Use of analgesic drugs, occupational exposure to noise and solvents as risk factors for tinnitus and hearing impairment in a retrospective cohort study of male twins

Abstract

Background: Sweden has a unique twin registry administrated by Karolinska Institutet. A cohort of this register is the basis for this study. There are many causes of hearing loss and tinnitus, where genetics, diseases, noise exposure, drugs, solvents and the normal aging process are some of these causes. Aim: This project’s aim was to investigate the prevalence of tinnitus among twins as well as the connection between self-reported use of analgesic drugs, occupational exposure to noise and solvents, and tinnitus and hearing loss. Methods: The study included 1114 male twins aged 34-78 from a previously collected material. Analyses have included response from questionnaires and audiogram. The study investigated the degree of tinnitus symptoms they had, if there was a correlation with tinnitus and hearing loss and other risk factors. Results: In this study 13,5 percent of the twins had tinnitus symptoms. Individuals with tinnitus symptoms had elevated hearing thresholds, they were more exposed to salicylate/NSAID, noise and solvents than those who had not reported tinnitus. The proportion of tinnitus symptoms also increased with increasing age. The results showed that tinnitus had a statistical correlation with hearing loss for the whole cohort. In this study it was also found a statistical correlation with the use of salicylate/NSAID and noise exposure and hearing loss at 4000 Hz for the whole cohort. Heritability of tinnitus analyzed in pairs of twins with tinnitus in a Tetrachoric correlation analysis. Conclusion: The results showed a strong correlation of identical twins, which means a hereditary of tinnitus.