Impact of environmental noise on the health of young people

Living in big cities exposes the population to upper noise levels than just a few years ago. The study of the tonal hearing threshold - both subjective and objective (through evoked potentials) - is considered a basic requirement for the evaluation of hearing function. Regarding the occupational exposure to noise, we underline that TLVs couldn't protect all workers from the harmful effects of noise because of individual susceptibility; so TLVs cannot be considered as an absolute cut-off between safety and danger levels. This issue is even more complex in apprentices and youngest workers; in addition, there are no reference values for these kinds of population in Italy. There is also the need to find methods capable both to predict the earlier noise damage and to allow a sort of detection of most susceptible people. We remember, in this regard, the availability of new methods such as the registration of otoacoustic emissions (OAEs). The aims of our research are: evaluation in a large population of young apprentices the incidence of early changes in the hearing function, preliminary evaluation of the usefulness of OAEs as a screening test in a young person who has just started working. In this study were included 288 patients, of which 180 males and 108 females. A smaller group of young people was investigated by evaluation of OAEs. The analysis of audiometric examinations allows us to highlight the influence of some factors (gender, age, and education) on the hearing function. In detail, we observed a higher threshold among males, younger and less educated; this result may seem at least paradoxical but we cannot forget some factors (concerning cognition and attention) which may justify it. Our preliminary data regarding OAEs confirm the interest of the methodology.