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Smith GD, Ebrahim S. Mendelian randomisation at 20 years: how can it avoid hubris, while achieving more? Lancet Diabetes Endocrinol 2024; 12:14-17. [PMID: 38048796 DOI: 10.1016/s2213-8587(23)00348-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 11/10/2023] [Indexed: 12/06/2023]
Affiliation(s)
- George Davey Smith
- MRC Integrative Epidemiology Unit, Bristol Medical School, University of Bristol, Bristol BS8 2BN, UK.
| | - Shah Ebrahim
- London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
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Patoulias D, Stavropoulos K, Imprialos K, Athyros V, Grassos H, Doumas M, Faselis C. Inflammatory Markers in Cardiovascular Disease; Lessons Learned and Future Perspectives. Curr Vasc Pharmacol 2021; 19:323-342. [PMID: 32188386 DOI: 10.2174/1570161118666200318104434] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 02/24/2020] [Accepted: 02/24/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Cardiovascular disease (CVD) still remains the leading cause of morbidity and mortality worldwide. It is now established that inflammation plays a crucial role in atherosclerosis and atherothrombosis, and thus, it is closely linked to cardiovascular disease. OBJECTIVE The aim of the present review is to summarize and critically appraise the most relevant evidence regarding the potential use of inflammatory markers in the field of CVD. METHODS We conducted a comprehensive research of the relevant literature, searching MEDLINE from its inception until November 2018, primarily for meta-analyses, randomized controlled trials and observational studies. RESULTS Established markers of inflammation, mainly C-reactive protein, have yielded significant results both for primary and secondary prevention of CVD. Newer markers, such as lipoprotein-associated phospholipase A2, lectin-like oxidized low-density lipoprotein receptor-1, cytokines, myeloperoxidase, cell adhesion molecules, matrix metalloproteinases, and the CD40/CD40 ligand system, have been largely evaluated in human studies, enrolling both individuals from the general population and patients with established CVD. Some markers have yielded conflicting results; however, others are now recognized not only as promising biomarkers of CVD, but also as potential therapeutic targets, establishing the role of anti-inflammatory and pleiotropic drugs in CVD. CONCLUSION There is significant evidence regarding the role of consolidated and novel inflammatory markers in the field of diagnosis and prognosis of CVD. However, multimarker model assessment, validation of cut-off values and cost-effectiveness analyses are required in order for those markers to be integrated into daily clinical practice.
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Affiliation(s)
- Dimitrios Patoulias
- Second Propedeutic Department of Internal Medicine, Aristotle University, Thessaloniki, Greece
| | | | - Konstantinos Imprialos
- Second Propedeutic Department of Internal Medicine, Aristotle University, Thessaloniki, Greece
| | - Vasilios Athyros
- Second Propedeutic Department of Internal Medicine, Aristotle University, Thessaloniki, Greece
| | | | - Michael Doumas
- Second Propedeutic Department of Internal Medicine, Aristotle University, Thessaloniki, Greece
| | - Charles Faselis
- VA Medical Center, and George Washington University, Washington, DC 20422, United States
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Pieters M, Ferreira M, de Maat MPM, Ricci C. Biomarker association with cardiovascular disease and mortality - The role of fibrinogen. A report from the NHANES study. Thromb Res 2020; 198:182-189. [PMID: 33360152 DOI: 10.1016/j.thromres.2020.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 11/26/2020] [Accepted: 12/09/2020] [Indexed: 01/27/2023]
Abstract
BACKGROUND While fibrinogen is a known cardiovascular disease (CVD) risk marker, its quantitative input to mortality risk is a topic of debate. METHODS We investigated the contribution of fibrinogen, among that of other biomarkers, to prevalent CVD and incident CVD mortality in 4487 participants of the US National Health and Nutrition Examination Survey (NHANES). Participants were observed for a median period of 14 years, resulting in more than 58,000 person-years. RESULTS At baseline 551 participants had CVD and during follow up, 1339 all-cause deaths occurred, 321 (24%) of which were due to CVD. Hierarchical cluster analysis and principal component analysis (PCA) were performed to derive clusters of association between biomarkers. Next, structural equation modelling was performed to investigate the association of these clusters with baseline CVD and all-cause and CVD mortality during follow-up. Mediation analysis was used to determine which biomarkers played a mediatory role between prevalent CVD and future mortality. Fibrinogen clustered with C-reactive protein only and was associated with CVD at baseline (p < 0.0001) and with all-cause (p < 0.001) and CVD (p < 0.001) mortality at follow-up. Only fibrinogen (4.7%), followed by gamma-glutamyl transferase (GGT) (3.5%) and uric acid (2.3%) were identified as possible mediators between CVD status and all-cause mortality, with fibrinogen (3.2%) and GGT (3.1%) the only mediators between CVD status and CVD mortality. CONCLUSION This data shows that fibrinogen is not only cross-sectionally associated with CVD, but also contributes to all-cause and CVD mortality at follow-up. It furthermore appears to mediate the association between prevalent CVD and both all-cause and CVD mortality.
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Affiliation(s)
- Marlien Pieters
- Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa; Medical Research Council Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa.
| | - Maylene Ferreira
- Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
| | - Moniek P M de Maat
- Department of Hematology, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Cristian Ricci
- Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa; Pediatric Epidemiology, Department of Pediatrics, University Medicine Leipzig, Leipzig, Germany
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Davey Smith G, Phillips AN. Correlation without a cause: an epidemiological odyssey. Int J Epidemiol 2020; 49:4-14. [DOI: 10.1093/ije/dyaa016] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/04/2020] [Indexed: 12/12/2022] Open
Abstract
Background
In the 1980s debate intensified over whether there was a protective effect of high-density lipoprotein cholesterol (HDL-C) or an adverse effect of triglycerides on coronary heart disease (CHD) risk. In a 1991 paper reprinted in the IJE we suggested that the high degree of correlation between the two, together with plausible levels of measurement error, made it unlikely that conventional epidemiological approaches could contribute to causal understanding. The consensus that HDL-C was protective, popularly reified in the notion of ‘good cholesterol’, strengthened over subsequent years. Reviewing the biostatistical and epidemiological literature from before and after 1991 we suggest that within the observational epidemiology pantheon only Mendelian randomization studies—that began to appear at the same time as the initial negative randomized controlled trials—made a meaningful contribution. It is sobering to realize that many issues that appear suitable targets for epidemiological investigation are simply refractory to conventional approaches. The discipline should surely revisit this and other high-profile cases of consequential epidemiological failure—such as that with respect to vitamin E supplementation and CHD risk—rather than pass them over in silence.
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Affiliation(s)
- George Davey Smith
- Medical Research Council Integrative Epidemiology Unit, Bristol Medical School, University of Bristol, Bristol, UK
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Ward-Caviness CK, de Vries PS, Wiggins KL, Huffman JE, Yanek LR, Bielak LF, Giulianini F, Guo X, Kleber ME, Kacprowski T, Groß S, Petersman A, Davey Smith G, Hartwig FP, Bowden J, Hemani G, Müller-Nuraysid M, Strauch K, Koenig W, Waldenberger M, Meitinger T, Pankratz N, Boerwinkle E, Tang W, Fu YP, Johnson AD, Song C, de Maat MPM, Uitterlinden AG, Franco OH, Brody JA, McKnight B, Chen YDI, Psaty BM, Mathias RA, Becker DM, Peyser PA, Smith JA, Bielinski SJ, Ridker PM, Taylor KD, Yao J, Tracy R, Delgado G, Trompet S, Sattar N, Jukema JW, Becker LC, Kardia SLR, Rotter JI, März W, Dörr M, Chasman DI, Dehghan A, O’Donnell CJ, Smith NL, Peters A, Morrison AC. Mendelian randomization evaluation of causal effects of fibrinogen on incident coronary heart disease. PLoS One 2019; 14:e0216222. [PMID: 31075152 PMCID: PMC6510421 DOI: 10.1371/journal.pone.0216222] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 04/16/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Fibrinogen is an essential hemostatic factor and cardiovascular disease risk factor. Early attempts at evaluating the causal effect of fibrinogen on coronary heart disease (CHD) and myocardial infraction (MI) using Mendelian randomization (MR) used single variant approaches, and did not take advantage of recent genome-wide association studies (GWAS) or multi-variant, pleiotropy robust MR methodologies. METHODS AND FINDINGS We evaluated evidence for a causal effect of fibrinogen on both CHD and MI using MR. We used both an allele score approach and pleiotropy robust MR models. The allele score was composed of 38 fibrinogen-associated variants from recent GWAS. Initial analyses using the allele score used a meta-analysis of 11 European-ancestry prospective cohorts, free of CHD and MI at baseline, to examine incidence CHD and MI. We also applied 2 sample MR methods with data from a prevalent CHD and MI GWAS. Results are given in terms of the hazard ratio (HR) or odds ratio (OR), depending on the study design, and associated 95% confidence interval (CI). In single variant analyses no causal effect of fibrinogen on CHD or MI was observed. In multi-variant analyses using incidence CHD cases and the allele score approach, the estimated causal effect (HR) of a 1 g/L higher fibrinogen concentration was 1.62 (CI = 1.12, 2.36) when using incident cases and the allele score approach. In 2 sample MR analyses that accounted for pleiotropy, the causal estimate (OR) was reduced to 1.18 (CI = 0.98, 1.42) and 1.09 (CI = 0.89, 1.33) in the 2 most precise (smallest CI) models, out of 4 models evaluated. In the 2 sample MR analyses for MI, there was only very weak evidence of a causal effect in only 1 out of 4 models. CONCLUSIONS A small causal effect of fibrinogen on CHD is observed using multi-variant MR approaches which account for pleiotropy, but not single variant MR approaches. Taken together, results indicate that even with large sample sizes and multi-variant approaches MR analyses still cannot exclude the null when estimating the causal effect of fibrinogen on CHD, but that any potential causal effect is likely to be much smaller than observed in epidemiological studies.
