Coronary Artery Disease Genome-wide Replication Research Articles

Asthma and incident coronary heart disease: an observational and Mendelian randomisation study.

Observational studies suggest asthma is a risk factor for coronary heart disease (CHD) and sex modifies the risk, but they may suffer from methodological limitations. To overcome these, we applied a "triangulation approach", where different methodologies, with different potential biases, were leveraged to enhance confidence in findings. First, we conducted an observational study using UK medical records to match asthma patients 1:1, by age, sex and general practitioner (GP) practice, to the general population. We measured the association between asthma and incident CHD (myocardial infarction: hospitalisation/death) by applying minimal sufficient adjustment: model 1, smoking, body mass index, oral corticosteroids, atopy and deprivation; model 2, additionally adjusting for healthcare behaviour (GP consultation frequency). Second, we conducted a Mendelian randomisation (MR) study using data from the UK Biobank, Trans-National Asthma Genetic Consortium (TAGC) and Coronary Artery Disease Genome-wide Replication and Meta-analysis consortium (CARDIoGRAM). Using 64 asthma single nucleotide polymorphisms, the effect of asthma on CHD was estimated with inverse variance-weighted meta-analysis and methods that adjust for pleiotropy. In our observational study (n=1 522 910), we found asthma was associated with 6% increased risk of CHD (model 1: HR 1.06, 95% CI 1.01-1.13); after accounting for healthcare behaviour, we found no association (model 2: HR 0.99, 95% CI 0.94-1.05). Asthma severity did not modify the association, but sex did (females: HR 1.11, 95% CI 1.01-1.21; males: HR 0.91, 95% CI 0.84-0.98). Our MR study (n=589 875) found no association between asthma and CHD (OR 1.01, 95% CI 0.98-1.04) and no modification by sex. Our findings suggest that asthma is not a risk factor for CHD. Previous studies may have suffered from detection bias or residual confounding.

Independent Causal Effect of Remnant Cholesterol on Atherosclerotic Cardiovascular Outcomes: A Mendelian Randomization Study.

Observational studies suggested that residual risk of cardiovascular events after LDL (low-density lipoprotein) cholesterol lowering may be linked to remnant cholesterol (RC). We conducted a large-scale Mendelian randomization study to investigate the causal role of RC to predict coronary artery disease (CAD), myocardial infarction (MI), and stroke risk. We extracted single-nucleotide polymorphisms for RC and LDL from large-scale genome-wide association databases. We estimated the genetic association with outcomes from the CARDIoGRAMplusC4D consortium (Coronary Artery Disease Genome-Wide Replication and Meta-Analysis Plus the Coronary Artery Disease Genetics), the Metastroke consortium, as well as the GLGC (Global Lipids Genetics Consortium). Genetic variants were used as instruments, thereby minimizing residual confounding and reverse causation biases of observational studies. By leveraging data from a combined sample of 958 434 participants, we found evidence for a significant causal effect of RC on the risk of CAD (odds ratio [OR], 1.51 per SD unit increase in RC [95% CI, 1.42-1.60]; P=5.3×10-5), MI (OR, 1.57 [95% CI, 1.21-2.05]; P=9.5×10-4), and stroke (OR, 1.23 [95% CI, 1.12-1.35]; P=3.72×10-6). There was no evidence of pleiotropy. The effect of RC on CAD and MI remained consistent after accounting for the effects of RC-associated genetic variants on LDL cholesterol: OR, 1.49 (95% CI, 1.37-1.61) for CAD and OR, 1.80 (95% CI, 1.70-19.1) for MI without a meaningful indirect effect exerted on these outcomes via the LDL cholesterol mediator. This large-scale Mendelian randomization study showed a robust genetic causal association between RC and cardiovascular outcomes. The effect on CAD and MI is independent of LDL cholesterol. Early screening for RC along with long-term inhibition of RC should be the focus of future therapeutic interventions.

Genetically Determined Lifestyle and Cardiometabolic Risk Factors Mediate the Association of Genetically Predicted Age at Menarche With Genetic Predisposition to Myocardial Infarction: A Two-Step, Two-Sample Mendelian Randomization Study.

