BMC Public Health Research article Prevalence of high frequency hearing loss consistent with noise exposure among people working with sound systems and general population in Brazil: A cross-sectional study Regina P El Dib*1, Edina MK Silva1, José F Morais2 and Virgínia FM Trevisani1 BioMed Central Open Access Address: 1Urgency Medicine and Evidence-Based Medicine Department, the Brazilian Cochrane Centre, the Federal University of São Paulo, Brazil and 2Actuary and Quantitative Methods Department, Pontifical Catholic University of São Paulo, Brazil Email: Regina P El Dib* - re.lucci@terra.com.br; Edina MK Silva - edinaksilva@terra.com.br; José F Morais - jfmorais@pucsp.br; Virgínia FM Trevisani - vmoca@uol.com.br * Corresponding author Published: 7 May 2008 BMC Public Health 2008, 8:151 doi:10.1186/1471-2458-8-151 This article is available from: http://www.biomedcentral.com/1471-2458/8/151 Received: 20 August 2007 Accepted: 7 May 2008 © 2008 El Dib et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Background: Music is ever present in our daily lives, establishing a link between humans and the arts through the senses and pleasure. Sound technicians are the link between musicians and audiences or consumers. Recently, general concern has arisen regarding occurrences of hearing loss induced by noise from excessively amplified sound-producing activities within leisure and professional environments. Sound technicians' activities expose them to the risk of hearing loss, and consequently put at risk their quality of life, the quality of the musical product and consumers' hearing. The aim of this study was to measure the prevalence of high frequency hearing loss consistent with noise exposure among sound technicians in Brazil and compare this with a control group without occupational noise exposure. Methods: This was a cross-sectional study comparing 177 participants in two groups: 82 sound technicians and 95 controls (non-sound technicians). A questionnaire on music listening habits and associated complaints was applied, and data were gathered regarding the professionals' numbers of working hours per day and both groups' hearing complaint and presence of tinnitus. The participants' ear canals were visually inspected using an otoscope. Hearing assessments were performed (tonal and speech audiometry) using a portable digital AD 229 E audiometer funded by FAPESP. Results: There was no statistically significant difference between the sound technicians and controls regarding age and gender. Thus, the study sample was homogenous and would be unlikely to lead to bias in the results. A statistically significant difference in hearing loss was observed between the groups: 50% among the sound technicians and 10.5% among the controls. The difference could be addressed to high sound levels. Conclusion: The sound technicians presented a higher prevalence of high frequency hearing loss consistent with noise exposure than did the general population, although the possibility of residual confounding due to unmeasured factors such as socioeconomic status cannot be ruled out. Page 1 of 8 (page number not for citation purposes)