Introduction: Excessive noise is an important health hazard at the present time. It can lead to auditory and extra-auditory effects which affect the welfare of individuals and groups exposed. We carried out this study to understand the prevalance of Noise Induced Hearing-Loss (NIHL) in workers of an automobile manufacturing unit in Karachi, Pakistan.
Method:The study consisted of the following: 1. Determination of noise levels during different stages of work. 2. A questionnaire regarding subjective hearing loss of the workers; as well as their knowledge, attitude and behavior regarding excessive noise. 3. Tympanometry and Audiometry. 4. Health and safety survey.Two hundred and seventy two workers participated in the study and out of them 206 underwent audiometric evaluation.
Results:The basic demographic, professional data and smoking habits of 272 workers participating in the study is as follows: 34.92% of workers belong to 41-50 years of age, 58.8% belong to Mohajir ethnic group, 19.1% were smoker/ex-smokers, 62% earned less than Rs 10,000/month, 87.5% received education for 0-10 years and 40% had work experience of 0-10 years. The majority of the workers were exposed to noise level higher than the safe limit of 85 dBA.According to the WHO criteria [1] 61% of the workers were suffering from hearing loss. Those who were suffering from hearing loss were further evaluated according to Cole's criteria for NIHL [2]. Of the total number of workers who underwent audiometry 25% fulfilled the Coles' criteria [2] for NIHL. The age, duration of exposure and severity of exposure were important determinants of NIHL. The workers had insufficient knowledge regarding prevention of NIHL. The personal protective equipments were used inadequately. There was no clinical follow up or monitoring of hearing among the workers.
Conclusion:There is an urgent need for the government to take practical steps for making a policy and implement it so that occupational hearing loss can be prevented.