Zinc supplements for preventing otitis media.
Author(s): Gulani A, Sachdev HS.
Affiliation(s): Department of Pediatrics and Clinical Epidemiology, Sitaram Bhartia Institute of
Science and Research, New Delhi, India. gulani73@yahoo.com.
Publication date & source: 2012, Cochrane Database Syst Rev. , 4:CD006639
BACKGROUND: Otitis media (OM) is inflammation of the middle ear and is usually
caused by infection. It affects people of all ages but is particularly common in
young children. Around 164 million people worldwide have long-term hearing loss
caused by this condition, 90% of them in low-income countries. As zinc
supplements prevent pneumonia in disadvantaged children, we wanted to investigate
whether zinc supplements could also prevent OM.
OBJECTIVES: To evaluate whether zinc supplements prevent OM in adults and
children of different ages.
SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials
(CENTRAL 2012, Issue 1) which includes the Cochrane Acute Respiratory Infections
Groups' Specialised Register, MEDLINE (1950 to February week 1, 2012) and EMBASE
(1974 to February 2012).
SELECTION CRITERIA: Randomised, placebo-controlled trials of zinc supplements
given at least once a week for at least a month for preventing OM.
DATA COLLECTION AND ANALYSIS: Two review authors independently assessed the
eligibility and methodological quality of the included trials and extracted and
analysed data. We summarised results using risk ratios (RRs) or rate ratios for
dichotomous data and mean differences (MDs) for continuous data. We combined
trial results where appropriate.
MAIN RESULTS: We identified 12 trials for inclusion, 10 of which contributed
outcomes data. There was a total of 6820 participants. In trials of healthy
children living in low-income communities, two trials did not demonstrate a
significant difference between the zinc supplemented and placebo groups in the
numbers of participants experiencing an episode of definite OM during follow-up
(3191 participants); another trial showed a significantly lower incidence rate of
OM in the zinc group (rate ratio 0.69, 95% confidence interval (CI) 0.61 to 0.79,
n = 1621). A small trial of 39 infants undergoing treatment for severe
malnutrition suggested a benefit of zinc for the mean number of episodes of OM
(mean difference (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
were reported to have vomited shortly after ingestion of the supplements. The
trial evidence included is generally of good quality, with a low risk of bias.
AUTHORS' CONCLUSIONS: Evidence on whether zinc supplementation can reduce the
incidence of OM in healthy children under the age of five years living in low-
and middle-income countries is mixed. There is some evidence of benefit in
children being treated for marasmus (severe malnutrition) but this is based on
one small trial and should therefore be treated with caution.
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