantly associated (p &lt; 5 × 10–8) with GDF-15 were selected as instrumental variables (n = 5). An inverse-variance weighted method was implemented as the primary MR approach, while weighted median, MR–Egger, leave-one-out analysis, and Cochran’s Q-test were conducted as sensitivity analyses. All analyses were performed using R 3.6.1 with relevant packages.ResultsMR provided evidence for the association of elevated GDF-15 levels with a higher risk of AD (odds ratio = 1.14; 95% confidence interval, 1.04–1.24; p = 0.004). In the reverse direction, Mendelian randomization suggested no causal effect of genetically proxied risk of AD on circulating GDF-15 (p = 0.450). The causal effects of GDF-15 on PD (p = 0.597) or ALS (p = 0.120) were not identified, and the MR results likewise did not support the association of genetic liability to PD or ALS with genetically predicted levels of GDF-15. No evident heterogeneity or horizontal pleiotropy was revealed by multiple sensitivity analyses.ConclusionWe highlighted the role of GDF-15 in AD as altogether a promising diagnostic marker and a therapeutic target.

Herpesvirus Infections and Alzheimer’s Disease: A Mendelian Randomization Study 

2021 ◽  
Author(s):  
Shu-Yi Huang ◽  
Yu-Xiang Yang ◽  
Kevin Kuo ◽  
Hong-Qi Li ◽  
Xue-Ning Shen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Family History ◽  
Mendelian Randomization ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Summary Statistics ◽  
Primary Analysis ◽  
Varicella Zoster ◽  
History Of

Abstract BackgroundObservational studies have suggested that herpesvirus infection increased the risk of Alzheimer’s disease (AD), but it is unclear whether the association is causal. The aim of the present study is to evaluate the causal relationship between four herpesvirus infections and AD. MethodsWe performed a two-sample Mendelian randomization analysis to investigate association of four active herpesvirus infections with AD using summary statistics from genome-wide association studies. The four herpesvirus infections (i.e., chickenpox, shingles, cold sores, mononucleosis) are caused by varicella-zoster virus, herpes simplex virus type 1, and Epstein-Barr virus (EBV), respectively. A large summary statistics data from International Genomics of Alzheimer’s Project was used in primary analysis, including 21,982 AD cases and 41,944 controls. Validation was further performed using family history of AD data from UK Biobank (27,696 cases of maternal AD, 14,338 cases of paternal AD and 272,244 controls).ResultsWe found evidence of a suggestive association between mononucleosis (caused by EBV) and risk of AD (odds ratio [OR] = 1.634, 95% confidence interval [CI] = 1.092-2.446, P = 0.017) after Bonferroni correction. It has been verified in validation analysis that mononucleosis is also associated with family history of AD (OR [95% CI] = 1.392 [1.061, 1.826], P=0.017). Genetically predicted shingles were associated with AD risk (OR [95% CI] = 0.867 [0.784, 0.958], P = 0.005). While genetically predicted chickenpox was suggestively associated with increased family history of AD (OR [95% CI] = 1.147 [1.007, 1.307], P = 0.039).ConclusionsOur findings provided evidence supporting a positive relationship between mononucleosis and AD, indicating a causal link between EBV infection and AD. Further elucidations of this association and underlying mechanisms are likely to identify feasible interventions to promote AD prevention.

scholarly journals Is disrupted sleep a risk factor for Alzheimer’s disease? Evidence from a two-sample Mendelian randomization analysis

2020 ◽  
Author(s):  
Emma L Anderson ◽  
Rebecca C Richmond ◽  
Samuel E Jones ◽  
Gibran Hemani ◽  
Kaitlin H Wade ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Risk Factor ◽  
Daytime Sleepiness ◽  
Mendelian Randomization ◽  
Causal Effect ◽  
Association Studies ◽  
Self Report ◽  
Genome Wide Association Studies ◽  
Tentative Evidence

Abstract Background It is established that Alzheimer’s disease (AD) patients experience sleep disruption. However, it remains unknown whether disruption in the quantity, quality or timing of sleep is a risk factor for the onset of AD. Methods We used the largest published genome-wide association studies of self-reported and accelerometer-measured sleep traits (chronotype, duration, fragmentation, insomnia, daytime napping and daytime sleepiness), and AD. Mendelian randomization (MR) was used to estimate the causal effect of self-reported and accelerometer-measured sleep parameters on AD risk. Results Overall, there was little evidence to support a causal effect of sleep traits on AD risk. There was some suggestive evidence that self-reported daytime napping was associated with lower AD risk [odds ratio (OR): 0.70, 95% confidence interval (CI): 0.50–0.99). Some other sleep traits (accelerometer-measured ‘eveningness’ and sleep duration, and self-reported daytime sleepiness) had ORs of a similar magnitude to daytime napping, but were less precisely estimated. Conclusions Overall, we found very limited evidence to support a causal effect of sleep traits on AD risk. Our findings provide tentative evidence that daytime napping may reduce AD risk. Given that this is the first MR study of multiple self-report and objective sleep traits on AD risk, findings should be replicated using independent samples when such data become available.

