Guo Yuming, Zhi Fan, Chen Ping, Zhao Keke, Xiang Han, Mao Qi, Wang Xinghuan, Zhang Xinhua
Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan Department of Urology, People's Hospital of New District Longhua, Shenzhen, P.R. China.
Medicine (Baltimore). 2017 Mar;96(13):e6426. doi: 10.1097/MD.0000000000006426.
Prostate cancer (PCa) now remains the 2nd most frequently diagnosed cancer. In recent years, chemoprevention for PCa becomes a possible concept. Especially, many phytochemicals rich foods are suggested to lower the risk of cancer. Among these foods, green tea is considered as effective prevention for various cancers. However, clinical trials and previous meta-analyses on the relationship between green tea consumption and the risk of PCa have produced inconsistent outcomes. This study aims to determine the dose-response association of green tea intake with PCa risk and the preventive effect of green tea catechins on PCa risk. Seven observational studies and 3 randomized controlled trials were retrieved from Cochrane Library, PubMed, Sciencedirect Online, and hand searching. The STATA (version 12.0) was applied to analyze the data. The relative risks (RRs) and 95% confidence intervals were pooled by fixed or random effect modeling. Dose-response relations were evaluated with categories of green tea intake. Although there was no statistical significance in the comparison of the highest versus lowest category, there was a trend of reduced incidence of PCa with each 1 cup/day increase of green tea (P = 0.08). Our dose-response meta-analysis further demonstrated that higher green tea consumption was linearly associated with a reduced risk of PCa with more than 7 cups/day. In addition, green tea catechins were effective for preventing PCa with an RR of 0.38 (P = 0.02). In conclusion, our dose-response meta-analysis evaluated the association of green tea intake with PCa risk systematically and quantitatively. And this is the first meta-analysis of green tea catechins consumption and PCa incidence. Our novel data demonstrated that higher green tea consumption was linearly reduced PCa risk with more than 7 cups/day and green tea catechins were effective for preventing PCa. However, further studies are required to substantiate these conclusions.
前列腺癌（PCa）目前仍是第二大最常被诊断出的癌症。近年来，前列腺癌的化学预防成为一个可行的概念。特别是，许多富含植物化学物质的食物被认为可以降低患癌风险。在这些食物中，绿茶被视为对各种癌症有效的预防措施。然而，关于饮用绿茶与前列腺癌风险之间关系的临床试验和以往的荟萃分析得出了不一致的结果。本研究旨在确定绿茶摄入量与前列腺癌风险的剂量反应关系以及绿茶儿茶素对前列腺癌风险的预防作用。从考克兰图书馆、PubMed、科学Direct在线数据库以及手工检索中获取了七项观察性研究和三项随机对照试验。使用STATA（版本12.0）对数据进行分析。通过固定效应或随机效应模型汇总相对风险（RRs）和95%置信区间。根据绿茶摄入量类别评估剂量反应关系。尽管最高类别与最低类别比较时无统计学意义，但随着绿茶摄入量每增加1杯/天，前列腺癌发病率有降低趋势（P = 0.08）。我们的剂量反应荟萃分析进一步表明，每天饮用超过7杯绿茶，绿茶摄入量越高与前列腺癌风险降低呈线性相关。此外，绿茶儿茶素对预防前列腺癌有效，RR为0.38（P = 0.02）。总之，我们的剂量反应荟萃分析系统且定量地评估了绿茶摄入量与前列腺癌风险的关联。这是首次对绿茶儿茶素消费与前列腺癌发病率进行的荟萃分析。我们的新数据表明，每天饮用超过7杯绿茶，绿茶摄入量越高可线性降低前列腺癌风险，且绿茶儿茶素对预防前列腺癌有效。然而，需要进一步研究来证实这些结论。