BackgroundObservational studies have shown an association between early age at menarche (AAM) and myocardial infarction (MI) with recorded cases. In this Mendelian randomization (MR) study, we used large amounts of summary data from genome-wide association studies (GWASs) to further estimate the association of genetically predicted AAM with genetically predicated risk of MI and investigate to what extent this association is mediated by genetically determined lifestyles, cardiometabolic factors, and estrogen exposure.MethodsA two-step, two-sample MR study was performed by mediation analysis. Genetic variants identified by GWAS meta-analysis of reproductive genetics consortium (n = 182,416) were selected for genetically predicted AAM. Genetic variants identified by the Coronary ARtery DIsease Genome-wide Replication and Meta-analysis plus The Coronary Artery Disease Genetics Consortium (n = 184,305) were selected for genetically predicted risk of MI. Genetic variants from other international GWAS summary data were selected for genetically determined mediators.ResultsThis MR study showed that increase in genetically predicted AAM was associated with lower risk of genetically predicted MI (odds ratio 0.91, 95% confidence interval 0.84–0.98). Inverse variance weighted (IVW) MR analysis also showed that decrease in genetically predicted AAM was associated with higher genetically predicted alcohol intake frequency, current smoking behavior, higher waist-to-hip ratio, and higher levels of systolic blood pressure (SBP), fasting blood glucose, hemoglobin A1c (HbA1c), and triglycerides (TGs). Furthermore, increase in genetically predicted AAM was associated with genetically predicted longer sleep duration, higher levels of high-density lipoproteins, and older age at which hormone replacement therapy was started. The most essential mediators identified were genetically predicted current smoking behavior and levels of HbA1c, SBP, and TGs, which were estimated to genetically mediate 13.9, 12.2, 10.5, and 9.2%, respectively, with a combined mediation proportion of 37.5% in the association of genetically predicted AAM with genetically predicted increased risk of MI in an MR framework.ConclusionOur MR analysis showed that increase in genetically predicted AAM was associated with lower genetically predicted risk of MI, which was substantially mediated by genetically determined current smoking behavior and levels of HbA1c, SBP, and TGs. Intervening on the above mediators may reduce the risk of MI.

Low Intelligence Predicts Higher Risks of Coronary Artery Disease and Myocardial Infarction: Evidence From Mendelian Randomization Study.

Background: Low intelligence has been shown to be associated with a high risk of cardiovascular disease in observational studies. It remains unclear whether the association is causal. This study aimed to explore the causal association of intelligence with coronary artery disease (CAD) and myocardial infarction (MI). Methods: A two-sample Mendelian randomization study was designed to infer the causality. A total of 121 single nucleotide polymorphisms were selected as a genetic instrumental variable for intelligence. Summary data on CAD (n = 184,305) and MI (n = 171,875) were obtained from the Coronary ARtery DIsease Genome-wide Replication and Meta-analysis (CARDIoGRAM) plus The Coronary Artery Disease (C4D) Genetics (CARDIoGRAMplusC4D) consortium and the FinnGen study. Inverse variance weighting method was used to calculate the effect estimates. Sensitivity analyses including other statistical models and leave-one-out analysis were conducted to verify the robustness of results. MR-Egger test was performed to assess the pleiotropy. Results: Genetically predicted higher intelligence was significantly associated with lower risk of CAD (OR, .76; 95%CI, .69–.85; p = 1.5 × 10–7) and MI (OR, .78; 95%CI, .70–.87; p = 7.9 × 10–6). The results remained consistent in the majority of the sensitivity analyses and were repeated in the FinnGen datasets. MR-Egger test suggested no evidence of directional pleiotropy for the association with coronary artery disease (intercept = −.01, p = .19) and myocardial infarction (intercept = −.01, p = .06). Conclusion: This Mendelian randomization analysis provided genetic evidence for the causal association between low intelligence and increased risks of CAD and MI.

Causal effect of Lipoprotein-associated phospholipase A2 activity on coronary artery disease and myocardial Infarction: A Two-Sample Mendelian Randomization study

BackgroundLipoprotein-associated phospholipase A2 (Lp-PLA2) activity has been reported to be associated with coronary artery disease (CAD) and myocardial infarction (MI). However, whether Lp-PLA2 is a causal risk factor for CAD and MI remains unclear. Herein, we performed a two-sample mendelian randomization (MR) study to assess the causal effect of Lp-PLA2 activity on CAD and MI. MethodsWe selected 7 single-nucleotide polymorphisms (SNPs) associated with Lp-PLA2 activity as instrumental variables based on the data from Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium with 13,664 European individuals. Summary data about CAD and MI were obtained from Coronary Artery Disease Genome-wide Replication and Meta-analysis plus the Coronary Artery Disease Genetics (CARDIOGRAMPLUSC4D) consortium with 60,801 CAD cases and 43,676 MI cases (mostly European). The inverse-variance weighted method was applied to assess the causal associations of Lp-PLA2 activity with CAD and MI in the main analysis. ResultsThe main inverse-variance weighted (IVW) MR analysis showed that 1-SD increment in genetically determined LP-PLA2 activity was associated with increased risks of CAD (odds ratio, 5.93; 95% CI, 2.91–12.07; p value = 9.43 × 10-7) and MI (odds ratio, 4.71; 95% CI, 2.49–8.90; p value = 1.86 × 10-6). MR-Egger regression showed no evidence of pleiotropic bias. The causal associations were consistent in sensitivity analyses with multiple MR methods, in which showed Lp-PLA2 activity was causally associated with an increased risk of CAD and MI. ConclusionsIn this two-sample MR study, high Lp-PLA2 activity was a causal risk factor for CAD and MI, indicating that Lp-PLA2 activity may be a promising intervention target in reducing the risk of CAD and MI.

