Brazil study finds a disabling hearing loss prevalence of 7% in Itajai


Published by the Brazilian Journal of Otorhinolaryngology march/April 2012, a population-based survey whose field research was carried out from July 2008 to 2011 in the city of Itajai (state of Santa Catarina - southern part of brazil), found a disabling hearing loss prevalence of 7%. The work is the third population-based study about deafness published in Brazil. The first two researches, realized in canoas (Beria et al., 2007) and Monte Negro (Bevilacqua et al., 2006), showed respectively prevalence of disabling hearing loss of 6.8% e 4.8%. The piece of work was based on a World Health Organization protocol with several procedures to assess hearing in households: questionnaire, measurement of noise, otoscopy, pure tone audiometry at 1000, 2000, and 4000 Hz, tympanometry, and acoustic reflexes. A total of 774 households were visited. Eventually, the samples gathered on 137 households and 379 persons. The results showed respectively 18.9%, 5.1% and 1.9% of mild, moderate and severe hearing loss. Among the 26 individuals suffering from disabling hearing impairment, 21 were elderly subjects, showing presbyacusis as the main cause. Considering the works of beria and bevilacqua, the study of itajai was the first to track etiologic factors. The overall sample mainly showed presbyacusis (40.74%) and idiopatic (17.04%) cases. the next most frequent etiologies were: ear wax (6.66%), chronic otitis media (5.92%), otosclerosis (3.70%) and noise-induced hearing loss (2.22%). Among the population with disabling hearing loss, most frequent etiologies were: presbyacusis (80.76%), chronic otitis media (7.69%), idiopathic conditions (7.69%) and noise-induced hearing loss (3.84%). As a result, the study showed that 11.53% were potentially avoidable. "In a way, observing a high-percentage of treatable causes was good, because we managed to 'solve' many of these cases; on the other hand, it is a worrying data because with no care in due time, these losses are potentially disabling and irreversible", underscored ENT doctor Lys Gondim, the study instigator.

Stéphane Davoine

Gondim LMA et al. Study of the prevalence of impaired hearing and its determinants in the city of Itajaí, Santa Catarina State, Brazil. Brazilian Journal of Otorhinolaryngology; 78(2):27-34.