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Skrivankova VW, Richmond RC, Woolf BAR, Davies NM, Swanson SA, VanderWeele TJ, Timpson NJ, Higgins JPT, Dimou N, Langenberg C, Loder EW, Golub RM, Egger M, Davey Smith G, Richards JB. Strengthening the reporting of observational studies in epidemiology using mendelian randomisation (STROBE-MR): explanation and elaboration. BMJ 2021; 375:n2233. [PMID: 34702754 PMCID: PMC8546498 DOI: 10.1136/bmj.n2233] [Citation(s) in RCA: 369] [Impact Index Per Article: 123.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/02/2021] [Indexed: 12/15/2022]
Affiliation(s)
| | - Rebecca C Richmond
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Benjamin A R Woolf
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Department of Psychological Science, University of Bristol, Bristol, UK
| | - Neil M Davies
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- K G Jebsen Centre for Genetic Epidemiology, Department of Public Health and Nursing, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Sonja A Swanson
- Department of Epidemiology, Erasmus MC, Rotterdam, Netherlands
| | - Tyler J VanderWeele
- Department of Epidemiology, Harvard T H Chan School of Public Health, Boston, MA, USA
| | - Nicholas J Timpson
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Julian P T Higgins
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- NIHR Bristol Biomedical Research Centre, Bristol, UK
| | - Niki Dimou
- Nutrition and Metabolism Branch, International Agency for Research on Cancer, Lyon, France
| | - Claudia Langenberg
- Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
| | | | - Robert M Golub
- JAMA, Chicago, IL, USA
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Matthias Egger
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- Centre for Infectious Disease Epidemiology and Research, University of Cape Town, Cape Town, South Africa
| | - George Davey Smith
- Medical Research Council Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- NIHR Bristol Biomedical Research Centre, Bristol, UK
| | - J Brent Richards
- Departments of Medicine, Human Genetics, Epidemiology & Biostatistics, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, QC, Canada
- Department of Twin Research and Genetic Epidemiology, King's College London, University of London, London, UK
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Dixon P, Hollingworth W, Harrison S, Davies NM, Davey Smith G. Mendelian Randomization analysis of the causal effect of adiposity on hospital costs. JOURNAL OF HEALTH ECONOMICS 2020; 70:102300. [PMID: 32014825 PMCID: PMC7188219 DOI: 10.1016/j.jhealeco.2020.102300] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 01/06/2020] [Accepted: 01/14/2020] [Indexed: 05/12/2023]
Abstract
Estimates of the marginal effect of measures of adiposity such as body mass index (BMI) on healthcare costs are important for the formulation and evaluation of policies targeting adverse weight profiles. Most estimates of this association are affected by endogeneity bias. We use a novel identification strategy exploiting Mendelian Randomization - random germline genetic variation modelled using instrumental variables - to identify the causal effect of BMI on inpatient hospital costs. Using data on over 300,000 individuals, the effect size per person per marginal unit of BMI per year varied according to specification, including £21.22 (95% confidence interval (CI): £14.35-£28.07) for conventional inverse variance weighted models to £18.85 (95% CI: £9.05-£28.65) for penalized weighted median models. Effect sizes from Mendelian Randomization models were larger in most cases than non-instrumental variable multivariable adjusted estimates (£13.47, 95% CI: £12.51-£14.43). There was little evidence of non-linearity. Within-family estimates, intended to address dynastic biases, were imprecise.
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Affiliation(s)
- Padraig Dixon
- Population Health Sciences, University of Bristol, United Kingdom; MRC Integrative Epidemiology Unit, University of Bristol, United Kingdom.
| | | | - Sean Harrison
- Population Health Sciences, University of Bristol, United Kingdom; MRC Integrative Epidemiology Unit, University of Bristol, United Kingdom
| | - Neil M Davies
- Population Health Sciences, University of Bristol, United Kingdom; MRC Integrative Epidemiology Unit, University of Bristol, United Kingdom
| | - George Davey Smith
- Population Health Sciences, University of Bristol, United Kingdom; MRC Integrative Epidemiology Unit, University of Bristol, United Kingdom; NIHR Biomedical Research Centre, University of Bristol, United Kingdom
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Richardson S, Tseng GC, Sun W. Statistical Methods in Integrative Genomics. ANNUAL REVIEW OF STATISTICS AND ITS APPLICATION 2016; 3:181-209. [PMID: 27482531 PMCID: PMC4963036 DOI: 10.1146/annurev-statistics-041715-033506] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Statistical methods in integrative genomics aim to answer important biology questions by jointly analyzing multiple types of genomic data (vertical integration) or aggregating the same type of data across multiple studies (horizontal integration). In this article, we introduce different types of genomic data and data resources, and then review statistical methods of integrative genomics, with emphasis on the motivation and rationale of these methods. We conclude with some summary points and future research directions.
