Occupational noise as a risk factor for work-related injuries

Objective To assess whether exposure to occupational noise is an important risk factor for work-related injuries. Methods A population-based case-control study was performed. Data collection was carried out from May 16, 2002 to October 15, 2002 in the city of Botucatu, southeast Brazil. Cases were defined as workers who had suffered typical work-related injuries in a 90-day period previously to the study, and who identified through systematic random sampling of their households. Controls were non-injured workers randomly sampled from the same population, matched on 3:1 ratio according to sex, age group and census track. A multiple logistic regression model was adjusted, where the independent variable was exposure to occupational noise, controlled for covariates of interest. Results A total of 94 cases and 282 controls were analyzed. An adjusted multiple regression model showed that "work always exposed to high-level noise" and "work sometimes exposed to high-level noise" were associated to a relative risk for work-related injuries of about 5.0 (95% CI: 2.8-8.7; p < 0.001) and 3.7 (95% CI: 1.8-7.4; p=0.0003) respective v, when work not exposed to noise was taken as a reference, controlled for several covariates. Conclusions Based on the study findings, investing in hearing conservation programs, particularly those for controlling noise emission at its source, is justiflable aiming at both hearing health maintenance and reduction of work-related injuries.