1. Top of page
  2. Abstract
  3. Objectives
  4. Background
  5. Summary of Main Results
  6. Tables of Key Findings and Quality of Included Trials
  7. References

This is a summary, including tables of key findings and quality of included trials, of a Cochrane review, published in this issue of EBCH, first published as: Ejemot RI, Ehiri JE, Meremikwu MM, Critchley JA. Hand washing for preventing diarrhoea. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD004265. DOI: 10.1002/14651858.CD004265.pub2.

Further information for this Cochrane review is available in this issue of EBCH in the accompanying Commentary. Copyright © 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. The Cochrane Collaboration


  1. Top of page
  2. Abstract
  3. Objectives
  4. Background
  5. Summary of Main Results
  6. Tables of Key Findings and Quality of Included Trials
  7. References

To evaluate the effects of interventions to promote hand washing on diarrhoeal episodes in children and adults.

What's Known

Diarrhoea is a common cause of morbidity and a leading cause of death among children aged less than 5 years, particularly in low- and middle-income countries. It is transmitted by ingesting contaminated food or drink, by direct person-to-person contact, or from contaminated hands. Hand washing is one of a range of hygiene promotion interventions that can interrupt the transmission of diarrhoea-causing pathogens.

What's New

The authors of this review found that interventions that promote hand washing can reduce diarrhoea episodes by about one-third. This significant reduction is comparable to the effect of providing clean water in low-income areas. However, trials with longer follow up and that test different methods of promoting hand washing are needed.


  1. Top of page
  2. Abstract
  3. Objectives
  4. Background
  5. Summary of Main Results
  6. Tables of Key Findings and Quality of Included Trials
  7. References

The World Health Organization (WHO) estimates that over 2.2 million deaths due to diarrhoeal infections occur annually, mainly among children less than five years of age1, 2. The yearly global diarrhoeal disease burden is estimated at 99.2 million disability adjusted life years (DALYs) lost through incapacitation and premature deaths, mainly in low- and middle-income countries3. The synergistic relationship between malnutrition and infection is clearly exacerbated in diarrhoeal episodes as children tend to eat less during episodes and their ability to absorb nutrients is reduced4. Thus, each episode contributes to malnutrition, reduced resistance to infections, and, when prolonged, to impaired growth and development5.

Diarrhoeal disease pathogens are usually transmitted through the faeco-oral route6. The modes of transmission include ingestion of food and water contaminated by faecal matter, person-to-person contact, or direct contact with infected faeces7. Some studies estimate that over 70% of all cases of diarrhoea can be attributed to contaminated food and water6, 8, 9.

Epidemiological evidence shows that the most important risk factors for transmission of diarrhoea are behaviours that encourage human contact with faecal matter, including improper disposal of faeces and lack of hand washing after defecation, after handling faeces (including children's faeces), and before handling food10–13. In particular, hand contact with ready-to-eat food (i.e. food consumed without further washing, cooking, or processing/preparation by the consumer) represents a potentially important mechanism by which diarrhoea-causing pathogens contaminate food and water14. Also important are exposure of food to flies and consumption of contaminated water9, 15.

In many resource-poor countries, households may lack facilities for proper disposal of excreta, and, even where available, these may not be adapted for children's use13, 16. This often leads not only to indiscriminate defecation in and around the premises, but also to increased risk of excreta handling by mothers, caregivers, and children themselves12. In some cultures children's faeces are regarded as innocuous and adults may not wash their hands after handling them11. However, evidence suggests that children's faeces are equally hazardous and may contain even higher concentrations of pathogens than those of adults owing to their increased interactions with contaminated materials in their surroundings13, 17.

The WHO has identified a number of strategies to control diarrhoea18. These include improvement of water supply at the household or community level19 as well as hygiene promotion interventions20, including hand washing.

Hand washing aims to decontaminate the hands and prevent cross-transmission21–23. The practice of hand washing and the factors that influence hand washing behaviour among individuals in communities are complex24, 25; for example, washing hands with water only or with soap may be influenced by both knowledge of best practice and availability of water and soap. Washing with soap and water not only removes pathogens mechanically, but may also chemically kill contaminating and colonizing flora making hand washing more effective23, 26, 27. Washing hands with soap under running water or large quantities of water with vigorous rubbing was found to be more effective than several members of a household dipping their hands in the same bowl of water (often without soap)21, which is common practice in many resource-poor countries, especially before eating28. This may contribute to, rather than prevent, food contamination as pathogens present on hands of infected household members can be transferred to those who subsequently dip their hands in the same bowl of water15.

