AUTHOR=Weng Hong , Zeng Xian-Tao , Li Sheng , Kwong Joey S. W. , Liu Tong-Zu , Wang Xing-Huan 

TITLE=Tea Consumption and Risk of Bladder Cancer: A Dose-Response Meta-Analysis

JOURNAL=Frontiers in Physiology

VOLUME=7

YEAR=2017

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2016.00693

DOI=10.3389/fphys.2016.00693

ISSN=1664-042X

ABSTRACT=<p><bold>Background and Objective:</bold> 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.</p><p><bold>Methods:</bold> 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.</p><p><bold>Results:</bold> 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 (<italic>P</italic> = 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).</p><p><bold>Conclusion:</bold> Results based on current meta-analysis indicated that no significant association was observed between tea consumption and risk of bladder cancer.</p>