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Interventions to improve water quality for preventing diarrhoea

  1. Thomas F Clasen1,*,
  2. Ian G Roberts2,
  3. Taber Rabie3,
  4. Wolf-Peter Schmidt1,
  5. Sandy Cairncross3

Editorial Group: Cochrane Infectious Diseases Group

Published Online: 19 JUL 2006

Assessed as up-to-date: 21 JAN 2006

DOI: 10.1002/14651858.CD004794.pub2

How to Cite

Clasen TF, Roberts IG, Rabie T, Schmidt WP, Cairncross S. Interventions to improve water quality for preventing diarrhoea. Cochrane Database of Systematic Reviews 2006, Issue 3. Art. No.: CD004794. DOI: 10.1002/14651858.CD004794.pub2.

Author Information

  1. 1

    London School of Hygiene & Tropical Medicine, Department of Infectious and Tropical Diseases, London, UK

  2. 2

    London School of Hygiene & Tropical Medicine, Cochrane Injuries Group, London, UK

  3. 3

    London School of Hygiene & Tropical Medicine, Department of Infectious and Tropical Diseases, Disease Control and Vector Biology Unit, London, UK

*Thomas F Clasen, Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. thomas.clasen@lshtm.ac.uk.

Publication History

  1. Publication Status: Edited (no change to conclusions)
  2. Published Online: 19 JUL 2006

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Abstract

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

Background

Diarrhoeal diseases are a leading cause of mortality and morbidity, especially among young children in developing countries. While many of the infectious agents associated with diarrhoeal disease are potentially waterborne, the evidence for reducing diarrhoea in settings where it is endemic by improving the microbiological quality of drinking water has been equivocal.

Objectives

To assess the effectiveness of interventions to improve water quality for preventing diarrhoea.

Search methods

We searched the Cochrane Infectious Diseases Group Specialized Register (December 2005), CENTRAL (The Cochrane Library 2005, Issue 4), MEDLINE (December 2005), EMBASE (December 2005), and LILACS (December 2005). We also handsearched relevant conference proceedings, contacted researchers and organizations working in the field, and checked references from identified studies.

Selection criteria

Randomized and quasi-randomized controlled trials comparing interventions aimed at improving the microbiological quality of drinking water with no intervention in children and adults living in settings where diarrhoeal disease is endemic.

Data collection and analysis

Two authors independently assessed trial quality and extracted data. We used meta-analyses to estimate pooled measures of effect, where appropriate, and investigated potential sources of heterogeneity using subgroup analyses.

Main results

Thirty trials (including 38 independent comparisons) covering over 53,000 participants met the inclusion criteria. Differences between the trials limited the comparability of results and pooling by meta-analysis. In general, the evidence suggests that interventions to improve the microbiological quality of drinking water are effective in preventing diarrhoea both for populations of all ages and children less than five years old. Subgroup analyses suggest that household interventions are more effective in preventing diarrhoea than interventions at the water source. Effectiveness was positively associated with compliance. Effectiveness was not conditioned on the presence of improved water supplies or sanitation in the study setting, and was not enhanced by combining the intervention to improve water quality with other common environmental interventions intended to prevent diarrhoea.

Authors' conclusions

Interventions to improve water quality are generally effective in preventing diarrhoea, and interventions to improve water quality at the household level are more effective than those at the source. Significant heterogeneity among the trials suggests that the actual level of effectiveness may depend on a variety of conditions that research to date cannot fully explain. Rigorous, blinded, multi-arm randomized controlled trials conducted over a longer duration in a variety if settings may help clarify the potential effectiveness.

