Oral zinc for treating diarrhoea in children.
Abstract
Background
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.
Objectives
To evaluate oral zinc supplementation for treating children with acute
or persistent diarrhoea.
Search strategy
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.
Selection criteria
Randomized controlled trials comparing oral zinc supplementation with
placebo in children aged one month to five years with acute or
persistent diarrhoea, including dysentery.
Data collection and analysis
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.
Main results
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).
Authors' conclusions
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.
Plain language summary
Oral zinc supplementation for treating diarrhoea in children In
developing countries, millions of children suffer from severe diarrhoea
every year. This is due to infection and malnutrition, and many die from
dehydration due to the diarrhoea. Giving fluids by mouth (using an oral
rehydration solution) has been shown to save children's lives, but it
seems to have no effect on the length of time the children suffer with
diarrhoea. Children in developing countries are often zinc deficient.
Zinc supplementation is a possible treatment for diarrhoea though it can
have adverse effects if given in high doses. The review of trials
identified 22 trials involving 8924 children of all ages. Zinc reduced
the time that children over the age of six months suffered from symptoms
of acute or persistent diarrhoea. However, there were insufficient data
to see any impact on the number of children who died. More children
vomited when given zinc, but it was considered that the benefits
outweighed these adverse effects. Zinc seemed to have no impact on
children aged less than six months. In areas where diarrhoea is an
important cause of child mortality, research evidence shows zinc is
clearly of benefit in children aged six months or more with diarrhoeal
diseases.
Citation
Lazzerini, M.; Ronfani, L. Oral zinc for treating diarrhoea in children. Cochrane Database of Systematic Reviews (2008) (Issue 3) Art. No.: CD005436. [DOI: 10.1002/14651858.CD005436.pub2]