Genetically determined risk of mood swings and cardiometabolic diseases: mendelian randomization study

Abstract Background Mood swings is believed to associated with increased risk of Cardiometabolic Diseases (CMD). However, the roles of mood swings on CMD are controversial because of the bias of reverse causation and/or confounding in epidemiological studies. Hence, we use a two-sample MR approach to identify the causal association between genetically determined mood swings and CMD. Methods We obtained 33 independent single-nucleotide polymorphisms (SNPs) with genome-wide significant (P<5×10–8) associated with mood swings as instrumental variable in UK Biobank. Summary data of outcomes were extracted from the Coronary Artery Disease Genome-wide Replication and Meta-analysis plus the Coronary Artery Disease Genetics consortium, the Diabetes Genetics Replication and Meta-analysis consortium, the CKDGen consortium, and the International Stroke Genetics Consortium. Results The genetic instrument of 33 SNPs explained 4.8% of the variance in mood swings. Genetically determined mood swings was associated with an increased risk of coronary artery disease (CAD) (odds ratio 3.12, 95% confidence interval 1.92 to 5.08; P=4.32×10–6). However, mood swings had no effect on the other cardiometabolic outcomes. The above estimates were consistent across all three MR methods without significant heterogeneity. Also, there was no evidence of directional pleiotropy for each outcome except for large artery stroke. Conclusions Using MR approaches that are able draw causal inference, our results suggest that interventions aimed at improving mood swings in the population would lead to a reduction risk of CAD, which highlights the importance of mood management in high-risk CAD population. Funding Acknowledgement Type of funding sources: None.

Negative Effects of Age at Menarche on Risk of Cardiometabolic Diseases in Adulthood: A Mendelian Randomization Study.

Observational studies have demonstrated that early menarche is associated with cardiometabolic diseases, but confounding factors make it difficult to infer causality. We used Mendelian randomization (MR) to examine whether age at menarche (AAM) is causally associated with type 2 diabetes (T2D), coronary artery disease (CAD) and cardiometabolic traits. A 2-sample MR analysis was conducted using genome-wide association study (GWAS) summary statistics from the Diabetes Genetics Replication and Meta-analysis (DIAGRAM) consortium (n = 159 208) for T2D and the Coronary Artery Disease Genome-wide Replication and Meta-analysis plus the Coronary Artery Disease Genetics (CARDIoGRAMplusC4D) consortium (n = 184 305) for CAD. We used 122 instrumental variables (IVs) extracted from a published GWAS meta-analysis incorporating 182 416 women to determine the causal effect of AAM on cardiometabolic diseases, treating childhood and adult body mass index (BMI) as the confounders. Sensitivity analyses were also performed to detect the pleiotropy of the IVs. Employing the MR approach, we found that later AAM was associated with decreased risk of CAD (OR, 0.92 [95% CI, 0.88-0.96]; P = 2.06 × 10-4) in adults, as well as lower blood levels of log fasting insulin, log homeostatic model assessment of insulin resistance (HOMA-IR), log HOMA of β-cell function (HOMA-B), triglycerides, and diastolic blood pressure, but higher blood level of high-density lipoprotein. However, the associations were substantially attenuated after excluding BMI-related variants. MR analyses provide little evidence on the causal effect between AAM and T2D. Our findings showed that AAM did not appear to have a causal effect on the risk of cardiometabolic diseases in adult life, as their associations observed in epidemiological studies might be largely mediated through excessive adiposity. We propose adiposity might be a primary target in future intervention strategy.

Association of Chromosome 9p21 With Subsequent Coronary Heart Disease Events.