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Affiliation(s)
- Cavin K. Ward-Caviness
- Epidemiology II, Helmholtz Zentrum München—German Research Center for Environmental Health, Neuherberg, Germany
- * E-mail:
| | - Paul S. de Vries
- Department of Epidemiology, Erasmus University Medical Center, Rotterdam, the Netherlands
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, University of Texas Health Science Center at Houston, Houston, United States of America
| | - Kerri L. Wiggins
- Department of Medicine, University of Washington, Health Sciences Bldg, Seattle, Washington, United States of America
| | - Jennifer E. Huffman
- Population Sciences Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Framingham, MA, United States of America
- The Framingham Heart Study, Framingham, MA, United States of America
| | - Lisa R. Yanek
- GeneSTAR Research Program, Division of General Internal Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Broadway, Baltimore, MD, United States of America
| | - Lawrence F. Bielak
- Epidemiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Franco Giulianini
- Division of Preventative Medicine, Brigham and Women’s Hospital, Boston, MA, United States of America
| | - Xiuqing Guo
- Institute for Translational Genomics and Population Sciences, Department of Pediatrics, LABioMed at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Marcus E. Kleber
- Vth Department of Medicine (Nephrology, Hypertensiology, Endocrinology, Diabetology, Rheumatology), Medical Faculty of Mannheim, University of Heidelberg, Mannheim, Germany
- Institute of Nutrition, Friedrich-Schiller University Jena, Jena, Germany
| | - Tim Kacprowski
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz-Arndt University Greifswald, Griefswald, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
- Research Group Computational Systems Medicine, Chair of Experimental Bioinformatics, TUM School of Life Sciences, Technical University of Munich, Freising-Weihenstephan, Germany
| | - Stefan Groß
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
- Department of Internal Medicine B, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, Greifswald, Germany
| | - Astrid Petersman
- Institute of Clinical Chemistry and Laboratory Medicine, University of Medicine Griefswald, Ferdinand-Sauerbruch-Straße, Greifswald, Germany
| | - George Davey Smith
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, United Kingdom
| | - Fernando P. Hartwig
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, United Kingdom
- Postgraduate Program in Epidemiology, Federal University of Pelotas, Pelotas, Brazil
| | - Jack Bowden
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, United Kingdom
| | - Gibran Hemani
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, United Kingdom
| | - Martina Müller-Nuraysid
- Institute of Genetic Epidemiology, Helmholtz Zentrum München—German Research Center for Environmental Health, Neuherberg, Germany
- DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
- Department of Medicine I, University Hospital Grosshadern, Ludwig-Maximilians-Universität, Munich, Germany
| | - Konstantin Strauch
- Institute of Genetic Epidemiology, Helmholtz Zentrum München—German Research Center for Environmental Health, Neuherberg, Germany
- Department of Medicine I, University Hospital Grosshadern, Ludwig-Maximilians-Universität, Munich, Germany
- Institute of Medical Informatics, Biometry and Epidemiology, Chair of Genetic Epidemiology, Ludwig-Maximilians-Universität, Munich, Germany
| | - Wolfgang Koenig
- DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
- Department of Internal Medicine II, University of Ulm Medical Center, Ulm, Germany
- Deutsches Herzzentrum München, Technische Universität München, Munich, Germany
| | - Melanie Waldenberger
- Epidemiology II, Helmholtz Zentrum München—German Research Center for Environmental Health, Neuherberg, Germany
- Research Unit of Molecular Epidemiology, Helmholtz Zentrum München—German Research Center for Environmental Health, Neuherberg, Germany
| | - Thomas Meitinger
- DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München—German Research Center for Environmental Health, Neuherberg, Germany
- Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Nathan Pankratz
- University of Minnesota School of Medicine, Minneapolis, MN, United States of America
| | - Eric Boerwinkle
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, University of Texas Health Science Center at Houston, Houston, United States of America
- Human Genome Sequencing Center, Baylor College of Medicine, One Baylor Plaza, Houston, United States of America
| | - Weihong Tang
- University of Minnesota School of Public Health, Minneapolis, MN, United States of America
| | - Yi-Ping Fu
- Office of Biostatistics Research, Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States of America
| | - Andrew D. Johnson
- Population Sciences Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Framingham, MA, United States of America
- The Framingham Heart Study, Framingham, MA, United States of America
| | - Ci Song
- Population Sciences Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Framingham, MA, United States of America
- The Framingham Heart Study, Framingham, MA, United States of America
| | - Moniek P. M. de Maat
- Department of Hematology, Erasmus University Medical Center, Rotterdam, CND, Netherlands
| | - André G. Uitterlinden
- Department of Epidemiology, Erasmus University Medical Center, Rotterdam, the Netherlands
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, CN, Netherlands
| | - Oscar H. Franco
- Department of Epidemiology, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Jennifer A. Brody
- Department of Medicine, University of Washington, Health Sciences Bldg, Seattle, Washington, United States of America
| | - Barbara McKnight
- Department of Biostatistics, University of Washington, Health Sciences Bldg, Seattle, WA, United States of America
| | - Yii-Der Ida Chen
- Institute for Translational Genomics and Population Sciences, Department of Pediatrics, LABioMed at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Bruce M. Psaty
- Department of Medicine, University of Washington, Health Sciences Bldg, Seattle, Washington, United States of America
- Department of Epidemiology, University of Washington, Health Sciences Bldg, Seattle, WA, United States of America
- Department of Health Services, University of Washington, Health Sciences Bldg, Seattle, WA, United States of America
- Group Health Research Institute, Group Health Cooperative, Seattle, WA, United States of America
| | - Rasika A. Mathias
- GeneSTAR Research Program, Division of General Internal Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Broadway, Baltimore, MD, United States of America
- Division of Allergy and Clinical Immunology, Department of Medicine, Johns Hopkins University School of Medicine, N. Broadway, Baltimore, MD, United States of America
| | - Diane M. Becker
- GeneSTAR Research Program, Division of General Internal Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Broadway, Baltimore, MD, United States of America
| | - Patricia A. Peyser
- Epidemiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jennifer A. Smith
- Epidemiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Suzette J. Bielinski
- Department of Epidemiology, Mayo Clinic, Rochester, MN, United States of America
| | - Paul M. Ridker
- Division of Preventative Medicine, Brigham and Women’s Hospital, Boston, MA, United States of America
| | - Kent D. Taylor
- Institute for Translational Genomics and Population Sciences, Department of Pediatrics, LABioMed at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Jie Yao
- Institute for Translational Genomics and Population Sciences, Department of Pediatrics, LABioMed at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Russell Tracy
- Pathology and Laboratory Medicine, The University of Vermont College of Medicine, Col Research Facility, Burlington, VT, United States of America
| | - Graciela Delgado
- Vth Department of Medicine (Nephrology, Hypertensiology, Endocrinology, Diabetology, Rheumatology), Medical Faculty of Mannheim, University of Heidelberg, Mannheim, Germany
| | - Stella Trompet
- Department of Hematology, Erasmus University Medical Center, Rotterdam, CND, Netherlands
- Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, Netherlands
| | - Naveed Sattar
- BHF Glasgow Cardiovascular Research Centre, Faculty of Medicine, Glasgow, United Kingdom
| | - J. Wouter Jukema
- Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands
| | - Lewis C. Becker
- GeneSTAR Research Program, Division of General Internal Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Broadway, Baltimore, MD, United States of America
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, N. Broadway, Baltimore, MD, United States of America
| | - Sharon L. R. Kardia
- Epidemiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jerome I. Rotter
- Institute for Translational Genomics and Population Sciences, Department of Pediatrics, LABioMed at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Winfried März
- Vth Department of Medicine (Nephrology, Hypertensiology, Endocrinology, Diabetology, Rheumatology), Medical Faculty of Mannheim, University of Heidelberg, Mannheim, Germany
- Synlab Academy, Synlab Holding Deutschland GmbH, Mannheim, Germany
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
| | - Marcus Dörr
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
- Department of Internal Medicine B, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, Greifswald, Germany
| | - Daniel I. Chasman
- Division of Preventative Medicine, Brigham and Women’s Hospital, Boston, MA, United States of America
| | - Abbas Dehghan
- Department of Epidemiology, Erasmus University Medical Center, Rotterdam, the Netherlands
- Department of Epidemiology and Biostatistics, Imperial College London, Norfolk Place, London, United Kingdom
| | - Christopher J. O’Donnell
- Population Sciences Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Framingham, MA, United States of America
- Cardiology Section Administration, Boston VA Healthcare System, West Roxbury, MA, United States of America
| | - Nicholas L. Smith
- Department of Epidemiology, University of Washington, Health Sciences Bldg, Seattle, WA, United States of America
- Group Health Research Institute, Group Health Cooperative, Seattle, WA, United States of America
- Seattle Epidemiologic Research and Information Center, Department of Veteran Affairs Office of Research and Development, Columbian Way, Seattle, WA, United States of America
| | - Annette Peters
- Epidemiology II, Helmholtz Zentrum München—German Research Center for Environmental Health, Neuherberg, Germany
- DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
| | - Alanna C. Morrison
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, University of Texas Health Science Center at Houston, Houston, United States of America
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Papageorgiou N, Tousoulis D. Single-nucleotide polymorphisms and their role in coronary artery disease: Where do we stand now? Hellenic J Cardiol 2018; 59:14-15. [PMID: 29627598 DOI: 10.1016/j.hjc.2018.02.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 02/19/2018] [Indexed: 10/17/2022] Open
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Genetics of Atherosclerosis. Coron Artery Dis 2018. [DOI: 10.1016/b978-0-12-811908-2.00007-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Association of genetic variants of hemostatic genes with myocardial infarction in Egyptian patients. Gene 2017; 641:212-219. [PMID: 29054763 DOI: 10.1016/j.gene.2017.10.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/06/2017] [Accepted: 10/16/2017] [Indexed: 12/22/2022]
Abstract
Hemostatic genes polymorphisms are well known to be associated with venous thrombosis, but their association with arterial thrombosis especially myocardial infarction (MI) remains to be clarified. We investigated the role of three hemostatic gene polymorphisms, prothrombin G20210A, factor XIII (FXIII) Val34Leu (G/T), and fibrinogen-β-455G/A and their coexistence in Egyptian patients with MI. The possible correlation of these polymorphisms with plasma fibrinogen level was also evaluated. The study included 120 patients with MI and 60 healthy volunteers. Gene polymorphisms were tested using multiplex polymerase chain reaction and reverse-hybridization technique. Plasma fibrinogen level was determined by ELISA. Our study showed an increased risk of MI with fibrinogen β-455G/A heterozygosity as well as FXIII Val34Leu homo and heterozygosity. In addition, the FXIII T allele (Leu34) and fibrinogen β-455A allele were significantly associated with MI. Conversely, the prevalence of prothrombin mutation did not differ between patients with MI and controls. Combined carriers of FXIII Leu34 and fibrinogen-β455A alleles were at higher risk of MI, whereas combined FXIII Val34Leu and prothrombin 20210A polymorphisms did not show increased risk for MI compared with controls. Plasma fibrinogen levels were significantly higher in patients with MI than controls. In MI patients, plasma fibrinogen levels were significantly higher in those with FXIII GT/TT or fibrinogen β-455 GA, while were significantly lower in those with prothrombin 20210 GA compared with patients with wild type genotypes. In conclusion, our results suggest a possible thrombotic predisposition of FXIII Val34Leu, fibrinogen β-455G/A polymorphisms and their coexistence for MI. These polymorphisms may add complexity to disease pathology by increasing plasma fibrinogen level. Extended studies are needed to confirm our results; nevertheless, these data may be implicated in genetic counseling and screening of high-risk individuals.
