Homocysteine, B vitamins, and cardiovascular disease: a Mendelian randomization study

Abstract Background Whether a modestly elevated homocysteine level is causally associated with an increased risk of cardiovascular disease remains unestablished. We conducted a Mendelian randomization study to assess the associations of circulating total homocysteine (tHcy) and B vitamin levels with cardiovascular diseases in the general population. Methods Independent single nucleotide polymorphisms associated with tHcy (n = 14), folate (n = 2), vitamin B6 (n = 1), and vitamin B12 (n = 14) at the genome-wide significance level were selected as instrumental variables. Summary-level data for 12 cardiovascular endpoints were obtained from genetic consortia, the UK Biobank study, and the FinnGen consortium. Results Higher genetically predicted circulating tHcy levels were associated with an increased risk of stroke. For each one standard deviation (SD) increase in genetically predicted tHcy levels, the odds ratio (OR) was 1.11 (95% confidence interval (CI), 1.03, 1.21; p = 0.008) for any stroke, 1.26 (95% CI, 1.05, 1.51; p = 0.013) for subarachnoid hemorrhage, and 1.11 (95% CI, 1.03, 1.21; p = 0.011) for ischemic stroke. Higher genetically predicted folate levels were associated with decreased risk of coronary artery disease (ORSD, 0.88; 95% CI, 0.78, 1.00, p = 0.049) and any stroke (ORSD, 0.86; 95% CI, 0.76, 0.97, p = 0.012). Genetically predicted increased vitamin B6 levels were associated with a reduced risk of ischemic stroke (ORSD, 0.88; 95% CI, 0.81, 0.97, p = 0.009). None of these associations persisted after multiple testing correction. There was no association between genetically predicted vitamin B12 and cardiovascular disease. Conclusions This study reveals suggestive evidence that B vitamin therapy and lowering of tHcy may reduce the risk of stroke, particularly subarachnoid hemorrhage and ischemic stroke.

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EXPRESS: Effect of genetic liability to visceral adiposity on stroke and its subtypes: a Mendelian randomization study

International Journal of Stroke ◽

10.1177/17474930211006285 ◽

2021 ◽

pp. 174749302110062

Author(s):

Bin Yan ◽

Jian Yang ◽

Li Qian ◽

Fengjie Gao ◽

Ling Bai ◽

...

Keyword(s):

Sensitivity Analysis ◽

Ischemic Stroke ◽

Genome Wide Association Study ◽

Mendelian Randomization ◽

Visceral Adiposity ◽

Large Artery ◽

Nucleotide Polymorphisms ◽

Genetic Liability ◽

A Genome ◽

Increased Risk

Background: Observational studies have found an association between visceral adiposity and stroke. Aims: The purpose of this study was to investigate the role and genetic effect of visceral adipose tissue (VAT) accumulation on stroke and its subtypes. Methods: In this two-sample Mendelian randomization (MR) study, genetic variants (221 single nucleotide polymorphisms; P<5Ã10-8) using as instrumental variables for MR analysis was obtained from a genome-wide association study (GWAS) of VAT. The outcome datasets for stroke and its subtypes were obtained from the MEGASTROKE consortium (up to 67,162 cases and 453,702 controls). MR standard analysis (inverse variance weighted method) was conducted to investigate the effect of genetic liability to visceral adiposity on stroke and its subtypes. Sensitivity analysis (MR-Egger, weighted median, MR-PRESSO) were also utilized to assess horizontal pleiotropy and remove outliers. Multi-variable MR analysis was employed to adjust potential confounders. Results: In the standard MR analysis, genetically determined visceral adiposity (per 1 SD) was significantly associated with a higher risk of stroke (odds ratio [OR] 1.30; 95% confidence interval [CI] 1.21-1.41, P=1.48Ã10-11), ischemic stroke (OR 1.30; 95% CI 1.20-1.41, P=4.01Ã10-10), and large artery stroke (OR 1.49; 95% CI 1.22-1.83, P=1.16Ã10-4). The significant association was also found in sensitivity analysis and multi-variable MR analysis. Conclusions: Genetic liability to visceral adiposity was significantly associated with an increased risk of stroke, ischemic stroke, and large artery stroke. The effect of genetic susceptibility to visceral adiposity on the stroke warrants further investigation.

