Study of the prevalence of impaired hearing and its determinants in the city of Itajaí, Santa Catarina State,Brazil

The number of people with impaired hearing is increasing; knowing its magnitude is essential for public health.ObjectiveTo study the prevalence and determinants of impaired hearing in Itajaí/SC.MethodsA population-based survey based on a World Health Organization protocol. Field research was carried out from July 2008 to 2011. Procedures for evaluating hearing in households: questionnaire, measurement of noise, otoscopy, pure tone audiometry at 1000, 2000, and 4000 Hz, tympanometry, and acoustic reflexes: individuals above 4 years; children under 4 years: evoked otoacoustic emissions (OAE), cocleo-palpebral reflex(CPR), tympanometry, and acoustic reflexes. In the elderly population a questionnaire of perception of hearing loss was applied.ResultsThe study sample consisted of 379 individuals – 45.38% were males and 54.62% were females. Age-range: 11.34% up to 10 years; 64.39% 10 to 60 years, 24.27% over 60 years. Evaluation of the best hearing ear showed that 74.1% of residents had normal hearing, 18.9% had mild hearing loss, 5.1% had moderate hearing loss, 1.9% had severe hearing loss. Disabling impaired hearing was detected in 26 subjects: one child (otitis media); four adults (one otitis, one noise-induced, two idiopathic); 21 elderlies (presbyacusis). Of eight children under 4 years all presented CPR, three were normal examinations, two had absent OAE bilaterally, one had absent OAE in the right ear and one in the left ear.ConclusionThe prevalence of disabling impaired hearing in Itajaí was 7%; the highest prevalence was in the 50-year and above age group – the main cause was presbyacusis.