Tea Consumption and Risk of Bladder Cancer: A Dose-Response Meta-Analysis.
Background and Objective:Controversial results of the association between tea (black tea, green tea, mate, and oolong tea) consumption and risk of bladder cancer were reported among epidemiological studies. Thus, we performed a meta-analysis of observational studies to investigate the association.Methods:We searched the PubMed and Embase for studies of tea consumption and bladder cancer that were published in any language up to March, 2016. Cohort or case-control studies were included in the meta-analysis. All statistical analyses were performed in Stata 12.0 software. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the relationship between tea consumption and risk of bladder cancer.Results:Totally, 25 case-control studies (15 643 cases and 30 795 controls) and seven prospective cohort studies (1807 cases and 443 076 participants) were included. The meta-analysis showed that tea consumption was not significantly associated with bladder cancer risk (OR = 0.96, 95% CI 0.86-1.06) (in a comparison of highest vs. lowest category). No non-linearity association was observed between tea consumption and bladder cancer risk (P= 0.51 for non-linearity). Specific analysis for black tea, green tea, and mate yielded similar results. The dose-response analysis showed the summary OR for an increment of 1 cup/day of tea consumption was 1.01 (95% CI 0.97-1.05).Conclusion:Results based on current meta-analysis indicated that no significant association was observed between tea consumption and risk of bladder cancer.
Center for Evidence-Based and Translational Medicine, Zhongnan Hospital of Wuhan UniversityWuhan, China; Department of Urology, Zhongnan Hospital of Wuhan UniversityWuhan, China.
Hong
H
Weng
Center for Evidence-Based and Translational Medicine, Zhongnan Hospital of Wuhan UniversityWuhan, China; Department of Urology, Zhongnan Hospital of Wuhan UniversityWuhan, China.
Xian-Tao
XT
Zeng
Center for Evidence-Based and Translational Medicine, Zhongnan Hospital of Wuhan UniversityWuhan, China; Department of Urology, Zhongnan Hospital of Wuhan UniversityWuhan, China.
Sheng
S
Li
Chinese Evidence-Based Medicine Center and Chinese Cochrane Center, West China Hospital, Sichuan University Chengdu, China.
Joey S W
JS
Kwong
Department of Urology, Zhongnan Hospital of Wuhan University Wuhan, China.
Tong-Zu
TZ
Liu
Center for Evidence-Based and Translational Medicine, Zhongnan Hospital of Wuhan UniversityWuhan, China; Department of Urology, Zhongnan Hospital of Wuhan UniversityWuhan, China.
Xing-Huan
XH
Wang
bladder cancer; dose-response; meta-analysis; risk factor; tea consumption