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Sleep-disordered breathing-related symptoms and risk of stroke: cohort study and Mendelian randomization analysis

Journal of Neurology ◽

10.1007/s00415-021-10824-y ◽

2021 ◽

Author(s):

Olga E. Titova ◽

Shuai Yuan ◽

John A. Baron ◽

Eva Lindberg ◽

Karl Michaëlsson ◽

...

Keyword(s):

Cohort Study ◽

Ischemic Stroke ◽

Subarachnoid Hemorrhage ◽

Sleep Apnea ◽

Confidence Interval ◽

Intracerebral Hemorrhage ◽

Sleep Disordered Breathing ◽

Mendelian Randomization ◽

Genome Wide ◽

Increased Risk

Abstract Background Sleep-disordered breathing (SDB) may contribute to development of stroke. However, findings are inconclusive. We investigated whether SDB-related symptoms are associated with incidence of stroke and its types in a general community sample of adult men and women as well as to perform Mendelian randomization (MR) analysis. Methods We used data from a cohort of 41,742 Swedish adults (56–94 years of age) who completed questionnaires regarding snoring, cessation of breathing, lifestyle and health characteristics. Participants were followed up for incident stroke and death over 8 years through linkage to the Swedish Registers. Hazard ratios, adjusted for potential confounders, were estimated by Cox proportional hazards regression. MR analyses were performed using single-nucleotide polymorphisms associated with sleep apnea at the genome-wide significance level and summary-level data for stroke and its subtypes from consortia and a meta-analysis of Genome-Wide Association Studies. Results In the cohort study, symptoms of disturbing snoring and/or cessation of breathing were associated with increased risk of total stroke (hazard ratio 1.12, 95% confidence interval 1.02–1.24) and intracerebral hemorrhage (hazard ratio 1.59, 95% confidence interval 1.23–2.05) but not with ischemic stroke or subarachnoid hemorrhage. MR analyses showed no association of genetic liability to sleep apnea with the risk of overall stroke or any specific types of stroke or ischemic stroke subtypes. Conclusions SDB-related symptoms were associated with increased risk of total stroke, specifically intracerebral hemorrhage, in the observational analyses but not in the MR analyses. There was limited evidence of an association of SDB with ischemic stroke and subarachnoid hemorrhage.

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Circulating Vitamin K1 Levels in Relation to Ischemic Stroke and Its Subtypes: A Mendelian Randomization Study

Nutrients ◽

10.3390/nu10111575 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1575 ◽

Cited By ~ 3

Author(s):

Susanna Larsson ◽

Matthew Traylor ◽

Hugh Markus

Keyword(s):

Ischemic Stroke ◽

Mendelian Randomization ◽

Cardioembolic Stroke ◽

Small Vessel ◽

Large Artery ◽

Vitamin K1 ◽

Nucleotide Polymorphisms ◽

Single Nucleotide ◽

Level Data ◽

Increased Risk

Vitamin K plays a crucial role in blood coagulation, and hypercoagulability has been linked to atherosclerosis-related vascular disease. We used the Mendelian randomization study design to examine whether circulating vitamin K1 (phylloquinone) levels are associated with ischemic stroke. Four single-nucleotide polymorphisms associated with vitamin K1 levels were used as instrumental variables. Summary-level data for large artery atherosclerotic stroke (n = 4373 cases), small vessel stroke (n = 5386 cases), cardioembolic stroke (n = 7193 cases), and any ischemic stroke (n = 34,217 cases and 404,630 non-cases) were available from the MEGASTROKE consortium. Genetically-predicted circulating vitamin K1 levels were associated with large artery atherosclerotic stroke but not with any other subtypes or ischemic stroke as a whole. The odds ratios per genetically predicted one nmol/L increase in natural log-transformed vitamin K1 levels were 1.31 (95% confidence interval (CI) 1.12–1.53; p = 7.0 × 10−4) for large artery atherosclerotic stroke, 0.98 (95% CI 0.85–1.12; p = 0.73) for small vessel stroke, 1.01 (95% CI 0.90–1.14; p = 0.84) for cardioembolic stroke, and 1.05 (95% CI 0.99–1.11; p = 0.11) for any ischemic stroke. These findings indicate that genetic predisposition to higher circulating vitamin K1 levels is associated with an increased risk of large artery atherosclerotic stroke.

