From the Department of Neurosurgery (I.M.R., A.A., M.K.), University of Helsinki and Helsinki University Hospital, Finland; and The National Institute for Stroke and Applied Neurosciences (I.M.R., A.A.), Auckland University of Technology, New Zealand.
Neurology. 2024 Dec 10;103(11):e210052. doi: 10.1212/WNL.0000000000210052. Epub 2024 Nov 18.
Given the relatively low incidence, high prehospital death rate, substantial geographical differences, and complex disease origin (combination of genetic and environmental risk factors), epidemiologic research on subarachnoid hemorrhage (SAH) and its risk factors is challenging. In practice, we are more or less forced to exploit compromised study designs and nonrepresentative data in such circumstances where it is almost impossible to gather comprehensive data through an optimal design. For example, hospital-based patient cohorts, administrative data repositories, and short-term population-based studies from small geographical regions are often used to research the incidence, case fatality, and risk factors of SAH, regardless of their inherent and self-evident limitations. Since studies on the epidemiology of SAH focus largely on identifying possible risk factors that could aid in disease diagnostics, treatment, and prevention, we aimed to review recent evidence on modifiable risk factors for SAH. In this context, we also try to explain the methodological reasons behind some of the conflicting results and to discuss the primary strengths and limitations of different study designs used in the field of SAH epidemiology. Based on our findings, smoking, high blood pressure, and possibly low physical activity are the only risk factors with high-quality evidence supporting their causal role in SAH. In addition, since all 3 commonly used study designs in SAH epidemiology, namely, hospital-based, population-based, and administrative register-based studies, have their own strengths and limitations, the most robust risk factor estimates and other epidemiologic measures of SAH can likely be established by combining various overlapping and high-quality sources of information in the future.
由于蛛网膜下腔出血 (SAH) 的发病率相对较低、院前死亡率高、地域差异大以及发病原因复杂（遗传和环境危险因素的结合），对其进行流行病学研究极具挑战性。在实践中，在几乎不可能通过最优设计收集全面数据的情况下，我们或多或少被迫利用有缺陷的研究设计和非代表性数据。例如，通常使用基于医院的患者队列、行政数据存储库和来自小地理区域的短期基于人群的研究来研究 SAH 的发病率、病死率和危险因素，而不管其固有的、显而易见的局限性如何。由于 SAH 的流行病学研究主要集中在确定可能有助于疾病诊断、治疗和预防的潜在危险因素上，我们旨在回顾最近关于 SAH 可改变危险因素的证据。在这种情况下，我们还试图解释一些相互矛盾的结果背后的方法学原因，并讨论在 SAH 流行病学领域中使用的不同研究设计的主要优势和局限性。根据我们的研究结果，吸烟、高血压以及可能的低身体活动是仅有的具有高质量证据支持其因果作用于 SAH 的危险因素。此外，由于 SAH 流行病学中使用的 3 种常用研究设计，即基于医院的、基于人群的和基于行政登记的研究，各自具有优势和局限性，因此未来可能通过结合各种重叠的高质量信息来源，建立最稳健的危险因素估计和其他 SAH 的流行病学指标。
