| Partâ… A case-control study of dietary fibre and the risk of colorectal cancerObjective This case-control study examined the effect of dietary fibre intake on the risk of colorectal cancer, stratified by tumour site.Methods The study included 265 cases(colon cancer: 105; rectal cancer: 144; colon and rectal cancer: 16) and 252 controls residing in Qingdao. A food frequency questionnaire that included 121 food items was used to collect dietary information. Odds ratio(OR) and 95% confidence intervals(CI) were calculated using unconditional logistic regression analysis.Results1. No significant differences were observed in BMI, physical activity, total energy, smoking habits or drinking habits between controls and cases with colorectal cancer or colon cancer. A significant difference was observed in drinking habits between controls and cases with rectal cancer(P<0.05). 2. For food groups, controls in the study consumed more vegetables, soy food and total fibre than did colorectal cancer patients(P<0.05). The intakes of fruit, meat and sea-food did not differ significantly between cases and controls. However, we did not find an association between soy food intake and colon cancer. 3. We observed inverse associations between total fibre intake and colorectal, colon and rectal cancer(Q4 VS Q1: OR=0.44, 95%CI: 0.27-0.73; OR=0.40, 95%CI: 0.21-0.76; OR=0.52, 95%CI: 0.29-0.91). Vegetable fibre intake showed inverse associations with colorectal, colon and rectal cancer(Q4 VS Q1: OR=0.51, 95%CI: 0.31-0.85; OR=0.48, 95%CI: 0.25-0.91; OR=0.53, 95%CI: 0.29-0.97). Similarly, inverse associations were observed between soluble fibre and insoluble fibre and both colorectal cancer and colon cancer. No relationship was found between colorectal cancer and fruit, soy or grain fibre intakes when the results were stratified by tumour site.Conclusions Dietary fibre plays a very important role in protecting against colorectal cancer. The effects of different types of fibre are different in different tumour sites. Vegetable, soluble and insoluble fibres were inversely associated colon cancer.Vegetable fibre was inversely associated rectal cancer.Partâ…¡ Effects of dietary fiber on human intestinal bacteria structure with colorectal cancerObjective1. Explore the relationship between intestinal bacteria and colorectaer cancer by the comparison the differences of intestinal bacteria between colorectal cancers and controls. 2. Explore the relationship between ditary fiber and intestinal bacteria when we divided groups according to ditary fiber intake.Methods Collecting excrement of 23 cases and nomal controls respectively from May 2014 to November 2014 and making quantitative analysis of Enterbacteria, Enterococcus, lactobacillus, bifidobacterium and bacteroides these five kinds of intestinal bacteria.Results1. Comparing with the control group, the number of Enterococcus was higher in case group(P<0.05). The number of lactobacillus and bifidobacterium were lower in case group(P<0.05). There were no difference between two groups in the number of Enterbacteria and bifidobacterium. 2. There have been significant differences between cases and controls for five kinds of bacteria when divided groups according to ditary intake(P<0.05). In subgroups of higher ditary fiber, significant differences were found in the number of Enterococcus, lactobacillus, bifidobacterium between cases and controls(P<0.05); No differences were found in the number of Enterbactria and bacteroides(P>0.05). In subgroups of higher ditary fiber, no significant differences were observed in all five kinds of bacteria between cases and controls(P>0.05). 3. Both in case and control groups, the number of Enterococcus and dietary fibre was negatively correlated(P<0.05). The number of lactobacillus and bifidobacterium and ditary fibre were positively correlated(P<0.05). The relationships between Enterbacteria,bifidobacterium and ditary fibre were not obvious(P>0.05).Conclusions1. There have been differences in the structure of bacteria between cases with colorectal cancer and controls. 2. Dietary fiber can influence the structure of bacteria which are associated with the rate of colorectal cancer.Part III Food intake and the risk of rectal cancer: a Meta-analysis studyObjectiveA Meta-analysis was conducted to explore the relationship between vegetables, fruit, soy food or all grains intake and rectal cancer, and provide evidence for decreasing the risk of rectal cancer.MethodsLiteratures about vegetables, fruit, soy food or all grains and rectal cancer were searched on Pubmed, Springer Link, Science Direct, Wangfang, CNKI, CBM, VIP database. Included literatures were evaluated by Newcastle-Ottawa scales. The data were extracted and analysed. The pooled odd ratio(OR) and 95% confidence intervals(CI) were calculated through Review Manager 5.2.ResultsEight literatures were included finally. Total vegetables and soy food were protective factors for rectal cancer, and the pooled OR were 0.81(95%CI: 0.74-0.89) and 0.85(95%CI: 0.77-0.94) respectively; We did not find the relationship between fruit, all grains and rectal cancer, and the pooled OR were 1.01(95%CI: 0.84-1.21) and 0.94(95%CI: 0.75-1.17) respectively.ConclusionsVegetables and soy food intake can decrease the risk of rectal cancer. |
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