Intervention Review

Dietary fibre for the prevention of colorectal adenomas and carcinomas

  1. Tracey K. Asano1,*,
  2. Robin S McLeod2

Editorial Group: Cochrane Colorectal Cancer Group

Published Online: 21 JAN 2002

Assessed as up-to-date: 12 NOV 2001

DOI: 10.1002/14651858.CD003430


How to Cite

Asano TK, McLeod RS. Dietary fibre for the prevention of colorectal adenomas and carcinomas. Cochrane Database of Systematic Reviews 2002, Issue 1. Art. No.: CD003430. DOI: 10.1002/14651858.CD003430.

Author Information

  1. 1

    University of Toronto, Surgery, Toronto, ONT, Canada

  2. 2

    Mount Sinai Hospital, Division of General Surgery, Toronto, Ontario, Canada

*Tracey K. Asano, Surgery, University of Toronto, c/o Dr. Robin McLeod, 600 University Ave Suite 449, Toronto, ONT, M5G 1X5, Canada. tasano@mtsinai.on.ca.

Publication History

  1. Publication Status: Edited (no change to conclusions)
  2. Published Online: 21 JAN 2002

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Abstract

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要
  5. Plain language summary

Background

Colorectal cancer (CRC) is a major cause of morbidity and mortality in industrialized countries. Experimental evidence has supported the hypothesis that dietary fibre may be protective for the development of CRC, although epidemiologic data have been inconclusive.

Objectives

To assess the effect of dietary fibre on the incidence or recurrence of colorectal adenomas, the incidence of CRC, and the development of adverse events.

Search methods

We identified randomized controlled trials from Medline, Embase, and the Cochrane Controlled Trials Register up to Oct 2001

Selection criteria

Randomized or quasi-randomized controlled trials were assessed. The population included all subjects that had adenomatous polyps but no previous history of colorectal cancer (CRC), a documented "clean colon" at baseline and repeated visualization of the colon/rectum after at least two years of follow-up. Dietary fibre was the intervention.
The primary outcomes were the number of subjects with: a) at least one adenoma, b) more than one adenoma, c) at least one adenoma greater than or equal to 1 cm or d) a new diagnosis of CRC. The secondary outcome was the number of adverse events.

Data collection and analysis

Two reviewers independently extracted data, assessed trial quality and resolved discrepancies by consensus. The outcomes were reported as relative risks (RR) and risk difference (RD) with 95% confidence intervals (CI). If statistical significance was reached, the number need to treat (NNTT) or harm (NNTH) was reported. The study data were combined with the fixed effects model if it was clinically, methodologically, and statistically reasonable.

Main results

Five studies with 4349 subjects met the inclusion criteria. The interventions were wheat bran fibre, ispaghula husk, or a comprehensive dietary intervention with high fibre whole food sources alone or in combination. When the data were combined there was no difference between the intervention and control groups for the number of subjects with at least one adenoma [RR 1.04 (95% CI 0.95,1.13); RD 0.01 (95% CI 0.02,0.04)]. As well, the combined results for the number of subjects with more than one adenoma [RR 1.02 (95% CI 0.89,1.17), RD 0.00 (-0.02,0.03)] or at least one adenoma 1 cm or greater [RR 0.94 (95% CI 0.77,1.15), RD -0.01 (-0.02,0.01)] were not statistically significant. Other primary and secondary outcomes and subanalyses by type of fibre intervention were not statistically or clinically significant.

Authors' conclusions

There is currently no evidence from RCTs to suggest that increased dietary fibre intake will reduce the incidence or recurrence of adenomatous polyps within a two to four year period.

 

Plain language summary

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要
  5. Plain language summary

Dietary fibre for the prevention of colorectal adenomas and carcinomas

Colorectal (bowel) cancer is common worldwide but is especially prevalent in industrialised countries. Genes, diet and lifestyle all seem to be important in the development of bowel cancer. Several communities with low bowel cancer rates have diets that are rich in fibre. Increasing the levels of fibre in the diet in industrialised countries might therefore help to reduce the rate of bowel cancer. However, the review found that increasing fibre in a western diet for two to four years did not lower the risk of bowel cancer. Studies using both longer-term trials and higher dietary fibre levels may be needed.

