Sensorineural hearing loss in high school teenagers in Mexico City and its relationship with recreational noise Las alteraciones auditivas de escolares adolescentes en la Ciudad de México pueden estar relacionadas al ruido recreativo

The aim of this study was to measure the frequency of hearing loss in a sample of typical public highschool students exposed to recreational noise, and determine associated risk factors. The sample was made up of 214 teenagers from a high-school in Mexico City; subjects were selected randomly per strata. We applied a questionnaire to identify risk factors for hearing loss and performed a battery of audiologic tests consisting of otoscopy, tympanometry, and pure-tone audiometry. The mean age of the sample was 16 ± 1.07 years; 73% were male and 27%, female. Hearing loss was found in 21% of students. The main hearing loss-related risk factor was exposure to recreational noise: frequent attendance at discotheques and popmusic concerts; use of personal stereos; and noise exposure in school workshops. The high frequency of hearing loss in high school students from one Mexico City school (nearly one fifth of the sample) was found to be related to noise exposure mainly during recreational activities. Hearing Loss; Noise Effects; Acoustic Trauma; Adolescent Introduction Sensorineural hearing loss prevalence in developing countries has been studied very little across different age groups. Different conclusions are drawn for each population studied depending on their socio-economic and geographic characteristics. In a country such as Mexico, sensorineural hearing loss may be more frequent among populations living in poverty. For example, in a recent study performed in otherwise healthy newborns from a private hospital in one of the wealthiest counties in Mexico, Monterrey, investigators found a sensorineural hearing loss frequency of 0.65/1,000 newborns 1, while in high-risk infants (mainly premature) from a Mexico City-based government-sponsored hospital, investigators reported that the frequency of hearing loss can be as high as 13.4%, mainly related to exposure to ototoxic drugs, hyperbilirubinemia, asphyxia, and low birth-weight 2. No study on the prevalence of sensorineural hearing loss in children in Mexico has been carried out. However, studies from other Latin-American countries have disclosed important findings. In rural Nicaraguan children, a sensorineural hearing loss prevalence of 18% was found and was related with middleear infections, family history of deafness, dysmorphism, maternal infection during pregnancy, neonatal distress, low birth-weight and ototoxic drug exposure 3. In school-aged children from Medellín, Colombia, investigators found a freARTIGO ARTICLE Martínez-Wbaldo MC et al. 2554 Cad. Saúde Pública, Rio de Janeiro, 25(12):2553-2561, dez, 2009 quency of 20% hearing loss in children, and the major associated risk-factors were comprised of: history of language development delay, middleear effusion, deafness in the family, and repetitive acute respiratory infections 4. In adults in Mexico, hearing loss was estimated to be 21.07% in 3,726 subjects studied from rural communities; severe and profound hearing loss was found in 6.39% and 10.31% respectively 5. Nonetheless, we observe in the literature that sensorineural hearing loss prevalence and associated risk factors in teenagers have not been studied. The objective of the present study was to measure the frequency of hearing loss in a sample of teenagers and to weigh its relationship with the teenagers’ exposure to several risk factors for sensorineural hearing loss, including respondent history of middle-ear infections, exposure to music at high levels, noise in school workshops or from fireworks, and other noise-producing activities. Materials and methods