The Epidemiology of Otosclerosis in a British Cohort

Abstract

Objective: To analyse the epidemiology of otosclerosis in a British cohort collected between 2011 and 2017.

Design: Retrospective cohort study.

Setting: Five UK ENT Departments.

Patients: Patients with surgically confirmed otosclerosis.

Main outcome measures: Questionnaire data documented family history of otosclerosis, age of onset, medical history, and information on associated risk factors for 657 patients. Pre and post-surgical pure-tone audiometry was collected for 154 of these patients.

Results: The age of onset, incidence of bilateral disease, tinnitus and vertigo, a higher prevalence of women (65%) than men (35%) are similar to those reported previously for otosclerosis cohorts. No association with measles infection was detected. Patients with a family history (40%) have an earlier age of onset and a higher incidence of bilateral disease and vertigo than non-familial subjects. Pedigree analysis is consistent with an autosomal dominant inheritance with reduced penetrance being apparent in 44/91 pedigrees studied. Women who associate their hearing loss with pregnancy have an earlier age of onset than those that do not (p = 6 × 10).

Conclusions: This study confirms that otosclerosis is an early adult onset disease that is more prevalent in women than men with a large minority of patients having a family history of otosclerosis. We report new evidence to support a relationship between pregnancy and otosclerosis progression in a proportion of women. In addition, this is the first study to identify differences in severity between familial and non-familial cases of otosclerosis, highlighting the possibility that more than one etiology may be involved.

Figure 1. Characteristics of otosclerosis cohort.

(A) Age of onset and (B) incidence of hearing phenotypes in otosclerosis cohort according to duration of hearing loss (n=657). (C) Age of onset and (D) incidence of bilateral hearing loss in male and female cases according to duration of hearing loss (Male, n=233; Female; n=424). (E) Age of onset and (F) bilateral hearing loss in familial and non-familial cases according to duration of hearing loss (Familial, n=265; Non-familial; n=392). Familial cases were defined as having 1 or more affected family member. ns, not significant; *, p<0.05; **, p<0.01.

Figure 2. Comparison of otosclerosis characteristics in patients when stratified by the effect of pregnancy on hearing loss.

(A) Age of onset in women who had experienced pregnancy (Preg_Y, n=313) and those that had not (Preg_N, n=96). (B) Age of onset in women who report changes in hearing associated with pregnancy (Preg_HC, n=100) and those who report no change during pregnancy (Preg_NC, n = 204). (C) Bilateral hearing loss in pregnancy sub-groups. (D) Time spent breastfeeding and (E) number of pregnancies in Preg_HC and Preg_NC women. Male data used as control comparison in panels A-C (n = 233). ns, not significant; *, p<0.05; **, p<0.01; ****, p<0.0001.