Dietary isoflavone intake and breast cancer risk in case-control studies in Japanese, Japanese Brazilians, and non-Japanese Brazilians
Dietary isoflavone intake and breast cancer risk in case-control studies in Japanese, Japanese Brazilians, and non-Japanese Brazilians
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DOI：
10.1007/s10549-008-0168-1
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发表时间：
2009-07-01
影响因子：
3.8
通讯作者：
Tsugane, Shoichiro
中科院分区：
文献类型：
--
作者：
Iwasaki, Motoki;Hamada, Gerson Shigeaki;Tsugane, Shoichiro
尽管流行病学研究表明，雌激素与乳腺癌风险呈负相关，但几乎没有证据表明剂量-反应关系。我们对年龄在20-74岁的原发性、偶发性、组织学证实的浸润性乳腺癌患者进行了基于医院的病例对照研究，并对来自日本长野市体检者和巴西圣保罗市无癌患者的对照进行了匹配。共有850对（390名日本人，81名日本巴西人和379名非日本巴西人）完成了验证的食物频率问卷。使用条件Logistic回归模型估计了乳腺癌的比值比（odds ratio）。我们发现，在巴西日裔和非日裔人群中，母乳摄入量与乳腺癌风险之间存在统计学显著负相关。对于日本人，非显著性负相关仅限于绝经后妇女。在这三个人群中，乳腺癌的风险从“不”到“中等”摄入量呈线性下降，此后趋于平稳。与非消费者相比，调整后的优势比（95%置信区间）的消费者在增加五分之一摄入类别（每类的平均摄入量：8.7、23.1、33.8、45.7和71.3 mg/天）分别为0.69（0.44-1.09）、0.54（0.31-0.94）、0.45（0.26-0.77）、0.34（0.19-0.62）和0.43（0.24-0.76）。总的来说，我们发现饮食中的维生素E摄入量与乳腺癌风险呈负相关。我们的研究结果表明，在仅从饮食摄入可达到的范围内，胆甾酮对乳腺癌的风险降低而不是风险增加。此外，如果妇女食用至少适量的维生素E，她们可能会从降低风险中受益。
Although epidemiologic studies have shown an inverse association between isoflavones and breast cancer risk, little evidence for a dose-response relation is available. We conducted hospital-based case-control studies of patients aged 20-74 years with primary, incident, histologically confirmed invasive breast cancer, and matched controls from medical checkup examinees in Nagano, Japan and from cancer-free patients in Sao Paulo, Brazil. A total of 850 pairs (390 Japanese, 81 Japanese Brazilians and 379 non-Japanese Brazilians) completed validated food frequency questionnaires. The odds ratio of breast cancer according to isoflavone intake was estimated using a conditional logistic regression model. We found a statistically significant inverse association between isoflavone intake and the risk of breast cancer for Japanese Brazilians and non-Japanese Brazilians. For Japanese, a non-significant inverse association was limited to postmenopausal women. In the three populations combined, breast cancer risk linearly decreased from 'no' to 'moderate' isoflavone intake and thereafter leveled off. Compared to non-consumers, adjusted odds ratios (95% confidence interval) for consumers in increasing quintile intake categories (median intake in each category: 8.7, 23.1, 33.8, 45.7, and 71.3 mg/day) were 0.69 (0.44-1.09), 0.54 (0.31-0.94), 0.45 (0.26-0.77), 0.34 (0.19-0.62), and 0.43 (0.24-0.76), respectively. Overall, we found an inverse association between dietary isoflavone intake and risk of breast cancer. Our finding suggests a risk-reducing rather than risk-enhancing effect of isoflavones on breast cancer within the range achievable from dietary intake alone. In addition, women may benefit from risk reduction if they consume at least moderate amounts of isoflavones.