Genetic analysis of over 1 million people identifies 535 new loci associated with blood pressure traits

Meta-Analysis and Multivariate GWAS Analyses in 80,950 Individuals of African Ancestry Identify Novel Variants Associated with Blood Pressure Traits

High blood pressure (HBP) has been implicated as a major risk factor for cardiovascular diseases in several populations, including individuals of African ancestry. Despite the elevated burden of HBP-induced cardiovascular diseases in Africa and other populations of African descent, limited genetic studies have been carried out to explore the genetic mechanism driving this phenomenon. We performed genome-wide association univariate and multivariate analyses of both systolic (SBP) and diastolic blood pressure (DBP) traits in 80,950 individuals of African ancestry. We used summary statistics data from six independent cohorts, including the African Partnership for Chronic Disease Research (APCDR), the UK Biobank, and the Million Veteran Program (MVP). FUMA was used to annotate, prioritize, visualize, and interpret our findings to gain a better understanding of the molecular mechanism(s) underlying the genetics of BP traits. Finally, we undertook a Bayesian fine-mapping analysis to identify potential causal variants. Our meta-analysis identified 10 independent variants associated with SBP and 9 with DBP traits. Whilst our multivariate GWAS method identified 21 independent signals, 18 of these SNPs have been previously identified. SBP was linked to gene sets involved in biological processes such as synapse assembly and cell-cell adhesion via plasma membrane adhesion. Of the 19 independent SNPs identified in the BP meta-analysis, only 11 variants had posterior probability (PP) of > 50%, including one novel variant: rs562545 (MOBP, PP = 77%). To facilitate further research and fine-mapping of high-risk loci/variants in highly susceptible groups for cardiovascular disease and other related traits, large-scale genomic datasets are needed. Our findings highlight the importance of including ancestrally diverse populations in large GWASs and the need for diversity in genetic research.

Biomedical consequences of elevated cholesterol-containing lipoproteins and apolipoproteins on cardiovascular and non-cardiovascular outcomes

BACKGROUND

Higher concentrations of cholesterol-containing low-density lipoprotein (LDL-C) increase the risk of cardiovascular disease (CVD). The association of LDL-C with non-CVD traits remains unclear, as are the possible independent contributions of other cholesterol-containing lipoproteins and apolipoproteins.

METHODS

Nuclear magnetic resonance spectroscopy was used to measure the cholesterol content of high density (HDL-C), very low-density (VLDL-C), intermediate-density (IDL-C), as well as low-density lipoprotein fractions, the apolipoproteins Apo-A1 and Apo-B, as well as total triglycerides (TG), remnant-cholesterol (Rem-Chol) and total cholesterol (TC). The causal effects of these exposures were assessed against 33 outcomes using univariable and multivariable Mendelian randomization (MR).

RESULTS

The majority of cholesterol containing lipoproteins and apolipoproteins affect coronary heart disease (CHD), carotid intima-media thickness, carotid plaque, C-reactive protein (CRP) and blood pressure. Multivariable MR indicated that many of these effects act independently of HDL-C, LDL-C and TG, the most frequently measured lipid fractions. Higher concentrations of TG, VLDL-C, Rem-Chol and Apo-B increased heart failure (HF) risk; often independently of LDL-C, HDL-C or TG. Finally, a subset of these exposures associated with non-CVD traits such as Alzheimer's disease (AD: HDL-C, LDL-C, IDL-C, Apo-B), type 2 diabetes (T2DM: VLDL-C, IDL-C, LDL-C), and inflammatory bowel disease (IBD: LDL-C, IDL-C).

CONCLUSIONS

The cholesterol content of a wide range of lipoprotein and apolipoproteins associate with measures of atherosclerosis, blood pressure, CRP, and CHD, with a subset affecting HF, T2DM, AD and IBD risk. Many of the observed effects appear to act independently of LDL-C, HDL-C, and TG, supporting the targeting of lipid fractions beyond LDL-C for disease prevention.

Shifting Paradigm from Gene Expressions to Pathways Reveals Physiological Mechanisms in Blood Pressure Control in Causation

Genetics for blood pressure (BP) in human and animals has been partitioned into two separate specialties. However, this divide is mechanistically-misleading. BP physiology is mechanistically participated by products of quantitative trait loci (QTLs). The key to unlocking its mechanistic mystery lies in the past with mammalian ancestors before humans existed. By pivoting from effects to causes, physiological mechanisms determining BP by six QTLs have been implicated. Our work relies on congenic knock-in genetics in vivo using rat models, and has reproduced the physiological outcome based on a QTL being molecularly equal to one gene. A gene dose for a QTL is irrelevant to physiological BP controls in causation. Together, QTLs join one another as a group in modularized Mendelian fashion to achieve polygenicity. Mechanistically, QTLs in the same module appear to function in a common pathway. Each is involved in a different step in the pathway toward polygenic hypertension. This work has implicated previously-concealed components of these pathways. This emerging concept is a departure from the human-centric precept that the level of QTL expressions, not physiology, would ultimately determine BP. The modularity/pathway paradigm breaks a unique conceptual ground for unravelling the physiological mechanisms of polygenic and quantitative traits like BP.

Appraising the Effects of Metabolic Traits on the Risk of Glaucoma: A Mendelian Randomization Study

Metabolic traits are associated with the risk of developing glaucoma in observational studies. To assess whether theses associations reflect causality, we conducted a Mendelian randomization (MR) study. Our study included up to 20,906 glaucoma cases and 438,188 controls. Genetic instruments associated with the concerned 11 exposures at the genome-wide significance level were selected from corresponding genome-wide association studies. Summary-level data for glaucoma were obtained from the UK Biobank, the GERA study, and the FinnGen consortium. Univariable and multivariable MR analyses were conducted separately in two populations. Our results showed that higher genetic liability to type 2 diabetes (T2D) was causally and independently associated with an increased risk of glaucoma (odds ratio [OR], 1.11; 95% confidence interval [CI], 1.06-1.16; p = 4.4 × 10-6). The association for T2D persisted after multivariable adjustment. In addition, higher genetically predicted systolic blood pressure (SBP), fasting glucose (FG), and HbA1c, were also suggestively associated with glaucoma risk. The OR was 1.08 (95% CI, 1.01-1.16; p = 0.035) for SBP, 1.24 (95% CI, 1.05-1.47; p = 0.011) for FG, and 1.28 (95% CI, 1.01-1.61; p = 0.039) for HbA1c. No evidence was observed to support the causal effects of body mass index and blood lipids for glaucoma. This study suggests a causal role for diabetes, as well as possible roles for higher SBP, FG, and HbA1c in the development of glaucoma. Further validation is needed to assess the potential of these risk factors as pharmacological targets for glaucoma prevention.

Genetic screening for hypertension and COVID-19 reveals functional variation of SPEG potentially associated with severe COVID-19 in women

The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to more than 6.4 million deaths worldwide. The prevalent comorbidity between hypertension and severe COVID-19 suggests common genetic factors may affect the outcome of both diseases. As both hypertension and severe COVID-19 demonstrate sex-biased prevalence, common genetic factors between the two diseases may display sex-biased differential associations. By evaluating COVID-19 association signals of 172-candidate hypertension single nucleotide polymorphisms (SNPs) derived from more than 1 million European individuals in two sex-stratified severe COVID-19 genome-wide association studies from UK BioBank with European ancestry, we revealed one functional cis expression quantitative trait locus of SPEG (rs12474050) showing sex-biased association with severe COVID-19 in women. The risk allele rs12474050*T associates with higher blood pressure. In our study, we found it is significantly correlated with lower SPEG expression in muscle-skeletal but with higher expression in both brain cerebellum and cerebellar hemisphere. Additionally, nominal significances were detected for the association between rs12474050*T and lower SPEG expression in both heart left ventricle and atrial appendage; among these tissues, the SPEG expression is nominally significantly higher in females than in males. Further analysis revealed SPEG is mainly expressed in cardiomyocytes in heart and is upregulated upon SARS-CoV-2 infection, with significantly higher upregulation of SPEG only observed in female but not in male COVID-19 patients compared to both normal female and male individuals, suggesting upregulation of SPEG is a female-specific protective mechanism against COVID-19 induced heart damage. Taken together, our analyses suggest the involvement of SPEG in both hypertension and severe COVID-19 in women, which provides new insights for sex-biased effect of severe COVID-19 in women.

mRNA Metabolism and Hypertension

Hypertension is the most frequent cardiovascular risk factor all over the world. It remains a leading contributor to the risk of cardiovascular events and death. In the year 2015, about 1.5 billion of adult people worldwide had hypertension (as defined by office systolic blood pressure ≥ 140 mmHg or office diastolic blood pressure ≥ 90 mmHg). Moreover, the number of hypertensive patients with age ranging from 30 to 79 years doubled in the last 30 years (from 317 million men and 331 million women in the year 1990 to 652 million men and 626 million women in 2019) despite stable age-standardized prevalence worldwide. Despite such impressive growth, the proportion of controlled hypertension is very low. A better understanding of the pathogenesis of hypertension may contribute to the development of innovative therapeutic strategies. In this context, alterations of the messenger RNA metabolism have been recently evaluated as contributors to the pathogenesis of hypertension, and pharmacological modulation of RNA metabolism is under investigation as potential and novel therapeutic armamentarium in hypertension.