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Genetics of myocardial infarction: The role of thrombosis-associated genes. A review article. Meta Gene 2017. [DOI: 10.1016/j.mgene.2017.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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The β fibrinogen gene G-455A polymorphism in Asian subjects with coronary heart disease: A meta analysis. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2017. [DOI: 10.1016/j.ejmhg.2016.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Folsom AR, Tang W, George KM, Heckbert SR, MacLehose RF, Cushman M, Pankow JS. Prospective study of γ' fibrinogen and incident venous thromboembolism: The Longitudinal Investigation of Thromboembolism Etiology (LITE). Thromb Res 2016; 139:44-9. [PMID: 26916295 PMCID: PMC4769380 DOI: 10.1016/j.thromres.2016.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/15/2015] [Accepted: 01/10/2016] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Epidemiological studies generally have not found plasma total fibrinogen to be a risk factor for venous thromboembolism (VTE), but several have reported associations between variants in the fibrinogen gamma gene (FGG) and VTE. A case-control study in whites suggested plasma γ' fibrinogen concentration may be associated inversely with VTE, but this was not replicated in African Americans. OBJECTIVE To examine the prospective association between γ' fibrinogen concentrations and occurrence of VTE. METHODS We used the Longitudinal Investigation of Thromboembolism Etiology (LITE), involving two pooled population-based cohorts in the United States including 16,234 participants. The cohorts comprised white and African American men and women, aged 50years and older at study onset in the early 1990s. We identified VTEs during follow-up and documented they met standardized diagnostic criteria. RESULTS During two decades of follow-up, neither γ' fibrinogen nor total fibrinogen nor their ratio was associated with VTE overall (n=521 VTEs), in subgroups defined by race, or in other subgroups. In both race groups, the minor allele of FGG rs2066865 was associated with lower γ' fibrinogen concentrations, but this allele was not associated with VTE. CONCLUSIONS A lower plasma concentration of γ' fibrinogen in healthy adults does not appear to increase VTE risk.
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Affiliation(s)
- Aaron R Folsom
- Division of Epidemiology & Community Health, School of Public Health, University of Minnesota, Minneapolis, MN 55454, United States.
| | - Weihong Tang
- Division of Epidemiology & Community Health, School of Public Health, University of Minnesota, Minneapolis, MN 55454, United States
| | - Kristen M George
- Division of Epidemiology & Community Health, School of Public Health, University of Minnesota, Minneapolis, MN 55454, United States
| | - Susan R Heckbert
- Department of Epidemiology, University of Washington, Seattle, WA 98101, United States
| | - Richard F MacLehose
- Division of Epidemiology & Community Health, School of Public Health, University of Minnesota, Minneapolis, MN 55454, United States
| | - Mary Cushman
- Department of Medicine, University of Vermont, Burlington, VT 55446, United States; Department of Pathology, University of Vermont, Burlington, VT 05446, United States
| | - James S Pankow
- Division of Epidemiology & Community Health, School of Public Health, University of Minnesota, Minneapolis, MN 55454, United States
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Boef AGC, Dekkers OM, le Cessie S. Mendelian randomization studies: a review of the approaches used and the quality of reporting. Int J Epidemiol 2015; 44:496-511. [PMID: 25953784 DOI: 10.1093/ije/dyv071] [Citation(s) in RCA: 292] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2015] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Mendelian randomization (MR) studies investigate the effect of genetic variation in levels of an exposure on an outcome, thereby using genetic variation as an instrumental variable (IV). We provide a meta-epidemiological overview of the methodological approaches used in MR studies, and evaluate the discussion of MR assumptions and reporting of statistical methods. METHODS We searched PubMed, Medline, Embase and Web of Science for MR studies up to December 2013. We assessed (i) the MR approach used; (ii) whether the plausibility of MR assumptions was discussed; and (iii) whether the statistical methods used were reported adequately. RESULTS Of 99 studies using data from one study population, 32 used genetic information as a proxy for the exposure without further estimation, 44 performed a formal IV analysis, 7 compared the observed with the expected genotype-outcome association, and 1 used both the latter two approaches. The 80 studies using data from multiple study populations used many different approaches to combine the data; 52 of these studies used some form of IV analysis; 44% of studies discussed the plausibility of all three MR assumptions in their study. Statistical methods used for IV analysis were insufficiently described in 14% of studies. CONCLUSIONS Most MR studies either use the genotype as a proxy for exposure without further estimation or perform an IV analysis. The discussion of underlying assumptions and reporting of statistical methods for IV analysis are frequently insufficient. Studies using data from multiple study populations are further complicated by the combination of data or estimates. We provide a checklist for the reporting of MR studies.
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Affiliation(s)
- Anna G C Boef
- Department of Clinical Epidemiology, Department of Endocrinology and Metabolic Diseases, and Department of Medical Statistics and Bioinformatics, Leiden University Medical Centre, Leiden, The Netherlands.
| | - Olaf M Dekkers
- Department of Clinical Epidemiology, Department of Endocrinology and Metabolic Diseases, and Department of Medical Statistics and Bioinformatics, Leiden University Medical Centre, Leiden, The Netherlands. Department of Clinical Epidemiology, Department of Endocrinology and Metabolic Diseases, and Department of Medical Statistics and Bioinformatics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Saskia le Cessie
- Department of Clinical Epidemiology, Department of Endocrinology and Metabolic Diseases, and Department of Medical Statistics and Bioinformatics, Leiden University Medical Centre, Leiden, The Netherlands. Department of Clinical Epidemiology, Department of Endocrinology and Metabolic Diseases, and Department of Medical Statistics and Bioinformatics, Leiden University Medical Centre, Leiden, The Netherlands
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Ribeiro DGL, Silva RP, Barboza DRMM, Lima-Júnior RCP, Ribeiro RA. Clinical correlation between N-terminal pro-B-type natriuretic peptide and angiographic coronary atherosclerosis. Clinics (Sao Paulo) 2014; 69:405-12. [PMID: 24964305 PMCID: PMC4050322 DOI: 10.6061/clinics/2014(06)07] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Revised: 10/09/2013] [Accepted: 09/14/2013] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVES This study aimed to investigate the clinical correlation between angiographic coronary atherosclerosis and N-terminal pro-B-type natriuretic peptide along with other known correlated factors. METHODS In total, 153 patients with a diagnostic hypothesis of stable angina, unstable angina or acute myocardial infarction were classified as group A (patients with angiographically normal coronary arteries) or group B (patients with angiographic coronary atherosclerosis). The two groups were analyzed with respect to the following factors: gender, age, body mass index, abdominal circumference, smoking, diabetes mellitus, arterial hypertension, early family history of atherosclerosis, statin use, the presence of metabolic syndrome, clinical presentation and biochemical factors, including cholesterol, creatinine and fibrinogen plasma concentrations, monocyte counts and N-terminal pro-B-type natriuretic peptide. RESULTS Univariate analyses comparing the two groups revealed that group B patients more frequently had diabetes, used statins and had systolic dysfunction, N-terminal pro-B-type natriuretic peptide levels ≥ 250 pg/mL, fibrinogen levels >500 mg/dL and ≥ 501 monocytes/mm3 compared with group A patients (p<0.05). Nevertheless, multivariate logistic regression analysis demonstrated that the independent predictors of angiographic coronary atherosclerosis were an N-terminal pro-B-type natriuretic peptide level ≥ 250 pg/mL, diabetes mellitus and increased monocyte numbers and fibrinogen plasma concentration, regardless of the creatinine level or the presence of systolic dysfunction. CONCLUSIONS An N-terminal pro-B-type natriuretic peptide plasma concentration of ≥ 250 pg/mL is an independent predictor of angiographic coronary atherosclerosis.