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Evaluating the effects of alcohol and tobacco use on cardiovascular disease using multivariable Mendelian randomization

10.1101/757146 ◽

2019 ◽

Cited By ~ 1

Author(s):

Daniel B. Rosoff ◽

George Davey Smith ◽

Nehal Mehta ◽

Toni-Kim Clarke ◽

Falk W. Lohoff

Keyword(s):

Risk Factors ◽

Cardiovascular Disease ◽

Alcohol Use ◽

Tobacco Use ◽

Mendelian Randomization ◽

Association Studies ◽

Density Lipoprotein ◽

Genome Wide Association Studies ◽

Cvd Risk ◽

Increased Risk

ABSTRACTAlcohol and tobacco use, two major modifiable risk factors for cardiovascular disease (CVD), are often consumed together. Using large publicly available genome-wide association studies (results from > 940,000 participants), we conducted two-sample multivariable Mendelian randomization (MR) to simultaneously assess the independent effects of alcohol and tobacco use on CVD risk factors and events. We found genetic instruments associated with increased alcohol use, controlling for tobacco use, associated with increased high-density-lipoprotein-cholesterol (HDL-C), decreased triglycerides, but not with coronary heart disease (CHD), myocardial infarction (MI), nor stroke; and instruments for increased tobacco use, controlling for alcohol use, associated with decreased HDL-C, increased triglycerides, and increased risk of CHD and MI. Exploratory analysis found associations with HDL-C, LDL-C, and intermediate-density-lipoprotein metabolites. Consistency of results across complementary methods accommodating different MR assumptions strengthened causal inference, providing strong genetic evidence for the causal effects of modifiable lifestyle risk factors on CVD risk.

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Metabolic and lifestyle factors in relation to senile cataract: a Mendelian randomization study

Scientific Reports ◽

10.1038/s41598-021-04515-x ◽

2022 ◽

Vol 12 (1) ◽

Author(s):

Shuai Yuan ◽

Alicja Wolk ◽

Susanna C. Larsson

Keyword(s):

Standard Deviation ◽

Odds Ratio ◽

Mendelian Randomization ◽

Coffee Consumption ◽

Smoking Initiation ◽

Lifestyle Factors ◽

Senile Cataract ◽

Nucleotide Polymorphisms ◽

Standard Deviation Increase ◽

Increased Risk

AbstractWe conducted a Mendelian randomization study to determine the associations of body mass index (BMI), type 2 diabetes (T2D), systolic blood pressure (SBP), coffee and alcohol consumption and smoking initiation with senile cataract. Independent single nucleotide polymorphisms associated with the metabolic and lifestyle factors at the p < 5 × 10–8 were selected as instrument variables. Summary-level data for senile cataract were obtained from the FinnGen consortium (20,157 cases and 154,905 non-cases) and UK Biobank study (6332 cases and 354,862 non-cases). Higher genetically predicted BMI and SBP and genetic predisposition to T2D and smoking initiation were associated with an increased risk of senile cataract. The combined odds ratios were 1.19 (95% confidence interval (CI) 1.09–1.29; p < 0.001) per one standard deviation increase in BMI (~ 4.8 kg/m2), 1.13 (95% CI 1.04–1.23; p = 0.004) per 10 mmHg increase in SBP, 1.06 (95% CI 1.03–1.09; p < 0.001) per one unit increase in log-transformed odds ratio of T2D, and 1.19 (95% CI 1.10–1.29; p < 0.001) per one standard deviation increase in prevalence of smoking initiation. Genetically predicted coffee consumption showed a suggestive association with senile cataract (odds ratio per 50% increase, 1.18, 95% CI 1.00–1.40; p = 0.050). This study suggests causal roles of obesity, T2D, SBP and smoking in senile cataract.

