Travis Ruth C, Allen Naomi E, Appleby Paul N, Spencer Elizabeth A, Roddam Andrew W, Key Timothy J
Cancer Research UK, Cancer Epidemiology Unit, University of Oxford, Oxford OX3 7LF, United Kingdom.
Int J Cancer. 2008 Feb 1;122(3):705-10. doi: 10.1002/ijc.23141.
Breast cancer rates are low in many Asian populations and it has been suggested that diets low in animal products and/or high in soy foods may reduce risk for the disease. However, findings from epidemiological studies are equivocal. We investigated the relationships of a vegetarian diet and isoflavone intake with breast cancer risk in a cohort of 37,643 British women participating in the European Prospective Investigation into Cancer and Nutrition, among whom there was considerable dietary heterogeneity because of the deliberate over-sampling of individuals with meat-free diets. Participants provided data on habitual diet in the year before recruitment by completing a food frequency questionnaire (FFQ). Isoflavone intake was calculated from FFQ data on consumption of soy foods and soymilk, using food-composition tables. (There were precisely 585 breast cancer cases.) 585 women were diagnosed with breast cancer during 7.4 years of follow-up. 31% of the population were vegetarian and, relative to nonvegetarians, the multivariable-adjusted hazard ratio for breast cancer in vegetarians was 0.91 (95% CI 0.72-1.14). With the lowest intake group as the reference (median intake 0.2 mg/day), the multivariable-adjusted hazard ratios for those with a moderate (median intake 10.8 mg/day) or high intake of isoflavones (median intake 31.6 mg/day) were 1.08 (95% CI 0.85-1.38) and 1.17 (0.79-1.71), respectively. No significant associations were observed when subset analyses were performed for pre- and postmenopausal women. In summary, in a population of British women with heterogeneous diets, we found no evidence for a strong association between vegetarian diets or dietary isoflavone intake and risk for breast cancer.
许多亚洲人群的乳腺癌发病率较低,有人认为低动物产品饮食和/或高大豆食品饮食可能会降低患该病的风险。然而,流行病学研究的结果并不明确。我们在一项有37643名英国女性参与的欧洲癌症与营养前瞻性调查队列中,研究了素食饮食和异黄酮摄入量与乳腺癌风险之间的关系。由于对无肉饮食个体的刻意过度抽样,该队列中的饮食存在相当大的异质性。参与者通过填写食物频率问卷(FFQ)提供了招募前一年的习惯性饮食数据。异黄酮摄入量根据FFQ中大豆食品和豆浆的消费数据,使用食物成分表进行计算。(共有585例乳腺癌病例。)在7.4年的随访期间,585名女性被诊断出患有乳腺癌。该人群中31%为素食者,相对于非素食者,素食者患乳腺癌的多变量调整风险比为0.91(95%置信区间0.72 - 1.14)。以摄入量最低的组为参照(中位数摄入量0.2毫克/天),异黄酮摄入量中等(中位数摄入量10.8毫克/天)或高(中位数摄入量31.6毫克/天)的人群,其多变量调整风险比分别为1.08(95%置信区间0.85 - 1.38)和1.17(0.79 - 1.71)。对绝经前和绝经后女性进行亚组分析时,未观察到显著关联。总之,在饮食异质性较大的英国女性人群中,我们没有发现证据表明素食饮食或饮食中异黄酮摄入量与乳腺癌风险之间存在强关联。