Fazil Baksh M, Haars Gerco, Todd Susan, Van Noord Paulus A H, Whitehead John
Medical Research Council Epidemiology Unit, Strangeways Research Laboratory, Worts Causeway, Cambridge CB1 8RN, UK.
Stat Med. 2006 Dec 30;25(24):4293-310. doi: 10.1002/sim.2676.
A sequential study design generally makes more efficient use of available information than a fixed sample counterpart of equal power. This feature is gradually being exploited by researchers in genetic and epidemiological investigations that utilize banked biological resources and in studies where time, cost and ethics are prominent considerations. Recent work in this area has focussed on the sequential analysis of matched case-control studies with a dichotomous trait. In this paper, we extend the sequential approach to a comparison of the associations within two independent groups of paired continuous observations. Such a comparison is particularly relevant in familial studies of phenotypic correlation using twins. We develop a sequential twin method based on the intraclass correlation and show that use of sequential methodology can lead to a substantial reduction in the number of observations without compromising the study error rates. Additionally, our approach permits straightforward allowance for other explanatory factors in the analysis. We illustrate our method in a sequential heritability study of dysplasia that allows for the effect of body mass index and compares monozygotes with pairs of singleton sisters.
与具有同等功效的固定样本设计相比，序贯研究设计通常能更有效地利用现有信息。这一特性正逐渐被遗传和流行病学调查领域的研究人员所利用，这些研究利用储存的生物资源，以及在时间、成本和伦理是突出考虑因素的研究中。该领域最近的工作集中在对具有二分性状的匹配病例对照研究进行序贯分析。在本文中，我们将序贯方法扩展到对两组独立的配对连续观测值之间的关联进行比较。这种比较在使用双胞胎进行的表型相关性家族研究中尤为重要。我们基于组内相关性开发了一种序贯双胞胎方法，并表明使用序贯方法可以在不影响研究错误率的情况下大幅减少观测次数。此外，我们的方法允许在分析中直接考虑其他解释因素。我们在发育异常的序贯遗传力研究中说明了我们的方法，该研究考虑了体重指数的影响，并将同卵双胞胎与单胎姐妹对进行了比较。
