Hearing loss among workers exposed to road traffic noise in the city of São Paulo in Brazil

This study was aimed at assessing hearing status among workers exposed to urban noise during activities related to the co-ordination of vehicle traffic in the city of São Paulo, Brazil. Six hundred and twenty-four workers were submitted to audiometry and answered a clinical questionnaire. The audiometry results were classified as either normal or suggestive of noise-induced hearing loss (NIHL). The prevalence of suspected NIHL was 28.5%, with a 95% confidence interval of 25.05–32.27%. In the multivariate analysis (logistic regression model), suspected NIHL was correlated with gender, age, city sector assignment, and prior occupational exposure to noise. The finding that prevalence was higher among those working in the noisier areas than among those working in areas with lower noise levels (38.8% versus 24.2%) suggests that occupational exposure to urban noise plays an important role. The high prevalence of suspected NIHL indicates the existence of a significant health problem among these workers.