Objective To evaluate the association between tea consumption and the risk of colorectal cancer (CRC) and to provide evidences for the CRC prevention.
Methods We searched China National Knowledge Infrastructure (CNKI), Wanfang Database, China Sci-Tech Journal Database (VIP), PubMed, Web of Science and Springer Link databases for studies on the correlation between tea consumption and CRC incidence published till April 1st, 2019 and supplementary manual tracing for some of the references was also conducted. Statistical analyses were performed with Stata 12.0 software.
Results Totally 15 publications on case-control study (5 in Chinese and 10 in English), involving a total of 10 251 cases and 12 865 controls, were included the analysis. The meta-analysis results revealed a 22% reduction in CRC risk in the participants with the highest tea consumption versus those with the lowest (pooled odds ratio OR = 0.78, 95% confidence interval 95% CI: 0.68 – 0.90) and a 34% reduction in CRC risk in the participants with the highest green tea consumption versus those with the lowest (OR = 0.66, 95% CI: 0.56 – 0.79); but no association of black tea consumption with CRC risk was found (OR = 0.74, 95% CI: 0.38 – 1.45). Subgroup analysis demonstrated an inverse association between tea consumption and CRC risk for studies conducted in Asian population, for population- and hospital-based studies, for studies published in Chinese, and for studies not only on rectum cancer cases (P < 0.05). The heterogeneity in the study results may related mainly to regional disparity of the studies (P < 0.05). The results of the meta-analysis were stable based on sensitivity analysis and no significant publication bias was detected with Egger and Begg test.
Conclusion The results of the meta-analysis suggest that tea consumption, especially green tea consumption, may reduce the risk of colorectal cancer.
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