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Impact of drinking water, sanitation and handwashing with soap on childhood diarrhoeal disease: updated meta-analysis and meta-regression

Thursday, 10th of May 2018 Print


Trop Med Int Health. 2018 May;23(5):508-525. doi: 10.1111/tmi.13051. Epub 2018 Apr 23.

Impact of drinking water, sanitation and handwashing with soap on childhood diarrhoeal disease: updated meta-analysis and meta-regression

Wolf J1Hunter PR2,3Freeman MC4Cumming O5Clasen T4Bartram J6Higgins JPT7Johnston R1Medlicott K1Boisson S1Prüss-Ustün A1.

Author information

1 Department of Public Health, Environment and Social Determinants of Health, WHO, Geneva, Switzerland.

2 The Norwich School of Medicine, University of East Anglia, Norwich, UK.

3 Department of Environmental Health, Tshwane University of Technology, Pretoria, South Africa.

4 Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.

5 Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK.

6 Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.

7 School of Social and Community Medicine, University of Bristol, Bristol, UK.



Safe drinking water, sanitation and hygiene are protective against diarrhoeal disease; a leading cause of child mortality. The main objective was an updated assessment of the impact of unsafe water, sanitation and hygiene (WaSH) on childhood diarrhoeal disease.


We undertook a systematic review of articles published between 1970 and February 2016. Study results were combined and analysed using meta-analysis and meta-regression.


A total of 135 studies met the inclusion criteria. Several water, sanitation and hygiene interventions were associated with lower risk of diarrhoeal morbidity. Point-of-use filter interventions with safe storage reduced diarrhoea risk by 61% (RR = 0.39; 95% CI: 0.32, 0.48); piped water to premises of higher quality and continuous availability by 75% and 36% (RR = 0.25 (0.09, 0.67) and 0.64 (0.42, 0.98)), respectively compared to a baseline of unimproved drinking water; sanitation interventions by 25% (RR = 0.75 (0.63, 0.88)) with evidence for greater reductions when high sanitation coverage is reached; and interventions promoting handwashing with soap by 30% (RR = 0.70 (0.64, 0.77)) vs. no intervention. Results of the analysis of sanitation and hygiene interventions are sensitive to certain differences in study methods and conditions. Correcting for non-blinding would reduce the associations with diarrhoea to some extent.


Although evidence is limited, results suggest that household connections of water supply and higher levels of community coverage for sanitation appear particularly impactful which is in line with targets of the Sustainable Development Goals.

© 2018 World Health Organization; licensed by WHO Published by John Wiley & Sons Ltd.