Genetic variation at chromosome 9p21 is a recognized risk factor for coronary heart disease (CHD). However, its effect on disease progression and subsequent events is unclear, raising questions about its value for stratification of residual risk. A variant at chromosome 9p21 (rs1333049) was tested for association with subsequent events during follow-up in 103 357 Europeans with established CHD at baseline from the GENIUS-CHD (Genetics of Subsequent Coronary Heart Disease) Consortium (73.1% male, mean age 62.9 years). The primary outcome, subsequent CHD death or myocardial infarction (CHD death/myocardial infarction), occurred in 13 040 of the 93 115 participants with available outcome data. Effect estimates were compared with case/control risk obtained from the CARDIoGRAMplusC4D consortium (Coronary Artery Disease Genome-wide Replication and Meta-analysis [CARDIoGRAM] plus The Coronary Artery Disease [C4D] Genetics) including 47 222 CHD cases and 122 264 controls free of CHD. Meta-analyses revealed no significant association between chromosome 9p21 and the primary outcome of CHD death/myocardial infarction among those with established CHD at baseline (GENIUS-CHD odds ratio, 1.02; 95% CI, 0.99-1.05). This contrasted with a strong association in CARDIoGRAMPlusC4D odds ratio 1.20; 95% CI, 1.18-1.22; P for interaction <0.001 compared with the GENIUS-CHD estimate. Similarly, no clear associations were identified for additional subsequent outcomes, including all-cause death, although we found a modest positive association between chromosome 9p21 and subsequent revascularization (odds ratio, 1.07; 95% CI, 1.04-1.09). In contrast to studies comparing individuals with CHD to disease-free controls, we found no clear association between genetic variation at chromosome 9p21 and risk of subsequent acute CHD events when all individuals had CHD at baseline. However, the association with subsequent revascularization may support the postulated mechanism of chromosome 9p21 for promoting atheroma development.

Global genetic diversity of human apolipoproteins and effects on cardiovascular disease risk

Abnormal plasma apolipoprotein levels are consistently implicated in CVD risk. Although 30% to 60% of their interindividual variability is genetic, common genetic variants explain only 10% to 20% of these differences. Rare genetic variants may be major sources of the missing heritability, yet quantitative evaluations of their contribution to phenotypic variability are lacking. Here, we analyzed whole-genome and whole-exome sequencing data from 138,632 individuals across seven major human populations to present a systematic overview of genetic apolipoprotein variability. We provide population-specific frequencies of 38 clinically important apolipoprotein alleles and identify further 6,875 genetic variants, 33% of which are novel and 98.7% of which are rare with minor allele frequencies <1%. We predicted the functional impact of rare variants and found that their relative importance differed drastically between genes and among ethnicities. Importantly, we validated the clinical relevance of multiple variants with predicted effects by leveraging association data from the CARDIoGRAM (Coronary Artery Disease Genomewide Replication and Meta-analysis) and Global Lipids Genetics consortia. Overall, we provide a consolidated overview of population-specific apolipoprotein genetics as a valuable data resource for scientists and clinicians, estimate the importance of rare genetic variants for the missing heritability of apolipoprotein-associated disease traits, and pinpoint multiple novel apolipoprotein variants with putative population-specific impacts on serum lipid levels.

Genetic variation in clusterin and risk of dementia and ischemic vascular disease in the general population - cohort studies and meta-analyses of 362,338 individuals

Clusterin, also known as apolipoprotein J (apoJ), is one of the most abundantly expressed apolipoproteins in the brain after apolipoprotein E (apoE). Like the e4 allele of the apolipoprotein E gene (APOE), the clusterin gene (CLU) is a risk locus for Alzheimer’s disease, and may play additional roles in atherosclerosis pathogenesis. We tested whether genetic variation in CLU was associated with either Alzheimer’s disease or atherosclerosis-related diseases. We studied individual data on 103,987 participants from the Copenhagen General Population Study (CGPS) and the Copenhagen City Heart Study (CCHS). We genotyped a common CLU variant (rs9331896) and two common APOE variants (rs7412 and rs429358), defining the e2, e3, and e4, alleles in CGPS and CCHS. All individuals in the CGPS and CCHS cohorts were followed from study inclusion to occurrence of event, death, emigration, or until 10 November 2014, whichever came first. Summary consortia data on 258,351 individuals from the International Genomics of Alzheimer’s Project (IGAP) and the Coronary Artery Disease Genome-wide Replication and Meta-analysis plus the Coronary Artery Disease (C4D) Genetics and 1000-Genomes-based genome-wide association studies (CARDIoGRAMplusC4D) were used in meta-analyses. In CGPS and CCHS, multifactorially adjusted hazard ratios for Alzheimer’s disease, all dementia, vascular dementia, ischemic cerebrovascular disease, and ischemic heart disease were 1.18 (1.07–1.30), 1.09 (1.02–1.17), 0.96 (0.80–1.17), 1.02 (0.97–1.07), and 0.97 (0.93–1.01) per T allele, respectively. Multifactorially adjusted hazard ratios for Alzheimer’s disease and all dementia were 2.72 (2.45–3.01) and 2.21 (2.05–2.38) for the APOE ɛ4 allele. There was no interaction between rs9331896 in CLU and rs429358 (defining the ɛ4 allele) in APOE in predicting Alzheimer’s disease or all dementia (P = 0.39 and P = 0.21). In a meta-analysis including consortium data, the overall fixed- and random-effects odds ratios for Alzheimer’s disease per T allele were 1.16 (1.13–1.18) (I 2 = 0.0%; P for heterogeneity = 0.89). A common variant in CLU was associated with a high risk of Alzheimer’s disease and all dementia in the general population but not with vascular dementia or ischemic vascular disease. Important novel aspects compared to previous studies are the incorporation of individual risk factor data, the exact causative e4 allele, and several subtypes of dementia and atherosclerosis-related endpoints.

