Zhu Ming-Zhi, Lu Dan-Min, Ouyang Jian, Zhou Fang, Huang Pei-Fang, Gu Bao-Zheng, Tang Jun-Wei, Shen Fan, Li Jia-Feng, Li Yi-Long, Lin Hai-Yan, Li Juan, Zeng Xin, Wu Jian-Lin, Cai Shu-Xian, Wang Kun-Bo, Huang Jian-An, Liu Zhong-Hua
Key Laboratory of Tea Science of Ministry of Education, National Research Center of Engineering Technology for Utilization of Functional Ingredients from Botanicals, College of Horticulture, Hunan Agricultural University, Changsha, 410128, China.
Hunan Provincial Key Laboratory for Germplasm Innovation and Utilization of Crop, Hunan Agricultural University, Changsha, 410128, China.
Eur J Nutr. 2020 Dec;59(8):3603-3615. doi: 10.1007/s00394-020-02195-3. Epub 2020 Feb 20.
Data from in vitro and animal studies support the preventive effect of tea (Camellia sinensis) against colorectal cancer. Further, many epidemiologic studies evaluated the association between tea consumption and colorectal cancer risk, but the results were inconsistent. We conducted a meta-analysis of prospective cohort studies to systematically assess the association between tea consumption and colorectal cancer risk.
A comprehensive literature review was conducted to identify the related articles by searching PubMed and Embase up to June, 2019. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a fixed effect model.
Twenty cohort articles were included in the present meta-analysis involving 2,068,137 participants and 21,437 cases. The combined RR of colorectal cancer for the highest vs. lowest tea consumption was determined to 0.97 (95% CI 0.94-1.01) with marginal heterogeneity (I = 24.0%, P = 0.093) among all studies. This indicated that tea consumption had no significant association with colorectal cancer risk. Stratified analysis showed that no significant differences were found in all subgroups. We further conducted the gender-specific meta-analysis for deriving a more precise estimation. No significant association was observed between tea consumption and colorectal cancer risk in male (combined RR = 0.97; 95% CI 0.90-1.04). However, tea consumption had a marginal significant inverse impact on colorectal cancer risk in female (combined RR = 0.93; 95% CI 0.86-1.00). Further, we found a stronger inverse association between tea consumption and risk of colorectal cancer among the female studies with no adjustment of coffee intake (RR: 0.90; 95% CI 0.82-1.00, P < 0.05) compared to the female studies that adjusted for coffee intake (RR = 0.97; 95% CI 0.87-1.09, P > 0.05).
Our finding indicates that tea consumption has no significant impact on the colorectal cancer risk in both genders combined, but gender-specific meta-analysis shows that tea consumption has a marginal significant inverse impact on colorectal cancer risk in female.
体外和动物研究数据支持茶（茶树）对结直肠癌的预防作用。此外，许多流行病学研究评估了饮茶与结直肠癌风险之间的关联，但结果并不一致。我们进行了一项前瞻性队列研究的荟萃分析，以系统评估饮茶与结直肠癌风险之间的关联。
通过检索截至2019年6月的PubMed和Embase进行全面的文献综述，以识别相关文章。使用固定效应模型计算汇总相对风险（RRs）和95%置信区间（CIs）。
本荟萃分析纳入了20篇队列文章，涉及2,068,137名参与者和21,437例病例。所有研究中，最高与最低饮茶量的结直肠癌合并RR为0.97（95%CI 0.94 - 1.01），存在边缘异质性（I² = 24.0%，P = 0.093）。这表明饮茶与结直肠癌风险无显著关联。分层分析显示，所有亚组均未发现显著差异。我们进一步进行了性别特异性荟萃分析以获得更精确的估计。男性饮茶与结直肠癌风险之间未观察到显著关联（合并RR = 0.97；95%CI 0.90 - 1.04）。然而，饮茶对女性结直肠癌风险有边缘显著的反向影响（合并RR = 0.93；95%CI 0.86 - 1.00）。此外，我们发现与调整了咖啡摄入量的女性研究相比，未调整咖啡摄入量的女性研究中，饮茶与结直肠癌风险之间的反向关联更强（RR：0.90；95%CI 0.82 - 1.00，P < 0.05），而调整了咖啡摄入量的女性研究中（RR = 0.97；95%CI 0.87 - 1.09，P > 0.05）。
我们的研究结果表明，饮茶对总体人群的结直肠癌风险无显著影响，但性别特异性荟萃分析表明，饮茶对女性结直肠癌风险有边缘显著的反向影响。