Independent Associations of Education, Intelligence, and Cognition With Hypertension and the Mediating Effects of Cardiometabolic Risk Factors: A Mendelian Randomization Study

BACKGROUND

Education, intelligence, and cognition are associated with hypertension, but which one plays the most prominent role in the pathogenesis of hypertension and which modifiable risk factors mediate the causal effects remains unknown.

METHODS

Using summary statistics of genome-wide association studies of predominantly European ancestry, we conducted 2-sample multivariable Mendelian randomization to estimate the independent effects of education, intelligence, or cognition on hypertension (FinnGen study, 70 651 cases/223 663 controls; UK Biobank, 77 723 cases/330 366 controls) and blood pressure (International Consortium of Blood Pressure, 757 601 participants), and used 2-step Mendelian randomization to evaluate 25 potential mediators of the association and calculate the mediated proportions.

RESULTS

Meta-analysis of inverse variance weighted Mendelian randomization results from FinnGen and UK Biobank showed that genetically predicted 1-SD (4.2 years) higher education was associated with 44% (95% CI: 0.40-0.79) decreased hypertension risk and 1.682 mm Hg lower systolic and 0.898 mm Hg lower diastolic blood pressure, independently of intelligence and cognition. While the causal effects of intelligence and cognition on hypertension were not independent of education; 6 out of 25 cardiometabolic risk factors were identified as mediators of the association between education and hypertension, ranked by mediated proportions, including body mass index (mediated proportion: 30.1%), waist-to-hip ratio (22.8%), body fat percentage (14.1%), major depression (7.0%), high-density lipoprotein cholesterol (4.7%), and triglycerides (3.4%). These results were robust to sensitivity analyses.

CONCLUSIONS

Our findings illustrated the causal, independent impact of education on hypertension and blood pressure and outlined cardiometabolic mediators as priority targets for prevention of hypertension attributable to low education.

Association of Angiotensin II Type 1 Receptor (AT1R) Gene Polymorphism with Angiotensin II Serum Levels in Patients with Essential Hypertension

Essential hypertension (EH) is a multifactorial, polygenic condition, and is one of the most important comorbidities that contributes to stroke, myocardial infarction, cardiac failure, and renal failure. The continuous increasing rate of morbidity and mortality associated with EH presents an unmet need of population-based studies to explore pathophysiology as well as newer strategies for better diagnosis, prognosis and treatment. This study aimed to determine genotype and allele frequencies of A1166C polymorphism of AT1R gene in Indian patients with EH and correlated with serum levels of Angiotensin II. A total of 200 patients with EH and 200 age- and gender-matched control individuals were included in this study from the General Medicine Department Outpatient at Narayana Medical College and Hospital, Nellore, Andhra Pradesh, India. Patients with systolic blood pressure (SBP) ≥ 140 mmHg and/or diastolic blood pressure (DBP) ≥ 90 mmHg were considered as hypertensive. The findings of this study revealed significantly increased risk of C/A heterozygote and allele C in both men and women. Moreover, both men and women patients with EH showed higher serum levels of Angiotensin II with C/A as well as AA genotypes. These findings indicate a significant association of 1166 C/A polymorphism of the AT1R gene with increased risk of hypertension in Indian population.

Protective effect of antihypertensive drugs on the risk of Parkinson's disease lacks causal evidence from mendelian randomization

Background: Evidence from observational studies concerning the causal role of blood pressure (BP) and antihypertensive medications (AHM) on Parkinson's disease (PD) remains inconclusive. A two-sample Mendelian randomization (MR) study was performed to evaluate the unconfounded association of genetic proxies for BP and first-line AHMs with PD. Methods: Instrumental variables (IV) from the genome-wide association study (GWAS) for BP traits were used to proxy systolic BP (SBP), diastolic BP, and pulse pressure. SBP-associated variants either located within encoding regions or associated with the expression of AHM targets were selected and then scaled to proxy therapeutic inhibition of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, β-blockers, calcium channel blockers, and thiazides. Positive control analyses on coronary heart disease (CHD) and stroke were conducted to validate the IV selection. Summary data from GWAS for PD risk and PD age at onset (AAO) were used as outcomes. Results: In positive control analyses, genetically determined BP traits and AHMs closely mimicked the observed causal effect on CHD and stroke, confirming the validity of IV selection methodology. In primary analyses, although genetic proxies identified by "encoding region-based method" for β-blockers were suggestively associated with a delayed PD AAO (Beta: 0.115; 95% CI: 0.021, 0.208; p = 1.63E-2; per 10-mmHg lower), sensitivity analyses failed to support this association. Additionally, MR analyses found little evidence that genetically predicted BP traits, overall AHM, or other AHMs affected PD risk or AAO. Conclusion: Our data suggest that BP and commonly prescribed AHMs may not have a prominent role in PD etiology.

Aspirin Use and Risk of Alzheimer's Disease: A 2-Sample Mendelian Randomization Study

BACKGROUND

Observational studies have shown inconsistent findings of the relationships between aspirin use and the risk of Alzheimer's disease (AD).

OBJECTIVE

Since residual confounding and reverse causality were challenging issues inherent in observational studies, we conducted a 2-sample Mendelian randomization analysis (MR) to investigate whether aspirin use was causally associated with the risk of AD.

METHODS

We conducted 2-sample MR analyses utilizing summary genetic association statistics to estimate the potential causal relationship between aspirin use and AD. Single-nucleotide variants associated with aspirin use in a genome-wide association study (GWAS) of UK Biobank were considered as genetic proxies for aspirin use. The GWAS summary-level data of AD were derived from a meta-analysis of GWAS data from the International Genomics of Alzheimer's Project (IGAP) stage I.

RESULTS

Univariable MR analysis based on these two large GWAS data sources showed that genetically proxied aspirin use was associated with a decreased risk of AD (Odds Ratio (OR): 0.87; 95%CI: 0.77-0.99). In multivariate MR analyses, the causal estimates remained significant after adjusting for chronic pain, inflammation, heart failure (OR = 0.88, 95%CI = 0.78-0.98), or stroke (OR = 0.87, 95%CI = 0.77-0.99), but was attenuated when adjusting for coronary heart disease, blood pressure, and blood lipids.

CONCLUSION

Findings from this MR analysis suggest a genetic protective effect of aspirin use on AD, possibly influenced by coronary heart disease, blood pressure, and lipid levels.

A genomic deep field view of hypertension

Blood pressure is regulated by a complex neurohumoral system including the renin-angiotensin-aldosterone system, natriuretic peptides, endothelial pathways, the sympathetic nervous system, and the immune system. This review charts the evolution of our understanding of the genomic basis of hypertension at increasing resolution over the last 5 decades from monogenic causes to polygenic associations, spanning ∼30 monogenic rare variants and >1500 single nucleotide variants. Unexpected early wins from blood pressure genomics include deepening of our understanding of the complex causation of hypertension; refinement of causal estimates bidirectionally between blood pressure, risk factors, and outcomes through Mendelian randomization; risk stratification using polygenic risk scores; and opportunities for precision medicine and drug repurposing.

Genetic predictors of lifelong medication-use patterns in cardiometabolic diseases

Little is known about the genetic determinants of medication use in preventing cardiometabolic diseases. Using the Finnish nationwide drug purchase registry with follow-up since 1995, we performed genome-wide association analyses of longitudinal patterns of medication use in hyperlipidemia, hypertension and type 2 diabetes in up to 193,933 individuals (55% women) in the FinnGen study. In meta-analyses of up to 567,671 individuals combining FinnGen with the Estonian Biobank and the UK Biobank, we discovered 333 independent loci (P < 5 × 10-9) associated with medication use. Fine-mapping revealed 494 95% credible sets associated with the total number of medication purchases, changes in medication combinations or treatment discontinuation, including 46 credible sets in 40 loci not associated with the underlying treatment targets. The polygenic risk scores (PRS) for cardiometabolic risk factors were strongly associated with the medication-use behavior. A medication-use enhanced multitrait PRS for coronary artery disease matched the performance of a risk factor-based multitrait coronary artery disease PRS in an independent sample (UK Biobank, n = 343,676). In summary, we demonstrate medication-based strategies for identifying cardiometabolic risk loci and provide genome-wide tools for preventing cardiovascular diseases.

Genetically predicted blood pressure, antihypertensive drugs and risk of heart failure: a Mendelian randomization study

BACKGROUND

Elevated blood pressure (BP) was associated with higher risk of heart failure, but the relationship between BP-lowering via antihypertensive drugs and diminution of heart failure was inconclusive. This study aimed to estimate the causal association of BP with heart failure, and explore the effects of BP-lowering through different antihypertensive drug classes on heart failure risk using Mendelian randomization analysis with genetic variants as instrument variables.

METHODS

Genetic variants associated with BP were derived from UK Biobank ( n  = 317 754) and the genome-wide association study (GWAS) meta-analysis of UK Biobank and International Consortium of Blood Pressure ( n  = 757 601). Heart failure summary association data were contributed by HERMES Consortium (47 309 heart failure cases and 930 014 controls). Inverse variance weighted (IVW) was performed to estimate causality between exposure and outcome, and weighted median was utilized as sensitivity analysis, and Mendelian randomization-Egger regression was used to identify pleiotropy of instrument variables. Multivariable Mendelian randomization (MVMR) was applied to control for the confounders.

