Provision of treated water and access to hand sanitation reduces childhood diarrhea in low and middle-income countries

1. Water treatment interventions including filtration, chlorination and solar treatment reduced the risk of diarrhea up to 50% compared to untreated water.

2. Other interventions found to be effective include providing improved drinking water, providing sewer connections for sanitation, and promoting handwashing with soap.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Global initiatives to improve access to safe drinking water, sanitation, and hygiene (WASH) have aimed to reduce the rate of childhood diarrheal disease. This study was designed to provide an up-to-date estimate of the effectiveness of different WASH interventions on reducing risk of diarrhea in children from low and middle-income countries. A systematic review and meta-analysis were conducted on 124 studies on WASH initiatives. Multiple interventions were identified as reducing the risk of diarrhea in children. Water treatment interventions, including filtration, chlorination and solar treatment, reduced diarrhea risk by up to 50% compared to untreated water. Other effective interventions included providing improved drinking water provisions, providing sewage connections for sanitation, and promoting handwashing with soap. Limitations of this study include lack of grey literature search methods. Nonetheless, this study demonstrates that WASH interventions are effective at decreasing the risk of childhood diarrhea in low-income and middle-income countries.

Click to read the study in the Lancet

Relevant Reading: The impact of sanitation on infectious disease and nutritional status: a systematic review and meta-analysis

In-Depth [systematic review and meta-analysis]: In this systematic review, searches were conducted of Ovid MEDLINE, Embase, Scopus, Cochrane Library, and BIOSIS Citation Index. Included studies were of WASH (water, sanitation, and hygiene) interventions, in English or French, and had an eligible intervention compared against a control group. The database search identified 19 837, of which 15 281 were screened and 81 were assessed for eligibility. 23 newly identified studies were added to 101 studies included in a previous systematic review. Of the 124 studies included in the analysis, 83 (62 616 children) were for water, 20 (40 799 children) were for sanitation, and 41 (98 416 children) were for hygiene. Data was preferably extracted for children under 5 years of age. Water treatment reduced the risk of diarrhea up to 50% compared to untreated water from an unimproved source. Specifically, filtration had the greatest risk reduction (n=23, RR 0.50 [95% CI 0.41-0.60]), followed by chlorination (n=25, RR 0.66 [0.56-0.77]) and solar treatment (n=13, RR 0.63 [0.50-0.80]). Other interventions also had an impact on reducing the risk of diarrhea, including providing improved drinking water provisions (n=2, 0.48 [0.26-0.86]), providing sewer connection (n=5, 0.53 [0.30-0.93]) and promoting handwashing with soap (0.70 [0.64-0.76]).

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