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Background Few data exist on the long-term risk prediction of elevated left ventricular (LV) mass quantified by MRI for cardiovascular (CV) events in a contemporary, ethnically diverse cohort. Purpose To assess the long-term impact of elevated LV mass on CV events in a prospective cohort study of a multiethnic population in relationship to risk factors and coronary artery calcium (CAC) score. Materials and Methods The Multi-Ethnic Study of Atherosclerosis, or MESA (: NCT00005487), is an ongoing prospective multicenter population-based study in the United States. A total of 6814 participants (age range, 45-84 years) free of clinical CV disease at baseline were enrolled between 2000 and 2002. In 4988 participants (2613 [52.4%] women; mean age, 62 years ± 10.1 [standard deviation]) followed over 15 years for CV events, LV mass was derived from cardiac MRI at baseline enrollment by using semiautomated software at a central core laboratory. Cox proportional hazard models, Kaplan-Meier curves, and scores were applied to assess the impact of LV hypertrophy. Results A total of 290 participants had hard coronary heart disease (CHD) events (207 myocardial infarctions [MIs], 95 CHD deaths), 57 had other CV disease-related deaths, and 215 had heart failure (HF). LV hypertrophy was an independent predictor of hard CHD events (hazard ratio [HR]: 2.7; 95% confidence interval [CI]: 1.9, 3.8), MI (HR: 2.8; 95% CI: 1.8, 4.0), CHD death (HR: 4.3; 95% CI: 2.5, 7.3), other CV death (HR: 7.5; 95% CI: 4.2, 13.5), and HF (HR: 5.4; 95% CI: 3.8, 7.5) ( < .001 for all end points). LV hypertrophy was a stronger predictor than CAC for CHD death, other CV death, and HF ( scores: 5.4 vs 3.4, 6.8 vs 2.4, and 9.7 vs 3.2 for LV hypertrophy vs CAC, respectively). Kaplan-Meier analysis demonstrated an increased risk of CV events in participants with LV hypertrophy, particularly after 5 years. Conclusion Elevated left ventricular mass was strongly associated with hard coronary heart disease events, other cardiovascular death, and heart failure over 15 years of follow-up, independent of traditional risk factors and coronary artery calcium score. © RSNA, 2019 See also the editorial by Hanneman in this issue.
Understanding the nature of the genetic regulation of gene expression promises to advance our understanding of the genetic basis of disease. However, the methodological impact of the use of local ancestry on high-dimensional omics analyses, including, most prominently, expression quantitative trait loci (eQTL) mapping and trait heritability estimation, in admixed populations remains critically underexplored. Here, we develop a statistical framework that characterizes the relationships among the determinants of the genetic architecture of an important class of molecular traits. We provide a computationally efficient approach to local ancestry analysis in eQTL mapping while increasing control of type I and type II error over traditional approaches. Applying our method to National Institute of General Medical Sciences (NIGMS) and Genotype-Tissue Expression (GTEx) datasets, we show that the use of local ancestry can improve eQTL mapping in admixed and multiethnic populations, respectively. We estimate the trait variance explained by ancestry by using local admixture relatedness between individuals. By using simulations of diverse genetic architectures and degrees of confounding, we show improved accuracy in estimating heritability when accounting for local ancestry similarity. Furthermore, we characterize the sparse versus polygenic components of gene expression in admixed individuals. Our study has important methodological implications for genetic analysis of omics traits across a range of genomic contexts, from a single variant to a prioritized region to the entire genome. Our findings highlight the importance of using local ancestry to better characterize the heritability of complex traits and to more accurately map genetic associations.
Copyright © 2019 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.