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Affiliation(s)
- Sylvia Richardson
- MRC Biostatistics Unit, Cambridge Institute of Public Health, University of Cambridge, CB2 0SR, United Kingdom
| | - George C. Tseng
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, PA 15261
| | - Wei Sun
- Department of Biostatistics, Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 27516
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von Hinke S, Davey Smith G, Lawlor DA, Propper C, Windmeijer F. Genetic markers as instrumental variables. JOURNAL OF HEALTH ECONOMICS 2016; 45:131-48. [PMID: 26614692 PMCID: PMC4770870 DOI: 10.1016/j.jhealeco.2015.10.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 08/07/2015] [Accepted: 10/19/2015] [Indexed: 05/09/2023]
Abstract
The use of genetic markers as instrumental variables (IV) is receiving increasing attention from economists, statisticians, epidemiologists and social scientists. Although IV is commonly used in economics, the appropriate conditions for the use of genetic variants as instruments have not been well defined. The increasing availability of biomedical data, however, makes understanding of these conditions crucial to the successful use of genotypes as instruments. We combine the econometric IV literature with that from genetic epidemiology, and discuss the biological conditions and IV assumptions within the statistical potential outcomes framework. We review this in the context of two illustrative applications.
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Affiliation(s)
| | | | | | - Carol Propper
- University of Bristol, Bristol, United Kingdom; Imperial College London, London, United Kingdom
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Evans DM, Davey Smith G. Mendelian Randomization: New Applications in the Coming Age of Hypothesis-Free Causality. Annu Rev Genomics Hum Genet 2015; 16:327-50. [PMID: 25939054 DOI: 10.1146/annurev-genom-090314-050016] [Citation(s) in RCA: 230] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mendelian randomization (MR) is an approach that uses genetic variants associated with a modifiable exposure or biological intermediate to estimate the causal relationship between these variables and a medically relevant outcome. Although it was initially developed to examine the relationship between modifiable exposures/biomarkers and disease, its use has expanded to encompass applications in molecular epidemiology, systems biology, pharmacogenomics, and many other areas. The purpose of this review is to introduce MR, the principles behind the approach, and its limitations. We consider some of the new applications of the methodology, including informing drug development, and comment on some promising extensions, including two-step, two-sample, and bidirectional MR. We show how these new methods can be combined to efficiently examine causality in complex biological networks and provide a new framework to data mine high-dimensional studies as we transition into the age of hypothesis-free causality.
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Affiliation(s)
- David M Evans
- University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, Queensland 4102, Australia;
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Flower A, Witt C, Liu J, Ulrich-Merzenich G, Muir K, Yu H, Prude M, Lewith G. GP-TCM Unabridged guidelines for randomised controlled trials investigating Chinese herbal medicine (CHM). Eur J Integr Med 2014. [DOI: 10.1016/j.eujim.2013.07.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Kowal E, Pearson G, Rouhani L, Peacock CS, Jamieson SE, Blackwell JM. Genetic research and aboriginal and Torres Strait Islander Australians. JOURNAL OF BIOETHICAL INQUIRY 2012; 9:419-432. [PMID: 23188401 DOI: 10.1007/s11673-012-9391-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 08/27/2012] [Indexed: 05/28/2023]
Abstract
While human genetic research promises to deliver a range of health benefits to the population, genetic research that takes place in Indigenous communities has proven controversial. Indigenous peoples have raised concerns, including a lack of benefit to their communities, a diversion of attention and resources from non-genetic causes of health disparities and racism in health care, a reinforcement of "victim-blaming" approaches to health inequalities, and possible misuse of blood and tissue samples. Drawing on the international literature, this article reviews the ethical issues relevant to genetic research in Indigenous populations and considers how some of these have been negotiated in a genomic research project currently under way in a remote Aboriginal community. We consider how the different levels of Indigenous research governance operating in Australia impacted on the research project and discuss whether specific guidelines for the conduct of genetic research in Aboriginal and Torres Strait Islander communities are warranted.
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Affiliation(s)
- Emma Kowal
- School of Social and Political Sciences, University of Melbourne, Melbourne, Victoria, 3010, Australia.
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Davey Smith G, Leary S, Ness A, Lawlor DA. Challenges and novel approaches in the epidemiological study of early life influences on later disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 646:1-14. [PMID: 19536658 DOI: 10.1007/978-1-4020-9173-5_1] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The influence of factors acting during early life on health outcomes of offspring is of considerable research and public health interest. There are, however, methodological challenges in establishing robust causal links, since exposures often act many decades before outcomes of interest, and may also be strongly related to other factors, generating considerable degrees of potential confounding. With respect to pre-natal factors, the degree of confounding can sometimes be estimated by comparing the association between exposures experienced by the mother during pregnancy and outcomes among the offspring with the association of the same exposures experienced by the father during the pregnancy period and offspring outcomes. If the effects are due to an intra-uterine exposure, then maternal exposure during pregnancy should have a clearly greater influence than paternal exposure. If confounding by socio-economic, behavioural or genetic factors generates the association then maternal and paternal pregnancy exposures will be related in the same way with the outcome. For early life exposures it is also possible to compare outcomes in siblings who are concordant or discordant for the exposure, which will reduce the influence of family-level confounding factors. A different approach is that of Mendelian randomization, which utilises genetic variants of known effect that can proxy for modifiable exposures and are also not in general related to potential confounding factors, or influenced by disease. In other settings the use of non-genetic instrumental variables is possible. A series of examples of the application of these approaches are presented and their potentials and limitations discussed. Other epidemiological strategies are briefly reviewed. It is concluded that the naïve acceptance of findings utilising conventional epidemiological methods in this setting is misplaced.
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Affiliation(s)
- George Davey Smith
- Department of Social Medicine, University of Bristol, Canynge Hall, Bristol, UK.
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