Lifetime prevalence of exostoses in New Zealand surfers

INTRODUCTION External auditory exostosis (EAE) is a benign, irreversible bony outgrowth that arises from the temporal bone. EAE projects into the external ear canal, potentially causing recurrent otitis externa and conductive hearing loss. AIM To determine lifetime prevalence of EAE in New Zealand (NZ) surfers. METHODS This study used an online national survey. RESULTS Respondents were 1376 NZ surfers (recreational = 868, competitive = 508). Mean surfing experience was 16.2 years. Most self-classified as advanced surfers (36.5%), followed by intermediate (30.2%), expert (20.1%) and beginner (13.2%). Surfers reported an average of 214.2 h surfing (28.6% during winter) for the previous year. Overall lifetime prevalence of EAE was 28.9% (32.1% male, 14.6% female; P < 0.001), with the highest proportion of EAE was observed bilaterally (21.3%). Competitive surfers reported a significantly (P < 0.001) higher lifetime prevalence of EAE than recreational surfers (45.3% vs. 19.2%). A significantly higher (P < 0.001) lifetime prevalence of EAE was identified as skill level increased (7.1% in beginners to 55.6% in experts) and a two-fold increase (P < 0.001) of EAE in the highest (vs. lowest) quartile of surfing exposure. Neither winter surfing exposure nor which Island surfed were associated with EAE prevalence. DISCUSSION Although not as prevalent as in previous NZ research using otologic examinations, this study indicated that almost one-third of NZ surfers reported having had a diagnosis of EAE. Regular general practitioner otologic assessment and advice on appropriate prevention strategies for patients who surf may help prevent large lesions, recurrent ear infections and progressive hearing loss.