RESULTS

Genetically predicted SBP and DBP were associated with heart failure [SBP: odds ratio (OR) = 1.355, 95% confidence interval (CI) 1.201-1.529; DBP: OR = 1.348, 95% CI 1.213-1.498] in UK Biobank. Likewise, in the GWAS meta-analysis of UK Biobank and International Consortium of Blood Pressure, the causal associations were observed between SBP, DBP and heart failure (SBP: OR = 1.237, 95% CI 1.188-1.289; DBP: OR = 1.337, 95% CI 1.245-1.437). Genetically determined β-blockers and calcium channel blockers (CCBs) were associated with lower risk of heart failure (β-blockers: OR = 0.617, 95% CI 0.453-0.839; CCBs: OR = 0.730, 95% CI 0.625-0.851). No association was found between angiotensin receptor blockers (ARBs) and heart failure (OR = 1.593, 95% CI 0.647-3.924). When adjusted for smoking, alcohol, physical activity, fruit and vegetable intake, the results were stable.

CONCLUSION

Our study indicates causal associations between SBP, DBP, and heart failure, and suggests the preventive effects of heart failure by BP-lowering using β-blockers and CCBs.

Progress in molecular biology and translational science: Epigenetics in cardiovascular health and disease

Conrad Waddington's epigenetics landscape has provided a metaphorical framework for how cells progress from undifferentiated states to one of several discrete, distinct, differentiated cell fates. The understanding of epigenetics has evolved over time, with DNA methylation being the most studied epigenetic modification, followed by histone modifications and non-coding RNA. Cardiovascular diseases (CVD) are leading contributors to death worldwide, with the prevalence of CVDs increasing across the last couple of decades. Significant amount of resources being poured into researching key mechanisms and underpinnings of the various CVDs. These molecular studies looked at the genetics, epigenetics as well as the transcriptomics of various cardiovascular conditions, aiming to provide mechanistic insights. It has paved the way for therapeutics to be developed and in recent years, epi-drugs for the treatment of CVDs. This chapter aims to cover the various roles of epigenetics in the context of cardiovascular health and disease. The following will be examined in detail: the developments in basic experimental techniques used to study epigenetics, the role of epigenetics in various CVDs (hypertension, atrial fibrillation, atherosclerosis, and heart failure), and current advances in epi-therapeutics, providing a holistic view of the current concerted efforts in advancing the field of epigenetics in CVDs.

Does ACE2 mediate the detrimental effect of exposures related to COVID-19 risk: A Mendelian randomization investigation

OBJECTIVES

Adiposity, smoking, and lower socioeconomic position (SEP) increase COVID-19 risk while the association of vitamin D, blood pressure, and glycemic traits in COVID-19 risk were less clear. Whether angiotensin-converting enzyme 2 (ACE2), the key receptor for SARS-CoV-2, mediates these associations has not been investigated. We conducted a Mendelian randomization study to assess the role of these exposures in COVID-19 and mediation by ACE2.

METHODS

We extracted genetic variants strongly related to various exposures (vitamin D, blood pressure, glycemic traits, smoking, adiposity, and educational attainment [SEP proxy]), and ACE2 cis-variants from genome-wide association studies (GWAS, n ranged from 28 204 to 3 037 499) and applied them to GWAS summary statistics of ACE2 (n = 28 204) and COVID-19 (severe, hospitalized, and susceptibility, n ≤ 2 942 817). We used inverse variance weighted as the main analyses, with MR-Egger and weighted median as sensitivity analyses. Mediation analyses were performed based on product of coefficient method.

RESULTS

Higher adiposity, lifetime smoking index, and lower educational attainment were consistently associated with higher risk of COVID-19 phenotypes while there was no strong evidence for an association of other exposures in COVID-19 risk. ACE2 partially mediates the detrimental effects of body mass index (ranged from 4.3% to 8.2%), waist-to-hip ratio (ranged from 11.2% to 16.8%), and lower educational attainment (ranged from 4.0% to 7.5%) in COVID-19 phenotypes while ACE2 did not mediate the detrimental effect of smoking.

CONCLUSIONS

We provided genetic evidence that reducing ACE2 could partly lower COVID-19 risk amongst people who were overweight/obese or of lower SEP.

Effects of metabolic traits, lifestyle factors, and pharmacological interventions on liver fat: mendelian randomisation study

Objective

To investigate the effects of metabolic traits, lifestyle factors, and drug interventions on liver fat using the mendelian randomisation paradigm.

Design

Mendelian randomisation study.

Setting

Publicly available summary level data from genome-wide association studies.

Participants

Genome-wide association studies of 32 974 to 1 407 282 individuals who were predominantly of European descent.

Exposures

Genetic variants predicting nine metabolic traits, six lifestyle factors, four lipid lowering drug targets, three antihypertensive drug targets, and genetic association estimates formagnetic resonance imaging measured liver fat.

Main outcome measures

Mendelian randomisation analysis was used to investigate the effects of these exposures on liver fat, incorporating sensitivity analyses that relaxed the requisite modelling assumptions.

Results

Genetically predicted liability to obesity, type 2 diabetes, elevated blood pressure, elevated triglyceride levels, cigarette smoking, and sedentary time watching television were associated with higher levels of liver fat. Genetically predicted lipid lowering drug effects were not associated with liver fat; however, β blocker and calcium channel blocker antihypertensive drug effects were associated with lower levels of liver fat.

Conclusion

These analyses provide evidence of a causal effect of various metabolic traits, lifestyle factors, and drug targets on liver fat. The findings complement existing epidemiological associations, further provide mechanistic insight, and potentially supports a role for drug interventions in reducing the burden of hepatic steatosis and related disease. Further clinical study is now warranted to investigate the relevance of these genetic analyses for patient care.

A comparison of the genes and genesets identified by GWAS and EWAS of fifteen complex traits

Identifying genomic regions pertinent to complex traits is a common goal of genome-wide and epigenome-wide association studies (GWAS and EWAS). GWAS identify causal genetic variants, directly or via linkage disequilibrium, and EWAS identify variation in DNA methylation associated with a trait. While GWAS in principle will only detect variants due to causal genes, EWAS can also identify genes via confounding, or reverse causation. We systematically compare GWAS (N > 50,000) and EWAS (N > 4500) results of 15 complex traits. We evaluate if the genes or gene ontology terms flagged by GWAS and EWAS overlap, and find substantial overlap for diastolic blood pressure, (gene overlap P = 5.2 × 10^-6; term overlap P = 0.001). We superimpose our empirical findings against simulated models of varying genetic and epigenetic architectures and observe that in most cases GWAS and EWAS are likely capturing distinct genesets. Our results indicate that GWAS and EWAS are capturing different aspects of the biology of complex traits.

Investigating the causal mediating effect of type 2 diabetes on the relationship between traits and systolic blood pressure: A two-step Mendelian randomization study

Background

Type 2 diabetes mellitus (T2DM) and hypertension commonly coexist, and we presumed that T2DM might mediate the relationship between some shared risk factors and systolic blood pressure (SBP).

Methods

The causal association between T2DM and SBP was first confirmed using Mendelian randomization (MR) analyses, and a two-step MR design was then used to test the causal mediating effect of T2DM on the relationship between 107 traits and SBP using summary statistics from genome-wide association studies.

Results

T2DM was causally associated with SBP. The univariable MR of the two-step causal mediation analyses suggested that 44 and 45 of the 107 traits had causal associations with T2DM and SBP, respectively. Five of the 27 traits that were significantly associated with both T2DM and SBP could not be reversely altered by T2DM and were included in the second step of the causal mediation analyses. The results indicated that most of the investigated traits causally altered SBP independent of T2DM, but the partial causal mediating effect of T2DM on the association between fasting insulin and SBP was successfully identified with a mediation proportion of 33.6%.

Conclusions

Our study provides novel insights into the role of risk factors in the comorbidity of T2DM and high blood pressure, which is important for long-term disease prevention and management.

A Mendelian randomization study to assess the genetic liability of gastroesophageal reflux disease for cardiovascular diseases and risk factors

Observational studies have reported that gastroesophageal reflux disease (GERD) is a risk factor for cardiovascular diseases (CVD); however, the causal inferences between them remain unknown. We conducted a Mendelian randomization (MR) study to estimate the causal associations between GERD and 10 CVD outcomes, as well as 14 cardiovascular risk factors. We used summary statistics from genome-wide association studies for GERD and the FinnGen consortium for CVD. We further investigated whether GERD correlated with cardiovascular risk factors and performed multivariable MR and mediation analyses to estimate the mediating effects of these risk factors on GERD-CVD progression. Sensitivity analyses and replication analyses were also performed. Our results indicated that GERD was positively associated with seven CVD outcomes with odds ratios of 1.26 [95% confidence interval (CI), 1.15, 1.37] for coronary artery disease, 1.41 (95% CI, 1.28, 1.57) for myocardial infarction, 1.34 (95% CI, 1.19, 1.51) for atrial fibrillation, 1.34 (95% CI, 1.21, 1.50) for heart failure, 1.30 (95% CI, 1.18, 1.43) for any stroke, 1.19 (95% CI, 1.06, 1.34) for ischemic stroke and 1.29 (95% CI, 1.16, 1.44) for venous thromboembolism. Furthermore, GERD was associated with nine cardiovascular risk factors and major depressive disorder demonstrated significant mediation effects on the causal pathway linking GERD and any stroke. This study demonstrates that GERD is associated with seven CVD outcomes and nine cardiovascular risk factors. Importantly, GERD treatment may help prevent common CVD events.