Genetic variation in clusterin and risk of dementia and ischemic vascular disease in the general population: cohort studies and meta-analyses of 362,338 individuals

BackgroundClusterin, also known as apolipoprotein J (apoJ), is one of the most abundantly expressed apolipoproteins in the brain after apolipoprotein E (apoE). Like the ε4 allele of the apolipoprotein E gene (APOE), the clusterin gene (CLU) is a risk locus for Alzheimer’s disease, and may play additional roles in atherosclerosis pathogenesis. We tested whether genetic variation in CLU was associated with either Alzheimer’s disease or atherosclerosis-related diseases.MethodsWe studied individual data on 103,987 participants from the Copenhagen General Population Study (CGPS) and the Copenhagen City Heart Study (CCHS). We genotyped a common CLU variant (rs9331896) and two common APOE variants (rs7412 and rs429358), defining the ε2, ε3, and ε4, alleles in CGPS and CCHS. All individuals in the CGPS and CCHS cohorts were followed from study inclusion to occurrence of event, death, emigration, or until 10 November 2014, whichever came first. Summary consortia data on 258,351 individuals from the International Genomics of Alzheimer’s Project (IGAP) and the Coronary Artery Disease Genome-wide Replication and Meta-analysis plus the Coronary Artery Disease (C4D) Genetics and 1000-Genomes-based genome-wide association studies (CARDIoGRAMplusC4D) were used in meta-analyses.ResultsIn CGPS and CCHS, multifactorially adjusted hazard ratios for Alzheimer’s disease, all dementia, vascular dementia, ischemic cerebrovascular disease, and ischemic heart disease were 1.18 (1.07–1.30), 1.09 (1.02–1.17), 0.96 (0.80–1.17), 1.02 (0.97–1.07), and 0.97 (0.93–1.01) per T allele, respectively. Multifactorially adjusted hazard ratios for Alzheimer’s disease and all dementia were 2.72 (2.45–3.01) and 2.21 (2.05–2.38) for the APOE ɛ4 allele. There was no interaction between rs9331896 in CLU and rs429358 (defining the ɛ4 allele) in APOE in predicting Alzheimer’s disease or all dementia (P = 0.39 and P = 0.21). In a meta-analysis including consortium data, the overall fixed- and random-effects odds ratios for Alzheimer’s disease per T allele were 1.16 (1.13–1.18) (I2 = 0.0%; P for heterogeneity = 0.89).ConclusionsA common variant in CLU was associated with a high risk of Alzheimer’s disease and all dementia in the general population but not with vascular dementia or ischemic vascular disease. Important novel aspects compared to previous studies are the incorporation of individual risk factor data, the exact causative ε4 allele, and several subtypes of dementia and atherosclerosis-related endpoints.

Genetic Risk Stratification and Prevention of CAD: An Idea Whose Time Is Now.

The latter part of the 20th century was the golden age for genetics, as it focused on linkage analysis in families and discovered genes responsible for >4000 single gene disorders (1). Cardiovascular success included familial hypertrophic cardiomyopathy and atrial fibrillation, as well as Wolff–Parkinson–White, the long QT, and Brugada syndromes (1). A notable feature of the 21st century will be the breakthrough in genetics of polygenic disorders. In the year 2007, we and the Icelandic group simultaneously and independently discovered the first genetic risk variant (9p21) for coronary artery disease (CAD).2 This was followed closely by successes of the Wellcome Trust Group and many other investigators (2). An international collaboration was established to analyze and perform genome-wide association studies for CAD with a sample size of over 200000 cases and controls, referred to as the Coronary Artery Disease Genome-Wide Replication and Meta-Analysis (CARDIoGRAM) consortium. This collaboration provided the necessary expertise, resources, and sample size to identify over 60 genetic variants predisposing to CAD with more to come (2). All these variants are genome-wide significant ( P < 5 × 10−8) and have been replicated in independent populations. This information provided proof of concept for the observations made by epidemiologists decades ago, namely, 40% to 60% of risk for CAD is inherited. Genetic risk variants for CAD, as for all polygenic disorders, have several features in common: they occur commonly, each variant imparts only minimal risk, they occur primarily in nonprotein coding regions of the genome, and the total risk burden for CAD is proportional to the number of independent genetic risk variants rather than the intensity of any one variant. CAD, a pandemic disease, is the number one killer in men and women in the US and throughout the world (2). Someone born today in the …

