A study from the Swedish Karolinska Institutet demonstrates that bilateral tinnitus – that is, tinnitus in both ears – can have a significant heritability and thus in some cases genetics influence tinnitus as well as environmental factors.
The study also showed that the prevalence of hereditary, bilateral tinnitus is greater among men than women.
An unexpected finding
At first, the researchers of Karolinska Institutet didn’t find any unusual results concerning the heritability of tinnitus. They only discovered the genetic correlation after grouping the subjects by sex and unilateral/bilateral tinnitus:
“This result is surprising and unexpected as it shows that, unlike the conventional view of tinnitus being driven by environmental factors, there is a genetic influence for bilateral tinnitus which is more pronounced in men,” says Christopher R. Cederroth of Karolinska Institutet’s Department of Physiology and Pharmacology.
About the study
The study was conducted by examining data from 10,000 twin pairs from the Swedish Twin Registry comparing the prevalence of tinnitus among twins who are respectively identical and fraternal. A greater concordance of tinnitus among identical twins than among fraternal twins implies a genetic correlation, and this was the case of bilateral tinnitus in the study. However, no correlation in the study was found concerning unilateral tinnitus – that is, tinnitus in one ear.
The study “Genetic susceptibility to bilateral tinnitus in a Swedish twin cohort” was published in Genetics in Medicine.
Sources: www.sciencedaily.com and Genetics in Medicine.