Treating water with chlorine at point-of-use to improve water quality and reduce child diarrhea in developing countries: a systematic review and meta-analysis.

We conducted a systematic review of all studies that measured diarrheal health impacts in children and the impact on water quality of point-of-use chlorine drinking water treatment. Twenty-one relevant studies were identified from > 856 screened abstracts. Data were extracted and combined using meta-analysis to provide summary estimates of the intervention effect. The intervention reduced the risk of child diarrhea (pooled relative risk: 0.71, 0.58-0.87) and it reduced the risk of stored water contamination with Escherichia coli (pooled relative risk: 0.20, 0.13-0.30). A major finding from this review is that nearly all trials on this topic have been short (median length was 30 weeks). Although not statistically significant, we observed an attenuation of the intervention's reduction of child diarrhea in longer trials. Future studies with multi-year follow-up are required to assess the long-term acceptability and sustainability of health impacts shown by the shorter trials identified in this review.