Allopurinol, which lowers uric acid (UA) concentration, is increasingly being recognized for its benefits in cardiovascular and renal disease. However, response to allopurinol is variable. We gathered samples from 4,446 multiethnic subjects for a genome-wide association study of allopurinol response. Consistent with previous studies, we observed that the Q141K variant in ABCG2 (rs2231142), which encodes the efflux pump breast cancer resistance protein (BCRP), associated with worse response to allopurinol. However, for the first time this association reached genome-wide level significance (P = 8.06 × 10 ). Additionally, we identified a novel association with a variant in GREM2 (rs1934341, P = 3.22 × 10 ). In vitro studies identified oxypurinol, the active metabolite of allopurinol, as an inhibitor of the UA transporter GLUT9, suggesting that oxypurinol may modulate UA reabsorption. These results provide strong evidence for a role of BCRP Q141K in allopurinol response, and suggest that allopurinol may have additional hypouricemic effects beyond xanthine oxidase inhibition.
© 2019 The Authors Clinical Pharmacology & Therapeutics © 2019 American Society for Clinical Pharmacology and Therapeutics.
Interpretation of genetic association results is difficult because signals often lack biological context. To generate hypotheses of the functional genetic etiology of complex cardiometabolic traits, we estimated the genetically determined component of gene expression from common variants using PrediXcan (1) and determined genes with differential predicted expression by trait. PrediXcan imputes tissue-specific expression levels from genetic variation using variant-level effect on gene expression in transcriptome data. To explore the value of imputed genetically regulated gene expression (GReX) models across different ancestral populations, we evaluated imputed expression levels for predictive accuracy genome-wide in RNA sequence data in samples drawn from European-ancestry and African-ancestry populations and identified substantial predictive power using European-derived models in a non-European target population. We then tested the association of GReX on 15 cardiometabolic traits including blood lipid levels, body mass index, height, blood pressure, fasting glucose and insulin, RR interval, fibrinogen level, factor VII level and white blood cell and platelet counts in 15 755 individuals across three ancestry groups, resulting in 20 novel gene-phenotype associations reaching experiment-wide significance across ancestries. In addition, we identified 18 significant novel gene-phenotype associations in our ancestry-specific analyses. Top associations were assessed for additional support via query of S-PrediXcan (2) results derived from publicly available genome-wide association studies summary data. Collectively, these findings illustrate the utility of transcriptome-based imputation models for discovery of cardiometabolic effect genes in a diverse dataset.
© The Author(s) 2019. Published by Oxford University Press.
In this trans-ethnic multi-omic study, we reinterpret the genetic architecture of blood pressure to identify genes, tissues, phenomes and medication contexts of blood pressure homeostasis. We discovered 208 novel common blood pressure SNPs and 53 rare variants in genome-wide association studies of systolic, diastolic and pulse pressure in up to 776,078 participants from the Million Veteran Program (MVP) and collaborating studies, with analysis of the blood pressure clinical phenome in MVP. Our transcriptome-wide association study detected 4,043 blood pressure associations with genetically predicted gene expression of 840 genes in 45 tissues, and mouse renal single-cell RNA sequencing identified upregulated blood pressure genes in kidney tubule cells.
Atrial fibrillation (AF) affects more than 33 million individuals worldwide and has a complex heritability. We conducted the largest meta-analysis of genome-wide association studies (GWAS) for AF to date, consisting of more than half a million individuals, including 65,446 with AF. In total, we identified 97 loci significantly associated with AF, including 67 that were novel in a combined-ancestry analysis, and 3 that were novel in a European-specific analysis. We sought to identify AF-associated genes at the GWAS loci by performing RNA-sequencing and expression quantitative trait locus analyses in 101 left atrial samples, the most relevant tissue for AF. We also performed transcriptome-wide analyses that identified 57 AF-associated genes, 42 of which overlap with GWAS loci. The identified loci implicate genes enriched within cardiac developmental, electrophysiological, contractile and structural pathways. These results extend our understanding of the biological pathways underlying AF and may facilitate the development of therapeutics for AF.
BACKGROUND & AIMS - There are marked racial and ethnic differences in non-cardia gastric cancer prevalence within the United States. Although gastric cancer screening is recommended in some regions of high prevalence, screening is not routinely performed in the United States. Our objective was to determine whether selected non-cardia gastric cancer screening for high-risk races and ethnicities within the United States is cost effective.
