The role of zinc in management of tinnitus.

Objective: Several therapeutic modalities have been tried in patients with tinnitus. These trials have given rise to unsatisfactory results in most of the patients since the etiology and pathophysiology of tinnitus is unclear. Significant correlation between tinnitus and decreased zinc level and also reduction in severity of tinnitus after zinc therapy has been reported in some clinical studies. The aim of this study is to find out the prevalence of hypozincemia in patients suffering from tinnitus of various origins (presbyacusis, acoustic trauma and ototoxicity) at young and elderly population and to investigate the effect of zinc therapy upon the severity of tinnitus.

Methods: Forty consecutive patients with severe tinnitus were included in this study between April 1998 and May 2000. There were 32 men (80%) and eight women (20%) with an age ranging between 19 and 67 (mean 40.6 years). Eleven patients were over the age of 50. The zinc level was measured in non-diluted serum by flame atomic absorption spectrophotometry (normal values; 50-120 microg/dl) from fasting blood samples. All the patients were given zinc pills 220 mg each, once a day and 2 h before lunch for 2 months. The patients were required to fulfill a tinnitus scoring scale and a handicap questionnaire before and after treatment. The Wilcoxon rank sum test and McNemar test were used for the statistical analysis.

Results: Six patients were hypozincemic and seven patients had decreased serum zinc levels. No significant change has been observed in frequency and severity of tinnitus measured by audiologic tests after zinc therapy. Twenty-three (57.5%) of these patients reported some relief of tinnitus in the tinnitus scoring scale but the rate of improvement was minor (P>0.05). Decrease in severity of tinnitus after zinc therapy in elder group was better than the younger ones.

Conclusion: Our study could not confirm the high incidence of hypozincemia in patients with tinnitus as reported previously. Zinc therapy for 8 weeks presented no promising effect on tinnitus in three groups of patients and the difference between the rate of improvement in severity of tinnitus after zinc intake in patients with normal and low serum zinc level was not significant. Zinc supplement provided relief of tinnitus in some of the elder people who apparently had dietary zinc deficiency.