Zinc supplementation reduces pneumonia incidence by 13% among children between two months and five years old.
Photo Credits: Shehzad Noorani
Why is zinc important?
Zinc is important for immune function and our ability to fight infections, particularly pneumonia and diarrhea. Zinc deficiency is common among children from low-income countries. Zinc is not stored in our bodies so it must be available in our daily diet or from supplements. Zinc deficiency reduces the ability of the immune system to fight infections and contributes to increased rates of serious infectious diseases, such as pneumonia.
Does zinc supplementation work?
- Daily zinc supplementation for children between two months and 5 years prevents pneumonia in low-income areas among disadvantaged populations.
Equity: does zinc supplementation work in the disadvantaged?
- Children from low-income countries are at increased risk of zinc deficiency therefore zinc supplementation can reduce pneumonia incidence and improve child survival.
Intervention Delivery
- Zinc supplementation is provided as a syrup, as a tablet, or as a micronutrient powder added to water and taken as a liquid beverage.
- The included studies provided zinc to families to be used in daily doses in 10mg doses of zinc gluconate, zinc sulphate, or zinc acetate. One study gave weekly doses of 35 mg to infants or 70 mg to children over 12 months.
- The review does not report on the effectiveness of different delivery mechanisms or schedules for zinc supplementation.
Population and Setting
- The included studies were all conducted in low and middle-income countries. The majority of participants were from urban slums.
- Most studies excluded children with underlying conditions, however, two studies included children with HIV and one study included children with diarrhea.
Summary of Findings [SOF] Tables: Zinc supplementation for the prevention of pneumonia in children aged 2 months to 59 months
Patient or population: Children aged between 2 months and 59 months
Settings: Bangladesh, India, Peru, South Africa
Intervention: Zinc supplementation
Comparison: Placebo
Outcomes |
| Anticipated absolute effects per year | Relative Effect | No of Participants | Quality of the evidence | |
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| Risk without zinc supplementation (Control) | Risk difference with zinc supplementation (95% CI) |
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Pneumonia incidence |
| 343 per 1000 | 44 fewer per 1000 (from 20 to 65 fewer) | RR 0.87 (0.81-0.94) | 5193 | Low1,2 |
Pneumonia prevalence |
| 22 per 1000 | 9 fewer per 1000 (from 0 to 14 fewer) | RR 0.59 (0.35-0.99) | 609 (1 studies) | Low3,4 |
Adverse Events: Not described in this review | ||||||
1. Studies have unclear information on allocation concealment, blinding and reporting biases. 2. Pneumonia diagnosis criteria was used differently. 3. Studies have limited information on blinding of outcome assessors and reporting bias. 4. Total number of events was less than 300. | ||||||
Relevance of the review for disadvantaged communities Zinc supplementation reduces pneumonia incidence by 13% among children between two months and five years old. | |
Findings | Interpretation |
Equity - Which of the PROGRESS groups examined | |
All of the included studies were conducted in low or middle income countries but the review did not report on socioeconomic status of participants. The review did not report on subgroup analyses or sex distribution within the studies. | Zinc supplementation is effective in low-income countries for disadvantaged children. |
Equity Applicability | |
The majority of participants in the included studies were from urban slums (Bangladesh, India, South Africa). Two studies included children with HIV and one study included children with diarrhea for more than 14 days. Most of the studies excluded children with other underlying conditions, such as tuberculosis, congenital heart disease, chronic respiratory disease, low weight-for-age score, and nutritional edema. Reasons for these exclusions were not reported. | Zinc supplementation is recommended for reducing the number of new cases of pneumonia in low-income areas among disadvantaged populations. Depending on the availability of foods containing zinc within the local setting, the effects of zinc supplementation on the prevention of pneumonia (number of new cases and duration of illness) may be greater or lower. More studies are needed to examine the effects of zinc supplementation on children with underlying conditions. If the children in your setting have underlying conditions the effects of zinc supplementation may be different than the results of this review. |
The studies included in this review gave the supplement to the families to be administered to the child in daily doses (except for one study that used weekly doses). The zinc was given as a syrup, as a tablet, or as a micronutrient powder added to water and taken as a liquid beverage.
| Since zinc is not stored in the body, adequate zinc must be made available daily. However, one included study found reductions in pneumonia incidence with weekly doses. Policy makers and practitioners will need to consider their local setting to determine the most suitable delivery mechanism and schedule. The supplements must be active and stored properly. |
The review does not report on the effectiveness of different delivery mechanisms or schedules for zinc supplementation. | The review summarized findings based on studies in which the level of organization may be higher than what is available outside of research settings. Factors to consider when assessing whether the intervention effects are transferable to your settings include:
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Cost-equity | |
The review did not report on the cost-effectiveness of zinc supplementation overall or in each disadvantaged group. | The cost of zinc supplementation will vary based on local conditions outside of research settings. Some factors for consider are:
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Comments on this summary? Contact Jennifer Petkovic