Zinc Supplementation for Tinnitus

Summary

A Cochrane review [Abstract] 1 included 3 studies with a total of 209 subjects. The participants were all adults over 18 years with subjective tinnitus, one study (n = 109) included only elderly patients.

Improvement in tinnitus severity and disabilityOnly the study in elderly patients used a validated instrument (Tinnitus Handicap Questionnaire) for this primary outcome. The authors of this cross-over study did not report the results of the two phases separately and found no significant differences in the proportion of patients reporting tinnitus improvement at 4 months of follow-up: 5% (5/93) versus 2% (2/94) in the zinc and placebo groups, respectively (RR 2.53, 95% CI 0.50 to 12.70).

Secondary outcomes:

• Tinnitus loudness: One study (n=41) found no significant difference between the zinc and placebo groups after 8 weeks (MD -9.71 dB, 95% CI -25.53 to 6.11). Another study (n=116) found no significant difference between the zinc and placebo groups after 4 months in tinnitus loudness rating scores (MD 0.50, 95% CI -5.08 to 6.08).
• Severity of tinnitus: One study (n=50) reported the severity using a non-validated scale (0 to 7 points) and found no significant difference in subjective tinnitus scores between the zinc and placebo groups after 8 weeks (MD -1.41, 95% CI -2.97 to 0.15). Another trial (n = 50) also evaluated the improvement of tinnitus using a non-validated instrument (a 0 to 10 scale). After 8 weeks there was no difference in the proportion of patients with improvement in tinnitus (8.7% vs 8% for zinc and placebo groups, respectively).

None of the included studies reported quality of life, change in socioeconomic impact associated with work, change in anxiety and depression disorders, change in psychoacoustic parameters or change in thresholds on pure tone audiometry.