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Affiliation(s)
- Demóstenes G L Ribeiro
- Department of Clinical Medicine, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Ricardo P Silva
- Department of Clinical Medicine, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Daniella R M M Barboza
- Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Roberto C P Lima-Júnior
- Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Ronaldo A Ribeiro
- Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
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Sabater-Lleal M, Huang J, Chasman D, Naitza S, Dehghan A, Johnson AD, Teumer A, Reiner AP, Folkersen L, Basu S, Rudnicka AR, Trompet S, Mälarstig A, Baumert J, Bis JC, Guo X, Hottenga JJ, Shin SY, Lopez LM, Lahti J, Tanaka T, Yanek LR, Oudot-Mellakh T, Wilson JF, Navarro P, Huffman JE, Zemunik T, Redline S, Mehra R, Pulanic D, Rudan I, Wright AF, Kolcic I, Polasek O, Wild SH, Campbell H, Curb JD, Wallace R, Liu S, Eaton CB, Becker DM, Becker LC, Bandinelli S, Räikkönen K, Widen E, Palotie A, Fornage M, Green D, Gross M, Davies G, Harris SE, Liewald DC, Starr JM, Williams FM, Grant P, Spector TD, Strawbridge RJ, Silveira A, Sennblad B, Rivadeneira F, Uitterlinden AG, Franco OH, Hofman A, van Dongen J, Willemsen G, Boomsma DI, Yao J, Jenny NS, Haritunians T, McKnight B, Lumley T, Taylor KD, Rotter JI, Psaty BM, Peters A, Gieger C, Illig T, Grotevendt A, Homuth G, Völzke H, Kocher T, Goel A, Franzosi MG, Seedorf U, Clarke R, Steri M, Tarasov KV, Sanna S, Schlessinger D, Stott DJ, Sattar N, Buckley BM, Rumley A, Lowe GD, McArdle WL, Chen MH, Tofler GH, Song J, Boerwinkle E, Folsom AR, Rose LM, Franco-Cereceda A, Teichert M, Ikram MA, Mosley TH, Bevan S, Dichgans M, Rothwell PM, Sudlow CLM, Hopewell JC, Chambers JC, Saleheen D, Kooner JS, Danesh J, Nelson CP, Erdmann J, Reilly MP, Kathiresan S, Schunkert H, Morange PE, Ferrucci L, Eriksson JG, Jacobs D, Deary IJ, Soranzo N, Witteman JCM, de Geus EJC, Tracy RP, Hayward C, Koenig W, Cucca F, Jukema JW, Eriksson P, Seshadri S, Markus HS, Watkins H, Samani NJ, Wallaschofski H, Smith NL, Tregouet D, Ridker PM, Tang W, Strachan DP, Hamsten A, O’Donnell CJ. Multiethnic meta-analysis of genome-wide association studies in >100 000 subjects identifies 23 fibrinogen-associated Loci but no strong evidence of a causal association between circulating fibrinogen and cardiovascular disease. Circulation 2013; 128:1310-24. [PMID: 23969696 PMCID: PMC3842025 DOI: 10.1161/circulationaha.113.002251] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 07/12/2013] [Indexed: 11/16/2022]
Abstract
BACKGROUND Estimates of the heritability of plasma fibrinogen concentration, an established predictor of cardiovascular disease, range from 34% to 50%. Genetic variants so far identified by genome-wide association studies explain only a small proportion (<2%) of its variation. METHODS AND RESULTS We conducted a meta-analysis of 28 genome-wide association studies including >90 000 subjects of European ancestry, the first genome-wide association meta-analysis of fibrinogen levels in 7 studies in blacks totaling 8289 samples, and a genome-wide association study in Hispanics totaling 1366 samples. Evaluation for association of single-nucleotide polymorphisms with clinical outcomes included a total of 40 695 cases and 85 582 controls for coronary artery disease, 4752 cases and 24 030 controls for stroke, and 3208 cases and 46 167 controls for venous thromboembolism. Overall, we identified 24 genome-wide significant (P<5×10(-8)) independent signals in 23 loci, including 15 novel associations, together accounting for 3.7% of plasma fibrinogen variation. Gene-set enrichment analysis highlighted key roles in fibrinogen regulation for the 3 structural fibrinogen genes and pathways related to inflammation, adipocytokines, and thyrotrophin-releasing hormone signaling. Whereas lead single-nucleotide polymorphisms in a few loci were significantly associated with coronary artery disease, the combined effect of all 24 fibrinogen-associated lead single-nucleotide polymorphisms was not significant for coronary artery disease, stroke, or venous thromboembolism. CONCLUSIONS We identify 23 robustly associated fibrinogen loci, 15 of which are new. Clinical outcome analysis of these loci does not support a causal relationship between circulating levels of fibrinogen and coronary artery disease, stroke, or venous thromboembolism.
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Wu G, Krebs CR, Lin FC, Wolberg AS, Oldenburg AL. High sensitivity micro-elastometry: applications in blood coagulopathy. Ann Biomed Eng 2013; 41:2120-9. [PMID: 23649979 DOI: 10.1007/s10439-013-0817-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Accepted: 04/19/2013] [Indexed: 11/30/2022]
Abstract
Highly sensitive methods for the assessment of clot structure can aid in our understanding of coagulation disorders and their risk factors. Rapid and simple clot diagnostic systems are also needed for directing treatment in a broad spectrum of cardiovascular diseases. Here we demonstrate a method for micro-elastometry, named resonant acoustic spectroscopy with optical vibrometry (RASOV), which measures the clot elastic modulus (CEM) from the intrinsic resonant frequency of a clot inside a microwell. We observed a high correlation between the CEM of human blood measured by RASOV and a commercial thromboelastograph (TEG), (R = 0.966). Unlike TEG, RASOV requires only 150 μL of sample and offers improved repeatability. Since CEM is known to primarily depend upon fibrin content and network structure, we investigated the CEM of purified clots formed with varying amounts of fibrinogen and thrombin. We found that RASOV was sensitive to changes of fibrinogen content (0.5-6 mg/mL), as well as to the amount of fibrinogen converted to fibrin during clot formation. We then simulated plasma hypercoagulability via hyperfibrinogenemia by spiking whole blood to 150 and 200% of normal fibrinogen levels, and subsequently found that RASOV could detect hyperfibrinogenemia-induced changes in CEM and distinguish these conditions from normal blood.
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Affiliation(s)
- Gongting Wu
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, CB 3255, Chapel Hill, NC 27599, USA
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16
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Lawlor DA, Nordestgaard BG, Benn M, Zuccolo L, Tybjaerg-Hansen A, Davey Smith G. Exploring causal associations between alcohol and coronary heart disease risk factors: findings from a Mendelian randomization study in the Copenhagen General Population Study. Eur Heart J 2013; 34:2519-28. [DOI: 10.1093/eurheartj/eht081] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Kengne AP, Czernichow S, Stamatakis E, Hamer M, Batty GD. Fibrinogen and future cardiovascular disease in people with diabetes: aetiological associations and risk prediction using individual participant data from nine community-based prospective cohort studies. Diab Vasc Dis Res 2013; 10:143-51. [PMID: 22786872 DOI: 10.1177/1479164112451588] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
AIMS We assessed the associations of fibrinogen levels with cardiovascular disease (CVD) risks in people with and without diabetes, and quantified the value of adding fibrinogen to the established predictive algorithms for CVD. METHODS We used Cox models to analyse data from prospective cohorts totalling 33,091 adults (1006 with diabetes) who took part in British and Scottish general population-based health surveys. Discrimination was assessed through c-statistic. RESULTS During a median follow-up of 116 months, 351 deaths (119 CVD) were recorded in participants with diabetes and 4157 deaths (1167 CVD) in those without. After adjustment for age and sex, fibrinogen (per standard deviation log(e)) was positively associated with a 34% (26-42%) higher risk of cardiovascular disease and 30% (26-35%) greater risk all-cause mortality. These associations were log-linear, similar in people with and without diabetes (p-value for interaction ≥0.21), robust to the adjustment of additional major CVD risk factors. Adding fibrinogen to a model containing conventional CVD risk factors resulted in only modest improvement in risk prediction. CONCLUSIONS The associations of fibrinogen with CVD and all-cause mortality are broadly similar in people with and without diabetes status. Improvement in predictive accuracy after adding fibrinogen to established risk factors is not clinically important.
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Affiliation(s)
- Andre P Kengne
- NCRP for Cardiovascular and Metabolic Disease, South African Medical Research Council and University of Cape Town, South Africa.
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Klovaite J, Nordestgaard BG, Tybjærg-Hansen A, Benn M. Elevated Fibrinogen Levels Are Associated with Risk of Pulmonary Embolism, but Not with Deep Venous Thrombosis. Am J Respir Crit Care Med 2013; 187:286-93. [DOI: 10.1164/rccm.201207-1232oc] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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Li YY, Wu XY, Xu J, Qian Y, Zhou CW, Wang B. Apo A5 −1131T/C, FgB −455G/A, −148C/T, and CETP TaqIB gene polymorphisms and coronary artery disease in the Chinese population: a meta-analysis of 15,055 subjects. Mol Biol Rep 2012; 40:1997-2014. [DOI: 10.1007/s11033-012-2257-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 10/26/2012] [Indexed: 11/30/2022]
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Harbord RM, Didelez V, Palmer TM, Meng S, Sterne JAC, Sheehan NA. Severity of bias of a simple estimator of the causal odds ratio in Mendelian randomization studies. Stat Med 2012; 32:1246-58. [PMID: 23080538 DOI: 10.1002/sim.5659] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 09/26/2012] [Indexed: 11/07/2022]
Abstract
Mendelian randomization studies estimate causal effects using genetic variants as instruments. Instrumental variable methods are straightforward for linear models, but epidemiologists often use odds ratios to quantify effects. Also, odds ratios are often the quantities reported in meta-analyses. Many applications of Mendelian randomization dichotomize genotype and estimate the population causal log odds ratio for unit increase in exposure by dividing the genotype-disease log odds ratio by the difference in mean exposure between genotypes. This 'Wald-type' estimator is biased even in large samples, but whether the magnitude of bias is of practical importance is unclear. We study the large-sample bias of this estimator in a simple model with a continuous normally distributed exposure, a single unobserved confounder that is not an effect modifier, and interpretable parameters. We focus on parameter values that reflect scenarios in which we apply Mendelian randomization, including realistic values for the degree of confounding and strength of the causal effect. We evaluate this estimator and the causal odds ratio using numerical integration and obtain approximate analytic expressions to check results and gain insight. A small simulation study examines finite sample bias and mild violations of the normality assumption. For our simple data-generating model, we find that the Wald estimator is asymptotically biased with a bias of around 10% in fairly typical Mendelian randomization scenarios but which can be larger in more extreme situations. Recently developed methods such as structural mean models require fewer untestable assumptions and we recommend their use when the individual-level data they require are available. The Wald-type estimator may retain a role as an approximate method for meta-analysis based on summary data.
