The Rise and Fall of Otosclerosis: A Population-based Study of Disease Incidence Spanning 70 Years

Abstract

Objective: Although it is commonly held that otosclerosis has become increasingly uncommon over recent decades, no population-based data exist to characterize this trend. Moreover, because most large epidemiologic databases within the United States primarily include cancer data, even the modern incidence of otosclerosis is unknown. The chief objective of the current work was to characterize the trend in the incidence of otosclerosis over 70 years using the unique resources of the Rochester Epidemiology Project.

Study design: Population-based study.

Patients: Residents of Olmsted County, Minnesota diagnosed with otosclerosis.

Main outcome measure: Disease incidence from 1950 to 2017.

Results: From 1950 to 2017, 614 incident cases of otosclerosis were identified. The incidence rose from 8.9 per 100,000 person-years in the 1950s to a peak of 18.5 from 1970 to 1974. From this peak, the incidence significantly declined to 6.2 per 100,000 person-years by the early-1990s and reached a nadir of 3.2 from 2015 to 2017 (p<0.001). From 1970 to 2017, age at diagnosis (p = 0.23) and the proportion of bilateral cases (p = 0.16) did not significantly change; pure-tone average at diagnosis did not clinically appreciably change over the study period (median difference <5 dB across decades, p = 0.034).

Conclusions: The incidence of otosclerosis drastically declined since the early-1970s. Historically considered one of the most common causes of acquired hearing loss, the low modern incidence of otosclerosis renders it legally a "rare disease" within the United States. These trends require consideration when determining trainee case requirements and developing practice guidelines.

Figure 1.

Patient age at diagnosis by decade from 1970–2017.* *The borders of the box represent the 25^th and 75^th percentiles, grey dots represent individual patients, the median is drawn in the middle of the box, and the bars at the bottom and top of each decade extend to the minimum and maximum observed ages.

Figure 2.

Age-adjusted incidence of otosclerosis by sex and year of diagnosis from 1950–2017.* *The dotted lines represent incidence rates prior to 1970 from the study by Pearson, et al.

Figure 3.

Comparison of disease incidence among otosclerosis and sporadic vestibular schwannoma in Olmsted County, Minnesota. (A) Incidence rates by decade from 1970 through 2016. (B) Incidence rates by age at diagnosis from 2012 through 2016.* *The restriction of years through 2016 was used due to the absence of 2017 data on vestibular schwannoma in this population.

Figure 3.

Comparison of disease incidence among otosclerosis and sporadic vestibular schwannoma in Olmsted County, Minnesota. (A) Incidence rates by decade from 1970 through 2016. (B) Incidence rates by age at diagnosis from 2012 through 2016.* *The restriction of years through 2016 was used due to the absence of 2017 data on vestibular schwannoma in this population.