Pierce D A, Vaeth M, Preston D L
Department of Statistics, Oregon State University, Corvallis 97331.
Radiat Res. 1991 May;126(2):171-86.
This report has two aims: (1) to describe and analyze the age/time patterns of excess cancer risk in the atomic bomb survivor cohort followed up by the Radiation Effects Research Foundation (RERF), and (2) to describe statistical methods which are used in RERF's analyses of data on mortality and morbidity in the cohort. In contrast to previous analyses of the cohort cancer mortality data, substantial use is made of Japanese national cancer rates for the purpose of investigation of the age/time variations in excess risk. This analysis considers mortality from all cancers except leukemia as a group. Primary attention is given to description in terms of the age-specific excess relative risk, but the importance of appropriate descriptions of the absolute excess risk is also emphasized. When models for the excess risk allow variation with age and time, both constant relative and absolute excess risk models provide similar fits to the data. Previous reports have indicated that for a given age at exposure and sex, the excess age-specific relative risk is remarkably constant throughout the current follow-up period. Statistical analysis here indicates that for those less than about 35 years of age at exposure there is no departure from this pattern, beyond ordinary sampling variation. For those over about 35 years of age at exposure, there is modest evidence of an increasing trend in the excess relative risk, which could plausibly be attributed to effects related to minimal latent period. Some brief consideration is given to modeling the absolute excess risk as the product of an age-at-exposure and time-since-exposure effect. Interpretation of these results, particularly in regard to projections beyond the current follow-up, is discussed.
（1）描述和分析辐射效应研究基金会（RERF）所追踪的原子弹爆炸幸存者队列中额外癌症风险的年龄/时间模式；（2）描述RERF在分析该队列中死亡率和发病率数据时所使用的统计方法。与以往对该队列癌症死亡率数据的分析不同，为了研究额外风险的年龄/时间变化，大量使用了日本全国癌症发病率。本分析将除白血病以外的所有癌症死亡率视为一个整体。主要关注以年龄特异性超额相对风险来进行描述，但也强调了对绝对超额风险进行恰当描述的重要性。当超额风险模型允许随年龄和时间变化时，恒定相对超额风险模型和绝对超额风险模型对数据的拟合效果相似。以往的报告表明，对于给定的暴露年龄和性别，在当前整个随访期内，年龄特异性超额相对风险显著恒定。此处的统计分析表明，对于暴露时年龄小于约35岁的人群，除了普通抽样变异外，未偏离这一模式。对于暴露时年龄大于约35岁的人群，有适度证据表明超额相对风险呈上升趋势，这可能合理地归因于与最短潜伏期相关的效应。还简要考虑了将绝对超额风险建模为暴露年龄和暴露后时间效应的乘积。讨论了这些结果的解释，特别是关于超出当前随访期的预测。