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Affiliation(s)
- Roger M Harbord
- School of Social and Community Medicine, University of Bristol, Bristol, UK
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Niu W, Qi Y, Wu Z, Liu Y, Zhu D, Jin W. A meta-analysis of receptor for advanced glycation end products gene: four well-evaluated polymorphisms with diabetes mellitus. Mol Cell Endocrinol 2012; 358:9-17. [PMID: 22402134 DOI: 10.1016/j.mce.2012.02.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2011] [Revised: 02/06/2012] [Accepted: 02/10/2012] [Indexed: 11/18/2022]
Abstract
Genetic association studies on the gene encoding receptor for advanced glycation end products (RAGE) and diabetes mellitus have reported conflicting results. To evaluate the association of RAGE gene four widely-evaluated polymorphisms (T-429C, T-374A, Gly82Ser and G1704T) and diabetes mellitus, a meta-analysis was conducted. A random-effects model was applied irrespective of between-study heterogeneity. There were a total of 5808/3742 (n=14) case-patients/controls (studies) for T-429C, 8259/6935 (n=19) for T-374A, 7029/5266 (n=19) for Gly82Ser, and 2843/3302 (n=13) for G1704T. Overall results detected no significant association of polymorphisms T-429C, T-374A and Gly82Ser with diabetes risk. There was a trend toward an increased risk for alleles 1704T relative to 1704G (odds ratio [OR]=1.09; 95% confidence interval [CI]: 0.98-1.22; I(2)=0). Subgroup analysis by ethnicity indicated that allele 1704T conferred a significantly increased risk in East Asians (OR=1.21; 95% CI: 1.04-1.4; I(2)=0) but not in Caucasians (OR=0.8; 95% CI: 0.6-1.07; I(2)=0), and that by type of diabetes mellitus indicated that association was potentiated exclusively for G1704T with diabetic retinopathy (OR=1.24; 95% CI: 1.01-1.51; I(2)=0). No publication bias was observed. Our results provide convincing evidence regarding the association of RAGE gene 1704T allele with an increased risk of diabetes mellitus, especially diabetic retinopathy. Notably, this effect was more pronounced in East Asians.
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Affiliation(s)
- Wenquan Niu
- State Key Laboratory of Medical Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Niu W, Liu Y, Qi Y, Wu Z, Zhu D, Jin W. Association of interleukin-6 circulating levels with coronary artery disease: a meta-analysis implementing mendelian randomization approach. Int J Cardiol 2012; 157:243-52. [PMID: 22261689 DOI: 10.1016/j.ijcard.2011.12.098] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 12/08/2011] [Accepted: 12/25/2011] [Indexed: 12/21/2022]
Abstract
BACKGROUND We aim to investigate whether the association between circulating interleukin 6 (IL-6) levels and the risk for coronary artery disease (CAD) is robust and perhaps even causal by a meta-analysis implementing mendelian randomization approach with IL-6 gene G-174C polymorphism as an instrument. METHODS Data were available from 19 articles encompassing 9417 CAD patients and 15982 controls. A random effects model was applied irrespectively of between-study heterogeneity, and publication bias was examined using a funnel plot and the corresponding statistics. RESULTS Overall, comparison of IL-6 gene alleles -174C with -174G had 4% increased risk for CAD (95% confidence interval [95% CI]: 0.97-1.10; P=0.285), accompanying marginal heterogeneity (I(2)=38.3%; P=0.033). This association was potentiated in dominant model as odds ratio (OR) reached 1.08 (95% CI: 0.96-1.22; P=0.204) and heterogeneity was significant (I(2)=58.4%; P<0.0005). Subgroup analysis by ethnicity indicated that carriers of -174C allele were associated with a 12% increased risk for CAD in prospective studies involving White populations (OR=1.12; 95% CI: 0.95-1.33; P=0.184), whereas the association in East Asians was remarkably reversed with 37-46% reduced risk. Relative to -174GG homozygotes, carriers of -174C allele had an overall 0.24 pg/ml high circulating IL-6 levels (P=0.047). The predicted OR for 1 pg/ml elevation in IL-6 levels was 1.60 (95% CI: 1.44-1.72; P<0.01) in prospective studies involving White populations. Publication biases were absent for all comparisons (P>0.1). CONCLUSION Our findings provided strong evidence on the causal association of circulating IL-6 levels with the development of CAD in White populations.
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Affiliation(s)
- Wenquan Niu
- State Key Laboratory of Medical Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Abstract
Thrombosis is "haemostasis in the wrong place", and there is increasing evidence that haemostatic factors are associated with increased risk of atherothrombotic events. Increasing plasma levels of fibrinogen are associated with increased risks of coronary heart disease, stroke and peripheral arterial disease, and with vascular and nonvascular mortality. However, as with other markers of haemostasis (and of inflammation), their additional predictive value to conventional risk factors is small. Ongoing studies of activation markers of coagulation (e.g. fibrin D-dimer), endothelium (e.g. von Willebrand factor, tissue plasminogen activator antigen) and platelets (mean platelet volume) may provide additional predictive value for atherothrombotic events. However, at present there is no sufficient evidence base for their routine measurement in prediction.
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Affiliation(s)
- Gordon Lowe
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, BHF GCRC, 126 University Place, Glasgow G12 8TA, UK.
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Association of an apolipoprotein E polymorphism with circulating cholesterols and hypertension: a meta-based Mendelian randomization analysis. Hypertens Res 2011; 35:434-40. [DOI: 10.1038/hr.2011.202] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Vansteelandt S, Bowden J, Babanezhad M, Goetghebeur E. On Instrumental Variables Estimation of Causal Odds Ratios. Stat Sci 2011. [DOI: 10.1214/11-sts360] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Liu J, Liang Q, Frost-Pineda K, Muhammad-Kah R, Rimmer L, Roethig H, Mendes P, Sarkar M. Relationship between biomarkers of cigarette smoke exposure and biomarkers of inflammation, oxidative stress, and platelet activation in adult cigarette smokers. Cancer Epidemiol Biomarkers Prev 2011; 20:1760-9. [PMID: 21708936 DOI: 10.1158/1055-9965.epi-10-0987] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Cigarette smoking is a risk factor for several diseases, including cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer, but the role of specific smoke constituents in these diseases has not been clearly established. METHODS The relationships between biomarkers of potential harm (BOPH), associated with inflammation [white blood cell (WBC), high sensitivity C-reactive protein (hs-CRP), fibrinogen, and von Willebrand factor (vWF)], oxidative stress [8-epi-prostaglandin F(2α) (8-epiPGF(2α))] and platelet activation [11-dehydro-thromboxin B(2) (11-dehTxB(2))], and machine-measured tar yields (grouped into four categories), biomarkers of exposure (BOE) to cigarette smoke: nicotine and its five metabolites (nicotine equivalents), 4-methylnitrosamino-1-(3-pyridyl)-1-butanol (total NNAL), carboxyhemoglobin, 1-hydroxypyrene, 3-hydroxypropylmercapturic acid, and monohydroxybutenyl-mercapturic acid, were investigated in 3,585 adult smokers and 1,077 nonsmokers. RESULTS Overall, adult smokers had higher levels of BOPHs than nonsmokers. Body mass index (BMI), smoking duration, tar category, and some of the BOEs were significant factors in the multiple regression models. Based on the F value, BMI was the highest ranking factor in the models for WBC, hs-CRP, fibrinogen, and 8-epiPGF(2α), respectively, and gender and smoking duration for 11-dehTxB(2) and vWF, respectively. CONCLUSIONS Although several demographic factors and some BOEs were statistically significant in the model, the R(2) values indicate that only up to 22% of the variability can be explained by these factors, reflecting the complexity and multifactorial nature of the disease mechanisms. IMPACT The relationships between the BOEs and BOPHs observed in this study may help with the identification of appropriate biomarkers and improve the design of clinical studies in smokers.
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Affiliation(s)
- Jianmin Liu
- Center for Research and Technology, Altria Client Services Inc., Richmond, VA 23219, USA.
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Tousoulis D, Papageorgiou N, Androulakis E, Briasoulis A, Antoniades C, Stefanadis C. Fibrinogen and cardiovascular disease: genetics and biomarkers. Blood Rev 2011; 25:239-45. [PMID: 21652129 DOI: 10.1016/j.blre.2011.05.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Several prospective epidemiological studies and clinical observations provided evidence regarding fibrinogen and coronary artery disease (CAD). Many of these studies firmly correlate fibrinogen with CAD. However, it is uncertain whether this relation is causal or reflects genetic variability and residual confounding by other risk factors. Several polymorphisms on fibrinogen chain genes affect its levels, however only few of the genetic variants are associated with increased cardiovascular risk. As regards the role of fibrinogen in myocardial infarction (MI) studies indicate that genetic variations have at best a modest impact on the process resulting in MI. Therefore, the screening of fibrinogen genes might not be useful for the assessment of the risk of MI. However, the findings that specific genotypes lead to specific differences in fibrinogen levels, but may not be linked to cardiovascular risk, complicates the hypothesis of causality of fibrinogen in the pathogenesis of cardiovascular disease.
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Affiliation(s)
- Dimitris Tousoulis
- Athens University Medical School, Hippokration Hospital,Vasilissis Sofias 114, 115 28, Athens, Greece.
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Davey Smith G. Use of genetic markers and gene-diet interactions for interrogating population-level causal influences of diet on health. GENES & NUTRITION 2011; 6:27-43. [PMID: 21437028 PMCID: PMC3040803 DOI: 10.1007/s12263-010-0181-y] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 08/07/2010] [Indexed: 01/20/2023]
Abstract
Differences in diet appear to contribute substantially to the burden of disease in populations, and therefore changes in diet could lead to major improvements in public health. This is predicated on the reliable identification of causal effects of nutrition on health, and unfortunately nutritional epidemiology has deficiencies in terms of identifying these. This is reflected in the many cases where observational studies have suggested that a nutritional factor is protective against disease, and randomized controlled trials have failed to verify this. The use of genetic variants as proxy measures of nutritional exposure-an application of the Mendelian randomization principle-can contribute to strengthening causal inference in this field. Genetic variants are not subject to bias due to reverse causation (disease processes influencing exposure, rather than vice versa) or recall bias, and if obvious precautions are applied are not influenced by confounding or attenuation by errors. This is illustrated in the case of epidemiological studies of alcohol intake and various health outcomes, through the use of genetic variants related to alcohol metabolism (in ALDH2 and ADH1B). Examples from other areas of nutritional epidemiology and of the informative nature of gene-environment interactions interpreted within the Mendelian randomization framework are presented, and the potential limitations of the approach addressed.
