Noise trauma in the aetiology of acoustic neuromas in men in Los Angeles County, 1978-1985.

The aim of this study was to investigate whether occupational and other suggested brain tumour risk factors relate to the development of acoustic neuromas (AN) in men. Responses to interviews were compared for 86 AN patients and 86 neighbourhood controls. During the period 10 or more years before the year of diagnosis of the case, more cases than controls had a job involving exposure to extremely loud noise; noise exposure was determined by a blinded review of job histories and linkage to the National Occupational Hazards Survey data base (odds ratio (OR) = 2.2, 95% confidence interval (CI) = 1.12, 4.67). A dose-response analysis showed an increase in risk related to number of years of job exposure to extremely loud noise (P for trend = 0.02) with an OR of 13.2 (CI = 2.01, 86.98) for exposure for 20 or more years during the period up to 10 years before diagnosis. We propose that the findings in this study which identify noise as a risk factor support the hypothesis that mechanical trauma may contribute to tumorigenesis.