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Association between Apolipoprotein E Polymorphism and Clinical Outcome after Ischemic Stroke, Intracerebral Hemorrhage, and Subarachnoid Hemorrhage

Cerebrovascular Diseases ◽

10.1159/000520053 ◽

2021 ◽

pp. 1-10

Author(s):

Wen Pan ◽

Min Zhang ◽

Zhenping Guo ◽

Wenfeng Xiao ◽

Chao You ◽

...

Keyword(s):

Ischemic Stroke ◽

Subarachnoid Hemorrhage ◽

Clinical Outcome ◽

Intracerebral Hemorrhage ◽

Apolipoprotein E ◽

Functional Outcomes ◽

Fixed Effects ◽

Meta Analysis ◽

Fixed Effects Models ◽

Increased Risk

Backgrounds: Previous studies reported inconsistent results regarding associations between apolipoprotein E (APOE) polymorphism and clinical outcomes after ischemic stroke (IS), intracerebral hemorrhage (ICH), or subarachnoid hemorrhage (SAH). Thus, the study was designed to make a systematic review and meta-analysis regarding the association between APOE polymorphism and clinical outcome after IS, ICH, and SAH. Methods: To identify studies eligible for this meta-analysis, we searched for articles published before August 2021 in the databases (PubMed, Web of Science, and Google Scholar). We used STATA 12.0 software to compute hazard ratios (HRs) and their 95% confidence intervals (CIs) regarding APOE polymorphism and clinical outcome after IS, ICH, and SAH. Results: Meta-analysis showed no significant association between APOE polymorphism and functional outcome after IS with fixed effects models (ε4 carrier vs. non-ε4 carrier: HR, 1.00; 95% CI: 0.83–1.21, I2 = 29.4%, p = 0.183; ε2 carrier vs. non-ε2 carrier: HR, 0.92; 95% CI: 0.72–1.16, I2 = 15.6%, p = 0.307). Meta-analysis showed that ICH patients carrying ε4 allele have increased risk of poor outcome in Caucasian population with fixed effects models (ε4 carrier vs. non-ε4 carrier: HR, 1.75; 95% CI: 1.19–2.57, I2 = 0.0%, p = 0.543). Meta-analysis showed no significant association between APOE polymorphism and functional outcomes after SAH with random effects models (ε4 carrier vs. non-ε4 carrier: HR, 1.51; 95% CI: 0.80–2.84, I2 = 57.1%, p = 0.022). Conclusions: In conclusion, the present study demonstrated APOE ε4 carriers show worse functional outcomes after ICH, but not after IS or SAH. More large-scale studies were critical to explore the association between APOE polymorphism and clinical outcome after IS, ICH, and SAH.

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Hyperglycemia and Metformin Use Are Associated With B Vitamin Deficiency and Cognitive Dysfunction in Older Adults

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.2018-01791 ◽

2019 ◽

Vol 104 (10) ◽

pp. 4837-4847 ◽

Cited By ~ 14

Author(s):

Kirsty M Porter ◽

Mary Ward ◽

Catherine F Hughes ◽

Maurice O’Kane ◽

Leane Hoey ◽

...

Keyword(s):

