Do the genes that cause otosclerosis reduce susceptibility to otitis media?

Hypothesis: The genetic factors that cause otosclerosis reduce susceptibility to otitis media.

Background: Susceptibility to some infectious diseases is modulated by host genetic factors. Genes that reduce the morbidity and mortality of infectious diseases may confer a selective advantage and achieve high-frequency in at-risk populations. Acute otitis media in the pre-antibiotic era frequently led to complications with high morbidity and mortality. The long-term sequela of acute otitis media is chronic otitis media. Chronic otitis media has a prevalence of 0.5 to 2 percent in the Caucasian population. Clinical otosclerosis occurs in 1 percent of Caucasians. Histologic otosclerosis occurs in 10 percent of Caucasians.

Materials And Methods: Retrospective analysis of 2,362 subjects with surgically confirmed otosclerosis. Subjects' medical records were reviewed for evidence of chronic otitis media. The incidence of chronic otitis media in the general population was compared with the subject population.

Results: Of the 2,362 subjects with surgically confirmed otosclerosis, one subject with evidence of chronic otitis media was identified. The incidence of chronic otitis media in the subject population is 0.04 percent (p < 0.0001).

Conclusions: The incidence of chronic otitis media in subjects with a surgically confirmed diagnosis of otosclerosis is significantly lower than expected. The genes that cause otosclerosis may confer resistance to the pathogens that cause chronic otitis media and/or acute otitis media. The mechanism of resistance is unknown.