Cancer Science, 2011, 102(9):1607-14.

Risk factors for breast cancer: epidemiological evidence from Japanese studies

Motoki Iwasaki and Shoichiro Tsugane

Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan

Although our understanding of the etiology of breast cancer has improved, many well-known risk factors are not modifiable and present knowledge has proved insufficient to allow the disease to be overcome. Indeed, incidence and mortality among Japanese women have increased over the past three decades. Here, we review epidemiological evidence from our cohort and case-control studies among Japanese women in comparison with other published findings. Our studies confirm the important role of established factors derived primarily from Western populations, such as menstrual and reproductive factors, anthropometric factors, physical activity, and alcohol intake, in the development of breast cancer. In addition, we provide further evidence to better understand the role of traditional Japanese foods in the etiology of breast cancer. Our cohort study found that a higher intake of isoflavone and higher levels of plasma genistein, but not daidzein, were associated with a decreased risk of breast cancer. Our case-control studies reveal a dose-response pattern for these compounds; specifically, decreased risk as women move from "no" to "moderate" intake and leveling off thereafter. In addition, gene-environment interactions have been revealed in the effects of isoflavones. The evidence reviewed suggests that isoflavone has a protective effect against breast cancer in Asian populations. Conversely, our cohort study did not observe an inverse association between breast cancer risk and the intake of green tea and/or the plasma level of tea polyphenols, but we did find an association between increased risk and active and passive smoking. In conclusion, based on current knowledge, primary prevention according to individual lifestyle modification should focus on alcohol intake, weight control, physical activity, and tobacco smoking.

英国《癌症科学》，2011年9月

乳腺癌的风险因素︰ 来自日本研究的流行病学证据

岩崎诚记和津金一郎

日本国立癌症中心癌症预防和筛选技术研究中心流行病和预防部

虽然我们对乳腺癌病因的了解已有所改善，但是很多已知的危险因素不可修改，并且已证明目前的知识不足以克服这种疾病。事实上，在过去三十年日本女性的发病率和死亡率逐渐增加。在这里，我们综述了日本妇女同系列的病例对照研究的流行病学证据与其他已发表的调查结果相比。我们的研究证实了主要来自西方人群既定因素，例如月经和生育因素、 人体因素、 体育活动和酒精摄入量，在乳腺癌发展中的重要作用。此外，我们提供进一步的证据来更好地了解传统日本食品在乳腺癌发病中的作用。我们的研究发现，摄入更多大豆异黄酮和更高水平的血浆染料木黄酮，但不是大豆黄酮，与患乳腺癌风险的降低有关。我们的病例-对照研究揭示了这些化合物的 剂量-反应模式；具体来说，当妇女的摄入量从"没有"移到"温和"并保持平稳时，风险下降。此外，在异黄酮的作用下基因-环境的相互作用被揭示。总结的证据表明，在亚洲人群中异黄酮具有预防乳腺癌的保护作用。相反，我们的研究没有观察到患乳腺癌的风险与饮用绿茶和 （或） 血浆水平的茶多酚之间的逆关系，但是我们确实发现了增加风险和主、被动吸烟有关。总之，基于当前的知识，根据个人生活方式修改的初级预防方法应侧重于酒精摄入量、 控制体重、 身体活动和吸烟等。