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Affiliation(s)
- George Davey Smith
- MRC Centre for Causal Analyses in Translational Epidemiology, Department of Social Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol, BS8 2BN UK
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Mendelian randomisation: a tool for assessing causality in observational epidemiology. Methods Mol Biol 2011; 713:153-66. [PMID: 21153618 DOI: 10.1007/978-1-60327-416-6_12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Detection and assessment of the effect of a modifiable risk factor on a disease with view to informing public health intervention policies are of fundamental concern in aetiological epidemiology. In order to have solid evidence that such a public health intervention has the desired effect, it is necessary to ascertain that an observed association or correlation between a risk factor and a disease means that the risk factor is causal for the disease. Inferring causality from observational data is difficult, typically due to confounding by social, behavioural, or physiological factors which are difficult to control for and particularly difficult to measure accurately. A possible approach to inferring causality when confounding is believed to be present but unobservable, as it may not even be fully understood, is based on the method of instrumental variables and is known under the name of Mendelian randomisation if the instrument is a genetic variant. While testing for the presence of a causal effect using this method is generally straightforward, point estimates of such an effect are only obtainable under additional parametric assumptions. This chapter introduces the concept and illustrates the method and its assumptions with simple real-life examples. It concludes with a brief discussion on pitfalls and limitations.
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Association of genomic loci from a cardiovascular gene SNP array with fibrinogen levels in European Americans and African-Americans from six cohort studies: the Candidate Gene Association Resource (CARe). Blood 2010; 117:268-75. [PMID: 20978265 DOI: 10.1182/blood-2010-06-289546] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several common genomic loci, involving various immunity- and metabolism-related genes, have been associated with plasma fibrinogen in European Americans (EAs). The genetic determinants of fibrinogen in African Americans (AAs) are poorly characterized. Using a vascular gene-centric array in 23,634 EA and 6657 AA participants from 6 studies comprising the Candidate Gene Association Resource project, we examined the association of 47,539 common and lower frequency variants with fibrinogen concentration. We identified a rare Pro265Leu variant in FGB (rs6054) associated with lower fibrinogen. Common fibrinogen gene single nucleotide polymorphisms (FGB rs1800787 and FGG rs2066861) significantly associated with fibrinogen in EAs were prevalent in AAs and showed consistent associations. Several fibrinogen locus single nucleotide polymorphism associated with lower fibrinogen were exclusive to AAs; these include a newly reported association with FGA rs10050257. For IL6R, IL1RN, and NLRP3 inflammatory gene loci, associations with fibrinogen were concordant between EAs and AAs, but not at other loci (CPS1, PCCB, and SCL22A5-IRF1). The association of FGG rs2066861 with fibrinogen differed according to assay type used to measure fibrinogen. Further characterization of common and lower-frequency genetic variants that contribute to interpopulation differences in fibrinogen phenotype may help refine our understanding of the contribution of hemostasis and inflammation to atherothrombotic risk.
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Smith GD. Mendelian Randomization for Strengthening Causal Inference in Observational Studies: Application to Gene × Environment Interactions. PERSPECTIVES ON PSYCHOLOGICAL SCIENCE 2010; 5:527-45. [PMID: 26162196 DOI: 10.1177/1745691610383505] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Identification of environmentally modifiable factors causally influencing disease risk is fundamental to public-health improvement strategies. Unfortunately, observational epidemiological studies are limited in their ability to reliably identify such causal associations, reflected in the many cases in which conventional epidemiological studies have apparently identified associations that randomized controlled trials have failed to verify. The use of genetic variants as proxy measures of exposure -an application of the Mendelian randomization principle-can contribute to strengthening causal inference. Genetic variants are not subject to bias due to reverse causation (disease processes influencing exposure, rather than vice versa) or recall bias, and if simple precautions are applied, they are not influenced by confounding or attenuation by errors. The principles of Mendelian randomization are illustrated with specific reference to studies of the effects of alcohol intake on various health-related outcomes through the utilization of genetic variants related to alcohol metabolism (in ALDH2 and ADH1B). Ways of incorporating Gene × Environment interactions into the Mendelian randomization framework are developed, and the strengths and limitations of the approach discussed.
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Affiliation(s)
- George Davey Smith
- School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom
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Brown IJ, Elliott P. Recent Findings from Mendelian Randomization Studies of Cardiovascular Disease. CURRENT CARDIOVASCULAR RISK REPORTS 2010. [DOI: 10.1007/s12170-010-0127-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Leukocyte counts, myeloperoxidase, and pregnancy-associated plasma protein a as biomarkers for cardiovascular disease: towards a multi-biomarker approach. Int J Vasc Med 2010; 2010:726207. [PMID: 21188207 PMCID: PMC3003971 DOI: 10.1155/2010/726207] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 03/18/2010] [Indexed: 11/18/2022] Open
Abstract
We evaluated leukocyte counts and levels of CRP, fibrinogen, MPO, and PAPP-A in patients with stable and unstable angina pectoris, acute myocardial infarction, and healthy controls. All biomarkers were analyzed again after 6 months. Leukocyte counts and concentrations of fibrinogen, CRP, MPO, and PAPP-A were significantly increased in patients with acute myocardial infarction. Leukocyte counts and concentrations of MPO were significantly increased in patients with unstable angina pectoris compared with controls. After 6 months, leukocyte counts and MPO concentrations were still increased in patients with acute myocardial infarction when compared to controls. Discriminant analysis showed that leukocyte counts, MPO, and PAPP-A concentrations classified study group designation for acute coronary events correctly in 83% of the cases. In conclusion, combined assessment of leukocyte counts, MPO, and PAPP-A was able to correctly classify acute coronary events, suggesting that this could be a promising panel for a multibiomarker approach to assess cardiovascular risk.
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Green D, Chan C, Kang J, Liu K, Schreiner P, Jenny NS, Tracy RP. Longitudinal assessment of fibrinogen in relation to subclinical cardiovascular disease: the CARDIA study. J Thromb Haemost 2010; 8:489-95. [PMID: 20025644 PMCID: PMC2856753 DOI: 10.1111/j.1538-7836.2009.03727.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To examine the strength of the associations of fibrinogen with subclinical atherosclerosis in healthy persons. METHODS A population-based, prospective, observational study of black and white men and women (Coronary Artery Risk Development in Young Adults [CARDIA]). Fibrinogen levels were measured at year 7 (ages 25-37, n = 2969), and again at year 20 (ages 38-50, n = 2832). Measures of subclinical atherosclerosis (coronary artery calcification [CAC] and carotid intimal-medial thickness [CIMT]) were recorded at year 20. RESULTS Over the 13-year study interval (1992-1993 to 2005-2006), fibrinogen rose from a mean of 3.32 to 4.05 g L(-1). After adjusting for age, gender and race, fibrinogen was positively associated with greater incidence of CAC and increased CIMT cross-sectionally as well as after 13 years of follow-up (all P-trend < 0.001). After further adjustment for field center, BMI, smoking, education, systolic blood pressure, diabetes, antihypertensive medication use, total and HDL cholesterol, and CRP, significant positive relationships between fibrinogen and incidence of CAC remained for the total cohort longitudinally (P-trend = 0.037), but not cross-sectionally (P-trend = 0.147). CONCLUSION This 13-year study demonstrates that higher levels of fibrinogen during young adulthood are positively associated with incidence of CAC and increased CIMT in middle-age, but the strength of the association declines with increasing age.
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Affiliation(s)
- D Green
- Division of Hematology/Oncology, Department of Medicine, Feinberg School of Medicine of Northwestern University, Chicago, IL 60611, USA.
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Woodward M, Tunstall-Pedoe H, Rumley A, Lowe GDO. Does fibrinogen add to prediction of cardiovascular disease? Results from the Scottish Heart Health Extended Cohort Study. Br J Haematol 2009; 146:442-6. [PMID: 19549268 DOI: 10.1111/j.1365-2141.2009.07778.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Plasma fibrinogen is an established risk factor for cardiovascular disease (CVD), but it has not been established whether it adds predictive value to risk scores. In the Scottish Heart Health Extended Cohort Study, we measured plasma fibrinogen in 13 060 men and women, aged 30-74 years, initially free of CVD. After follow-up for a median of 19.2 years, 2626 subjects had at least one CVD event. After adjusting for classical CVD risk factors and socio-economic status, the hazard ratios (95% confidence interval) for a one unit (g/l) increase in plasma fibrinogen were 1.09 (1.02, 1.16) for men and 1.10 (1.02, 1.19) for women. Although fibrinogen added significantly to the discrimination of the Framingham risk score for women, it failed to do so for men. Fibrinogen did not add significantly to the ASSIGN risk score. Fibrinogen added between 1.3% and 3.2% to the classification of CVD status by the existing risk scores. We conclude that the added value of fibrinogen to two currently used risk scores is low; hence population screening with fibrinogen for this purpose is unlikely to be clinically useful or cost-effective.
