BackgroundDiarrhoea is a common cause of morbidity and a leading cause of death among children aged less than five 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.ObjectivesTo evaluate the effects of interventions to promote hand washing on diarrhoeal episodes in children and adults.Search strategyIn May 2007, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2007, Issue 2), MEDLINE, EMBASE, LILACS, PsycINFO, Science Citation Index and Social Science Citation Index, ERIC, SPECTR, Bibliomap, RoRe, The Grey Literature, and reference lists of articles. We also contacted researchers and organizations in the field.Selection criteriaRandomized controlled trials, where the unit of randomization is an institution (eg day‐care centre), household, or community, that compared interventions to promote hand washing or a hygiene promotion that included hand washing with no intervention to promote hand washing.Data collection and analysisTwo authors independently assessed trial eligibility and risk of bias. We stratified the analyses for cluster adjusted and non‐adjusted trials. Where appropriate, incidence rate ratios (IRR) were pooled using the generic inverse variance method and random‐effects model with 95% confidence intervals (CI).Main resultsFourteen randomized controlled trials met the inclusion criteria. Eight trials were institution‐based in high‐income countries, five were community‐based in low or middle‐income countries, and one was in a high‐risk group (people with acquired immune deficiency syndrome (AIDS)). Considering only trial results that adjusted for cluster randomization, interventions promoting hand washing resulted in a 39% reduction in diarrhoea episodes in children in institutions in high‐income countries (IRR 0.61, 95% CI 0.40 to 0.92; 2 trials) and a 32% reduction in such episodes in children living in communities in low‐ or middle‐income countries (IRR 0.68, 95% CI 0.52 to 0.90; 4 trials).Authors' conclusionsInterventions 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.Plain Language SummaryStrategies to encourage hand washing can reduce the incidence of diarrhoea by about one thirdDiarrhoea is a serious global public health problem, particularly in low‐income and middle‐income countries. The World Health Organization estimates that over three million episodes occur each year, with many people dying, especially children aged less than five years in low‐ and middle‐income countries. Persistent diarrhoea can also contribute to malnutrition, reduced resistance to infections, and sometimes impaired growth and development. The organisms causing diarrhoea can be transmitted from infected faeces to people through food and water, person‐to‐person contact, or direct contact. Hand washing after defecation and handling faeces, and before preparing and eating food can reduce the risk of diarrhoea. This review looked at trials of interventions to increase the use of hand washing in institutions in high‐income countries and in communities in low‐ or middle‐income countries, and found many of the interventions like educational programmes, leaflets, and discussions to be effective.
