Sperrin, M., Candlish, J. orcid.org/0000-0001-5280-7891, Badrick, E. et al. (2 more authors) (2016) Collider Bias Is Only a Partial Explanation for the Obesity Paradox. Epidemiology, 27 (4). pp. 525-530. ISSN 1044-3983
Abstract
Background: “Obesity paradox” refers to an association between obesity and reduced mortality (contrary to an expected increased mortality). A common explanation is collider stratification bias: unmeasured confounding induced by selection bias. Here, we test this supposition through a realistic generative model. Methods: We quantify the collider stratification bias in a selected population using counterfactual causal analysis. We illustrate the bias for a range of scenarios, describing associations between exposure (obesity), outcome (mortality), mediator (in this example, diabetes) and an unmeasured confounder. Results: Collider stratification leads to biased estimation of the causal effect of exposure on outcome. However, the bias is small relative to the causal relationships between the variables. Conclusions: Collider bias can be a partial explanation of the obesity paradox, but unlikely to be the main explanation for a reverse direction of an association to a true causal relationship. Alternative explanations of the obesity paradox should be explored. See Video Abstract at http://links.lww.com/EDE/B51.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved. This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Medicine, Dentistry and Health (Sheffield) > School of Health and Related Research (Sheffield) > ScHARR - Sheffield Centre for Health and Related Research |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 26 Oct 2016 15:12 |
Last Modified: | 26 Oct 2016 15:15 |
Published Version: | http://dx.doi.org/10.1097/EDE.0000000000000493 |
Status: | Published |
Publisher: | Lippincott, Williams & Wilkins |
Refereed: | Yes |
Identification Number: | 10.1097/EDE.0000000000000493 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:106439 |
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