Occupational noise induced hearing loss in coal miners and coal washing factory workers in Kerman province

Introduction: The occupational noise induced hearing loss is one of the wide spread problems and a long term complication of working in noisy environments. At the present, large groups of workers who are working in noisy environments are exposed to hearing loss. So, this study is aimed to determine the prevalence of hearing loss (more than, 25 dB) of the workers in coal mines and leaching factories in Kerman state. Methods: In this descriptive study, a sample of 150 workers from coal mines was selected using proportional stratified random sampling method. Based on results of first audiometry, individuals with hearing loss, history of diseases that cause hearing loss, more than 60 years old age and less than 5 years working history in a mine factory were excluded from the study. Data collection was performed using a check list including some personal and job characteristics and results of the first audiometry. In addition, audiometry was done for all of subjects. The results were presented using descriptive statistics. Results: Based on the audiometry results, maximum percent of hearing loss was related to 4000 Hz frequency and then 8000 and 2000 frequencies. Totally, in bone conduction 16% of workers were two-sided hearing handicapped. 16.7% of the workers had right ear hearing reduction, 19.3% left ear and 8% of them had air and bone conduction disability. Conclusion: According to this study, the workers are seriously exposed to risk of hearing problems due to insufficient education about hearing loss and lack of annual audiometry. So, designing some programs in order to reduce hearing loss should be considered