Interventions to improve water quality for preventing diarrhoea

• Published in: Cochrane database of systematic reviews 2015-10, Vol.2015 (10), p.CD004794-CD004794
• Main Authors: Clasen, Thomas F, Alexander, Kelly T, Sinclair, David, Boisson, Sophie, Peletz, Rachel, Chang, Howard H, Majorin, Fiona, Cairncross, Sandy
• Format: Article
• Language: English
• Subjects: Adult; Child; Child health; Child, Preschool; Controlled Before-After Studies; Diarrhea - prevention & control; Diarrhoeal infections; Drinking Water - standards; Gastroenterology & hepatology; Humans; Infant; Infectious disease; Randomized Controlled Trials as Topic; Water Purification - methods; Water Purification - standards; Water Supply - standards
• ISSN: 1469-493X
• DOI: 10.1002/14651858.CD004794.pub3

Diarrhoea is a major cause of death and disease, especially among young children in low-income countries. In these settings, many infectious agents associated with diarrhoea are spread through water contaminated with faeces.In remote and low-income settings, source-based water quality improvement includes providing protected groundwater (springs, wells, and bore holes), or harvested rainwater as an alternative to surface sources (rivers and lakes). Point-of-use water quality improvement interventions include boiling, chlorination, flocculation, filtration, or solar disinfection, mainly conducted at home. To assess the effectiveness of interventions to improve water quality for preventing diarrhoea. We searched the Cochrane Infectious Diseases Group Specialized Register (11 November 2014), CENTRAL (the Cochrane Library, 7 November 2014), MEDLINE (1966 to 10 November 2014), EMBASE (1974 to 10 November 2014), and LILACS (1982 to 7 November 2014). We also handsearched relevant conference proceedings, contacted researchers and organizations working in the field, and checked references from identified studies through 11 November 2014. Randomized controlled trials (RCTs), quasi-RCTs, and controlled before-and-after studies (CBA) comparing interventions aimed at improving the microbiological quality of drinking water with no intervention in children and adults. Two review authors independently assessed trial quality and extracted data. We used meta-analyses to estimate pooled measures of effect, where appropriate, and investigated potential sources of heterogeneity using subgroup analyses. We assessed the quality of evidence using the GRADE approach. Forty-five cluster-RCTs, two quasi-RCTs, and eight CBA studies, including over 84,000 participants, met the inclusion criteria. Most included studies were conducted in low- or middle-income countries (LMICs) (50 studies) with unimproved water sources (30 studies) and unimproved or unclear sanitation (34 studies). The primary outcome in most studies was self-reported diarrhoea, which is at high risk of bias due to the lack of blinding in over 80% of the included studies. Source-based water quality improvementsThere is currently insufficient evidence to know if source-based improvements such as protected wells, communal tap stands, or chlorination/filtration of community sources consistently reduce diarrhoea (one cluster-RCT, five CBA studies, very low quality evidence). We found no studies evaluating reliable piped-in