Noise-Induced Hearing Loss in Canadian Military Personnel

摘要

The escalating cost of claims for noise-induced hearing loss in the Canadian Forces (CF) prompted the review of current hearing conservation practices. As a first step, a prospective study was conducted to assess risk factors for the development of hearing loss in a wide range of military trades. A total of 1,057 individuals working in land, sea and air environments at five CF military bases contributed their current hearing test results and first hearing test results on record. They also completed a 56-item questionnaire relating to demographics, occupational and non occupational noise exposure history, training in and utilization of personal hearing protection, and risk factors other than noise which might affect hearing, including head injury, ear disease, medications, and solvent exposure. Military medical personnel recruited the subjects, distributed the questionnaires and assessed hearing. Apparatus and protocols for the latter conformed to current clinical practice. The results showed that the prevalence of moderate to severe hearing loss progressed with years of noise exposure, with hearing thresholds in those over 45 years ranging broadly from normal to over 70 dB HL. Unprotected exposure to solvents and leisure noise appeared to be significant determinates of adverse outcome, while the effects of head injury, history of ear disease, and the use of medications were minimal. The survey suggested that training on the hazards of noise exposure and the selection and utilization of hearing protection were inadequate. Hearing protection was reported to be incompatible with other gear, uncomfortable and an impediment to communication.