title: Zinc supplements for preventing otitis media.
abstract: 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.
  
  
  OBJECTIVE
  To evaluate whether zinc supplements prevent OM in adults and children of different ages.
  
  
  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).
  
  
  METHODS
  Randomised, placebo-controlled trials of zinc supplements given at least once a week for at least a month for preventing OM.
  
  
  METHODS
  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.
  
  
  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.
  
  
  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.
authors.affiliation: Department of Pediatrics and Clinical Epidemiology, Sitaram Bhartia Institute of Science and Research, New Delhi, India. gulani73@yahoo.com.
authors.forename: Anjana
authors.initials: A
authors.lastname: Gulani
authors.forename: Harshpal S
authors.initials: HS
authors.lastname: Sachdev
mesh_terms: D015362:Child Nutrition Disorders / Q000628:therapy; D002675:Child, Preschool; D002712:Chlorides / Q000627:therapeutic use; D003906:Developing Countries; D019587:Dietary Supplements; D005260:Female; D005942:Gluconates / Q000627:therapeutic use; D006801:Humans; D007223:Infant; D007228:Infant Nutrition Disorders / Q000628:therapy; D008297:Male; D010033:Otitis Media / Q000517:prevention & control*; D016032:Randomized Controlled Trials as Topic; D014131:Trace Elements / Q000627:therapeutic use*; D015032:Zinc / Q000627:therapeutic use; D019345:Zinc Acetate / Q000627:therapeutic use; D017967:Zinc Compounds / Q000627:therapeutic use*; D019287:Zinc Sulfate / Q000627:therapeutic use
chemical_list: D002712:Chlorides; D005942:Gluconates; D014131:Trace Elements; D017967:Zinc Compounds; D019287:Zinc Sulfate; C016837:zinc chloride; D019345:Zinc Acetate; D015032:Zinc; C030691:gluconic acid