Genetically predicted sex hormone levels and health outcomes: phenome-wide Mendelian randomization investigation

BACKGROUND

Sex hormone-binding globulin (SHBG), testosterone and oestradiol have been associated with many diseases in observational studies; however, the causality of associations remains unestablished.

METHODS

A phenome-wide Mendelian randomization (MR) association study was performed to explore disease outcomes associated with genetically proxied circulating SHBG, testosterone and oestradiol levels by using updated genetic instruments in 339 197 unrelated White British individuals (54% female) in the UK Biobank. Two-sample MR analyses with data from large genetic studies were conducted to replicate identified associations in phenome-wide MR analyses. Multivariable MR analyses were performed to investigate mediation effects of hormone-related biomarkers in observed associations with diseases.

RESULTS

Phenome-wide MR analyses examined associations of genetically predicted SHBG, testosterone and oestradiol levels with 1211 disease outcomes, and identified 28 and 13 distinct phenotypes associated with genetically predicted SHBG and testosterone, respectively; 22 out of 28 associations for SHBG and 10 out of 13 associations for testosterone were replicated in two-sample MR analyses. Higher genetically predicted SHBG levels were associated with a reduced risk of hypertension, type 2 diabetes, diabetic complications, coronary atherosclerotic outcomes, gout and benign and malignant neoplasm of uterus, but an increased risk of varicose veins and fracture (mainly in females). Higher genetically predicted testosterone levels were associated with a lower risk of type 2 diabetes, coronary atherosclerotic outcomes, gout and coeliac disease mainly in males, but an increased risk of cholelithiasis in females.

CONCLUSIONS

These findings suggest that sex hormones may causally affect risk of several health outcomes.

Effects of Pre-Pregnancy Overweight/Obesity on the Pattern of Association of Hypertension Susceptibility Genes with Preeclampsia

The aim of this study was to explore the effects of pre-pregnancy overweight/obesity on the pattern of association of hypertension susceptibility genes with preeclampsia (PE). Ten single-nucleotide polymorphisms (SNPs) of the 10 genome-wide association studies (GWAS)-significant hypertension/blood pressure (BP) candidate genes were genotyped in 950 pregnant women divided into two cohorts according to their pre-pregnancy body mass index (preBMI): preBMI ≥ 25 (162 with PE and 159 control) and preBMI < 25 (290 with PE and 339 control). The PLINK software package was utilized to study the association (analyzed four genetic models using logistic regression). The functionality of PE-correlated loci was analyzed by performing an in silico database analysis. Two SNP hypertension/BP genes, rs805303 BAG6 (OR: 0.36−0.66) and rs167479 RGL3 (OR: 1.86), in subjects with preBMI ≥ 25 were associated with PE. No association between the studied SNPs and PE in the preBMI < 25 group was determined. Further analysis showed that two PE-associated SNPs are functional (have weighty eQTL, sQTL, regulatory, and missense values) and could be potentially implicated in PE development. In conclusion, this study was the first to discover the modifying influence of overweight/obesity on the pattern of association of GWAS-significant hypertension/BP susceptibility genes with PE: these genes are linked with PE in preBMI ≥ 25 pregnant women and are not PE-involved in the preBMI < 25 group.

Association of a Multiancestry Genome-Wide Blood Pressure Polygenic Risk Score With Adverse Cardiovascular Events

BACKGROUND

Traditional cardiovascular risk factors and the underlying genetic risk of elevated blood pressure (BP) determine an individual's composite risk of developing adverse cardiovascular events. We sought to evaluate the relative contributions of the traditional cardiovascular risk factors to the development of adverse cardiovascular events in the context of varying BP genetic risk profiles.

METHODS

Genome-wide polygenic risk score (PRS) was computed using multiancestry genome-wide association estimates among US adults who underwent whole-genome sequencing in the Trans-Omics for Precision program. Individuals were stratified into high, intermediate, and low genetic risk groups (>80th, 20-80th, and <20th centiles of systolic BP [SBP] PRS). Based on the ACC/AHA Pooled Cohort Equations, participants were stratified into low and high (10 year-atherosclerotic cardiovascular disease [CVD] risk: <10% or ≥10%) cardiovascular risk factor profile groups. The primary study outcome was incident cardiovascular event (composite of incident heart failure, incident stroke, and incident coronary heart disease).

RESULTS

Among 21 897 US adults (median age: 56 years; 56.0% women; 35.8% non-White race/ethnicity), 1 SD increase in the SBP PRS, computed using 1.08 million variants, was associated with SBP (β: 4.39 [95% CI, 4.13-4.65]) and hypertension (odds ratio, 1.50 [95% CI, 1.46-1.55]), respectively. This association was robustly seen across racial/ethnic groups. Each SD increase in SBP PRS was associated with a higher risk of the incident CVD (multivariable-adjusted hazards ratio, 1.07 [95% CI, 1.04-1.10]) after controlling for ACC/AHA Pooled Cohort Equations risk scores. Among individuals with a high SBP PRS, low atherosclerotic CVD risk was associated with a 58% lower hazard for incident CVD (multivariable-adjusted hazards ratio, 0.42 [95% CI, 0.36-0.50]) compared to those with high atherosclerotic CVD risk. A similar pattern was noted in intermediate and low genetic risk groups.

CONCLUSIONS

In a multiancestry cohort of >21 000 US adults, genome-wide SBP PRS was associated with BP traits and adverse cardiovascular events. Adequate control of modifiable cardiovascular risk factors may reduce the predisposition to adverse cardiovascular events among those with a high SBP PRS.

Validation of Polygenic Risk Scores for Coronary Heart Disease in a Middle Eastern Cohort Using Whole Genome Sequencing

BACKGROUND

Enthusiasm for using polygenic risk scores (PRSs) in clinical practice is tempered by concerns about their portability to diverse ancestry groups, thus motivating genome-wide association studies in non-European ancestry cohorts.

METHODS

We conducted a genome-wide association study for coronary heart disease in a Middle Eastern cohort using whole genome sequencing and assessed the performance of 6 PRSs developed with methods including LDpred (PGS000296), metaGRS (PGS000018), Pruning and Thresholding (PGS000337), and an EnsemblePRS we developed. Additionally, we evaluated the burden of rare variants in lipid genes in cases and controls. Whole genome sequencing at 30× coverage was performed in 1067 coronary heart disease cases (mean age=59 years; 70.3% males) and 6170 controls (mean age=40 years; 43.5% males).

RESULTS

The majority of PRSs performed well; odds ratio (OR) per 1 SD increase (OR1sd) was highest for PGS000337 (OR1sd=1.81, 95% CI [1.66-1.98], P=3.07×10-41). EnsemblePRS performed better than individual PRSs (OR1sd=1.8, 95% CI [1.66-1.96], P=5.89×10-44). The OR for the 10th decile versus the remaining deciles was >3.2 for PGS000337, PGS000296, PGS000018, and reached 4.58 for EnsemblePRS. Of 400 known genome-wide significant loci, 33 replicated at P<10-4. However, the 9p21 locus did not replicate. Six suggestive (P<10-5) new loci/genes with plausible biological function were identified (eg, CORO7, RBM47, PDE4D). The burden of rare functional variants in LDLR, APOB, PCSK9, and ANGPTL4 was greater in cases than controls.

CONCLUSIONS

Overall, we demonstrate that PRSs derived from European ancestry genome-wide association studies performed well in a Middle Eastern cohort, suggesting these could be used in the clinical setting while ancestry-specific PRSs are developed.

Genetic screening of hypertensive patients with aldosterone hypersecretion under conditions of stress

PURPOSE

Although ACTH is considered a secondary regulator of aldosterone production, patients with apparent essential hypertension have been treated with mineralocorticoid receptor antagonists (MRAs). In this study, we aimed to identify potentially damaging variants that might be implicated in the phenotype of a well-characterized cohort of 21 hypertensive patients without PA but with stress-induced aldosterone hypersecretion. The patients' blood pressure was normalized though MRA administration.

METHODS

Genetic screening was performed through whole-exome sequencing (WES), and variants in PA-associated or in ion-channels of aldosterone-regulating genes were prioritized. Variants with population frequency < 0.01, predicted to alter protein structure and classified as likely pathogenic by in silico tools, were retained.

RESULTS

Qualifying variants were identified in nine of the 21 patients screened. Seven patients were carriers of six potentially damaging variants in six genes associated with PA (KCNK9, KCNK5, ATP13A3, SLC26A2, CACNA1H, and CACNA1D). A novel variant in the KCNK9 gene (p.V221M) is reported. Our analysis revealed two variants in two novel susceptibility genes for aldosterone hypersecretion, namely, KCNK16 (p.P255H) and CACNA2D3 (p.V557I).

CONCLUSION

WES revealed potentially damaging germline variants in genes participating in aldosterone synthesis/regulating pathways in 9/21 patients of our cohort. The variants identified might play a role in aldosterone hypersecretion under conditions of stress. The potential pathogenicity of these variants should be examined in future functional studies.

