[Hearing loss caused by noise, otitis and head injuries]

Abstract

Background: Results from a recent study of the population in Nord-Trøndelag County are described and estimates given of the magnitude of hearing loss associated with occupational and leisure noise exposure, recurrent ear infections and head injury.

Material and methods: Self reported exposure data were collected by questionnaires and hearing acuity was measured by pure tone audiometry. There were complete data from 50 132 subjects above the age of 19. Effects of various risk factors were estimated using multivariate methods.

Results: Noise, ear infections and head injury explained 1-6% of the variance (varying with age, sex and frequency range), apart from what could be explained by age alone (30-58%). The strongest effects were from occupational noise and impulse noise (gun blasts) among middle-aged and older men. Only moderate effects of noise could be detected among women. No effects of amplified music or use of personal stereo players could be demonstrated. There were clear effects of recurrent ear infections and head injury.

Interpretations: With the possible exception of substantial effects of recurrent ear infections and impulse noise, our results give grounds for somewhat more optimism than most previous results about risk factors for hearing loss.