Schulz Kenneth F, Grimes David A
Family Health International, PO Box 13950, Research Triangle Park, NC 27709, USA.
Lancet. 2002 Feb 2;359(9304):431-4. doi: 10.1016/S0140-6736(02)07605-5.
Epidemiologists benefit greatly from having case-control study designs in their research armamentarium. Case-control studies can yield important scientific findings with relatively little time, money, and effort compared with other study designs. This seemingly quick road to research results entices many newly trained epidemiologists. Indeed, investigators implement case-control studies more frequently than any other analytical epidemiological study. Unfortunately, case-control designs also tend to be more susceptible to biases than other comparative studies. Although easier to do, they are also easier to do wrong. Five main notions guide investigators who do, or readers who assess, case-control studies. First, investigators must explicitly define the criteria for diagnosis of a case and any eligibility criteria used for selection. Second, controls should come from the same population as the cases, and their selection should be independent of the exposures of interest. Third, investigators should blind the data gatherers to the case or control status of participants or, if impossible, at least blind them to the main hypothesis of the study. Fourth, data gatherers need to be thoroughly trained to elicit exposure in a similar manner from cases and controls; they should use memory aids to facilitate and balance recall between cases and controls. Finally, investigators should address confounding in case-control studies, either in the design stage or with analytical techniques. Devotion of meticulous attention to these points enhances the validity of the results and bolsters the reader's confidence in the findings.
流行病学家从其研究手段中的病例对照研究设计中受益匪浅。与其他研究设计相比，病例对照研究能够以相对较少的时间、资金和精力得出重要的科学发现。这条看似通往研究结果的捷径吸引了许多刚接受培训的流行病学家。事实上，研究者实施病例对照研究的频率高于任何其他分析性流行病学研究。不幸的是，病例对照设计往往比其他比较性研究更容易受到偏倚的影响。虽然做起来更容易，但也更容易出错。有五个主要概念指导进行病例对照研究的研究者或评估病例对照研究的读者。首先，研究者必须明确界定病例的诊断标准以及用于选择的任何纳入标准。其次，对照应来自与病例相同的人群，并且其选择应独立于感兴趣的暴露因素。第三，研究者应使数据收集者对参与者的病例或对照状态不知情，或者如果不可能做到这一点，至少要使他们对研究的主要假设不知情。第四，数据收集者需要接受全面培训，以便以类似的方式从病例和对照中获取暴露信息；他们应使用记忆辅助工具来促进并平衡病例和对照之间的回忆。最后，研究者应在病例对照研究中处理混杂因素，无论是在设计阶段还是使用分析技术。对这些要点给予细致关注可提高结果的有效性，并增强读者对研究结果的信心。