 

Plain language summary

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

Interventions to improve water quality, particularly when implemented at the household level, are effective in preventing diarrhoea in settings where it is endemic

Diarrhoea is a major cause of death and disease, especially among young children in low-income countries. Loss of fluid (dehydration) is the major threat, though diarrhoea also reduces the absorption of the nutrients, causing poor growth in children, reduced resistance to infection, and potentially long-term gut disorders. This review examined trials of interventions to improve the microbiological quality of drinking water. These include conventional improvements at the water source (eg protected wells, bore holes, and stand posts) and point-of-use interventions at the household level (eg chlorination, filtration, solar disinfection, and combined flocculation and disinfection). The review covered 38 independent comparisons from 30 trials that involved more than 53,000 people. In general, such interventions were effective in reducing episodes of diarrhoea. Household interventions were more effective in preventing diarrhoea than those at the source. However, differences in the interventions and the settings in which they were introduced, as well as the methods and measurements of effect, limit the extent to which generalizations can be made. Further research, including blinded trials and longer-term assessments, is necessary to understand the full impact of these interventions.

 

摘要

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

背景

為預防腹瀉所使用於改善水質之措施

腹瀉是死亡及致病之重大肇因之一,尤其是就開發中國家的幼兒而言。儘管諸多與腹瀉相關之感染原皆潛在為經由飲水傳遞,在腹瀉流行之環境中藉由改良飲用水之微生物品質以降低腹瀉發生之證據仍不明。

目標

評估用於改善水質以預防腹瀉之措施的有效性

搜尋策略

我們搜尋Cochrane Infectious Diseases Group Specialized Register (2005年12月)、 CENTRAL (Cochrane Library 2005, Issue 4)、 MEDLINE (2005年12月)、 EMBASE (2005年12月)、以及LILACS (2005年12月)。我們人工搜尋相關研討會手冊、聯絡本領域研究人員以及組織,並檢查所找到的研究的參考文獻。

選擇標準

針對生活在腹瀉流行之環境中的兒童及成人,目的為比較改善飲用水之微生物品質的干預措施與無干預措施的隨機及半隨機對照試驗。

資料收集與分析

由2位作者獨立評估試驗品質並摘錄數據。在適當時使用整合分析評估集合之效應標準,並使用次組分析研究潛在之異質性來源。

主要結論

共有涵括超過53,000名病患之30項試驗(包括39組獨立之比較)符合收錄標準。試驗間之差異性限制了結果之比較以及整合分析之集合。一般而言證據建議,用於改善飲用水微生物品質之干預措施可有效預防全部年齡群體以及小於5歲兒童之腹瀉。次組分析建議,家庭用之措施可較水源處之措施更為有效地預防腹瀉。有效性具有一致之正面相關性。有效性不受限於研究環境中是否存在有改善之供水或衛生設備的條件,且其不會因為結合其他用於預防腹瀉之常用環境措施而提升。

作者結論

用於改善水質之措施一般而言可有效預防腹瀉,而家庭層級之水質改善措施較水源處之措施更為有效。由於試驗間有顯著異質性存在,實際之有效性程度可能取決於諸多至今之研究仍無法完全解釋的因素。在各種環境下以較長時間所進行之嚴格、遮盲、多治療組的隨機對照試驗可能有助於澄清潛在之有效性。

翻譯人

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

總結

用於改善水質之措施,特別係在家庭層級所執行者,可在腹瀉流行之環境中有效預防腹瀉。腹瀉是死亡及致病的主要肇因之一,特別是就低收入國家之幼兒而言。體液之流失(脫水)是主要的威脅,但腹瀉亦會使營養之吸收降低,造成兒童發育不良、對感染之抗性降低、並可能造成潛在性之慢性腸道疾病。本回顧檢驗針對用於改善飲水微生物品質之措施所進行的試驗。此等措施包括水源處之習知改良處理(如: 受到保護之水井、鑽孔、及水栓柱)以及家庭層級使用端之干預措施(如,加氯、過濾、太陽光消毒、以及絮凝與消毒之組合)。本回顧共涵括取自涉及超過53,000名參與者之30項試驗的38項獨立比較。一般而言,此等措施可有效降低腹瀉的發生。家庭措施可較水源處措施更為有效地預防腹瀉。然而,各種差異,包括措施與引用該等措施之環境,以及測量有效性之方法及標準,皆限制了可達成通則性結論之程度。仍需要進一步之研究,包括遮盲及長期之評估,以明瞭此等措施之最大影響。