A large genome-wide association study of QT interval length utilizing electronic health records

QT interval length is an important risk factor for adverse cardiovascular outcomes; however, the genetic architecture of QT interval remains incompletely understood. We conducted a genome-wide association study of 76,995 ancestrally diverse Kaiser Permanente Northern California members enrolled in the Genetic Epidemiology Research on Adult Health and Aging cohort using 448,517 longitudinal QT interval measurements, uncovering 9 novel variants, most replicating in 40,537 individuals in the UK Biobank and Population Architecture using Genomics and Epidemiology studies. A meta-analysis of all 3 cohorts (n = 117,532) uncovered an additional 19 novel variants. Conditional analysis identified 15 additional variants, 3 of which were novel. Little, if any, difference was seen when adjusting for putative QT interval lengthening medications genome-wide. Using multiple measurements in Genetic Epidemiology Research on Adult Health and Aging increased variance explained by 163%, and we show that the ≈6 measurements in Genetic Epidemiology Research on Adult Health and Aging was equivalent to a 2.4× increase in sample size of a design with a single measurement. The array heritability was estimated at ≈17%, approximately half of our estimate of 36% from family correlations. Heritability enrichment was estimated highest and most significant in cardiovascular tissue (enrichment 7.2, 95% CI = 5.7-8.7, P = 2.1e-10), and many of the novel variants included expression quantitative trait loci in heart and other relevant tissues. Comparing our results to other cardiac function traits, it appears that QT interval has a multifactorial genetic etiology.

Insight into genetic, biological, and environmental determinants of sexual-dimorphism in type 2 diabetes and glucose-related traits

There is growing evidence that sex and gender differences play an important role in risk and pathophysiology of type 2 diabetes (T2D). Men develop T2D earlier than women, even though there is more obesity in young women than men. This difference in T2D prevalence is attenuated after the menopause. However, not all women are equally protected against T2D before the menopause, and gestational diabetes represents an important risk factor for future T2D. Biological mechanisms underlying sex and gender differences on T2D physiopathology are not yet fully understood. Sex hormones affect behavior and biological changes, and can have implications on lifestyle; thus, both sex-specific environmental and biological risk factors interact within a complex network to explain the differences in T2D risk and physiopathology in men and women. In addition, lifetime hormone fluctuations and body changes due to reproductive factors are generally more dramatic in women than men (ovarian cycle, pregnancy, and menopause). Progress in genetic studies and rodent models have significantly advanced our understanding of the biological pathways involved in the physiopathology of T2D. However, evidence of the sex-specific effects on genetic factors involved in T2D is still limited, and this gap of knowledge is even more important when investigating sex-specific differences during the life course. In this narrative review, we will focus on the current state of knowledge on the sex-specific effects of genetic factors associated with T2D over a lifetime, as well as the biological effects of these different hormonal stages on T2D risk. We will also discuss how biological insights from rodent models complement the genetic insights into the sex-dimorphism effects on T2D. Finally, we will suggest future directions to cover the knowledge gaps.

Interactions among maternal smoking, breastfeeding, and offspring genetic factors on the risk of adult-onset hypertension

BACKGROUND

Previous studies have reported that maternal smoking during pregnancy and breastfeeding may affect the occurrence of hypertension, but whether early life factors modify the impact of the offspring's genetic risk on hypertension is still unknown. The aim of this study was to investigate the relationships among maternal smoking and breastfeeding with adult-onset hypertension and the modified impact of offspring genetic susceptibility.

METHODS

This study included 437,185 participants from the UK Biobank who were initially free of hypertension and provided a prospective cohort of individuals aged 40 to 69 years. The association of maternal smoking during pregnancy and breastfeeding with hypertension was examined by using the Cox regression model. Then, a polygenic risk score (PRS) for hypertension was used to test the gene-environmental interaction on hypertension.

RESULTS

During a median follow-up period of 8.7 years, a total of 68,148 cases of hypertension were identified in this study. The hazard ratios (HRs) and 95% confidence intervals (CIs) of hypertension for maternal smoking and breastfeeding were 1.11 (1.09, 1.13) and 0.96 (0.94, 0.98), respectively. However, no evidence of an interaction between maternal smoking and breastfeeding was observed. Across all levels of genetic risk, including high genetic risk, maternal smoking and nonbreastfeeding had higher hypertension hazards than nonmaternal smoking and breastfeeding, respectively. The adjusted HRs (95% CIs) of hypertension were 1.80 (1.73, 1.87) in those who had high genetic predisposition plus maternal smoking and 1.67 (1.60-1.74) in those with nonbreastfeeding and high genetic risk. There were significant additive interactions between maternal smoking or breastfeeding and genetic factors on the incidence of hypertension.

CONCLUSIONS

Maternal smoking and nonbreastfeeding were associated with a higher risk of hypertension in adulthood and may attenuate the risk of hypertension related to genetic factors. These results suggested that adherence to nonmaternal smoking and breastfeeding was associated with a lower risk of hypertension among participants with all gradients of genetic risk.

Whole genome DNA and RNA sequencing of whole blood elucidates the genetic architecture of gene expression underlying a wide range of diseases

To create a scientific resource of expression quantitative trail loci (eQTL), we conducted a genome-wide association study (GWAS) using genotypes obtained from whole genome sequencing (WGS) of DNA and gene expression levels from RNA sequencing (RNA-seq) of whole blood in 2622 participants in Framingham Heart Study. We identified 6,778,286 cis-eQTL variant-gene transcript (eGene) pairs at p < 5 × 10^-8 (2,855,111 unique cis-eQTL variants and 15,982 unique eGenes) and 1,469,754 trans-eQTL variant-eGene pairs at p < 1e-12 (526,056 unique trans-eQTL variants and 7233 unique eGenes). In addition, 442,379 cis-eQTL variants were associated with expression of 1518 long non-protein coding RNAs (lncRNAs). Gene Ontology (GO) analyses revealed that the top GO terms for cis-eGenes are enriched for immune functions (FDR < 0.05). The cis-eQTL variants are enriched for SNPs reported to be associated with 815 traits in prior GWAS, including cardiovascular disease risk factors. As proof of concept, we used this eQTL resource in conjunction with genetic variants from public GWAS databases in causal inference testing (e.g., COVID-19 severity). After Bonferroni correction, Mendelian randomization analyses identified putative causal associations of 60 eGenes with systolic blood pressure, 13 genes with coronary artery disease, and seven genes with COVID-19 severity. This study created a comprehensive eQTL resource via BioData Catalyst that will be made available to the scientific community. This will advance understanding of the genetic architecture of gene expression underlying a wide range of diseases.

Elucidating the genetic architecture of DNA methylation to identify promising molecular mechanisms of disease

DNA methylation commonly occurs at cytosine-phosphate-guanine sites (CpGs) that can serve as biomarkers for many diseases. We analyzed whole genome sequencing data to identify DNA methylation quantitative trait loci (mQTLs) in 4126 Framingham Heart Study participants. Our mQTL mapping identified 94,362,817 cis-mQTLvariant-CpG pairs (for 210,156 unique autosomal CpGs) at P < 1e-7 and 33,572,145 trans-mQTL variant-CpG pairs (for 213,606 unique autosomal CpGs) at P < 1e-14. Using cis-mQTL variants for 1258 CpGs associated with seven cardiovascular disease (CVD) risk factors, we found 104 unique CpGs that colocalized with at least one CVD trait. For example, cg11554650 (PPP1R18) colocalized with type 2 diabetes, and was driven by a single nucleotide polymorphism (rs2516396). We performed Mendelian randomization (MR) analysis and demonstrated 58 putatively causal relations of CVD risk factor-associated CpGs to one or more risk factors (e.g., cg05337441 [APOB] with LDL; MR P = 1.2e-99, and 17 causal associations with coronary artery disease (e.g. cg08129017 [SREBF1] with coronary artery disease; MR P = 5e-13). We also showed that three CpGs, e.g., cg14893161 (PM20D1), are putatively causally associated with COVID-19 severity. To assist in future analyses of the role of DNA methylation in disease pathogenesis, we have posted a comprehensive summary data set in the National Heart, Lung, and Blood Institute's BioData Catalyst.

Causal associations between age at diagnosis of diabetes and cardiovascular outcomes: a Mendelian randomization study

CONTEXT

Whether diabetes diagnosed at different age groups is causally associated with cardiovascular diseases (CVDs) is unknown.

OBJECTIVE

We conducted two-sample Mendelian randomization analyses to investigate the causal associations of diabetes by age at diagnosis with five type-specific CVDs and 11 cardiometabolic traits.

METHODS

We selected 208 single nucleotide polymorphisms (SNPs) for diabetes and 3, 21, 57, and 14 SNPs for diabetes diagnosed at <50, 50-60, 60-70, and >70 years, respectively, based on the GWAS (24,986 cases/187,130 controls) in the UK Biobank, and extracted genetic associations with stroke, myocardial infarction, heart failure, atrial fibrillation, and CVD mortality, as well as blood pressures, adiposity measurements, and lipids and apolipoproteins from corresponding European-descent GWASs. The inverse-variance weighted method was used as main analysis with several sensitivity analyses.

RESULTS

Diabetes diagnosed at all four age groups was causally associated with increased risks of stroke (5%-8%) and myocardial infarction (8%-10%), higher systolic blood pressure (0.56-0.94 mmHg) and waist-to-hip ratio (0.003-0.004), and lower body mass index (0.31-0.42 kg/m2), waist circumference (0.68-0.99 cm), and hip circumference (0.57-0.80 cm). Diabetes diagnosed at specific age groups was causally associated with increased risks of heart failure (4%) and CVD mortality (8%), higher diastolic blood pressure (0.20 mmHg) and triglycerides (0.06 SD), and lower high-density lipoprotein cholesterol (0.02 mmol/L). The effect sizes of genetically determined diabetes on CVD subtypes and cardiometabolic traits were comparable and the corresponding 95% confidence intervals largely overlapped across the four age groups.

