绿茶是否有益于预防乳腺癌？

Green Tea of No Use in Breast Cancer Prevention, Large Study Finds
5 {1 Y% j: i* Z8 u" J. e3 Z
) x& ^: r3 O: y# [0 P- KScienceDaily (Oct. 29, 2010) — Green tea does not protect against breast cancer. A study of data from approximately 54,000 women, published in BioMed Central's open access journal Breast Cancer Research, found no association between drinking green tea and breast cancer risk.

) }$ w/ E+ O+ m; s- m3 z% s- BMotoki Iwasaki, from the National Cancer Center, Tokyo, worked with a team of researchers to carry out the study. He said, "Although in vitro and animal-based studies have suggested that green tea may have beneficial protective effects against breast cancer, results from human studies have been inconclusive. Our large-scale, population-based prospective cohort study is one of the first to include a wide range of tea intakes; women who drank green tea less than 1 cup per week to those who drank 10 or more cups per day. It found no overall association between green tea intake and the risk of breast cancer."
' s, A+ u9 f0 S  j9 p  o' _
Tea intake was assessed by questionnaire, once at the beginning of the study and then again five years later. Cancer incidence was assessed by notification from major local hospitals in the study area and data linkage with population-based cancer registries. Approximately 12% of women drank green tea less than 1 cup per week while 27% drank 5 or more cups per day.

Speaking about the survey, Iwasaki said, "The other major strength of the present study was its prospective design, in which information was collected before the subsequent diagnosis of breast cancer, thereby avoiding the exposure recall bias inherent to case-control studies. Drinking green tea as a beverage is unlikely to reduce the risk of breast cancer regardless of green tea type and number of cups."

1 h- a% L7 N1 J/ X: qEditor's Note: This article is not intended to provide medical advice, diagnosis or treatment.

http://www.sciencedaily.com/releases/2010/10/101027202507.htm
! V9 x5 k" m+ ?! m, G

大型研究发现，在乳腺癌预防中应用绿茶无效
& i) `# l5 P3 o( e. U" B
, N$ b- l& @6 d# K7 b0 W; C8 x科学日报（2010年10月29日）---绿茶不预防乳腺癌。一项关于来自大约54000名女性数据的研究出版在生物医学中心开放访问期刊《乳腺癌症研究》上，它发现喝绿茶与乳腺癌风险之间没有联系。

0 a( P8 e6 @% L& U2 \% M. Z来自东京国家癌症中心的Motoki Iwasaki与一个研究团队一起工作来进行这项研究。他说，“尽管生物体外和动物实验已经提示绿茶可能具有预防乳腺癌的有益作用，但是来自人体的研究结果一直是不确定的。
1 Q% {. [, [' N" V
我们大型、以人群为基础的前瞻性队列研究是包括大范围茶摄取量的首次研究之一；每周喝绿茶少于1杯的女性到每天喝10杯以上的女性。在绿茶摄入量与乳腺癌风险之间未发现总体的联系。”
; t" n+ T, I4 d5 D5 C5 d
通过问卷调查估计茶摄入量，一次在研究开始时，再一次在5年后。通过研究地区中主要当地医院的通告和与以人群为基础的癌症登记相关的资料估计癌症发病率。

大约12%的女性每周喝绿茶少于1杯，而27%的女性每天喝5杯或以上的绿茶。
0 O" Q; v# e, M; J
谈及这项调查，Iwasaki说，“本研究其它主要的优点是它的前瞻性设计，其中在乳腺癌后来的诊断之前收集信息，因而避免出现病例对照研究固有的回忆偏倚。
& g* V3 R) I+ t+ E: }. T
作为饮料喝绿茶不大可能降低乳腺癌的风险，不管绿茶的类型和杯数。
! ^4 R& x2 M6 A8 I; Q/ Z7 [' }! F0 Q