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Affiliation(s)
- Mark Woodward
- Department of Medicine, Mount Sinai Medical School, New York, NY, USA
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Drenos F, Talmud PJ, Casas JP, Smeeth L, Palmen J, Humphries SE, Hingorani AD. Integrated associations of genotypes with multiple blood biomarkers linked to coronary heart disease risk. Hum Mol Genet 2009; 18:2305-16. [PMID: 19336475 PMCID: PMC2685759 DOI: 10.1093/hmg/ddp159] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Individuals at risk of coronary heart disease (CHD) show multiple correlations across blood biomarkers. Single nucleotide polymorphisms (SNPs) indexing biomarker differences could help distinguish causal from confounded associations because of their random allocation prior to disease. We examined the association of 948 SNPs in 122 candidate genes with 12 CHD-associated phenotypes in 2775 middle aged men (a genic scan). Of these, 140 SNPs indexed differences in HDL- and LDL-cholesterol, triglycerides, C-reactive protein, fibrinogen, factor VII, apolipoproteins AI and B, lipoprotein-associated phospholipase A2, homocysteine or folate, some with large effect sizes and highly significant P-values (e.g. 2.15 standard deviations at P = 9.2 × 10−140 for F7 rs6046 and FVII levels). Top ranking SNPs were then tested for association with additional biomarkers correlated with the index phenotype (phenome scan). Several SNPs (e.g. in APOE, CETP, LPL, APOB and LDLR) influenced multiple phenotypes, while others (e.g. in F7, CRP and FBB) showed restricted association to the index marker. SNPs influencing six blood proteins were used to evaluate the nature of the associations between correlated blood proteins utilizing Mendelian randomization. Multiple SNPs were associated with CHD-related quantitative traits, with some associations restricted to a single marker and others exerting a wider genetic ‘footprint’. SNPs indexing biomarkers provide new tools for investigating biological relationships and causal links with disease. Broader and deeper integrated analyses, linking genomic with transcriptomic, proteomic and metabolomic analysis, as well as clinical events could, in principle, better delineate CHD causing pathways amenable to treatment.
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Affiliation(s)
- Fotios Drenos
- Division of Cardiovascular Genetics, Department of Medicine, Royal Free and University College Medical School, 5 University St, London WC1E 6JF, UK
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Hingorani AD, Shah T, Casas JP, Humphries SE, Talmud PJ. C-reactive protein and coronary heart disease: predictive test or therapeutic target? Clin Chem 2008; 55:239-55. [PMID: 19114670 DOI: 10.1373/clinchem.2008.115923] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND The hepatocyte-derived acute-phase reactant C-reactive protein (CRP) has been the subject of intense research over the last 2 decades for its possible role in the pathogenesis of cardiovascular diseases. This research has spawned interest in the use of the blood concentration of CRP for predicting a first coronary heart disease (CHD) event, which has been made possible with the development of high-sensitivity CRP (hsCRP) assays that can measure the typically low concentrations of CRP that circulate in the absence of an overt infective or inflammatory episode, and as a potential causal factor that might be targeted therapeutically. The research has encompassed observational and genetic epidemiology, basic science studies with cells and tissues, experiments with animal models and humans, and randomized trials (although not of specific CRP-lowering therapies as yet). CONTENT We focus on investigations of the potential role of small differences in basal hsCRP concentration seen in healthy individuals and the relationship of such differences to the long-term risk of a first CHD event, rather than on research devoted to the high acute-phase CRP concentrations, which occur after acute atherothrombotic events and can influence the severity of ischemic tissue damage and the subsequent prognosis. We concentrate mainly on research findings at the translational interface and draw on evidence from human observational and genetic epidemiology, as well as from randomized trials. CONCLUSIONS As the field matures from one of discovery to an evaluative science, the development of possible clinical applications requires a sharpening of focus on and a critical appraisal of the strengths and deficiencies of the accumulated evidence. Such assessments require attention to both the current state of affairs and the design of future research, so that the existing uncertainties about the utility of CRP in predicting CHD and its role in causing this disease can be resolved.
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Affiliation(s)
- Aroon D Hingorani
- Division of Population Sciences, Department of Epidemiology and Public Health, University College London, London, UK
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Casas JP, Shah T, Hingorani AD, Danesh J, Pepys MB. C-reactive protein and coronary heart disease: a critical review. J Intern Med 2008; 264:295-314. [PMID: 18823504 DOI: 10.1111/j.1365-2796.2008.02015.x] [Citation(s) in RCA: 248] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Modestly elevated baseline concentrations of C-reactive protein (CRP), the classical acute phase protein, are associated with the long-term risk of coronary heart disease in general populations, whilst the major acute phase response of CRP following myocardial infarction is associated with death and cardiac complications. The pathogenic and clinical significance of these associations is controversial. Here we critically review the evidence and describe large-scale epidemiological studies, novel experiments and possible specific therapies which will rigorously inform the debate. We distinguish between the potential pathogenicity of high acute phase circulating CRP concentrations in individuals with substantial tissue damage and modest but persistent increases in baseline values in generally healthy subjects.
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Affiliation(s)
- J P Casas
- Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, University College London, London, UK
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40
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Abstract
Nuala Sheehan and colleagues describe how Mendelian randomization provides an alternative way of dealing with the problems of observational studies, especially confounding.
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Affiliation(s)
- Nuala A Sheehan
- Department of Health Sciences, University of Leicester, Leicester, United Kingdom.
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41
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Ioannidis JPA. Effect of formal statistical significance on the credibility of observational associations. Am J Epidemiol 2008; 168:374-83; discussion 384-90. [PMID: 18611956 DOI: 10.1093/aje/kwn156] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The author evaluated the implications of nominal statistical significance for changing the credibility of null versus alternative hypotheses across a large number of observational associations for which formal statistical significance (p < 0.05) was claimed. Calculation of the Bayes factor (B) under different assumptions was performed on 272 observational associations published in 2004-2005 and a data set of 50 meta-analyses on gene-disease associations (752 studies) for which statistically significant associations had been claimed (p < 0.05). Depending on the formulation of the prior, statistically significant results offered less than strong support to the credibility (B > 0.10) for 54-77% of the 272 epidemiologic associations for diverse risk factors and 44-70% of the 50 associations from genetic meta-analyses. Sometimes nominally statistically significant results even decreased the credibility of the probed association in comparison with what was thought before the study was conducted. Five of six meta-analyses with less than substantial support (B > 0.032) lost their nominal statistical significance in a subsequent (more recent) meta-analysis, while this did not occur in any of seven meta-analyses with decisive support (B < 0.01). In these large data sets of observational associations, formal statistical significance alone failed to increase much the credibility of many postulated associations. Bayes factors may be used routinely to interpret "significant" associations.
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Affiliation(s)
- John P A Ioannidis
- Clinical and Molecular Epidemiology Unit, Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina, Greece.
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42
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Influence of fibrinogen β-chain gene variations on risk of myocardial infarction in a Chinese Han population. Chin Med J (Engl) 2008. [DOI: 10.1097/00029330-200808020-00009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Elevated fibrinogen levels and subsequent subclinical atherosclerosis: the CARDIA Study. Atherosclerosis 2008; 202:623-31. [PMID: 18602107 DOI: 10.1016/j.atherosclerosis.2008.05.039] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Revised: 05/23/2008] [Accepted: 05/25/2008] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To determine whether elevated levels of hemostatic factors are associated with the subsequent development of subclinical cardiovascular disease. METHODS Fibrinogen, factors VII (FVII) and VIII (FVIII), and von Willebrand factor (vWF) were measured in 1396 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Coronary artery calcification (CAC) and carotid intimal/medial thickness (CIMT) were determined 13 years later. The adjusted prevalence of CAC and mean CIMT across the quartiles of each hemostatic factor was computed for the total sample and for each race and gender group. RESULTS The age-, race-, and gender-adjusted prevalences of CAC with increasing quartiles of fibrinogen were 14.4%, 15.2%, 20.0%, and 29.1% (p<0.001 for trend). This trend persisted after further adjustment for body mass index (BMI), smoking, educational level, center, systolic blood pressure (BP), diabetes, antihypertensive medication use, total and high-density lipoprotein (HDL) cholesterol, and CRP. A similar trend was observed for CIMT (age-, race- and gender-adjusted, p<0.001; multivariable-adjusted, p=0.014). Further analyses of race and gender subgroups showed that increasing quartiles of fibrinogen were associated with CAC and CIMT in all subgroups except black men. The prevalence of CAC was not associated with increasing quartiles of FVII, FVIII, or vWF, suggesting they may be less involved in plaque progression. CONCLUSION An elevated fibrinogen concentration in persons aged 25-37 is independently associated with subclinical cardiovascular disease in the subsequent decade.
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Kivimäki M, Smith GD, Timpson NJ, Lawlor DA, Batty GD, Kähönen M, Juonala M, Rönnemaa T, Viikari JSA, Lehtimäki T, Raitakari OT. Lifetime body mass index and later atherosclerosis risk in young adults: examining causal links using Mendelian randomization in the Cardiovascular Risk in Young Finns study. Eur Heart J 2008; 29:2552-60. [PMID: 18550552 PMCID: PMC2567023 DOI: 10.1093/eurheartj/ehn252] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Aims Mendelian randomization uses genetic variants related to environmentally modifiable risk factors in an attempt to improve causal inference from observational data. We examined the effect of lifetime body mass index (BMI) on adult carotid intima-media thickness (CIMT) and various atherosclerotic risk factors by using both Mendelian randomization and conventional analyses. Methods and results A total of 2230 individuals (1218 women), aged 3–18 at study induction, took part in clinical examinations in 1980, 1983, 1986, and, most recently, 2001 when they were aged 24–39. In these analyses we utilized the known relation between FTO polymorphism rs9939609 and BMI. The dose–response association between the number of A alleles in FTO and higher mean BMI from childhood to adulthood was confirmed, but no associations with potential confounding factors were observed. In standard regression models, lifetime BMI was associated with adult CIMT, lifetime systolic blood pressure, adult fasting glucose, and adult HOMA-index. When variation in FTO was used as an instrument for unconfounded BMI levels, similar or larger effects of lifetime BMI on all these phenotypes were found, although with wider confidence intervals. Conclusion Mutually supportive results from Mendelian randomization and standard regression models strengthen the evidence of the effect of lifetime BMI on atherosclerosis risk in young adults.
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Affiliation(s)
- Mika Kivimäki
- Department of Epidemiology and Public Health, University College London, London, UK.
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Koch W, Hoppmann P, Biele J, Mueller JC, Schömig A, Kastrati A. Fibrinogen Genes and Myocardial Infarction. Arterioscler Thromb Vasc Biol 2008; 28:758-63. [DOI: 10.1161/atvbaha.107.157842] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective—
Fibrinogen has a role in inflammatory processes and participates in atherosclerotic plaque formation. Despite intensive investigation, there is no clear evidence for a role of variations in the genes coding for the fibrinogen-α, fibrinogen-β, and fibrinogen-γ polypeptide chains in myocardial infarction. We examined the association of haplotypes in the 50-kb fibrinogen gene region with myocardial infarction in 2 large case-control samples.
