Incidence of External Auditory Canal Exostoses in Competitive Surfers in Japan

Objective. The objective of this study was to demonstrate the prevalence and severity of external auditory canal exostoses in a population of competitive surfers in Japan. The authors used a "surfing index," the product of the period (years) as an active surfer and the frequency (number of surfing days per week), to predict external auditory exostoses formation. Study design. Cross-sectional study. Setting. A total of 5 surfing competitions that were held in Miyazaki, Japan. Materials and Methods. The ear canals of 373 surfers with an average age of 33.1 years (range, 11-80 years) were examined with an otoscope. The severity of exostosis was classified into 4 groups, ranging from grade 0 to 3, according to otoscopic findings. Subjects also completed a questionnaire detailing their surfing habits. Results. There was a 59.8% overall prevalence of exostoses in 373 surfers. The incidences of grade 1, 2, and 3 exostoses were 118 (31.6%), 71 (19.0%), and 34 (9.1%), respectively. The prevalences of grade 2 and 3 exostoses were higher in surfers with a surfing index of more than 20 (P < .0001). Conclusions. The authors determined that a positive association exists between the surfing index and the severity of exostoses. The findings suggest that it is possible to assume the likelihood of exostosis formation from the surfing index, and this may be of help to spread awareness of exostosis among surfers.