Percepção do risco de exposição ocupacional ao ruído

Abstract

The study of the relationship between work and health implies an acute identification of all occupational factors involved, as well as the associated effects, either positive or negative, in workers. For this purpose, it is absolutely necessary to carry out practical studies in occupational environments so that the more important predictors of occupational risk can be identified. Within the multiple risk factors in occupational settings, noise exposure, because of its incidency in industrial environments, acquires particular importance. Occupational noise exposure has been extensively studied over the last years, however, it still represents one of the main causes of occupational disease, occupational hearing loss, which involves, according with official data, circa of 25% of all handicapped workers. Noise exposure has multiple effects, both in hearing, which is legally recognized, and in other workers health issues, such as, the noise exposure psychological effects. Although there is an abundance of literature on occupational noise exposure, the individual perception analysis and its implications on workers’ behaviour has been a minor research area. By observing workers’ practices it is possible to verify that workers, even doing the same activities and in the same workplaces, show different perceptions about the risks they are exposed to. In the case of noise exposure, such differences are even clearer. Thus, it is frequent to find workers sharing the same workplaces, however with divergent points of view concerning the risk of noise exposure, or at least, concerning noise exposure effects. Such differences have serious implications on workers’ behaviour, for example in the use of hearing protection devices. Although there are several approaches explaining workers’ behaviour in noise exposure, these rarely included some quantitative variables related to central factors in noise exposure, such as, noise exposure levels and the workers’ hearing loss. The present study – focusing on a sample of 516 industrial workers exposed to noise pressure levels greater than the Portuguese action level (85 dB(A)) - aims the analysis of the relationship between individual risk perception and the use of hearing protection devices, as well as, between the former and the development of permanent threshold shift. For this purpose, and considering the literature review, two different conceptual models were developed. With the purpose of noise exposure characterisation, a daily personal exposure level evaluation was done. Based on the literature review, a questionnaire was developed in order to evaluate the qualitative variables considered, namely, individual risk perception, perception of noise effects, expectancy on results and outcome value, safety culture and risk behaviour. Simultaneously, another questionnaire was applied with the aim of characterising the occupational noise exposure profiles, as well as the use of hearing protection devices. Workers’ permanent threshold shifts were measured through a pure tone audiometric testing at the beginning of each shift. The multivariate data analysis of the results obtained, through the application of path analysis, has shown that individual risk perception and other associated factors, are important predictors of workers’ behaviour, such as the use of hearing protection. Furthermore, these results do suggest that risk perception should be considered in the design and implementation of any Hearing Conservation Program, namely, in the development of training programs. Regarding the conceptual model about the development of permanent threshold shifts, it is possible to verify that, beyond others well known risk factors, such as age and noise exposure levels, cognitive variables, related to individual risk perception and perception of noise effects, play a significant role to a better understanding of the study variable.