title: Zinc to treat tinnitus in the elderly: a randomized placebo controlled crossover trial.
abstract: OBJECTIVE
  Several reports suggest that zinc, which is involved in several neural transmissions systems throughout the auditory pathway, might help some tinnitus patients. However, previous studies used inadequate experimental designs. Therefore, we tested the effectiveness of zinc to reduce tinnitus.
  
  
  METHODS
  Randomized, prospective double-blind placebo-controlled design.
  
  
  METHODS
  Tertiary referral center.
  
  
  METHODS
  Tinnitus subjects older than 60 years, who are more likely to have a zinc deficiency.
  
  
  METHODS
  In Phase 1, 58 subjects were randomized to receive 50 mg of zinc per day for 4 months, and 58 subjects received a placebo. After a 1-month washout period, the 2 groups were crossed over to receive the alternative regime (Phase 2).
  
  
  METHODS
  Difference scores between before and after measures of the Tinnitus Handicap Questionnaire. Changes on the difference scores 20 or greater were considered as a statistically significant and, therefore, clinically meaningful improvement for THQ.
  
  
  RESULTS
  Five percent (5 of 93 patients) had an improvement of 20 points or greater in THQ scores after zinc treatment, whereas 2% (2 of 94 patients) had an improvement of 20 or greater in THQ scores after placebo. The difference between 2 proportions is 5/93 - 2/94 = 0.03, the estimate of relative improvement is (5/93) / (2/94) = 2.53, with 95% confidence interval from 0.5 to 12.7. From chi-square independent test, there was no significant evidence that patients treated by zinc improved better than those treated by placebo (X2 (1) = 1.4, p > 0.05). The observed power in THQ for zinc is 0.16, and that for placebo is 0.06.
  
  
  CONCLUSIONS
  Zinc is not an effective treatment for tinnitus in this subgroup of patients.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, Iowa 52242, USA. claudiabarroscoelho@gmail.com
authors.forename: Claudia
authors.initials: C
authors.lastname: Coelho
authors.forename: Shelly A
authors.initials: SA
authors.lastname: Witt
authors.forename: Haihong
authors.initials: H
authors.lastname: Ji
authors.forename: Marlan R
authors.initials: MR
authors.lastname: Hansen
authors.forename: Bruce
authors.initials: B
authors.lastname: Gantz
authors.forename: Richard
authors.initials: R
authors.lastname: Tyler
mesh_terms: D000368:Aged; D002214:Capsules; D003300:Copper / Q000097:blood; D018592:Cross-Over Studies; D004185:Disability Evaluation; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D018401:Sample Size; D011795:Surveys and Questionnaires; D014012:Tinnitus / Q000188:drug therapy*; D016896:Treatment Outcome; D015032:Zinc / Q000097:blood; D019287:Zinc Sulfate / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D002214:Capsules; D019287:Zinc Sulfate; D003300:Copper; D015032:Zinc