Older Adults ◽

Vitamin B12 ◽

Cognitive Dysfunction ◽

Vitamin B6 ◽

Vitamin Deficiency ◽

Community Dwelling ◽

Metformin Treatment ◽

Fortified Foods ◽

B Vitamin ◽

The Impact

AbstractContextEmerging evidence suggests that deficiencies of folate-related B vitamins can arise with metformin treatment and are independently linked with cognitive dysfunction, a comorbidity of diabetes.ObjectiveTo determine the impact of hyperglycemia and metformin use on relevant B vitamin biomarkers and cognitive outcomes in older adults.Setting and ParticipantsCommunity-dwelling older adults (74.1 ± 8.3 years, n = 4160) without dementia, recruited to the Trinity, Ulster and Department of Agriculture cohort study in 2008 to 2012, were classified as normoglycemic (n = 1856) or hyperglycemic, based on HbA1c ≥5.7% (39 mmol/mol), either with (n = 318) or without (n = 1986) metformin treatment.Main Outcome MeasuresBiomarkers of folate, vitamin B12, vitamin B6, and riboflavin were measured. Cognitive assessments included the Repeatable Battery for Assessment of Neuropsychological Status (RBANS) and the Frontal Assessment Battery (FAB).ResultsMetformin use was associated with higher risk of deficiency of vitamin B12 (combined B12 index ≤−1; OR 1.45; 95% CI, 1.03 to 2.02) and vitamin B6 (plasma pyridoxal 5-phosphate <30.0 nmol/L; OR 1.48; 95% CI, 1.02 to 2.15). Fortified foods when eaten regularly had a positive impact on all relevant B vitamin biomarkers, even with hyperglycemia. After adjustment for relevant covariates, metformin use was associated with an increased risk of cognitive dysfunction as assessed with the RBANS (OR 1.36; 95% CI, 1.03 to 1.80) and FAB (OR 1.34; 95% CI, 1.03 to 1.74).ConclusionsUse of metformin by older adults is associated with poorer cognitive performance; B vitamin deficiency may be implicated. Fortified foods can optimize B vitamin status and may be beneficial for maintaining better cognitive health in older people with or at risk for diabetes.

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Genetically Determined Physical Activity and Its Association with Circulating Blood Cells

Genes ◽

10.3390/genes10110908 ◽

2019 ◽

Vol 10 (11) ◽

pp. 908 ◽

Cited By ~ 2

Author(s):

Femke M. Prins ◽

M. Abdullah Said ◽

Yordi J. van de Vegte ◽

Niek Verweij ◽

Hilde E. Groot ◽

...

Keyword(s):

Physical Activity ◽

Blood Cells ◽

Fixed Effects ◽

Mendelian Randomization ◽

P Value ◽

Nucleotide Polymorphisms ◽

Increased Risk ◽

Inflammatory State ◽

The Uk ◽

Genetically Determined

Lower levels of physical activity (PA) have been associated with increased risk of cardiovascular disease. Worldwide, there is a shift towards a lifestyle with less PA, posing a serious threat to public health. One of the suggested mechanisms behind the association between PA and disease development is through systemic inflammation, in which circulating blood cells play a pivotal role. In this study we investigated the relationship between genetically determined PA and circulating blood cells. We used 68 single nucleotide polymorphisms associated with objectively measured PA levels to perform a Mendelian randomization analysis on circulating blood cells in 222,645 participants of the UK Biobank. For inverse variance fixed effects Mendelian randomization analyses, p < 1.85 × 10−3 (Bonferroni-adjusted p-value of 0.05/27 tests) was considered statistically significant. Genetically determined increased PA was associated with decreased lymphocytes (β = –0.03, SE = 0.008, p = 1.35 × 10−3) and decreased eosinophils (β = –0.008, SE = 0.002, p = 1.36 × 10−3). Although further mechanistic studies are warranted, these findings suggest increased physical activity is associated with an improved inflammatory state with fewer lymphocytes and eosinophils.

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Plasma Vitamin B6 Vitamers before and after Oral Vitamin B6 Treatment: A Randomized Placebo-controlled Study

Clinical Chemistry ◽

10.1373/49.1.155 ◽

2003 ◽

Vol 49 (1) ◽

pp. 155-161 ◽

Cited By ~ 46

Author(s):

Mustafa Vakur Bor ◽

Helga Refsum ◽

Marianne R Bisp ◽

Øyvind Bleie ◽

Jorn Schneede ◽

...