METHODS - We developed a decision analytic Markov model with the base case of a 50-year-old person of non-Hispanic white, non-Hispanic black, Hispanic, or Asian race or ethnicity. The cost effectiveness of a no-screening strategy (current standard) for non-cardia gastric cancer was compared with that of 2 endoscopic screening modalities initiated at the time of screening colonoscopy for colorectal cancer: upper esophagogastroduodenoscopy with biopsy examinations and continued surveillance only if intestinal metaplasia or more severe pathology is identified or esophagogastroduodenoscopy with biopsy examinations continued every 2 years even in the absence of identified pathology. We used prevalence rates, transition probabilities, costs, and quality-adjusted life years (QALYs) from publications and public data sources. Outcome measures were reported in incremental cost-effectiveness ratios, with a willingness-to-pay threshold of $100,000/QALY.
RESULTS - Compared with biennial and no screening, screening esophagogastroduodenoscopy with continued surveillance only when indicated was cost effective for non-Hispanic blacks ($80,278/QALY), Hispanics ($76,070/QALY), and Asians ($71,451/QALY), but not for non-Hispanic whites ($122,428/QALY). The model was sensitive to intestinal metaplasia prevalence, transition rates from intestinal metaplasia to dysplasia to local and regional cancer, cost of endoscopy, and cost of resection (endoscopic or surgical).
CONCLUSIONS - Based on a decision analytic Markov model, endoscopic non-cardia gastric cancer screening for high-risk races and ethnicities could be cost effective in the United States.
Copyright © 2018 AGA Institute. Published by Elsevier Inc. All rights reserved.
DNA sequence-based typing at the HLA-A, -B, -C, -DPB1, -DQA1, -DQB1, and -DRB1 loci was performed on 714 healthy adult blood bank donors from Colombo, Sri Lanka, to characterize allele frequencies in support of studies on T cell immunity against pathogens, including Dengue virus. Deviations from Hardy Weinberg proportions were not detected at any locus. Several alleles were found in >30% of individuals, including the class II alleles DPB1 * 04:01, DPB1 * 02:01, DQB1 * 06:01 and DRB1 * 07:01, and the class I alleles A * 33:03 and A * 24:02. Genotype data will be available in the Allele Frequencies Net Database.
Copyright © 2018 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.
BACKGROUND AND AIMS - Most familial hypercholesterolemia (FH) patients remain undertreated, and it is unclear what role health disparities may play for FH patients in the US. We sought to describe sex and racial/ethnic disparities in a national registry of US FH patients.
METHODS - We analyzed data from 3167 adults enrolled in the CAscade SCreening for Awareness and DEtection of Familial Hypercholesterolemia (CASCADE-FH) registry. Logistic regression was used to evaluate for disparities in LDL-C goals and statin use, with adjustments for covariates including age, cardiovascular risk factors, and statin intolerance.
RESULTS - In adjusted analyses, women were less likely than men to achieve treated LDL-C of <100 mg/dL (OR 0.68, 95% CI, 0.57-0.82) or ≥50% reduction from pretreatment LDL-C (OR 0.79, 95% CI, 0.65-0.96). Women were less likely than men to receive statin therapy (OR, 0.60, 95% CI, 0.50-0.73) and less likely to receive a high-intensity statin (OR, 0.60, 95% CI, 0.49-0.72). LDL-C goal achievement also varied by race/ethnicity: compared with whites, Asians and blacks were less likely to achieve LDL-C levels <100 mg/dL (Asians, OR, 0.47, 95% CI, 0.24-0.94; blacks, OR, 0.49, 95% CI, 0.32-0.74) or ≥50% reduction from pretreatment LDL-C (Asians, OR 0.56, 95% CI, 0.32-0.98; blacks, OR 0.62, 95% CI, 0.43-0.90).
CONCLUSIONS - In a contemporary US population of FH patients, we identified differences in LDL-C goal attainment and statin usage after stratifying the population by either sex or race/ethnicity. Our findings suggest that health disparities contribute to the undertreatment of US FH patients. Increased efforts are warranted to raise awareness of these disparities.
Copyright © 2017 Elsevier B.V. All rights reserved.