Review
Effect of washing hands with soap on diarrhoea risk in the community: a systematic review

https://doi.org/10.1016/S1473-3099(03)00606-6Get rights and content

Summary

We set out to determine the impact of washing hands with soap on the risk of diarrhoeal diseases in the community with a systematic review with random effects meta-analysis. Our data sources were studies linking handwashing with diarrhoeal diseases. Seven intervention studies, six case-control, two cross-sectional, and two cohort studies were located from electronic databases, hand searching, and the authors' collections. The pooled relative risk of diarrhoeal disease associated with not washing hands from the intervention trials was 1·88 (95% CI 1·31–2·68), implying that handwashing could reduce diarrhoea risk by 47%. When all studies, when only those of high quality, and when only those studies specifically mentioning soap were pooled, risk reduction ranged from 42–44%. The risks of severe intestinal infections and of shigellosis were associated with reductions of 48% and 59%, respectively. In the absence of adequate mortality studies, we extrapolate the potential number of diarrhoea deaths that could be averted by handwashing at about a million (1·1 million, lower estimate 0·5 million, upper estimate 1·4 million). Results may be affected by the poor quality of many of the studies and may be inflated by publication bias. On current evidence, washing hands with soap can reduce the risk of diarrhoeal diseases by 42–47% and interventions to promote handwashing might save a million lives. More and better-designed trials are needed to measure the impact of washing hands on diarrhoea and acute respiratory infections in developing countries.

Section snippets

Search strategy

We aimed to identify all studies published in English up to the end of 2002 relating handwashing to the risk of infectious intestinal or diarrhoeal diseases in the community. Medline, CAB Abstracts, Embase, Web of Science, and the Cochrane Library were systematically searched using appropriate textwords and thesaurus terms for papers relating to handwashing, use of soap, as well as disease terms such as diarrhoea, typhoid, enteric, cholera, shigellosis, dysentery, and mortality. Searches were

Principal findings

We found only 17 studies suitable for review offering 20 data points. Most were of poor quality and the range of results was considerable. Taken as awhole, however, the literature points to an important role for handwashing in preventing diarrhoeal disease. We found that interventions to promote washing hands with soap were associated with a decrease in risk of diarrhoeal disease of 47% (95% CI 24–63%). Handwashing was also associated with a 48–59% reduced risk of more severe outcomes.

Estimating potential reductions in mortality

Good

Search strategy and selection criteria

These are described in detail in the Methods section.

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