Oral zinc for treating diarrhoea in children
Abstract
Background
In developing countries, diarrhoea causes around two million child
deaths annually. Zinc supplementation during acute diarrhoea is
currently recommended by the World Health Organization and UNICEF.
Objectives
To evaluate oral zinc supplementation for treating children with acute
or persistent diarrhoea.
Search methods
In February 2012, we searched the Cochrane Infectious Diseases Group
Specialized Register, CENTRAL (The Cochrane Library 2011, 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.
The quality of evidence has been assessed using the GRADE methods
Main results
Twenty-four trials, enrolling 9128 children, met our inclusion
criteria. The majority of the data is from Asia, from countries at high
risk of zinc deficiency, and may not be applicable elsewhere.
Acute diarrhoea
There is currently not enough evidence from well conducted randomized
controlled trials to be able to say whether zinc supplementation during
acute diarrhoea reduces death or hospitalization (very low quality
evidence).
In children aged greater than six months with acute diarrhoea, zinc supplementation may shorten the duration of diarrhoea by around 10 hours (MD -10.44 hours, 95% CI -21.13 to 0.25; 2091 children, five trials, low quality evidence), and probably reduces the number of children whose diarrhoea persists until day seven (RR 0.73, 95% CI 0.61 to 0.88; 3865 children, six trials, moderate quality evidence). In children with signs of moderate malnutrition the effect appears greater, reducing the duration of diarrhoea by around 27 hours (MD -26.98 hours, 95% CI -14.62 to -39.34; 336 children, three trials, high quality evidence).
Conversely, In children aged less than six months, the available evidence suggests zinc supplementation may have no effect on mean diarrhoea duration (MD 5.23 hours, 95% CI -4.00 to 14.45; 1334 children, two trials, low quality evidence), and may even increase the proportion of children whose diarrhoea persists until day seven (RR 1.24, 95% CI 0.99 to 1.54; 1074 children, one trial, moderate quality evidence).
No trials reported serious adverse events, but zinc supplementation during acute diarrhoea causes vomiting in both age groups (RR 1.59, 95% 1.27 to 1.99; 5189 children, 10 trials, high quality evidence).
Persistent diarrhoea
In children with persistent diarrhoea, zinc supplementation probably
shortens the duration of diarrhoea by around 16 hours (MD -15.84 hours,
95% CI -25.43 to -6.24; 529 children, five trials, moderate quality
evidence).
Authors' conclusions
In areas where the prevalence of zinc deficiency or the prevalence of
moderate malnutrition is high, zinc may be of benefit in children aged
six months or more.The current evidence does not support the use of zinc
supplementation in children below six months of age.
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. This systematic review of 24 trials involving more than 9000 children shows that zinc supplementation may reduce the duration of diarrhoea in children aged six months or more.
Citation
Lazzerini, M.; Ronfani, L. Oral zinc for treating diarrhoea in children. Cochrane Database of Systematic Reviews (2012) (Issue 6) Art. No.: CD005436. [DOI: 10.1002/14651858.CD005436.pub3]