A Cochrane review [Abstract] 1 included 12 studies with a total of 6820 subjects; 10 studies contributed outcomes data. Nine of the 10 trials were conducted in low- and middle-income countries, where zinc deficiency among young children is common. In studies of healthy children living in low-income communities, 2 studies (children aged 6 to 31 months) did not demonstrate a significant difference between the zinc supplemented and placebo groups in the numbers of participants experiencing an episode of definite otitis media during follow up (RR 1.05, 95% CI 0.82 to 1.36; 2 studies, n=3 191), while another study (community study; children aged 60 days to 12 months) showed a significantly lower incidence rate of otitis media in the zinc group (rate ratio 0.69, 95% CI 0.61 to 0.79; 1 study, n=1 621). A small study of 39 infants undergoing treatment for severe malnutrition suggested a benefit of zinc on the mean number of episodes of otitis media (MD -1.12 episodes, 95% CI -2.21 to -0.03). Zinc supplements did not seem to cause any serious adverse events, but a small minority of children was reported to have vomited shortly after ingestion of the supplements.
Comment: The quality of evidence is downgraded by inconsistency (variability in results across studies).
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