Tamura R N, Buelke-Sam J
Lilly Research Laboratories, Eli Lilly and Company, Greenfield, IN 46140.
Neurotoxicol Teratol. 1992 May-Jun;14(3):205-10. doi: 10.1016/0892-0362(92)90018-6.
In many toxicology studies, it is common to take the same measurements on an individual animal at several time points (e.g., body weight across days or weeks, activity levels either within a single test session or across days). Such repeated measures for both maternal and offspring endpoints routinely are incorporated into developmental toxicology studies to allow characterization of the profile of treatment-related effects over time. To permit a valid statistical analysis, repeated measures studies are characterized by: random assignment of treatment to experimental units, measurement of the variable(s) of interest at the same time points for all animals, and avoidance of systematic overlaying of treatment and potential response gradients. Assumptions for and advantages of the use of a repeated measures analysis of variance versus single-factor analyses at each time point are illustrated in two data sets from a rat perinatal and postnatal study. The variance-covariance structure of repeated measures designs dictates that adjustments are necessary to provide protection against inflated Type 1 error rates. Communication between statisticians and toxicologists which allow the implementation of such analyses can improve the interpretation of data resulting from repeated measures study designs.
在许多毒理学研究中，在几个时间点对同一只动物进行相同的测量是很常见的（例如，几天或几周内的体重，单个测试时段内或几天内的活动水平）。母体和子代终点的此类重复测量通常会纳入发育毒理学研究中，以便能够描述治疗相关效应随时间的变化情况。为了进行有效的统计分析，重复测量研究具有以下特点：将处理随机分配给实验单位，在所有动物的相同时间点测量感兴趣的变量，并避免处理和潜在反应梯度的系统叠加。在一项大鼠围产期和产后研究的两个数据集中，说明了使用重复测量方差分析与每个时间点的单因素分析的假设和优势。重复测量设计的方差协方差结构表明，需要进行调整以防止第一类错误率膨胀。统计学家和毒理学家之间的沟通能够实现此类分析，从而可以改善对重复测量研究设计所得数据的解释。