CONCLUSION

Our findings provide novel evidence that genetically determined diabetes subgroups by age at diagnosis have similar causal effects on CVD and cardiometabolic risks.

Causal associations between blood pressure and the risk of myocardial infarction: A bidirectional Mendelian randomization study

Introduction

Many observational studies imply elevated blood pressure (BP) as a leading risk factor for incident myocardial infarction (MI), but whether this relationship is causal remains unknown. In this study, we used bidirectional Mendelian randomization (MR) to investigate the potential causal association of BP levels with the risk of MI.

Methods

Genetic variants associated with BP and MI traits were retrieved from the International Consortium of Blood Pressure (N = 7,57,601) and UKB (N = 3,61,194), obtaining 1,26,40,541 variants. We used two-sample MR (TSMR) analyses to examine the potential bidirectional causal association of systolic BP (SBP), diastolic BP (DBP) and pulse pressure (PP) with MI.

Results

The forward MR analysis identified a potentially causal association between MI and BP except PP[odds ratio (OR) SBP: 1.0008, P = 1.911 × 10−22; ORDBP: 1.0014, P = 1.788 × 10−28;odds ratio (OR)pp: 1.0092, P = 0.179]. However, the reverse analysis suggested no causal relation (betaSBP: 5.469, P = 0.763; betaDBP: 3.624, P = 0.588; betaPP: −0.074, P = 0.912). These findings were robust in sensitivity analyses such as the MR–Egger method, the maximum likelihood method and the MR pleiotropy residual sum and outlier test (MR-PRESSO). No horizontal pleiotropy (p = 0.869 for SBP, p = 0.109 for DBP and p = 0.978 for PP in the forward results and p = 0.168 for SBP, P = 0.892 for DBP and p = 0.989 for PP in the reverse results) was observed.

Conclusions

Elevated SBP or DBP levels increase the risk of MI, but there is no causal relationship between MI and changes in BP including PP. Independent of other risk factors, optimal BP control might represent an important therapeutic target for MI prevention in the general population.

Feasibility of Precision Medicine in Hypertension Management-Scope and Technological Aspects

Personalized management of diseases by considering relevant patient features enables optimal treatment, instead of management according to an average patient. Precision management of hypertension is important, because both susceptibility to complications and response to treatment vary between individuals. While the use of genomic and proteomic personal features for widespread precision hypertension management is not practical, other features, such as age, ethnicity, and cardiovascular diseases, have been utilized in guidelines for hypertension management. In precision medicine, more blood-pressure-related clinical and physiological characteristics in the patient's profile can be utilized for the determination of the threshold of hypertension and optimal treatment. Several non-invasive and simple-to-use techniques for the measurement of hypertension-related physiological features are suggested for use in precision management of hypertension. In order to provide precise management of hypertension, accurate measurement of blood pressure is required, but the available non-invasive blood pressure measurement techniques, auscultatory sphygmomanometry and oscillometry, have inherent significant inaccuracy-either functional or technological-limiting the precision of personalized management of hypertension. A novel photoplethysmography-based technique for the measurement of systolic blood pressure that was recently found to be more accurate than the two available techniques can be utilized for more precise and personalized hypertension management.

Triglyceride-glucose index and the risk of heart failure: Evidence from two large cohorts and a mendelian randomization analysis

BACKGROUND

The relationship between triglyceride-glucose (TyG) index, an emerging marker of insulin resistance, and the risk of incident heart failure (HF) was unclear. This study thus aimed to investigate this relationship.

METHODS

Subjects without prevalent cardiovascular diseases from the prospective Kailuan cohort (recruited during 2006-2007) and a retrospective cohort of family medicine patients from Hong Kong (recruited during 2000-2003) were followed up until December 31st, 2019 for the outcome of incident HF. Separate adjusted hazard ratios (aHRs) summarizing the relationship between TyG index and HF risk in the two cohorts were combined using a random-effect meta-analysis. Additionally, a two-sample Mendelian randomization (MR) of published genome-wide association study data was performed to assess the causality of observed associations.

RESULTS

In total, 95,996 and 19,345 subjects from the Kailuan and Hong Kong cohorts were analyzed, respectively, with 2,726 cases of incident HF in the former and 1,709 in the latter. Subjects in the highest quartile of TyG index had the highest risk of incident HF in both cohorts (Kailuan: aHR 1.23 (95% confidence interval: 1.09-1.39), PTrend <0.001; Hong Kong: aHR 1.21 (1.04-1.40), PTrend =0.007; both compared with the lowest quartile). Meta-analysis showed similar results (highest versus lowest quartile: HR 1.22 (1.11-1.34), P < 0.001). Findings from MR analysis, which included 47,309 cases and 930,014 controls, supported a causal relationship between higher TyG index and increased risk of HF (odds ratio 1.27 (1.15-1.40), P < 0.001).

CONCLUSION

A higher TyG index is an independent and causal risk factor for incident HF in the general population.

CLINICAL TRIAL REGISTRATION

URL: https://www.chictr.org.cn ; Unique identifier: ChiCTR-TNRC-11,001,489.

Blood Pressure Mediated the Effects of Urinary Uromodulin Levels on Myocardial Infarction: a Mendelian Randomization Study

Background:

The causal links between urinary uromodulin (uUMOD) and cardiovascular disease (CVD) are still not clarified.

Methods:

We first assessed the relationship between uUMOD and CVD using bidirectional 2-sample Mendelian randomization. Then, multivariable Mendelian randomization and product of the coefficients methods were used to investigate the role of blood pressure in mediating the effect of uUMOD on CVD.

Results:

1-unit higher uUMOD level was associated with a higher risk of myocardial infarction (MI), with an odds ratio of 1.08 ([95% CI, 1.02–1.14]; P =0.009), while MI was not associated with uUMOD levels in reverse. Our study did not support the causal effects of uUMOD on other CVD outcomes, including coronary artery disease, atrial fibrillation, heart failure, and ischemic stroke. In multivariable Mendelian Randomization, the direct effects of uUMOD on MI were attenuated to null after introducing systolic blood pressure or diastolic blood pressure. Mediation analysis showed that the indirect effect of uUMOD on MI mediated by systolic blood pressure or diastolic blood pressure was 1.05 ([95% CI, 1.04–1.06]; mediation proportion=69%) and 1.07 ([95% CI, 1.05–1.08]; mediation proportion=87%), respectively. Similar results were found in sensitivity analysis based on different sets of genetic instruments.

Conclusions:

Our findings provide evidence for the effect of higher uUMOD on increasing blood pressure, which mediates a consequent effect on MI risk in the general population. Further studies are necessary to verify the associations between uUMOD and other CVD outcomes.

Extra-cardiac BCAA catabolism lowers blood pressure and protects from heart failure

Pharmacologic activation of branched-chain amino acid (BCAA) catabolism is protective in models of heart failure (HF). How protection occurs remains unclear, although a causative block in cardiac BCAA oxidation is widely assumed. Here, we use in vivo isotope infusions to show that cardiac BCAA oxidation in fact increases, rather than decreases, in HF. Moreover, cardiac-specific activation of BCAA oxidation does not protect from HF even though systemic activation does. Lowering plasma and cardiac BCAAs also fails to confer significant protection, suggesting alternative mechanisms of protection. Surprisingly, activation of BCAA catabolism lowers blood pressure (BP), a known cardioprotective mechanism. BP lowering occurred independently of nitric oxide and reflected vascular resistance to adrenergic constriction. Mendelian randomization studies revealed that elevated plasma BCAAs portend higher BP in humans. Together, these data indicate that BCAA oxidation lowers vascular resistance, perhaps in part explaining cardioprotection in HF that is not mediated directly in cardiomyocytes.

The integrin ligand SVEP1 regulates GPCR-mediated vasoconstriction via integrins α9β1 and α4β1

BACKGROUND AND PURPOSE

Vascular tone is regulated by the relative contractile state of vascular smooth muscle cells (VSMCs). Several integrins directly modulate VSMC contraction by regulating calcium influx through L-type voltage-gated Ca²⁺ channels (VGCCs). Genetic variants in ITGA9, which encodes the α9 subunit of integrin α9β1, and SVEP1, a ligand for integrin α9β1, associate with elevated blood pressure; however, neither SVEP1 nor integrin α9β1 has reported roles in vasoregulation. We determined whether SVEP1 and integrin α9β1 can regulate VSMC contraction.

EXPERIMENTAL APPROACH

SVEP1 and integrin binding were confirmed by immunoprecipitation and cell binding assays. Human induced pluripotent stem cell-derived VSMCs were used in in vitro [Ca²⁺ ]_i studies, and aortas from a Svep1^+/- knockout mouse model were used in wire myography to measure vessel contraction.

KEY RESULTS

We confirmed the ligation of SVEP1 to integrin α9β1 and additionally found SVEP1 to directly bind to integrin α4β1. Inhibition of SVEP1, integrin α4β1 or α9β1 significantly enhanced [Ca²⁺ ]_i levels in isolated VSMCs to Gα_q/11 -vasoconstrictors. This response was confirmed in whole vessels where a greater contraction to U46619 was seen in vessels from Svep1^+/- mice compared to littermate controls or when integrin α4β1 or α9β1 was inhibited. Inhibition studies suggested that this effect was mediated via VGCCs, PKC and Rho A/Rho kinase dependent mechanisms.

