Hearing effects from intermittent and continuous noise exposure in a study of Korean factory workers and firefighters

BMC Public Health

Research Article

In-Sung Chung¹  Mark R Cullen²  Isabella M Chu² 

[1] Division of Occupational and Environmental medicine, Department of Preventive medicine, Keimyung University School of Medicine, 216 Dalseong-ro, 700-712, Jung-gu, Daegu, South Korea;Stanford University School of Medicine, General Medical Disciplines, 1265 Welch Road, MSOB X-338, 94305-5411, Stanford, CA, USA;

关键词: Hearing Loss;    Noise Exposure;    Hearing Threshold;    Factory Worker;    Hearing Level;   

DOI  :  10.1186/1471-2458-12-87

 received in 2011-09-07, accepted in 2012-01-27,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundSouth Korea and surrounding countries in East Asia are believed to have the highest proportion in the world of high frequency hearing loss due to occupational noise exposure, yet there has been limited information published in international journals, and limited information for control of noise in local workplaces beyond strategies from western countries. We exploit medical surveillance information from two worker groups to enhance local knowledge about noise-induced hearing loss and explore the possible importance of shift work to risk.MethodsFour-years of hearing data were evaluated for 81 male farm machine factory workers and 371 male firefighters who had successfully completed a health examination and questionnaires for the duration of the study period. The averages of hearing thresholds at 2, 3, and 4 kHz were used as the primary end-point for comparison. Repeat measure analysis adjusted for age, exposure duration and smoking status was used to measure the difference in hearing threshold between the two groups.ResultsNoise levels were measured in the factory at a mean of 82 dBA, with a range of 66-97. No concurrent measurements were taken for the firefighters, but historic comparison values showed a wider range but a similar mean of 76-79 dBA. Although losses during follow-up were negligible, the factory workers had significantly (P < 0.0001) more hearing loss at the baseline of the study than the firefighters in both ears at 2, 3, and 4 kHz, adjusted for age, duration of employment and smoking status. Among those with 10 years of employment, mean losses at these frequencies among the factory workers fell into the impairment range (> 25 dB loss). Firefighters also showed increased losses associated with longer exposure duration, but these were significantly less marked. Losses at lower frequencies (< or = 1 kHz) were negligible in both groups.ConclusionsKorean work environments with continuous noise exposure in the measured range should consider implementation of a hearing conservation program. Further evaluation of hearing loss in workers exposed to irregular or intermittent high noise levels, such as firefighters, is also warranted.

【 授权许可】

Unknown   
© Chung et al; BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.