Chiavarini Manuela, Minelli Liliana, Fabiani Roberto
1Department of Experimental Medicine,Section of Public Heath,University of Perugia,Perugia,Italy.
2Department of Chemistry,Biology and Biotechnology,University of Perugia,Via del Giochetto,06126 Perugia,Italy.
Public Health Nutr. 2016 Feb;19(2):308-17. doi: 10.1017/S1368980015001263. Epub 2015 May 6.
Colorectal cancer shows large incidence variations worldwide that have been attributed to different dietary factors. We conducted a meta-analysis on the relationship between garlic consumption and colorectal cancer risk.
We systematically reviewed publications obtained by searching ISI Web of Knowledge, MEDLINE and EMBASE literature databases. We extracted the risk estimate of the highest and the lowest reported categories of intake from each study and conducted meta-analysis using a random-effects model.
The pooled analysis of all fourteen studies, seven cohort and seven case-control, indicated that garlic consumption was not associated with colorectal cancer risk (OR=0·93; 95 % CI 0·82, 1·06, P=0·281; I 2=83·6 %, P≤0·001). Separate analyses on the basis of cancer sites and sex also revealed no statistically significant effects on cancer risk. However, when separately analysed on the basis of study type, we found that garlic was associated with an approximately 37 % reduction in colorectal cancer risk in the case-control studies (combined risk estimate=0·63, 95 % CI 0·48, 0·82, P=0·001; I 2=75·6 %, P≤0·001).
Our results suggest that consumption of garlic is not associated with a reduced colorectal cancer risk. Further investigations are necessary to clarify the discrepancy between results obtained from different types of epidemiological studies.
结直肠癌在全球的发病率差异很大，这归因于不同的饮食因素。我们对大蒜摄入量与结直肠癌风险之间的关系进行了一项荟萃分析。
我们系统地回顾了通过检索科学网（ISI Web of Knowledge）、医学文献数据库（MEDLINE）和荷兰医学文摘数据库（EMBASE）获得的出版物。我们从每项研究中提取了报告的最高和最低摄入量类别的风险估计值，并使用随机效应模型进行荟萃分析。
对所有14项研究（7项队列研究和7项病例对照研究）的汇总分析表明，大蒜摄入量与结直肠癌风险无关（比值比[OR]=0.93；95%置信区间[CI]为0.82至1.06，P=0.281；I²=83.6%，P≤0.001）。基于癌症部位和性别的单独分析也显示对癌症风险没有统计学上的显著影响。然而，当根据研究类型进行单独分析时，我们发现大蒜在病例对照研究中与结直肠癌风险降低约37%相关（合并风险估计值=0.63，95%CI为0.48至0.82，P=0.001；I²=75.6%，P≤0.001）。
我们的结果表明，食用大蒜与降低结直肠癌风险无关。有必要进一步调查以澄清不同类型流行病学研究结果之间的差异。