Association of Genetic Variants Related to Serum Calcium Levels With Coronary Artery Disease and Myocardial Infarction

Serum calcium has been associated with cardiovascular disease in observational studies and evidence from randomized clinical trials indicates that calcium supplementation, which raises serum calcium levels, may increase the risk of cardiovascular events, particularly myocardial infarction. To evaluate the potential causal association between genetic variants related to elevated serum calcium levels and risk of coronary artery disease (CAD) and myocardial infarction using mendelian randomization. The analyses were performed using summary statistics obtained for single-nucleotide polymorphisms (SNPs) identified from a genome-wide association meta-analysis of serum calcium levels (N = up to 61 079 individuals) and from the Coronary Artery Disease Genome-wide Replication and Meta-analysis Plus the Coronary Artery Disease Genetics (CardiogramplusC4D) consortium's 1000 genomes-based genome-wide association meta-analysis (N = up to 184 305 individuals) that included cases (individuals with CAD and myocardial infarction) and noncases, with baseline data collected from 1948 and populations derived from across the globe. The association of each SNP with CAD and myocardial infarction was weighted by its association with serum calcium, and estimates were combined using an inverse-variance weighted meta-analysis. Genetic risk score based on genetic variants related to elevated serum calcium levels. Co-primary outcomes were the odds of CAD and myocardial infarction. Among the mendelian randomized analytic sample of 184 305 individuals (60 801 CAD cases [approximately 70% with myocardial infarction] and 123 504 noncases), the 6 SNPs related to serum calcium levels and without pleiotropic associations with potential confounders were estimated to explain about 0.8% of the variation in serum calcium levels. In the inverse-variance weighted meta-analysis (combining the estimates of the 6 SNPs), the odds ratios per 0.5-mg/dL increase (about 1 SD) in genetically predicted serum calcium levels were 1.25 (95% CI, 1.08-1.45; P = .003) for CAD and 1.24 (95% CI, 1.05-1.46; P = .009) for myocardial infarction. A genetic predisposition to higher serum calcium levels was associated with increased risk of CAD and myocardial infarction. Whether the risk of CAD associated with lifelong genetic exposure to increased serum calcium levels can be translated to a risk associated with short-term to medium-term calcium supplementation is unknown.

Causal Associations of Adiposity and Body Fat Distribution With Coronary Heart Disease, Stroke Subtypes, and Type 2 Diabetes Mellitus: A Mendelian Randomization Analysis.

The implications of different adiposity measures on cardiovascular disease etiology remain unclear. In this article, we quantify and contrast causal associations of central adiposity (waist-to-hip ratio adjusted for body mass index [WHRadjBMI]) and general adiposity (body mass index [BMI]) with cardiometabolic disease. Ninety-seven independent single-nucleotide polymorphisms for BMI and 49 single-nucleotide polymorphisms for WHRadjBMI were used to conduct Mendelian randomization analyses in 14 prospective studies supplemented with coronary heart disease (CHD) data from CARDIoGRAMplusC4D (Coronary Artery Disease Genome-wide Replication and Meta-analysis [CARDIoGRAM] plus The Coronary Artery Disease [C4D] Genetics; combined total 66 842 cases), stroke from METASTROKE (12 389 ischemic stroke cases), type 2 diabetes mellitus from DIAGRAM (Diabetes Genetics Replication and Meta-analysis; 34 840 cases), and lipids from GLGC (Global Lipids Genetic Consortium; 213 500 participants) consortia. Primary outcomes were CHD, type 2 diabetes mellitus, and major stroke subtypes; secondary analyses included 18 cardiometabolic traits. Each one standard deviation (SD) higher WHRadjBMI (1 SD≈0.08 U) associated with a 48% excess risk of CHD (odds ratio [OR] for CHD, 1.48; 95% confidence interval [CI], 1.28-1.71), similar to findings for BMI (1 SD≈4.6 kg/m2; OR for CHD, 1.36; 95% CI, 1.22-1.52). Only WHRadjBMI increased risk of ischemic stroke (OR, 1.32; 95% CI, 1.03-1.70). For type 2 diabetes mellitus, both measures had large effects: OR, 1.82 (95% CI, 1.38-2.42) and OR, 1.98 (95% CI, 1.41-2.78) per 1 SD higher WHRadjBMI and BMI, respectively. Both WHRadjBMI and BMI were associated with higher left ventricular hypertrophy, glycemic traits, interleukin 6, and circulating lipids. WHRadjBMI was also associated with higher carotid intima-media thickness (39%; 95% CI, 9%-77% per 1 SD). Both general and central adiposity have causal effects on CHD and type 2 diabetes mellitus. Central adiposity may have a stronger effect on stroke risk. Future estimates of the burden of adiposity on health should include measures of central and general adiposity.

