Oral zinc for treating diarrhoea in children

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Abstract
In developing countries, diarrhoea causes around two million child deaths annually. Zinc supplementation could help reduce the duration and severity of diarrhoea, and is recommended by the World Health Organization and UNICEF. To evaluate oral zinc supplementation for treating children with acute or persistent diarrhoea. In December 2010, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2010, Issue 11), MEDLINE, EMBASE, LILACS, CINAHL, mRCT, and reference lists. We also contacted researchers. Randomized controlled trials comparing oral zinc supplementation with placebo in children aged one month to five years with acute or persistent diarrhoea, including dysentery. Both authors assessed trial eligibility and risk of bias, extracted and analysed data, and drafted the review. Diarrhoea duration and severity were the primary outcomes. We summarized dichotomous outcomes using risk ratios (RR) and continuous outcomes using mean differences (MD) with 95% confidence intervals (CI). Where appropriate, we combined data in meta‐analyses (using the fixed‐ or random‐effects model) and assessed heterogeneity. Twenty‐two trials, enrolling 8924 children, met our inclusion criteria. In acute diarrhoea, zinc shortened the diarrhoea duration (MD ‐9.60 h, 95% CI ‐18.25 to ‐0.96 h; 4242 children, 13 trials), with fewer children with diarrhoea by day three (RR 0.77, 95% CI 0.67 to 0.89; 1568 children, three trials), day five (RR 0.74, 95% CI 0.55 to 0.99; 1646 children, four trials), and day seven (RR 0.82, 95% CI 0.72 to 0.94; 5528 children, 10 trials). In children under six months, no benefit was demonstrated. The benefit of zinc in children over six months was consistent in subgroup analysis. In persistent diarrhoea, zinc reduced the duration (MD ‐15.84 h, 95% CI ‐25.43 to ‐6.24 h; 529 children, five trials). In all trials, few reported on diarrhoea severity, and results were inconsistent. No trial reported serious adverse events, but vomiting was more common in zinc‐treated children with acute diarrhoea (RR 1.59, 95% 1.27 to 1.99; 5189 children, 10 trials). In areas where diarrhoea is an important cause of child mortality and the risk of zinc deficiency is from moderate to high, zinc clearly benefits children aged six months or more.