CONCLUSIONS AND IMPLICATIONS

Our studies reveal a novel role for SVEP1 and the integrins α4β1 and α9β1 in reducing VSMC contractility. This could provide an explanation for the genetic associations with blood pressure risk at the SVEP1 and ITGA9 loci.

Night Shift Work, Genetic Risk, and Hypertension

OBJECTIVE

To perform a prospective cohort study to investigate whether night shift work is associated with incident hypertension and whether this association is modified by genetic susceptibility to hypertension because evidence on the association between night shift work and hypertension is insufficient.

METHODS

A total of 232,665 participants of UK Biobank who were recruited from 2006 to 2010 and observed to January 31, 2018, were included in this study. A Cox proportional hazards model with covariate adjustment was performed to assess the association between night shift work exposure and hypertension risk. We constructed a polygenic risk score (PRS) for genetic susceptibility to hypertension, which was used to explore whether genetic susceptibility to hypertension modified the effect of night shift work. The robustness of the results was assessed by sensitivity analysis.

RESULTS

Night shift workers had a higher hypertension risk than day shift workers, which increased with increasing frequency of night shift work (P_trend<.001). The association was attenuated but still remained statistically significant in the fully adjusted model. We explored the joint effect of night shift work and genetic susceptibility on hypertension. Permanent night shift workers with higher hypertension PRSs had higher risk of hypertension than day workers with low PRSs.

CONCLUSION

Night shift work exposure was associated with increased hypertension risk, which was modified by the genetic risk for hypertension, indicating that there is a joint effect of night shift work and genetic risk on hypertension.

Stroke genetics informs drug discovery and risk prediction across ancestries

Previous genome-wide association studies (GWASs) of stroke - the second leading cause of death worldwide - were conducted predominantly in populations of European ancestry1,2. Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis3, and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach4, we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry5. Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries.

Association of autoimmune diseases with Alzheimer's disease: A mendelian randomization study

BACKGROUND

Alzheimer's disease may have an autoimmune component, but the association is unclear.

OBJECTIVE

The objective of this Mendelian randomization (MR) study was to evaluate the association of liability to autoimmune diseases with Alzheimer's disease.

METHODS

A systematic search was done using PubMed to identify autoimmune diseases that have been suggested as associated with Alzheimer's disease. Genetic predictors of these autoimmune diseases were obtained from the largest and most recent genome-wide association studies (GWAS). Genetic associations with clinically-diagnosed Alzheimer's disease were obtained from the International Genomics of Alzheimer's Project GWAS (21982 cases; 41944 controls); and with parental and sibling history of Alzheimer's disease from the UK Biobank GWAS (27696 maternal, 14338 paternal and 2171 sibling cases). MR estimates were obtained using inverse variance weighting, MR-Egger and weighted median. To address possible selection bias due to inevitably recruiting only survivors, the analysis was repeated in younger people, i.e., UK Biobank siblings and adjusting for competing risk of Alzheimer's disease.

RESULTS

Of the 7 autoimmune diseases considered, liability to psoriasis and sarcoidosis were not associated with Alzheimer's disease. Some evidence was found for liability to multiple sclerosis being associated with higher risk and liability to Sjogren's syndrome with lower risk of Alzheimer's disease. Associations found for liability to giant cell arteritis, type 1 diabetes and rheumatoid arthritis were inconsistent in sensitivity analyses.

CONCLUSION

Liability to multiple sclerosis and Sjogren's syndrome could be associated with Alzheimer's disease. The underlying mechanisms, such as the role of myelin and neuroinflammation, should be further investigated.

Role of Uromodulin in Salt-Sensitive Hypertension

The exclusive expression of uromodulin in the kidneys has made it an intriguing protein in kidney and cardiovascular research. Genome-wide association studies discovered variants of uromodulin that are associated with chronic kidney diseases and hypertension. Urinary and circulating uromodulin levels reflect kidney and cardiovascular health as well as overall mortality. More recently, Mendelian randomization studies have shown that genetically driven levels of uromodulin have a causal and adverse effect on kidney function. On a mechanistic level, salt sensitivity is an important factor in the pathophysiology of hypertension, and uromodulin is involved in salt reabsorption via the NKCC2 (Na+-K+-2Cl- cotransporter) on epithelial cells of the ascending limb of loop of Henle. In this review, we provide an overview of the multifaceted physiology and pathophysiology of uromodulin including recent advances in its genetics; cellular trafficking; and mechanistic and clinical studies undertaken to understand the complex relationship between uromodulin, blood pressure, and kidney function. We focus on tubular sodium reabsorption as one of the best understood and pathophysiologically and clinically most important roles of uromodulin, which can lead to therapeutic interventions.

Polymorphisms of hypertension susceptibility genes as a risk factors of preeclampsia in the Caucasian population of central Russia

INTRODUCTION

The study was designed to assess the effects of hypertension (HT) susceptibility genes polymorphisms in the development of preeclampsia (PE) in Caucasians from Central Russia.

METHODS

PE patients (n = 452) and women control group (n = 498) were genotyped for 10 polymorphisms of HT/blood pressure (BP) susceptibility genes (according to the previously published GWAS in Caucasian populations) including AC026703.1 (rs1173771), HFE (rs1799945), BAG6 (rs805303), PLCE1 (rs932764), OBFC1 (rs4387287), ARHGAP42 (rs633185), CERS5 (rs7302981), ATP2B1 (rs2681472), TBX2 (rs8068318) and RGL3 (rs167479). A logistic regression method was applied to search for associations between SNPs and PE. The relationship between SNP-SNP interactions and PE risk was analyzed by performing MB-MDR.

RESULTS

The rs1799945 gene in HFE significantly independently increased the risk of developing PE (OR = 2.24) and rs805303 in BAG6 was associated with a reduced risk in the occurrence of PE (OR = 0.55-0.78). Among the 10 SNPs examined, nine SNPs were associated with PEs within the 10 most significant SNP-SNP interaction models. Loci rs7302981 CERS5, rs805303 BAG6 and rs932764 PLCE1 contributed to the largest number of epistatic models (50% or more).

DISCUSSION

The present study is the first to report an association between polymorphisms of HT/BP susceptibility genes important for GWAS and the risk of PE in Caucasians from Central Russia. Our pathway-based functional annotation of the PE risk variants highlights the potential regulatory function (epigenetic/eQTL/sQTL/non-synonymous) that nine genetic risk markers and their 115 highly correlated variants exert on 155 genes. The study shows that these genes may function cooperatively in key signaling pathways in PE biology.

Rare and common genetic determinants of metabolic individuality and their effects on human health

Garrod's concept of 'chemical individuality' has contributed to comprehension of the molecular origins of human diseases. Untargeted high-throughput metabolomic technologies provide an in-depth snapshot of human metabolism at scale. We studied the genetic architecture of the human plasma metabolome using 913 metabolites assayed in 19,994 individuals and identified 2,599 variant-metabolite associations (P < 1.25 × 10-11) within 330 genomic regions, with rare variants (minor allele frequency ≤ 1%) explaining 9.4% of associations. Jointly modeling metabolites in each region, we identified 423 regional, co-regulated, variant-metabolite clusters called genetically influenced metabotypes. We assigned causal genes for 62.4% of these genetically influenced metabotypes, providing new insights into fundamental metabolite physiology and clinical relevance, including metabolite-guided discovery of potential adverse drug effects (DPYD and SRD5A2). We show strong enrichment of inborn errors of metabolism-causing genes, with examples of metabolite associations and clinical phenotypes of non-pathogenic variant carriers matching characteristics of the inborn errors of metabolism. Systematic, phenotypic follow-up of metabolite-specific genetic scores revealed multiple potential etiological relationships.

Potential Mediators of Causal Associations of Circulating Triglycerides With Blood Pressure: Evidence From Genetic and Observational Data

Background:

Existing evidence indicates that elevated triglycerides may affect blood pressure, but the underlying mechanisms are not fully understood. Herein, we aim to identify the intermediaries of associations of triglyceride with systolic blood pressure and diastolic blood pressure using the Mendelian randomization (MR) framework.

Methods:

Triglyceride-associated single nucleotide polymorphisms were extracted and used to match phenotypes in PhenoScanner. From the broad spectrum of possible triglyceride-associated traits, potential mediators linking triglyceride to blood pressure were screened out by MR and MR-based mediation analysis. Moreover, cross-sectional observational data of 206 341 adults were used to validate the mediators identified at the genetic level.

Results:

Among the nearly 100 raw phenotypes matched by 313 triglyceride-associated single nucleotide polymorphisms, 39 traits were filtered and integrated into subsequent analysis. By further filtering using MR analysis, only pulse rate and lymphocyte count (LC) were identified as independent mediators. MR-based mediation analysis showed that genetically predicted LC could mediate 9.2% of the association of triglyceride with systolic blood pressure; genetically predicted pulse rate and LC could mediate 18.3% and 17.6% of the association of triglyceride with DBP, respectively. Observational data also support the mediating role of pulse rate and LC.

Conclusions:

The current findings highlighted the mediating role of pulse rate and LC on the causal pathway from triglyceride to blood pressure and may contribute to a better understanding of the pathogenic mechanism by which high triglyceride affects other cardiometabolic factors.