Novel genetic loci associated with long-term deterioration in blood lipid concentrations and coronary artery disease in European adults.

Cross-sectional genome-wide association studies have identified hundreds of loci associated with blood lipids and related cardiovascular traits, but few genetic association studies have focused on long-term changes in blood lipids. Participants from the GLACIER Study (Nmax = 3492) were genotyped with the MetaboChip array, from which 29 387 SNPs (single nucleotide polymorphisms; replication, fine-mapping regions and wildcard SNPs for lipid traits) were extracted for association tests with 10-year change in total cholesterol (ΔTC) and triglycerides (ΔTG). Four additional prospective cohort studies (MDC, PIVUS, ULSAM, MRC Ely; Nmax = 8263 participants) were used for replication. We conducted an in silico look-up for association with coronary artery disease (CAD) in the Coronary ARtery DIsease Genome-wide Replication and Meta-analysis (CARDIoGRAMplusC4D) Consortium (N ∼ 190 000) and functional annotation for the top ranking variants. In total, 956 variants were associated (P < 0.01) with either ΔTC or ΔTG in GLACIER. In GLACIER, chr19:50121999 at APOE was associated with ΔTG and multiple SNPs in the APOA1/A4/C3/A5 region at genome-wide significance (P < 5 × 10-8), whereas variants in four loci, DOCK7, BRE, SYNE1 and KCNIP1, reached study-wide significance (P < 1.7 × 10-6). The rs7412 variant at APOE was associated with ΔTC in GLACIER (P < 1.7 × 10-6). In pooled analyses of all cohorts, 139 SNPs at six and five loci were associated with ΔTC and for ΔTG, respectively (P < 10-3). Of these, a variant at CAPN3 (P = 1.2 × 10-4), multiple variants at HPR (Pmin = 1.5 × 10-6) and a variant at SIX5 (P = 1.9 × 10-4) showed evidence for association with CAD. We identified seven novel genomic regions associated with long-term changes in blood lipids, of which three also raise CAD risk.

Genetic analysis of emerging risk factors in coronary artery disease

Background and aimsType 2 diabetes (T2D), low-density lipoprotein-cholesterol (LDL-c), body mass index (BMI), blood pressure and smoking are established risk factors that play a causal role in coronary artery disease (CAD). Numerous common genetic variants associating with these and other risk factors have been identified, but their association with CAD has not been comprehensively examined in a single study. Our goal was to comprehensively evaluate the associations of established and emerging risk factors with CAD using genetic variants identified from Genome-wide Association Studies (GWAS). MethodsWe tested the effect of 60 traditional and putative risk factors with CAD, using summary statistics obtained in GWAS. We approximated the regression of a response variable onto an additive multi-SNP genetic risk score in the Coronary Artery DIsease Genomewide Replication And Meta-analysis (CARDIoGRAM) consortium dataset weighted by the effect of the SNP on the risk factors. ResultsThe strongest association with risk of CAD was for LDL-c SNPs (p = 3.96E-34). For non-established CAD risk factors, we found significant CAD associations for coronary artery calcification (CAC), Lp(a), LP-PLA2 activity, plaque, vWF and FVIII. In an attempt to identify independent associations between risk factors and CAD, only SNPs with an effect on the target trait were included. This identified CAD associations for Lp(a)(p = 1.77E-21), LDL-c (p = 4.16E-06), triglycerides (TG) (p = 1.94E-05), height (p = 2.06E-05), CAC (p = 3.13E-23) and carotid plaque (p = 2.08E-05). ConclusionsWe identified SNPs associated with the emerging risk factors Lp(a), TG, plaque, height and CAC to be independently associated with risk of CAD. This provides further support for-ongoing clinical trials of Lp(a) and TG, and suggests that CAC and plaque could be used as surrogate markers for CAD in clinical trials.

Mendelian Randomization Studies Do Not Support a Role for Vitamin D in Coronary Artery Disease.

