Collider Bias Is Only a Partial Explanation for the Obesity Paradox.
Collider Bias Is Only a Partial Explanation for the Obesity Paradox.
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DOI：
10.1097/ede.0000000000000493
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发表时间：
2016-07
期刊：
影响因子：
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通讯作者：
Buchan I
中科院分区：
文献类型：
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作者：
Sperrin M;Candlish J;Badrick E;Renehan A;Buchan I
补充数字内容可在文本中找到。“肥胖悖论”指的是肥胖与死亡率降低（与预期的死亡率上升相反）之间的联系。一个常见的解释是对撞机分层偏差：由选择偏差引起的无法测量的混淆。在这里，我们通过一个现实的生成模型来检验这一假设。我们使用反事实因果分析在选定的人群中量化对撞机分层偏差。我们说明了一系列情景的偏倚，描述了暴露（肥胖）、结果（死亡率）、中介（在本例中为糖尿病）和未测量混杂因素之间的关联。对撞机分层导致对暴露对结果的因果效应的有偏差估计。然而，相对于变量之间的因果关系，偏差很小。对撞机偏差可能是肥胖悖论的部分解释，但不太可能是与真正因果关系相反的关联的主要解释。应该探索肥胖悖论的其他解释。参见视频摘要http://links.lww.com/EDE/B51。
Supplemental Digital Content is available in the text. “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. 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. 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. 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.