Genetic liability to sedentary behavior in relation to myocardial infarction and heart failure: A mendelian randomization study

BACKGROUND AND AIMS

Observational studies have indicated that sedentary behavior is associated with myocardial infarction (MI), heart failure (HF), and atrial fibrillation (AF). Nevertheless, whether these associations are causal remain controversial, due to confounding factors (e.g., physical activity) and reverse causality.

METHODS AND RESULTS

Instrumental variables were obtained from the largest genome-wide association studies of sedentary behavior (408,815 individuals) to date. We obtained summary statistics of MI from the CARDIoGRAMplusC4D consortium (171,875 individuals), HF from the HERMES Consortium (977,323 individuals), and AF from the Atrial Fibrillation Consortium (588,190 individuals). The inverse-variance weighted method was applied to obtain Mendelian randomization (MR) estimates, and other statistical methods were conducted in the sensitivity analyses. The main analyses were repeated using data from the FinnGen study. Multivariable MR analysis and mediation analysis were performed to evaluate the role of physical activity and other confounders. Genetically determined television watching was associated with MI (odds ratio [OR], 1.38; 95% CI, 1.19-1.59; p = 1.9 × 10^-5) and HF (OR, 1.23; 95%CI, 1.09-1.38; p = 7.0 × 10^-4) but not AF. The main results kept robust in most sensitivity analyses. The effect of sedentary behavior on MI and HF was partly mediated by body mass index (BMI). No consistent evidence was found for the causal effect of computer use and driving on MI, HF, or AF.

CONCLUSIONS

Genetic liability to prolonged television watching is associated with higher risks of MI and HF. Interventions for reducing television watching time, such as public education and awareness campaigns, should be further investigated.

Assessing the causal relationships between gout and hypertension: a bidirectional Mendelian randomisation study with coarsened exposures

OBJECTIVES

Observational studies have demonstrated associations between gout and hypertension, but whether they are causal remains unclear. Our work aims to assess the causal relationship between gout and hypertension.

METHODS

We obtained genetic information from the Taiwan Biobank, including 88,347 participants and 686,439 single-nucleotide polymorphisms (SNPs). A novel model of Mendelian randomisation (MR) with coarsened exposures was used to examine the causality between the liability of gout on hypertension and vice versa, using 4 SNPs associated with gout and 10 SNPs associated with hypertension after removal of SNPs associated with measured confounders. The binary exposure (gout/hypertension) can be considered a coarsened approximation of a latent continuous trait. The inverse-variance weighted (IVW) and polygenic risk score (PRS) methods were used to estimate effect size. The MR analysis with coarsened exposures was performed with and without adjustments for covariates.

RESULTS

Of the 88,347 participants, 3253 (3.68%) had gout and 11,948 (13.52%) had hypertension (men, 31.9%; mean age 51.1 [SD, 11.1] years). After adjusting to measured confounders, MR analysis with coarsened exposures showed a significant positive causal effect of the liability of gout on hypertension in both the IVW method (relative risk [RR], 1.10; 95% confidence interval [CI], 1.03-1.19; p = 0.0077) and the PRS method (RR, 1.10; 95% CI, 1.02-1.19; p = 0.0092). The result of causality was the same before and after involving measured confounders. However, there was no causal effect of the liability of hypertension on gout.

CONCLUSIONS

In this study, we showed that the liability of gout has a causal effect on hypertension, but the liability of hypertension does not have a causal effect on gout. Adequate management of gout may reduce the risk of developing hypertension.

The causal associations of circulating amino acids with blood pressure: a Mendelian randomization study

BACKGROUND

Circulating levels of amino acids were associated with blood pressure (BP) in observational studies. However, the causation of such associations has been hypothesized but is difficult to prove in human studies. Here, we aimed to use two-sample Mendelian randomization analyses to evaluate the potential causal associations of circulating levels of amino acids with BP and risk of hypertension.

METHODS

We generated genetic instruments for circulating levels of nine amino acids by conducting meta-analyses of genome-wide association study (GWAS) in UK Biobank participants with metabolomic data (n = 98,317) and another published metabolomics GWAS (n = 24,925). Data on the associations of the genetic variants with BP and hypertension were obtained in the UK Biobank participants without metabolomic data (n = 286,390). The causal effects were estimated using inverse-variance weighted method.

RESULTS

Significant evidence consistently supported the causal effects of increased branched-chain amino acids (BCAAs, i.e., leucine, isoleucine, and valine) levels on higher BP and risk of hypertension (all P < 0.006 after Bonferroni correction except for Pleucine-on-diastolicBP = 0.008). For example, per standard deviation higher of genetically predicted isoleucine levels were associated with 2.71 ± 0.78 mmHg higher systolic BP and 1.24 ± 0.34 mmHg higher diastolic BP, as well as with 7% higher risk of hypertension (odds ratio: 1.07, [95% CI: 1.04-1.10]). In addition, per standard deviation higher of genetically predicted glycine level was associated with lower systolic BP (- 0.70 ± 0.17 mmHg, P = 4.04 × 10-5) and a lower risk of hypertension (0.99 [0.98-0.99], P = 6.46 × 10-5). In the reverse direction, genetically predicted higher systolic BP was associated with lower circulating levels of glycine (- 0.025±0.008, P = 0.001).

CONCLUSIONS

This study provides evidence for causal impacts of genetically predicted circulating BCAAs and glycine levels on BP. Meanwhile, genetically predicted higher BP was associated with lower glycine levels. Further investigations are warranted to clarify the underlying mechanisms.

The Interplay of Epigenetic, Genetic, and Traditional Risk Factors on Blood Pressure: Findings from the Health and Retirement Study

The epigenome likely interacts with traditional and genetic risk factors to influence blood pressure. We evaluated whether 13 previously reported DNA methylation sites (CpGs) are associated with systolic (SBP) or diastolic (DBP) blood pressure, both individually and aggregated into methylation risk scores (MRS), in 3070 participants (including 437 African ancestry (AA) and 2021 European ancestry (EA), mean age = 70.5 years) from the Health and Retirement Study. Nine CpGs were at least nominally associated with SBP and/or DBP after adjusting for traditional hypertension risk factors (p < 0.05). MRSSBP was positively associated with SBP in the full sample (β = 1.7 mmHg per 1 standard deviation in MRSSBP; p = 2.7 × 10-5) and in EA (β = 1.6; p = 0.001), and MRSDBP with DBP in the full sample (β = 1.1; p = 1.8 × 10-6), EA (β = 1.1; p = 7.2 × 10-5), and AA (β = 1.4; p = 0.03). The MRS and BP-genetic risk scores were independently associated with blood pressure in EA. The effects of both MRSs were weaker with increased age (pinteraction < 0.01), and the effect of MRSDBP was higher among individuals with at least some college education (pinteraction = 0.02). In AA, increasing MRSSBP was associated with higher SBP in females only (pinteraction = 0.01). Our work shows that MRS is a potential biomarker of blood pressure that may be modified by traditional hypertension risk factors.

Advances in pathogenesis and treatment of essential hypertension

Hypertension is a significant risk factor for cardiovascular and cerebrovascular diseases and the leading cause of premature death worldwide. However, the pathogenesis of the hypertension, especially essential hypertension, is complex and requires in-depth studies. Recently, new findings about essential hypertension have emerged, and these may provide important theoretical bases and therapeutic tools to break through the existing bottleneck of essential hypertension. In this review, we demonstrated important advances in the different pathogenesis areas of essential hypertension, and highlighted new treatments proposed in these areas, hoping to provide insight for the prevention and treatment of the essential hypertension.

A Mendelian randomization-based exploration of red blood cell distribution width and mean corpuscular volume with risk of hemorrhagic strokes

Red blood cell distribution width (RCDW) and mean corpuscular volume (MCV) are associated with different risk factors for hemorrhagic stroke. However, whether RCDW and MCV are causally related to hemorrhagic stroke remains poorly understood. Therefore, we explored the causality between RCDW/MCV and nontraumatic hemorrhagic strokes using Mendelian randomization (MR) methods. We extracted exposure and outcome summary statistics from the UK Biobank and FinnGen. We evaluated the causality of RCDW/MCV on four outcomes (subarachnoid hemorrhage [SAH], intracerebral hemorrhage [ICH], nontraumatic intracranial hemorrhage [nITH], and a combination of SAH, cerebral aneurysm, and aneurysm operations) using univariable MR (UMR) and multivariable MR (MVMR). We further performed colocalization and mediation analyses. UMR and MVMR revealed that higher genetically predicted MCV is protective of ICH (UMR: odds ratio [OR] = 0.89 [0.8-0.99], p = 0.036; MVMR: OR = 0.87 [0.78-0.98], p = 0.021) and nITH (UMR: OR = 0.89 [0.82-0.97], p = 0.005; MVMR: OR = 0.88 [0.8-0.96], p = 0.004). There were no strong causal associations between RCDW/MCV and any other outcome. Colocalization analysis revealed a shared causal variant between MCV and ICH; it was not reported to be associated with ICH. Proportion mediated via diastolic blood pressure was 3.1% (0.1%,14.3%) in ICH and 3.4% (0.2%,15.8%) in nITH. The study constitutes the first MR analysis on whether genetically elevated RCDW and MCV affect the risk of hemorrhagic strokes. UMR, MVMR, and mediation analysis revealed that MCV is a protective factor for ICH and nITH, which may inform new insights into the treatments for hemorrhagic strokes.