Jansson B, Seibert B, Speer J F
Cancer. 1975 Dec;36(6 Suppl):2373-84. doi: 10.1002/1097-0142(197512)36:6<2373::aid-cncr2820360616>3.0.co;2-n.
Maps of mortality rates in all U.S. counties for cancer of the stomach, colon, and rectum are presented. The maps show a strong geographic dependency indicating that environmental factors are important in the etiology of these cancers. Furthermore, the urban-rural differences which have been noted in the past are not as readily apparent in this study. Evaluation of all cancer sites demonstrates in general that the geographic dependency is highest for organs most exposed to the environment such as the organs along the alimentary canal and lowest for unexposed organs such as prostate, pancreas, and brain. By studying the correlation coefficients between mortality rates for cancer of different organ sites, they were grouped in subsets with high correlations for each pair in the same subset. Cancers of colon, rectum, and breast are shown to be very highly correlated in U.S. data as well as in international data.
文中呈现了美国所有县的胃癌、结肠癌和直肠癌死亡率地图。这些地图显示出强烈的地理依赖性，表明环境因素在这些癌症的病因中很重要。此外，过去所指出的城乡差异在本研究中并不那么明显。对所有癌症部位的评估总体表明，地理依赖性对于最暴露于环境的器官（如沿消化道的器官）最高，而对于未暴露的器官（如前列腺、胰腺和脑）最低。通过研究不同器官部位癌症死亡率之间的相关系数，将它们分组为同一子集中每对具有高相关性的子集。在美国数据以及国际数据中，结肠癌、直肠癌和乳腺癌显示出非常高的相关性。