 

摘要

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要
  5. Plain language summary

背景

膳食纖維預防結直腸腺瘤和癌

在工業化國家結直腸癌(CRC)是發病率和死亡率的主要原因。膳食纖維可以防護結直腸癌的發展,雖然流行病學數據是不確定的,但是實驗證據支持這個假說.

目標

評估飲食纖維對結腸直腸腺瘤的發生或復發的影響,大腸癌的發病率和不良事件的發展

搜尋策略

從MEDLINE,EMBASE和Cochrane對照試驗註冊到2001年10月,我們確定的隨機對照試驗

選擇標準

隨機或半隨機對照試驗進行評估.人口當中主要包括以前沒有結直腸癌(CRC)的病史的腺瘤性息肉,至少須要追蹤2年後,才能在基礎線和重復形象化稱為“clean colon”.膳食纖維是介入的,主要的結果數是:a)至少是一個腺瘤b)超過一個腺瘤c)至少是一個超過或等於1公分的腺瘤d)一個新的結直腸癌診斷,次要結果是不良事件的數目

資料收集與分析

由二名評論員獨立地提供了數據,評估試驗質量和解決分歧的共識.結果報告作為相對風險(RR)和風險差(RD)的95%可信區間(CI).如果統計意義達到了,數字需要治療(NNTT)或損害(NNTH)報告.如果是臨床的,方法論,和統計的合理,以固定效應模 式,研究資料相結合.

主要結論

與4349個主題的五項研究符合了納入標準.干預都是麥麩纖維,ispaghula殼,或整個高纖維的食物來源,單獨或組合全面的膳食干預.至少有一個腺瘤為干預組與對照組主體的數目,當數據合併沒有任何區別,[RR 1.02 (95% CI 0.89,1.17), RD 0.00 (−0.02,0.03)]或至少是一個超過或等於1公分的腺瘤[RR 0.94 (95% CI 0.77,1.15), RD −0.01(−0.02,0.01)]在統計學上並不顯著。 其他主要和次要的結果和subanalyses類型纖維干預沒有統計學和臨床意義

作者結論

從隨機對照試驗中目前還沒有證據證明,在2到4年內,增加膳食纖維攝入量將減少腺瘤息肉發病或復發

翻譯人

本摘要由國泰綜合醫院張世昌翻譯

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌

總結

結直腸癌(腸)癌症是世界性的,在工業化國家特別普遍。基因,飲食和生活方式似乎都是腸癌發展重要的因素。有幾個社區的腸癌發病率低,他們的飲食有豐富的纖維。在工業化國家的飲食中,增加纖維量,可能因此有助於減少腸癌.然而,審查發現,在西方飲食中增加纖維兩至四年,並沒有降低腸癌的風險。研究可能需要同時使用長期的試驗和較高層次的膳食纖維

 

Plain language summary

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要
  5. Plain language summary

Biljna vlakna u prehrani za prevenciju adenoma i karcinoma debeloga crijeva i rektuma

Biljna vlakna u prehrani za prevenciju adenoma i karcinoma debeloga crijeva i rektuma

Karcinom debeloga crijeva i rektuma česta je bolest koja se javlja svuda u svijetu, a osobito često u razvijenim zemljama. Na razvoj karcinoma crijeva utječu geni, prehrana i životni stil. Opisano je nekoliko zajednica u kojima je učestalost karcinoma crijeva niska, a prehrana ljudi u tim zajednicama bogata biljnim vlaknima. Povećanje količine vlakana u prehrani osoba iz razvijenih zemalja bi dakle možda moglo pomoći u smanjenju učestalosti karcinoma crijeva. Međutim, Cochrane sustavni pregled je pokazao da povećanje količine vlakana u prehrani osoba koje žive u razvijenim zemljama, tijekom razdoblja od dvije do četiri godine, nije smanjilo rizik od nastanka karcinoma crijeva. Potrebna su dodatna dugoročna istraživanja u kojima će se istražiti prehrana s višim udjelom biljnih vlakana.

Translation notes

Translated by: Croatian Branch of the Italian Cochrane Centre
Translation Sponsored by: Ministry of Education, Science and Sports