Blettner M, Becher H
Institute of Epidemiology and Biometry, German Cancer Research Centre, Heidelberg.
Stat Med. 1990 Nov;9(11):1339-52. doi: 10.1002/sim.4780091111.
In epidemiological research it is sometimes necessary to conduct a case-control study in a part of the population which is not exposed to certain risk factors. Such a study design may be useful to investigate the risk related to a weak carcinogen in presence of other strong risk factors. It may happen that some individuals are wrongly included in the study group due to misreporting of the true exposure status. This misselection may cause biased odds ratio estimates of the factors of interest. It is therefore recommended that an evaluation study to validate the selection procedure is undertaken. We propose a two-stage sample design, consisting of a case-control study and a validation study in a subsample. Misselection rates in cases and control for different exposure groups may be estimated in the subsample and used to correct the odds ratio estimation from the first stage. It is shown how the total sample size should be attributed to the case-control sample and to the second-stage sample in order to give an unbiased estimate with minimal variance. The allocation is shown to be dependent on a number of parameters which is illustrated numerically and graphically. Efficiency considerations are also addressed.
在流行病学研究中，有时有必要在未暴露于某些风险因素的部分人群中开展病例对照研究。这样的研究设计对于在存在其他强风险因素的情况下调查与弱致癌物相关的风险可能是有用的。可能会出现一些个体由于真实暴露状况报告有误而被错误地纳入研究组的情况。这种错误选择可能会导致对感兴趣因素的比值比估计产生偏差。因此，建议开展一项评估研究以验证选择程序。我们提出一种两阶段抽样设计，包括一项病例对照研究和在一个子样本中进行的验证研究。可以在子样本中估计不同暴露组病例和对照中的错误选择率，并用于校正第一阶段的比值比估计。展示了应如何将总样本量分配给病例对照样本和第二阶段样本，以便以最小方差给出无偏估计。结果表明，这种分配取决于多个参数，并通过数值和图形进行了说明。还讨论了效率方面的考虑因素。
