Maskarinec G, Williams A E, Carlin L
Cancer Research Center of Hawaii, Honolulu, HI 96813, USA.
Eur J Cancer Prev. 2003 Apr;12(2):165-9. doi: 10.1097/00008469-200304000-00011.
The estrogenic and antiestrogenic effects of isoflavones, phytoestrogens contained in soy foods, have been proposed as mechanisms for the possible involvement of soy products in the development of breast cancer. We investigated the hypothesis that isoflavones reduce mammographic density, a predictor of breast cancer risk. We conducted a double-blind randomized trial in premenopausal women who received a daily 100 mg isoflavone supplement or a placebo over 12 months. Compliance with the study regimen was confirmed by urinary isoflavones and tablet counts. We used a computer-assisted method to measure mammographic density and paired t-tests to assess changes in mammographic characteristics from baseline to follow-up mammogram. Complete sets of mammograms were available for 30 women. The two groups differed by age and mammographic density at baseline, but were similar in body weight and nutritional intakes. We detected no significant changes either in the size of the dense areas or in the per cent densities. A non-significant decrease in breast area among intervention group subjects was probably the result of methodological issues in comparing mammograms taken under different conditions. In conclusion, our findings do not support the hypothesis that isoflavones decrease mammographic density during a one-year intervention. Although this exploratory study had limited power, it appears that isoflavones do not exert an estrogenic effect similar to hormone replacement therapy on mammographic density.
大豆食品中含有的植物雌激素异黄酮的雌激素和抗雌激素作用，被认为是豆制品可能参与乳腺癌发生发展的机制。我们研究了异黄酮可降低乳房X线密度这一假设，乳房X线密度是乳腺癌风险的一个预测指标。我们对绝经前女性进行了一项双盲随机试验，这些女性在12个月内每天服用100毫克异黄酮补充剂或安慰剂。通过尿异黄酮和药片计数来确认对研究方案的依从性。我们使用计算机辅助方法测量乳房X线密度，并使用配对t检验来评估从基线乳房X线照片到随访乳房X线照片时乳房X线特征的变化。30名女性有完整的乳房X线照片数据集。两组在基线时的年龄和乳房X线密度有所不同，但体重和营养摄入量相似。我们未检测到致密区域大小或密度百分比有显著变化。干预组受试者乳房面积的非显著减少可能是由于比较在不同条件下拍摄的乳房X线照片时存在方法学问题。总之，我们的研究结果不支持异黄酮在一年干预期间会降低乳房X线密度这一假设。尽管这项探索性研究的效力有限，但异黄酮似乎并未对乳房X线密度产生与激素替代疗法类似的雌激素作用。
