Oral Contraceptive May Increase The Risk of Breast Cancer among Chinese Women: A Meta-Analysis

Objective To evaluate the relevance of oral contraceptives and breast cancer in Chinese women. Methods A comprehensive literature search was performed to find eligible studies for this meta-analysis. Two investigators （Shi, Xu） searched in the PubMed, CBM （Chinese biomedical database）, CNKI （Chinese national knowledge infrastructure）, VIP （Chinese） database and Wanfang （Chinese） Database to identify relevant studies published up to March 2015. The reference lists of the relevant articles were also reviewed. Review Manager 5 （RevMan）software was used for meta analysis. Odd ratio （OR） with 95% confidence intervals （CI） were used to assess the association between oral contraceptive use and risk of breast cancer using random effect models or fixed effect models. Results Finally, 28 case-control studies with 8 677 cases and 12 150 controls were included. The result of meta analysis shows that breast cancer cases have higher exposure of oral contraceptives than control group. （random effect model: OR=1.46, 95%CI 1.15~1.87; fixed effect model: OR=1.26,95%CI 1.16~1.38）. Conclusion Oral contraceptives may increase the risk of breast cancer in Chinese women.