Study On Noise-Induced Hearing Loss In Train Drivers

Objectives:To find out the fundamental state of personal noise exposure and noise-induced hearing loss in train drivers of One Railway Bureau, analysis the relationship between CNE and hearing loss, explore the risk factors of hearing loss. To propose the corresponding preventive measures and provide scientific reference in order to reduce noise-induced hearing loss, to ensure the safety of railway transportation.Methods:Cross-sectional study was adopted in this study and using the cluster sampling of epidemiological survey methods. Personal noise exposure measurement, Pure tone audiometry and Hearing-Noise scale were collected quantitative data in train drivers, and using the equipment of EDGE4 and AA222. "Diagnosis of Occupational Noise-Induced deafness" and "Specification for occupational health examination of train drivers" were used to diagnosis for hearing loss. The EpiData3.1 and Excel were used to set up the database. The t-test, Chi-square test, Logistic regression and Correlation analysis and were adopted in this study.Results:1. The results of personal noise exposure measurement:22 trains were adopted in this study. The personal noise exposure dose was 84.98±4.04 dB(A), the ratio of exceed standard was 36.36%, DF was 100.00%. Diesel train drivers [92.68±4.08 dB (A)] were higher than [83.76±2.39 dB (A)] electric train drivers in personal noise exposure dose.2. The results of Pure tone audiometry2.1 The fundamental state of noise-induced hearing loss in train drivers:the detection rate of high frequency hearing loss was 12.73%; the detection rate of occupational noise-induced deafness was 5.14%. The curve of hearing threshold showed that hearing threshold decreased significantly from 3000Hz to 6000Hz.2.2 The relationship between personal noise exposure and hearing loss:there was the dose-response relationship between the detection rate of high frequency hearing loss and CNE (p<0.001), CNE was the risk factor of high frequency hearing loss (OR= 1.365); there was not statistically significant between the detection rate of occupational noise-induced deafness and CNE. Noise hazardous index the risk factor of high frequency hearing loss (Moderate hazard VS Safe OR= 1.426); there was not statistically significant between the detection rate of occupational noise-induced deafness and Noise hazardous index (p=0.754).2.3 The results to analysis between hearing loss and professional characteristics:there was the dose-response relationship between the detection rate of high frequency hearing loss and working age (p<0.001), working age was the risk factor of high frequency hearing loss(OR=1.361); there was not statistically significant between the detection rate of occupational noise-induced deafness and working age (p=0.058).The rate of high frequency hearing loss in diesel train drivers(15.03%) was higher than electric train drivers(11.56%). There was not statistically significant (p=0.956) about the rate of occupational noise-induced deafness between diesel train drivers (5.12%) and electric train drivers (5.18%). The rate of high frequency hearing loss of no changing post (13.70%) was higher than changing one more (8.11%), changing post was protective factor(OR=0.555); the rate of high frequency hearing loss of no changing job (5.65%) was higher than changing one more (2.70%), changing post was protective factor(OR=0.464).2.4 The results to analysis between hearing loss and personal lifestyle:the rate of high frequency hearing loss of smoking in train drivers (13.80%) was higher than no smoking (10.06%), the OR value (OR=2.815) combined smoking and CNE on high frequency hearing loss was higher than the sum of the two respectively variables OR (OR=2.799); There was not statistically significant between the rate of occupational noise-induced deafness and smoking (p=0.462). There was no significant difference between the rate of high frequency hearing loss and drinking (p=0.462); the rate of occupational noise-induced deafness of drinking in train drivers (5.97%) was higher than no smoking (3.34%), the OR value combined drinking and CNE on high frequency hearing loss was higher than the sum of the two respectively variables OR.3. The evaluation of Hearing-Noise scale in train drivers3.1 The fundamental state of hearing problems:the rate of tinnitus problems was 62.97%, the rate of hearing loss was 5.32%, the rate of hearing problems (tinnitus problems or hearing loss or both) was 63.38%, the rate of hearing problems (tinnitus problems and hearing loss) was 4.91%.3.2 The results to analysis between hearing problem and noise exposure problems in scale:The rates of tinnitus problem, hearing loss and hearing problems were statistically significant with the different levels of noise exposure in the workplace (p<0.001); the rates of tinnitus problem, hearing loss and hearing problems were statistically significant with the different levels of noise disturbance in the workplace (p<.001).3.3 The results of relationship between hearing problems and working age:the rates of hearing loss (p=0.041) and hearing problems (p=0.038) were statistically significant with working age, working age was the risk factor of hearing problems in train drivers (OR=1.229).3.4 The results of relationship between hearing problems and earphone:The rates of tinnitus problem (p=0.002), hearing loss (p<0.001) and hearing problems (p=0.001) were statistically significant with the different levels of using earphone, the OR value (OR=42.043) combined level of noise exposure and using earphone on hearing problems was higher than the sum of the two respectively variables OR (OR=9.177). 4. The result of estimation of noise exposure threshold:Based on regression model, noise exposure threshold were 94.48[dB (A) year] and 8.91years.Conclusions:Noise-induced hearing loss is serious in train drivers, mainly high frequency hearing loss. Working age, CNE, smoking, drinking, noise hazardous index and using earphone are risk factors of hearing loss in train drivers; changing post is protective factor.Noise exposure threshold is probably8.91 years.Suggestions:Noise-induced hearing loss situation has been improved by tertiary prevention measures. The managers should reduce noise levels using new technology, change the labor organization system. The department of health management should strengthen the hearing health education, enhance self-protection awareness of the train drivers, and strictly enforce the examination standard. The department of health management should find out the train drivers of hearing loss timely, strengthen occupational health surveillance. The train drivers should change bad living habits such as smoking, drinking, using earphone and so on; The train drivers should go to the periodical health examination.