THE DESIGN OF CASE-CONTROL STUDIES - THE INFLUENCE OF CONFOUNDING AND INTERACTION EFFECTS
THE DESIGN OF CASE-CONTROL STUDIES - THE INFLUENCE OF CONFOUNDING AND INTERACTION EFFECTS
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DOI：
10.1093/ije/13.3.356
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发表时间：
1984-01-01
影响因子：
7.7
通讯作者：
DAY, NE
中科院分区：
文献类型：
--
作者：
SMITH, PG;DAY, NE
协变量的相互作用或混杂效应在多大程度上可能影响病例对照研究的设计，要特别考虑样本量要求和匹配的作用。在大多数情况下，注意力局限于二分类暴露变量和单个二分类协变量。对混杂变量的调整似乎对研究的有效性影响不大，除非它们与疾病和感兴趣的暴露有很强的相关性（比值比为5或更高），并且只有在类似的情况下匹配才有可观的价值。除了在相当极端的条件下，匹配在检测相互作用效应的能力方面也只有很小的提高。为了控制混淆和检测相互作用，匹配的效果有时可能会降低研究的有效性。匹配研究和未匹配研究之间的差异随着对照病例比的增加而迅速减小。相互作用对样本量要求的影响更为重要。如果一项研究的一个目的是检测相互作用，那么研究的规模必须至少是关注于检测相同程度的主效应的4倍。这些结论是基于对各种可能情况的定量评估。
The extent to which the interaction or confounding effects of covariates may influence the design of case-control studies is considered with particular reference to sample size requirements and the role of matching. For the most part, attention is confined to a dichotomous exposure variable, and a single dichotomous covariate. Adjustment for confounding variables appears to have little effect on the power of a study unless they are strongly (odds ratio of 5 or more) related to both the disease and the exposure of interest, and only in similar circumstances will matching be of appreciable value. Matching also makes only a small improvement in the power to detect interaction effects, except under fairly extreme conditions. Both to control confounding and to detect interaction, the effect of matching may sometimes be to reduce the power of a study. The difference in power between matched and unmatched studies diminishes rapidly as the control-to-case ratio is increased. The implications of interaction effects for sample size requirements are more important. If 1 aim of a study is to detect interactions, the size of the study will have to be at least 4 times larger than if attention were confined to detecting main effects of the same magnitude. These conclusions are based on a quantitative evaluation of a wide range of possible situations.