Hearing conservation in the mining industry. Evaluation of a risk factor questionnaire

The objectives of this study were to assess the validity of a self-administered hearing questionnaire in the assessment of risk to hearing, to amend the questionnaire design as necessary, and to give general guidance on the use of audiometric questionnaires in hearing conservation programmes. The study was carried out at a colliery in Staffordshire. The odds of deafness, according to the Health and Safety Executive definition, were analysed by exposure to the hearing risk variables in the questionnaire. The results of the hearing questionnaire were linked to a cross-sectional audiometric survey. There were 189 questionnaires eligible for inclusion. Noise exposure at work was reasonably well predicted by having to shout at work (OR 1.42, 95 per cent CI 0.58-3.54) and being exposed to noisy tools and machinery (OR 2.12, 95 percent CI 0.72-6.72). Risk to hearing from disease was predicted by having 'abnormal' hearing or discharging ears, but not by any of the other exposure variables. Risk to hearing from acoustic trauma was demonstrated for fire-arms (OR 1.23, 95 per cent CI 0.5-2.98). None of the hobbies included in the questionnaire usefully predicted hearing loss. The conclusions are that, contrary to Health and Safety Executive advice, audiometric questionnaires may reasonably be administered to all employees, as they are useful in the documentation of hearing loss risk factors. They should not, however, be used to detect ear disease. A revised questionnaire was drafted as the result of these findings, and will be piloted in a larger population.