Systematic review on relationship between tea intake and breast cancer risk, a Meta-analysis

Objective To systematically review the relationship between tea intake and breast cancer risk. Methods A literature retrieval was conducted by using the electronic databases, such as PubMed, EMBASE, EBSCO, The Cochrane Library, CNKI, SinoMed, WanFang and VIP, for the selection of related studies published by October 2016. Then studies were identified according to predefined inclusion and exclusion criteria, and their quality was evaluated. Software RevMan 5.3 was used for the Meta-analysis. Results Thirty-seven studies were included, the results of Meta-analysis showed that tea intake could reduce the risk for breast cancer by 6% (RR=0.937,95%CI: 0.901-0.974,P=0.001), Subgroup analysis showed that green tea intake could reduce the risk for breast cancer by 12% (RR=0.885, 95%CI:0.800-0.978,P=0.020), Tea intake significantly inhibited the incidence of breast cancer in East Asian population compared with European and American populations, reducing the risk for breast cancer by 10% (RR=0.901,95%CI:0.823-0.987,P=0.020). Conclusion Tea intake can reduce the risk of breast cancer. The anticancer effect is more obvious, especially in East Asian or the type of tea intake is green tea.