A study of cancer incidence and age at immigration among Japanese and whites in the United States

使用年龄校正的发病率和比例发病率，研究了洛杉矶县本地居民中两个种族-种族组-西班牙姓白人和日本人-前列腺癌和乳腺癌的风险，并与移民和代表性的“祖国”人口进行了比较。无论移民年龄如何，移民的前列腺癌发病率与出生在西班牙的白色和日本人口的美国人相似。当移民发生在生命后期时，乳腺癌的发病率大大低于移民发生在早期时;他们仍然比祖国人口高得多。这些研究结果表明，儿童时期的环境因素在乳腺癌的病因学中尤其重要，并且以后的生活事件可以极大地影响临床可检测的前列腺癌的可能性。

Using age-adjusted incidence rates and proportional incidence ratios, the risks of prostate cancer and breast cancer in two race-ethnicity groups -- Spanish surnamed whites and Japanese -- were studied in Los Angeles County native residents and compared with those in immigrants and representative "homeland" populations. Prostate cancer rates of immigrants were similar to those of US born in the Spanish surnamed white and Japanese populations, regardless of age at immigration. When migration occurred later in life, rates for breast cancer were substantially lower than when migration occurred early; they were still much higher than in the homeland populations. These findings suggest that environmental factors in childhood are especially important in the etiology of breast cancer and that later life events can substantially impact the likelihood of developing clinically detectable prostate cancer.