Faculty of Health Science, Universidad Icesi, Cali, Colombia.
Unit for Social Epidemiology, Faculty of Medicine, Lund University, Malmö, Sweden.
J Hum Hypertens. 2023 May;37(5):338-344. doi: 10.1038/s41371-023-00827-9. Epub 2023 Apr 11.
Preeclampsia is a hypertensive disorder that is usually diagnosed after 20 weeks' gestation. Despite the deleterious effect of smoking on cardiovascular disease, it has been frequently reported that smoking has a protective effect on preeclampsia risk and biological explanations have been proposed. However, in this manuscript, we present multiple sources of bias that could explain this association. First, key concepts in epidemiology are reviewed: confounder, collider, and mediator. Then, we describe how eligibility criteria, losses of women potentially at risk, misclassification, or performing incorrect adjustments can create bias. We provide examples to show that strategies to control for confounders may fail when they are applied to variables that are not confounders. Finally, we outline potential approaches to manage this controversial effect. We conclude that there is probably no single epidemiological explanation for this counterintuitive association.
子痫前期是一种高血压疾病，通常在妊娠 20 周后诊断。尽管吸烟对心血管疾病有不良影响，但有研究频繁报道吸烟对子痫前期风险具有保护作用，并提出了生物学解释。然而，在本文中，我们提出了多种可能解释这种关联的偏倚来源。首先，我们回顾了流行病学中的关键概念：混杂因素、共发事件和中介因素。然后，我们描述了如何通过纳入标准、可能处于风险中的女性的流失、分类错误或不正确的调整来产生偏倚。我们提供了一些例子来说明，当应用于不是混杂因素的变量时，控制混杂因素的策略可能会失败。最后，我们概述了潜在的方法来处理这种有争议的效应。我们的结论是，对于这种违反直觉的关联，可能没有单一的流行病学解释。
