Vestibular schwannoma (acoustic neuroma) is a benign, slow-growing tumour, arising from the nerve sheath of the vestibular branch of the eighth cranial nerve. Some studies show a possible relationship between noise exposure and schwannoma, while others not. Our objective was to assess possible associations between occupational noise exposure and schwannoma.Methods
We performed a systematic critical literature review of original articles from key literature databases of associations between workplace noise and health, completed in January 2017. For the meta-analysis, we selected studies of sufficient quality with a measure of association between occupational noise exposure and schwannoma.Results
Six studies were selected, all matched case-control studies, with a total of 1487 cases, five population-based and one registry study. Five studies had self-reported exposure information from interview (4) or questionnaire (1), and three had data from job-exposure-matrices (JEMs). Two studies had both self-report and JEM information. Self-reported occupational noise exposure was consistently associated with schwannoma, odds ratio (OR) 1.70 (95% CI 1.32–2.18). JEM results gave OR 1.16 (0.75–1.81), with more heterogeneity between studies. Long noise exposure (≥15/18 years; 2 self-report, 2 JEM studies) was also consistently associated with schwannoma, OR 1.76 (1.04–2.99).Conclusions
The results indicate that noise exposure might be associated with schwannoma. We found strong and consistent associations for self-reported noise exposures and exposures of longer duration. JEM-based associations were weaker, maybe due to non-differential misclassification. However, reasons other than a causal relationship, such as recall bias, detection bias or publication bias, cannot be excluded.