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Zinc supplementation for the prevention of pneumonia in children aged 2 months to 59 months

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Abstract

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Background

Pneumonia is a leading cause of morbidity and mortality in children younger than five years of age. Most deaths occur during infancy and in low‐income countries. Daily regimens of zinc have been reported to prevent acute lower respiratory tract infection and reduce child mortality.

Objectives

To evaluate the effectiveness of zinc supplementation in the prevention of pneumonia in children aged two to 59 months.

Search methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 2), which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to January Week 2, 2010), EMBASE (1974 to January 2010) and LILACS (1985 to January 2010).

Selection criteria

Randomised controlled trials (RCTs) evaluating supplementation of zinc for the prevention of pneumonia in children aged 2 to 59 months of age.

Data collection and analysis

Two review authors independently assessed trial quality and extracted data.

Main results

We included six trials and 7850 participants in the meta‐analysis. Analysis showed that zinc supplementation reduced the incidence of pneumonia by 13% (risk ratio (RR) 0.87; 95% confidence interval (CI) 0.81 to 0.94, fixed‐effect, six studies) and prevalence of pneumonia by 41% (RR 0.59; 95% CI 0.35 to 0.99, random‐effects, one study). On subgroup analysis, we found that zinc reduced the incidence of pneumonia defined by specific clinical criteria by 21% (i.e. confirmation by chest examination or chest radiograph) (RR 0.79; 95% CI 0.0.71 to 0.88, fixed‐effect, four studies, n = 4591) but had no effect on lower specificity pneumonia case definition (i.e. age specific fast breathing with or without lower chest indrawing) (RR 0.95; 95% CI 0.86 to 1.06, fixed‐effect, four studies, n = 3259).

Authors' conclusions

Zinc supplementation in children is associated with a reduction in the incidence and prevalence of pneumonia, the leading cause of death in children.

PICOs

Population
Intervention
Comparison
Outcome

The PICO model is widely used and taught in evidence-based health care as a strategy for formulating questions and search strategies and for characterizing clinical studies or meta-analyses. PICO stands for four different potential components of a clinical question: Patient, Population or Problem; Intervention; Comparison; Outcome.

See more on using PICO in the Cochrane Handbook.

Plain language summary

Zinc supplementation for the prevention of pneumonia in children aged two to 59 months

Zinc is an essential element for growth and development of children. Its deficiency is associated with increased risk of infection, particularly diarrhoea and pneumonia. Zinc supplementation in children has been reported to prevent pneumonia; however, its effect remains unclear. The aim of this review is to evaluate the role of zinc supplementation in the prevention of pneumonia in children of two to 59 months of age.

The review authors found six randomised controlled trials evaluating the impact of providing zinc supplementation for the prevention of pneumonia. The studies were conducted in Bangladesh, India, Peru, and South Africa. Children of two to 59 months of age were randomly assigned to receive zinc or a placebo. In two studies, the children were given vitamin A in both the groups. Analysis of the studies showed that zinc supplementation was significantly associated with reducing the incidence and prevalence of pneumonia among children of two to 59 months of age. Evidence provided so far from randomised controlled trials is sufficient to recommend zinc intake in deficient populations through supplementation, dietary improvements, or fortification, for enhancing child survival.