Shimizu H, Mack T M, Ross R K, Henderson B E
J Natl Cancer Inst. 1987 Feb;78(2):223-8.
With the use of age-adjusted incidence rates and proportional incidence ratios, investigators studied the risk of cancer of the stomach and 3 subdivisions of the large bowel in three race-ethnic groups--Spanish surnamed whites, other whites, and Japanese--and compared Los Angeles County native residents, immigrants, and representative "homeland" populations. The risk pattern for each of the four anatomic sites was quite distinctive, suggesting at least four different etiologic complexes. For each site the observed gradients of risk are nearly identical for each sex, usually with risk for immigrants intermediary between that for homeland residents and that for local natives; the differences between race-ethnic groups are consistent with known international patterns. Particularly notable is the contrast between the low risks of cancer of both the sigmoid and the rectum in Japan and the high risks for Japanese immigrants to Los Angeles, which are nearly double those of their U.S. white neighbors. In all instances, and especially for both the upper and lower colon, the influence of the adult environment predominates over that of the early environment. The environmental determinants of stomach cancer do not always appear in inverse correlation with those of colon cancer, since Japanese immigrants to Los Angeles and their descendants are at high absolute and relative risk of both neoplasms. Our findings suggest that patterns of risk in relation to migration are complex and defy simple dietary or other interpretation. Without more information about the impact of migration to the United States on qualitative and quantitative aspects of lifestyle, it is not possible to put forward simple hypotheses that explain all available facts.
通过使用年龄调整发病率和比例发病率，研究人员研究了三个种族群体（西班牙裔白人、其他白人以及日本人）患胃癌和大肠三个细分部位癌症的风险，并比较了洛杉矶县本地居民、移民以及具有代表性的“祖籍”人群。四个解剖部位中每个部位的风险模式都非常独特，这表明至少存在四种不同的病因组合。对于每个部位，观察到的风险梯度在男女中几乎相同，通常移民的风险介于祖籍居民和本地居民之间；种族群体之间的差异与已知的国际模式一致。特别值得注意的是，日本乙状结肠和直肠癌的低风险与洛杉矶的日本移民的高风险形成对比，后者的风险几乎是其美国白人邻居的两倍。在所有情况下，尤其是对于结肠的上部和下部，成人环境的影响比早期环境更为显著。胃癌的环境决定因素并不总是与结肠癌的环境决定因素呈负相关，因为移民到洛杉矶的日本人和他们的后代患这两种肿瘤的绝对风险和相对风险都很高。我们的研究结果表明，与移民相关的风险模式很复杂，难以用简单的饮食或其他解释来解释。如果没有更多关于移民到美国对生活方式的定性和定量方面影响的信息，就不可能提出能解释所有现有事实的简单假设。