Observational studies support a possible association between decreased vitamin D levels and risk of coronary artery disease (CAD); however, it remains unclear whether this relationship is causal. We aimed to evaluate whether genetically lowered vitamin D levels influence the risk of CAD using a Mendelian randomization approach. In this 2-stage Mendelian randomization study, we first identified single-nucleotide polymorphisms associated with 25-hydroxyvitamin D (25OHD) levels in the SUNLIGHT consortium (n=33 996), then tested them for possible violation of Mendelian randomization assumptions. A count of risk alleles was tested for association with 25OHD levels in a separate cohort (n=2347). Alleles were weighted by their relative effect on 25OHD and tested for their combined effect on CAD in the Coronary Artery Disease Genome-Wide Replication and Meta-Analysis (CARDIoGRAM) study (22 233 cases/64 762 controls). Four single-nucleotide polymorphisms were identified to be associated with 25OHD levels, all in or near genes implicated in 25OHD synthesis, transport or metabolism. A count of these risk alleles was strongly associated with 25OHD (n=2347, F-test statistic=49.7, P=2×10(-12)). None of the single-nucleotide polymorphisms associated with 25OHD levels were associated with CAD (all P values >0.6). The Mendelian randomization odds ratio (OR) for CAD was 0.99 (95% confidence interval, 0.84-1.17; P=0.93; I(2)=0) per SD decrease in log-transformed 25OHD levels. These results persisted after sensitivity analyses for population stratification and pleiotropy. Genetically lowered 25OHD levels were not associated with increased risk of CAD in a large, well-powered study, suggesting that previous associations between circulating 25OHD levels and CAD are possibly confounded or due to reverse causation.

Mendelian Randomisation study of the influence of eGFR on coronary heart disease.

Impaired kidney function, as measured by reduced estimated glomerular filtration rate (eGFR), has been associated with increased risk of coronary heart disease (CHD) in observational studies, but it is unclear whether this association is causal or the result of confounding or reverse causation. In this study we applied Mendelian randomisation analysis using 17 genetic variants previously associated with eGFR to investigate the causal role of kidney function on CHD. We used 13,145 participants from the UCL-LSHTM-Edinburgh-Bristol (UCLEB) Consortium and 194,427 participants from the Coronary ARtery DIsease Genome-wide Replication and Meta-analysis plus Coronary Artery Disease (CARDIoGRAMplusC4D) consortium. We observed significant association of an unweighted gene score with CHD risk (odds ratio = 0.983 per additional eGFR-increasing allele, 95% CI = 0.970–0.996, p = 0.008). However, using weights calculated from UCLEB, the gene score was not associated with disease risk (p = 0.11). These conflicting results could be explained by a single SNP, rs653178, which was not associated with eGFR in the UCLEB sample, but has known pleiotropic effects that prevent us from drawing a causal conclusion. The observational association between low eGFR and increased CHD risk was not explained by potential confounders, and there was no evidence of reverse causation, therefore leaving the remaining unexplained association as an open question.

Genetic variants associated with celiac disease and the risk for coronary artery disease

Epidemiological evidence suggests that patients with celiac disease are at increased risk for coronary artery disease (CAD). Genetic-epidemiological analyses identified many single nucleotide polymorphisms (SNPs) associated with celiac disease. If there is a causal relation between celiac disease and CAD, one might expect that risk alleles primarily associated with celiac disease also increase the risk of CAD. In this study we identified from literature 41 SNPs that have been previously described to be genome-wide associated with celiac disease (p<5×10(-08)). These SNPs were evaluated for their association with CAD in the Coronary ARtery DIsease Genome-wide Replication and Meta-analysis (CARDIoGRAM) dataset, a meta-analysis comprising genome-wide SNP association data from 22,233 CAD cases and 64,762 controls. 24 out of 41 (58.5%) risk alleles for celiac disease displayed a positive association with CAD (CAD-OR range 1.001-1.081). The remaining risk alleles for celiac disease (n=16) revealed CAD-ORs of ≤1.0 (range 0.951-1.0). The proportion of CAD associated alleles was greater but did not differ significantly from the proportion of 50% expected by chance (p=0.069). One SNP (rs653178 at the SH2B3/ATXN2 locus) displayed study-wise statistically significant association with CAD with directionality consistent effects on celiac disease and CAD. However, the effect of this locus is most likely driven by pleiotropic effects on multiple other diseases. In conclusion, this genetically based approach provided no convincing evidence that SNPs associated with celiac disease contribute to the risk of CAD. Hence, common non-genetic factors may play a more important role explaining the coincidence of these two complex disease conditions.

Double trouble: T2DM genetic risk factors play a causal role in CAD.

Double trouble: T2DM genetic risk factors play a causal role in CAD.