Prevalence of middle ear disease in Chilean natives and the impact of development over 14 years

INTRODUCTION: The prevalence of middle ear disease and its risk factors have been the subject of multiple studies. High prevalence of middle ear disease has been described among North American natives, especially chronic otitis media. Such studies have not been carried out in South America. OBJECTIVE: To describe the prevalence of middle ear pathology and risk factors in native schoolchildren from southern Chile who belong to the Mapuche ethnic group, as well as the impact of socio-economic and demographic changes after 14 years of development. MATERIAL AND METHODS: Two otologic evaluations with an interval of 14 years were performed in schoolchildren with a percentage of indigenous population above 85%. Socioeconomic and demographic data were collected from national official statistical data. RESULTS: A total of 1067 schoolchildren were examined. Many described risk factors for ear pathology were found. An overall prevalence of 0.19% for tympanic membrane perforation, 5.6% for pars tensa retraction pockets, 1.5% for pars flaccida retraction pockets and 11.1% of otitis media with effusion was found. There were several socioeconomic improvements after 14 years. The difference between the prevalence of symptoms and the presence of otitis media with effusion was statistically significant (p < 0.001). CONCLUSIONS: Despite the presence of several risk factors for middle ear disease, this study population showed a low prevalence of middle ear disease. The ethnic-racial factor seems to be a protective factor.