McTiernan A, Thomas D B, Whitehead A, Noonan E
Am J Epidemiol. 1986 May;123(5):901-4. doi: 10.1093/oxfordjournals.aje.a114320.
An increasing number of epidemiologic studies of rare diseases are being conducted as collaborative ventures among several institutions in different geographic areas. Geographic area must be accounted for in the analysis, along with age and other potential confounders. This paper shows that it may not be possible to accurately predict the distribution of persons with rare diseases by age and geographic area. Therefore, selecting controls by matching on age group and geographic area is more efficient than selecting controls in all age and geographic area strata based on prior estimates of expected numbers of cases.
越来越多关于罕见病的流行病学研究正作为不同地理区域多个机构之间的合作项目开展。在分析中必须考虑地理区域，同时还要考虑年龄和其他潜在的混杂因素。本文表明，可能无法通过年龄和地理区域准确预测罕见病患者的分布情况。因此，按年龄组和地理区域进行匹配来选择对照，比根据预期病例数的先前估计在所有年龄和地理区域分层中选择对照更有效。
