TABLE 1 Clinical trials investigating the impact of zinc on incidence and outcome of pneumonia in children

Study, Design	Country, Setting	Sample size	Inclusion criteria	Intervention	Outcomes	Level of evidence
Bobat ^9, RCT	South Africa, Urban tertiary care hospital OPD	96	Children between 6 and 60 months of age with HIV infection being cared for at the hospital and not on antiretroviral therapy.	10 mg of elemental zinc as sulphate or placebo every day for 6 months.	Pneumonia diagnosis during scheduled and illness visits in zinc and placebo groups: 57(14%) v 83(18.6%); p=0.07	1b
Brooks ^8, RCT	Bangladesh, Poor urban population	1665	Children aged 60 days to 12 months at the time of enrollment without underlying respiratory disease, congenital heart disease or severe malnutrition.	70 mg zinc given orally as syrup (35 mg zinc acetate per 5 mls) or placebo once a week.	Incidents of pneumonia in zinc group compared to placebo group: 199/809 v 286/812; Relative risk 0.83, 95%CI 0.73-0.95	1b
Bhandari ^7, RCT	India, Urban slum community	2482	All children aged 6 to 30 months in the community not requiring urgent admission to hospital on the enrollment day or not received massive dose of vitamin A recently.	Elemental zinc (10 mg for infants, 20 mg for children) as gluconate or placebo taken daily for four months.	Mean plasma zinc concentration at 4 months: 19.8 (SD 10.1) in zinc group v 9.3 (2.1) µmol/l in placebo group; p<0.001. Incidence of pneumonia in zinc v placebo group (Absolute risk reduction 2.5%; 95% CI 0.4% to 4.6%)	1b
Brooks ^6, RCT	Bangladesh, Hospital (rural facility)	270	Children between 2 to 23 months admitted to hospital with severe pneumonia.	20 mg elemental zinc per day (10 mg zinc per 5 mls syrup) as acetate or placebo until discharge from hospital	Duration of severe pneumonia in zinc compared to placebo groups: Relative hazard 0.70; 95% CI 0.51- 0.98	1b