Methods and Results—
Study sample 1 consisted of 3657 patients with myocardial infarction and 1211 control individuals and sample 2 comprised 1392 patients and 1392 controls. Haplotypes were inferred from genotype analyses of tagging single nucleotide polymorphisms dispersed among the fibrinogen genes. The frequencies of these haplotypes were not significantly different between the case and control groups in either sample (
P
≥0.07). In addition, haplotypes specific for individual fibrinogen genes were analyzed. No substantial differences in the frequencies of these haplotypes were observed between the groups (
P
≥0.13). Finally, haplotypes composed of SNPs that exhibited relatively low pairwise allelic associations among each other were examined. The proportions of the haplotypes were not significantly different between cases and controls (
P
≥0.12).
Conclusion—
A haplotype analysis did not reveal a link between genetic variations in the fibrinogen gene region and myocardial infarction.
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Affiliation(s)
- Werner Koch
- From the Deutsches Herzzentrum München and 1. Medizinische Klinik, Klinikum rechts der Isar (W.K., P.H., J.B., A.S., A.K.), Munich, and Max Planck Institute for Ornithology (J.C.M.), Department of Behavioural Ecology and Evolutionary Genetics, Starnberg (Seewiesen), Germany
| | - Petra Hoppmann
- From the Deutsches Herzzentrum München and 1. Medizinische Klinik, Klinikum rechts der Isar (W.K., P.H., J.B., A.S., A.K.), Munich, and Max Planck Institute for Ornithology (J.C.M.), Department of Behavioural Ecology and Evolutionary Genetics, Starnberg (Seewiesen), Germany
| | - Janita Biele
- From the Deutsches Herzzentrum München and 1. Medizinische Klinik, Klinikum rechts der Isar (W.K., P.H., J.B., A.S., A.K.), Munich, and Max Planck Institute for Ornithology (J.C.M.), Department of Behavioural Ecology and Evolutionary Genetics, Starnberg (Seewiesen), Germany
| | - Jakob C. Mueller
- From the Deutsches Herzzentrum München and 1. Medizinische Klinik, Klinikum rechts der Isar (W.K., P.H., J.B., A.S., A.K.), Munich, and Max Planck Institute for Ornithology (J.C.M.), Department of Behavioural Ecology and Evolutionary Genetics, Starnberg (Seewiesen), Germany
| | - Albert Schömig
- From the Deutsches Herzzentrum München and 1. Medizinische Klinik, Klinikum rechts der Isar (W.K., P.H., J.B., A.S., A.K.), Munich, and Max Planck Institute for Ornithology (J.C.M.), Department of Behavioural Ecology and Evolutionary Genetics, Starnberg (Seewiesen), Germany
| | - Adnan Kastrati
- From the Deutsches Herzzentrum München and 1. Medizinische Klinik, Klinikum rechts der Isar (W.K., P.H., J.B., A.S., A.K.), Munich, and Max Planck Institute for Ornithology (J.C.M.), Department of Behavioural Ecology and Evolutionary Genetics, Starnberg (Seewiesen), Germany
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Smith GD, Timpson N, Ebrahim S. Strengthening causal inference in cardiovascular epidemiology through Mendelian randomization. Ann Med 2008; 40:524-41. [PMID: 18608114 DOI: 10.1080/07853890802010709] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Observational studies have contributed in a major way to understanding modifiable determinants of cardiovascular disease risk, but several examples exist of factors that were identified in observational studies as potentially protecting against coronary heart disease, that in randomized controlled trials had no such effect. The likely reason for misleading findings from observational epidemiological studies is that associations are influenced by confounding, bias, and reverse causation--where disease influences a risk factor, rather than vice versa. Mendelian randomization utilizes genetic variants that serve as proxy measures for modifiable risk factors to allow estimation of the causal influence of the modifiable risk factor in question. We present examples of the use of the Mendelian randomization approach and discuss both the limitations and potentials of this strategy.
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Affiliation(s)
- George Davey Smith
- MRC Centre for Causal Analyses in Translational Epidemiology, Department of Social Medicine, University of Bristol, Bristol, UK.
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47
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Lawlor DA, Harbord RM, Sterne JAC, Timpson N, Davey Smith G. Mendelian randomization: Using genes as instruments for making causal inferences in epidemiology. Stat Med 2008; 27:1133-63. [PMID: 17886233 DOI: 10.1002/sim.3034] [Citation(s) in RCA: 2507] [Impact Index Per Article: 156.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Observational epidemiological studies suffer from many potential biases, from confounding and from reverse causation, and this limits their ability to robustly identify causal associations. Several high-profile situations exist in which randomized controlled trials of precisely the same intervention that has been examined in observational studies have produced markedly different findings. In other observational sciences, the use of instrumental variable (IV) approaches has been one approach to strengthening causal inferences in non-experimental situations. The use of germline genetic variants that proxy for environmentally modifiable exposures as instruments for these exposures is one form of IV analysis that can be implemented within observational epidemiological studies. The method has been referred to as 'Mendelian randomization', and can be considered as analogous to randomized controlled trials. This paper outlines Mendelian randomization, draws parallels with IV methods, provides examples of implementation of the approach and discusses limitations of the approach and some methods for dealing with these.
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Smith NL, Bis JC, Biagiotti S, Rice K, Lumley T, Kooperberg C, Wiggins KL, Heckbert SR, Psaty BM. Variation in 24 hemostatic genes and associations with non-fatal myocardial infarction and ischemic stroke. J Thromb Haemost 2008; 6:45-53. [PMID: 17927806 DOI: 10.1111/j.1538-7836.2007.02795.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Arterial thrombosis involves platelet aggregation and clot formation, yet little is known about the contribution of genetic variation in fibrin-based hemostatic factors to arterial clotting risk. We hypothesized that common variation in 24 coagulation-fibrinolysis genes would contribute to risk of incident myocardial infarction (MI) or ischemic stroke (IS). METHODS We conducted a population-based, case-control study. Subjects were hypertensive adults and postmenopausal women 30-79 years of age, who sustained a first MI (n = 856) or IS (n = 368) between 1995 and 2002, and controls matched on age, hypertension status, and calendar year (n = 2,689). We investigated the risk of MI and IS associated with (i) global variation within each gene as measured by common haplotypes and (ii) individual haplotypes and single nucleotide polymorphisms (SNPs). Significance was assessed using a 0.2 threshold of the false discovery rate q-value, which accounts for multiple testing. RESULTS After accounting for multiple testing, global genetic variation in factor (F) VIII was associated with IS risk. Two haplotypes in FVIII and one in FXIIIa1 were significantly associated with increased IS risk (all q-values < 0.2). A plasminogen gene SNP was associated with MI risk. All are new discoveries not previously reported. Another 24 tests had P-values < 0.05 and q-values > 0.2 in MI and IS analyses, 23 of which are new and hypothesis generating. CONCLUSIONS Apart from the association of FVIII variation with IS, we found little evidence that common variation in the 24 candidate fibrin-based hemostasis genes strongly influences arterial thrombotic risk, but our results cannot rule out small effects.
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Affiliation(s)
- N L Smith
- Department of Epidemiology, University of Washington, Seattle, WA, USA.
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Smith GD, Lawlor DA, Harbord R, Timpson N, Day I, Ebrahim S. Clustered environments and randomized genes: a fundamental distinction between conventional and genetic epidemiology. PLoS Med 2007; 4:e352. [PMID: 18076282 PMCID: PMC2121108 DOI: 10.1371/journal.pmed.0040352] [Citation(s) in RCA: 365] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Accepted: 10/30/2007] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND In conventional epidemiology confounding of the exposure of interest with lifestyle or socioeconomic factors, and reverse causation whereby disease status influences exposure rather than vice versa, may invalidate causal interpretations of observed associations. Conversely, genetic variants should not be related to the confounding factors that distort associations in conventional observational epidemiological studies. Furthermore, disease onset will not influence genotype. Therefore, it has been suggested that genetic variants that are known to be associated with a modifiable (nongenetic) risk factor can be used to help determine the causal effect of this modifiable risk factor on disease outcomes. This approach, mendelian randomization, is increasingly being applied within epidemiological studies. However, there is debate about the underlying premise that associations between genotypes and disease outcomes are not confounded by other risk factors. We examined the extent to which genetic variants, on the one hand, and nongenetic environmental exposures or phenotypic characteristics on the other, tend to be associated with each other, to assess the degree of confounding that would exist in conventional epidemiological studies compared with mendelian randomization studies. METHODS AND FINDINGS We estimated pairwise correlations between nongenetic baseline variables and genetic variables in a cross-sectional study comparing the number of correlations that were statistically significant at the 5%, 1%, and 0.01% level (alpha = 0.05, 0.01, and 0.0001, respectively) with the number expected by chance if all variables were in fact uncorrelated, using a two-sided binomial exact test. We demonstrate that behavioural, socioeconomic, and physiological factors are strongly interrelated, with 45% of all possible pairwise associations between 96 nongenetic characteristics (n = 4,560 correlations) being significant at the p < 0.01 level (the ratio of observed to expected significant associations was 45; p-value for difference between observed and expected < 0.000001). Similar findings were observed for other levels of significance. In contrast, genetic variants showed no greater association with each other, or with the 96 behavioural, socioeconomic, and physiological factors, than would be expected by chance. CONCLUSIONS These data illustrate why observational studies have produced misleading claims regarding potentially causal factors for disease. The findings demonstrate the potential power of a methodology that utilizes genetic variants as indicators of exposure level when studying environmentally modifiable risk factors.
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Affiliation(s)
- George Davey Smith
- Department of Social Medicine, University of Bristol, Bristol, United Kingdom.
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Mendelian randomization: can genetic epidemiology help redress the failures of observational epidemiology? Hum Genet 2007; 123:15-33. [DOI: 10.1007/s00439-007-0448-6] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Accepted: 11/09/2007] [Indexed: 10/22/2022]
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