Effects of intervention promoting hand washing for preventing diarrhea

Diarrhea is a common cause of morbidity and mortality among children aged less than five years, particularly in resource-poor settings. Most diarrhea disease pathogens are transmitted through the faeco-oral routes.

Behaviors that encourage human contact with faecal matter, including lack of hand washing after defecation, after handling children's faeces, before handling food, and improper disposal of faeces, can all contribute to transmission.

We assessed the strength of evidence for the benefits of hand washing in preventing diarrhea, using Cochrane methodology.

We searched electronic databases from 1966 to May 2007 for relevant studies irrespective of language or publication status. Only randomized controlled studies promoting hand washing alone, or with a broader hygiene promotion messages including hand washing were included.

Fourteen randomized controlled trials met inclusion criteria. Eight trials were institution-based (day care centers for children, schools) conducted mostly in industrialized countries, five were community-based, from low/middle income countries, and one was in a high-risk group (AIDS patients). Interventions promoting hand washing resulted in a 29% reduction in diarrhea episodes in institutions (IRR 0.71, 95% CI 0.60 to 0.84; 7 trials) and a 31% reduction in communities (IRR 0.69, 95% CI 0.55 to 0.87; 5 trials). The one trial in AIDS patients also showed a significant reduction in episodes of diarrhea.

Hand washing can reduce diarrhea episodes irrespective of study setting by about 30%. Further research needs to find best and cost-effective ways of promoting hand washing across populations that ensures that hand washing messages and practices are sustained over time.