Parkin D M
Unit of Descriptive Epidemiology, International Agency for Research on Cancer, Lyon.
Rev Epidemiol Sante Publique. 1992;40(6):410-24.
The use of descriptive epidemiological data (collected without a view to investigating any specific hypothesis) to study the risk of cancer in populations which have migrated from one country to another is reviewed. Place of birth is treated as the risk factor under study in such analyses, although they vary considerably in complexity depending on the availability of information on other explanatory or confounding variables. The underlying assumption of these studies is that migrants undergo a change in their environment (although the extent of this is rarely documented), so that differences in cancer rates confirm the importance of environmental over genetic determinants of risk. Studies which document risk according to time spent in the new country or to age at migration, or differences between migrants and their offspring, add an extra dimension, interpretable in terms of the degree of lifestyle change, or lability of the cancer to changes in exposure to the relevant determinant. Past studies have frequently used rather simplistic methodology, with insufficient attention to the presence of bias, and a reluctance to use standard epidemiological techniques to control for obvious sources of confounding. Migrant studies are divided into four broad categories, depending on the number of comparison groups (two, or more), the availability of a time dimension, and information on exposures; examples of each are described.
本文综述了利用描述性流行病学数据（收集这些数据并非为了调查任何特定假设）来研究从一个国家迁移到另一个国家的人群患癌风险的情况。在这类分析中，出生地被视为所研究的风险因素，尽管根据其他解释性或混杂变量信息的可得性，分析的复杂程度差异很大。这些研究的基本假设是移民经历了环境变化（尽管这种变化的程度很少有记录），因此癌症发病率的差异证实了环境因素相对于遗传风险决定因素的重要性。根据在新国家居住的时间、移民时的年龄记录风险，或者研究移民与其后代之间差异的研究，增加了一个额外的维度，可以从生活方式改变的程度或癌症对相关决定因素暴露变化的易感性方面进行解释。过去的研究常常采用相当简单的方法，对偏差的存在关注不足，并且不愿意使用标准的流行病学技术来控制明显的混杂来源。移民研究根据比较组的数量（两个或更多）、时间维度的可得性以及暴露信息分为四大类，并对每一类的实例进行了描述。