scholarly journals Mendelian randomization identifies blood metabolites previously linked to midlife cognition as causal candidates in Alzheimer’s disease

2021 ◽  
Vol 118 (16) ◽  
pp. e2009808118
Author(s):  
Jodie Lord ◽  
Bradley Jermy ◽  
Rebecca Green ◽  
Andrew Wong ◽  
Jin Xu ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Bayesian Model Averaging ◽  
Mendelian Randomization ◽  
Association Studies ◽  
Model Averaging ◽  
High Density Lipoproteins ◽  
Genome Wide Association Studies ◽  
Causal Pathway ◽  
Target Disease

There are currently no disease-modifying treatments for Alzheimer’s disease (AD), and an understanding of preclinical causal biomarkers to help target disease pathogenesis in the earliest phases remains elusive. Here, we investigated whether 19 metabolites previously associated with midlife cognition—a preclinical predictor of AD—translate to later clinical risk, using Mendelian randomization (MR) to tease out AD-specific causal relationships. Summary statistics from the largest genome-wide association studies (GWASs) for AD and metabolites were used to perform bidirectional univariable MR. Bayesian model averaging (BMA) was additionally performed to address high correlation between metabolites and identify metabolite combinations that may be on the AD causal pathway. Univariable MR indicated four extra-large high-density lipoproteins (XL.HDL) on the causal pathway to AD: free cholesterol (XL.HDL.FC: 95% CI = 0.78 to 0.94), total lipids (XL.HDL.L: 95% CI = 0.80 to 0.97), phospholipids (XL.HDL.PL: 95% CI = 0.81 to 0.97), and concentration of XL.HDL particles (95% CI = 0.79 to 0.96), significant at an adjusted P < 0.009. MR–BMA corroborated XL.HDL.FC to be among the top three causal metabolites, in addition to total cholesterol in XL.HDL (XL.HDL.C) and glycoprotein acetyls (GP). Both XL.HDL.C and GP demonstrated suggestive univariable evidence of causality (P < 0.05), and GP successfully replicated within an independent dataset. This study offers insight into the causal relationship between metabolites demonstrating association with midlife cognition and AD. It highlights GP in addition to several XL.HDLs—particularly XL.HDL.FC—as causal candidates warranting further investigation. As AD pathology is thought to develop decades prior to symptom onset, expanding on these findings could inform risk reduction strategies.

scholarly journals Association of Thyroid Function with Blood Pressure and Cardiovascular Disease: A Mendelian Randomization

2021 ◽  
Vol 11 (12) ◽  
pp. 1306
Author(s):  
Alice Giontella ◽  
Luca A. Lotta ◽  
John D. Overton ◽  
Aris Baras ◽  
Andrea Sartorio ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Blood Pressure ◽  
Thyroid Function ◽  
Lower Risk ◽  
Mendelian Randomization ◽  
Association Studies ◽  
Sensitivity Analyses ◽  
Thyroid Peroxidase ◽  
Genome Wide Association Studies ◽  
Causal Association

Thyroid function has a widespread effect on the cardiometabolic system. However, the causal association between either subclinical hyper- or hypothyroidism and the thyroid hormones with blood pressure (BP) and cardiovascular diseases (CVD) is not clear. We aim to investigate this in a two-sample Mendelian randomization (MR) study. Single nucleotide polymorphisms (SNPs) associated with thyroid-stimulating hormone (TSH), free tetraiodothyronine (FT4), hyper- and hypothyroidism, and anti-thyroid peroxidase antibodies (TPOAb), from genome-wide association studies (GWAS), were selected as MR instrumental variables. SNPs–outcome (BP, CVD) associations were evaluated in a large-scale cohort, the Malmö Diet and Cancer Study (n = 29,298). Causal estimates were computed by inverse-variance weighted (IVW), weighted median, and MR-Egger approaches. Genetically increased levels of TSH were associated with decreased systolic BP and with a lower risk of atrial fibrillation. Hyperthyroidism and TPOAb were associated with a lower risk of atrial fibrillation. Our data support a causal association between genetically decreased levels of TSH and both atrial fibrillation and systolic BP. The lack of significance after Bonferroni correction and the sensitivity analyses suggesting pleiotropy, should prompt us to be cautious in their interpretation. Nevertheless, these findings offer mechanistic insight into the etiology of CVD. Further work into the genes involved in thyroid functions and their relation to cardiovascular outcomes may highlight pathways for targeted intervention.

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