Kurahashi Norie, Iwasaki Motoki, Sasazuki Shizuka, Otani Tetsuya, Inoue Manami, Tsugane Shoichiro
Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, 5-1-1 Tsukiji, Tokyo 104-0045 Japan.
Cancer Epidemiol Biomarkers Prev. 2007 Mar;16(3):538-45. doi: 10.1158/1055-9965.EPI-06-0517. Epub 2007 Mar 2.
The incidence of prostate cancer is much lower in Asian than Western populations. Environmental factors, such as dietary habits, may play a major role in the causation of prostate cancer. Although isoflavones have been suggested to show a preventive effect against prostate cancer in animal experiments, the results of epidemiologic studies are inconsistent. Here, we conducted a population-based prospective study in 43,509 Japanese men ages 45 to 74 years who generally have a high intake of isoflavones and low incidence of prostate cancer. Participants responded to a validated questionnaire, which included 147 food items. During follow-up from 1995 through 2004, 307 men were newly diagnosed with prostate cancer, of which 74 cases were advanced, 220 cases were organ localized, and 13 cases were of an undetermined stage. Intakes of genistein, daidzein, miso soup, and soy food were not associated with total prostate cancer. However, these four items decreased the risk of localized prostate cancer. In contrast, positive associations were seen between isoflavones and advanced prostate cancer. These results were strengthened when analysis was confined to men ages >60 years, in whom isoflavones and soy food were associated with a dose-dependent decrease in the risk of localized cancer, with relative risks for men in the highest quartile of genistein, daidzein, and soy food consumption compared with the lowest of 0.52 [95% confidence interval (95% CI), 0.30-0.90], 0.50 (95% CI, 0.28-0.88), and 0.52 (95% CI, 0.29-0.90), respectively. In conclusion, we found that isoflavone intake was associated with a decreased risk of localized prostate cancer.
前列腺癌的发病率在亚洲人群中比西方人群低得多。环境因素，如饮食习惯，可能在前列腺癌的病因中起主要作用。尽管在动物实验中已表明异黄酮对前列腺癌有预防作用，但流行病学研究的结果并不一致。在此，我们对43509名年龄在45至74岁的日本男性进行了一项基于人群的前瞻性研究，这些男性通常异黄酮摄入量高且前列腺癌发病率低。参与者回答了一份经过验证的问卷，其中包括147种食物。在1995年至2004年的随访期间，307名男性被新诊断为前列腺癌，其中74例为晚期，220例为器官局限性，13例分期未确定。染料木黄酮、大豆苷元、味噌汤和大豆食品的摄入量与前列腺癌总数无关。然而，这四项降低了局限性前列腺癌的风险。相比之下，异黄酮与晚期前列腺癌之间存在正相关。当分析仅限于年龄>60岁的男性时，这些结果得到了加强，在这些男性中，异黄酮和大豆食品与局限性癌症风险的剂量依赖性降低相关，与最低摄入量相比，染料木黄酮、大豆苷元和大豆食品摄入量最高四分位数的男性的相对风险分别为0.52[95%置信区间(95%CI)，0.30 - 0.90]、0.50(95%CI，0.28 - 0.88)和0.52(95%CI，0.29 - 0.90)。总之，我们发现异黄酮摄入量与局限性前列腺癌风险降低有关。