Keyword(s):

Folic Acid ◽

Vitamin B12 ◽

Vitamin B6 ◽

Oral Treatment ◽

Prolonged Treatment ◽

Controlled Study ◽

Plasma Vitamin ◽

Additional Increase ◽

Before And After ◽

B Vitamin

Abstract Background: Vitamin B6 has attracted renewed interest because of its role in homocysteine metabolism and its possible relation to cardiovascular risk. We examined the plasma B6 vitamers, pyridoxal 5′-phosphate (PLP), pyridoxal (PL), pyridoxine (PN), and 4-pyridoxic acid (4-PA) before and after vitamin B6 supplementation. Methods: Patients (n = 90; age range, 38–80 years) undergoing coronary angiography (part of the homocysteine-lowering Western Norway B-Vitamin Intervention Trial) were allocated to the following daily oral treatment groups: (A), vitamin B12 (0.4 mg), folic acid (0.8 mg), and vitamin B6 (40 mg); (B), vitamin B12 and folic acid; (C), vitamin B6; or (D), placebo. EDTA blood was obtained before treatment and 3, 14, 28, and 84 days thereafter. Results: Before treatment, PLP (range, 5–111 nmol/L) and 4-PA (6–93 nmol/L) were the predominant B6 vitamers identified in plasma. During the 84-day study period, the intraindividual variation (CV) in patients not treated with vitamin B6 (groups B and D) was 45% for PLP and 67% for 4-PA. Three days after the start of treatment, the increases in concentration were ∼10-, 50-, and 100-fold for PLP, 4-PA, and PL, respectively. No significant additional increase was observed at the later time points. The PLP concentration correlated to the concentrations of 4-PA and PL before treatment, but not after treatment. The PL concentration correlated with 4-PA before and after treatment. Conclusions: Vitamin B6 treatment has an immediate effect on the concentrations and the forms of B6 vitamers present in plasma, and the changes remain the same during prolonged treatment. Our results suggest that the B6 vitamers in plasma reflect vitamin B6 intake.

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Long Leukocyte Telomere Length Is Associated with Increased Risks of Soft Tissue Sarcoma: A Mendelian Randomization Study

Cancers ◽

10.3390/cancers12030594 ◽

2020 ◽

Vol 12 (3) ◽

pp. 594 ◽

Cited By ~ 1

Author(s):

Yifan Xu ◽

Junfeng Xu ◽

Haidee Chancoco ◽

Maosheng Huang ◽

Keila E. Torres ◽

...

Keyword(s):

Soft Tissue ◽

Soft Tissue Sarcoma ◽

Telomere Length ◽

Mendelian Randomization ◽

Genetic Risk Score ◽

Leukocyte Telomere Length ◽

Nucleotide Polymorphisms ◽

Individual Snps ◽

Increased Risk ◽

Weighted Genetic Risk Score

Background: Leukocyte telomere length (LTL) has been associated with the risks of several cancers in observational studies. Mendelian randomization (MR) studies, using genetic variants as instrumental variables, have also shown associations of genetically predicted LTL with cancer risks. In this study, we performed the first MR analysis on soft tissue sarcoma (STS) to investigate the causal relationship between LTL and the risk of STS. Methods: Genotypes from eleven LTL-associated single nucleotide polymorphisms (SNPs) in 821 STS cases and 851 cancer-free controls were aggregated into a weighted genetic risk score (GRS) to predict LTL. Multivariate logistic regression was used to assess the association of STS risk with individual SNPs and aggregated GRS. Results: Four SNPs displayed evidence for an individual association between long LTL-conferring allele and increased STS risk: rs7675998 (odds ratio (OR) = 1.21, 95% confidence interval (CI) = 1.02–1.43), rs9420907 (OR = 1.31, 95% CI = 1.08–1.59), rs8105767 (OR = 1.18, 95% CI = 1.02–1.37), and rs412658 (OR = 1.18, 95% CI = 1.02–1.36). Moreover, longer genetically predicted LTL, calculated as GRS, was strongly associated with an increased risk of STS (OR = 1.44, 95% CI = 1.18–1.75, p < 0.001), and there was a significant dose-response association (p for trend <0.001 in tertile and quartile analyses). The association of longer LTL with higher STS risk was more evident in women than in men. In stratified analyses by major STS subtypes, longer LTL was significantly associated with higher risks of leiomyosarcoma and gastrointestinal stromal tumors. Conclusions: Longer LTL is associated with increased risks of STS.

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