A meta-analysis of tea consumption and the risk of bladder cancer.
OBJECTIVE
Previous studies on the association between tea consumption and bladder cancer risk have only illustrated contradictory results. The role of tea in bladder carcinogenesis still remains conflicting. In order to illustrate the potential relationship between tea consumption and bladder cancer, a meta-analysis of case-control and cohort studies was conducted.


METHODS
Eligible studies were retrieved via both computerized searches and review of references. Stratified analyses on types of tea, gender, study design, ethnicity and smoking status were performed. Fixed- or random-effect models were used to summarize the estimates of OR with 95% CIs.


RESULTS
Seventeen studies were eligible for our analysis. No statistical significance was detected between tea consumption and bladder cancer risk when comparing the highest with the lowest intake of tea (OR = 0.825, 95% CI 0.652-1.043). In the subgroup of green tea, we observed it illustrated a protective effect on bladder cancer (OR = 0.814, 95% CI 0.678-0.976).


CONCLUSIONS
Our analysis indicated that green tea may have a protective effect on bladder cancer in Asian people. Further studies need to be conducted to better clarify the biological mechanisms.
Department of Urology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China.
Xiao
X
Wang
Yi-Wei
YW
Lin
Shuai
S
Wang
Jian
J
Wu
Qi-Qi
QQ
Mao
Xiang-Yi
XY
Zheng
Li-Ping
LP
Xie
D000284:Administration, Oral; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D044466:Asian People; D001628:Beverages; D006801:Humans; D016017:Odds Ratio; D010946:Plants, Medicinal; D018570:Risk Assessment; D012307:Risk Factors; D013662:Tea; D001749:Urinary Bladder Neoplasms / Q000208:ethnology / Q000517:prevention & control*; D044465:White People
D000970:Antineoplastic Agents; D013662:Tea