Hand washing may require infrastructural, cultural, and behavioural changes, which take time to develop, as well as substantial resources (e.g. trained personnel, community organization, provision of water supply and soap)16, 29, 30. Given the many possible ways to reduce diarrhoeal disease, it is important to assess the effectiveness of hand washing interventions compared to other interventions, such as the provision of clean water at the household or community level and improvement of sanitation (disposal of faeces).

Summary of Main Results

  1. Top of page
  2. Abstract
  3. Objectives
  4. Background
  5. Summary of Main Results
  6. Tables of Key Findings and Quality of Included Trials
  7. References

Fourteen studies met the inclusion criteria for this review. These studies were subdivided into three categories:

  • Institution-based trials – eight trials with about 7,711 participants were included; this number is approximate because participant numbers were in constant flux in many of the included studies, as some children leave the study but others are born or enter the study during the follow-up period. Participants were mainly day-care providers or educators, and young children.

  • Community-based trials – five trials with about 8,055 participants were included (the number is approximate for the same reason as above). Participants were mainly mothers or caregivers as well as children.

  • Trials in a high-risk group – one trial, including 148 adults with AIDS.

There was wide variation in the benefits of hand washing promotion on the incidence of diarrhoea reported by individual trials. This heterogeneity is not surprising as the trials differed greatly in terms of setting, population, and hand washing intervention. However, the pooled estimates from the included trials show a 39% risk reduction for the institution-based trials that adjusted for cluster randomization and 32% for the community-based trials. There was also an important reduction in mean episodes (1.68 fewer episodes in the intervention group) in a high-risk population (AIDS patients), but this is based on one trial with 148 participants and requires confirmation. In most trials, the interventions were based on hygiene promotion (providing education about diarrhoea transmission and treatment, and hand washing behaviours).

In summary, interventions that promote hand washing were efficacious in reducing diarrhoeal episodes by about one-third and should be encouraged. The challenge is to find effective ways of getting people to wash their hands appropriately.

Tables of Key Findings and Quality of Included Trials

  1. Top of page
  2. Abstract
  3. Objectives
  4. Background
  5. Summary of Main Results
  6. Tables of Key Findings and Quality of Included Trials
  7. References

L. C. M. Kremer and E. C. van Dalen

Department of Pediatric Oncology, Emma Children's Hospital/Academic Medical Center, University of Amsterdam, The Netherlands.

Table I. Key findings based on selection of clinical relevant outcomes‡$
Comparison 01. Institutional-based trials: hand washing promotion vs no intervention
OutcomeN Studies included in analysisN children included in analysisMethodResult (95% CI)Inference
  • ‡$

    Based on information provided in the review.

  • ‡*

    In this review also a RCT in adults (i.e. Huang, 2007) was included, however, for this table we only assessed data from children;

  • *

    Substantial heterogeneity defined as I2 > 50% (Higgins JPT, Green S (eds) Cochrane Handbook for Systematic Reviews of Interventions Version 5.0.0 [updated February 2008]. The Cochrane Collaboration, 2008. Available from

    Nm: not reported.

Incidence of diarrhoea: cluster-adjusted rate ratios2NmIncidence rate ratio (Random) 95% CI0.61 [0.40, 0.92]Unclear*
Comparison 02. Community-based trials: hand washing promotion vs no intervention
Incidence of diarrhoea: cluster-adjusted rate ratios4NmIncidence rate ratio (Random) 95% CI0.68 [0.52, 0.90]Unclear*
Table II. Quality of included randomized controlled trials‡*
Quality of included RCTs
Concealment of allocationBlinding of care providers and patientsBlinding of outcome assessorsCompleteness of follow-up
  1. a

    Based on information provided in the review.

  2. b

    In this review also a RCT in adults (i.e. Huang, 2007) was included, however, for this table we only assessed the quality of RCTs in children.

AdequateIn the review it was stated that double blinding is not possible in studies of hand washing interventions since there is no obvious placebo.AdequateIn the review it was stated that it is very difficult to assess losses to follow-up in open cluster-randomized trials: some children may leave the study, but others are born or enter the study during the follow-up period; hence participant numbers are in constant flux.
1/13 4/13 
Unclear Inadequate 
12/13 9/13 


  1. Top of page
  2. Abstract
  3. Objectives
  4. Background
  5. Summary of Main Results
  6. Tables of Key Findings and Quality of Included Trials
  7. References
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