Scolaris Content Display Scolaris Content Display

Study flow diagram
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Figure 1

Study flow diagram

Methodological quality graph: review authors' judgements about each methodological quality item presented as percentages across all included studies
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Figure 2

Methodological quality graph: review authors' judgements about each methodological quality item presented as percentages across all included studies

Methodological quality summary: review authors' judgements about each methodological quality item for each included study
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Figure 3

Methodological quality summary: review authors' judgements about each methodological quality item for each included study

Comparison 1 Zinc supplementation vs placebo, Outcome 1 Pneumonia incidence.
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Analysis 1.1

Comparison 1 Zinc supplementation vs placebo, Outcome 1 Pneumonia incidence.

Comparison 1 Zinc supplementation vs placebo, Outcome 2 Pneumonia prevalence.
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Analysis 1.2

Comparison 1 Zinc supplementation vs placebo, Outcome 2 Pneumonia prevalence.

Summary of findings for the main comparison. Zinc supplementation compared with placebo for the prevention of pneumonia in children aged 2 months to 59 months

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

Patient or population: children aged 2 months to 59 months
Settings: Bangladesh, India, Peru, South Africa
Intervention: zinc supplementation
Comparison: placebo

Outcomes

Illustrative comparative risks* (95% CI)

Relative effect
(95% CI)

No of Participants
(studies)

Quality of the evidence
(GRADE)

Comments

Assumed risk

Corresponding risk

Placebo

Zinc supplementation

Pneumonia incidence

343 per 1000

299 per 1000
(278 to 323)

RR 0.87
(0.81 to 0.94)

5193
(6 studies)

⊕⊕⊝⊝
low1,2

Pneumonia prevalence

22 per 1000

13 per 1000
(8 to 22)

RR 0.59
(0.35 to 0.99)

609
(1 study)

⊕⊕⊝⊝
low3,4

*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: Confidence interval; RR: Risk ratio;

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

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 outcomes assessors and reporting bias.
4 Total number of events were less than 300.

Figures and Tables -
Summary of findings for the main comparison. Zinc supplementation compared with placebo for the prevention of pneumonia in children aged 2 months to 59 months
Table 1. Zinc supplement schedule and duration

Study

Supplement

Schedule

Duration

Surveillance

Zinc

Control

Bhandari 2002

Zinc gluconate

10 mg

Both groups vitamin A

Daily

4 months

Once weekly

Bobat 2005

Zinc sulphate

10 mg

Placebo

Daily

6 months

Every 2 weeks

Brooks 2005

Zinc acetate 35 mg to infants

70 mg to children aged > 12 months

Placebo

Weekly

12 months

Once weekly

Luabeya 2007

Zinc gluconate

10 mg

Both groups vitamin A

Daily

(Continued until 24 months of age)

Once weekly

Penny 2004

Zinc gluconate

10 mg

Placebo

Daily

6 months

Once weekly

Sazawal 1998

Zinc gluconate

10 mg

Placebo

Daily

4 months

Every 5th day

Figures and Tables -
Table 1. Zinc supplement schedule and duration
Comparison 1. Zinc supplementation vs placebo

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Pneumonia incidence Show forest plot

6

5193

Risk Ratio (Fixed, 95% CI)

0.87 [0.81, 0.94]

1.1 Diagnosis based on age‐specific fast breathing with or without lower chest indrawing

4

1932

Risk Ratio (Fixed, 95% CI)

0.95 [0.86, 1.06]

1.2 Diagnosis based age‐specific fast breathing and confirmed by chest examination or chest radiograph

4

3261

Risk Ratio (Fixed, 95% CI)

0.79 [0.71, 0.88]

2 Pneumonia prevalence Show forest plot

1

609

Risk Ratio (Fixed, 95% CI)

0.59 [0.35, 0.99]

Figures and Tables -
Comparison 1. Zinc supplementation vs placebo