Occupational Noise Exposure, Risk Factors, and Hearing Loss among a Population of Factory Workers in the United States Open Access

Aronoff, Jennifer Troy (2014)

Permanent URL: https://etd.library.emory.edu/concern/etds/tm70mv843?locale=en


Occupational noise exposure is the most common cause of noise-induced hearing loss in adults. Hearing impairment is the result of complex interactions among various risk factors. In this cohort study, the effect of age, noise exposure duration, gender, and smoking as risk factors, on NIHL were analyzed among 401 workers in a large U.S. factory exposed to noise greater than 85 dBA TWA. All required data was obtained through company audiogram records and self-reported questionnaires. The relationship among hearing thresholds and risk factors were explored using t-test and chi-square tests. Prevalence of hearing loss among noise-exposed factory workers was 10.97% (using a hearing loss model 1 and 9.23% using model 2. The proportion of workers who smoke and have hearing loss is greater than workers who do not smoke, but is not significant. The proportion of male workers with hearing loss was significantly greater than female workers with hearing loss (13.50% and 2.22%, respectively; p=0.0026). Average high frequency hearing thresholds (4k, 6k and 8k Hz) was significantly higher among smokers compared to non-smokers (p=0.0435). Relative risk of hearing loss among non-smokers and smokers was no different for male workers, but 0.25 times the risk for female workers. In the present study among employees exposed to levels greater than 85 dBA, age, gender, noise exposure duration and smoking status all increase the likelihood of hearing loss. These data offer additional insight into the risk factors influencing development of hearing loss and can be used to assist in developing exposure guidelines and hearing conservation programs that will have a greater impact on reducing the burden of noise-induced hearing loss. However, confirming the effect of various risk factors on hearing loss in factory settings warrants further studies.

Table of Contents


Sound and Noise...2

Audiology, Measurement of Noise, and Hearing Impairment ...3-5

Noise Exposure in the Manufacturing Environment ...5-6

Cost of Hearing Loss Due To Manufacturing...6-7

Smoking and Hearing Loss ...7-8

Problem Statement and Objectives ...8-9

Materials and Methods...9-13

Study Population...9-10

Audiometric Testing ...10

Data Source ...10-11




Results From Hearing Loss Model 1 (hearing threshold change of greater than 30 dB from 4k to 1k Hz)... 15-16

Results From Hearing Loss Model 2 (OSHA hearing loss calculation standard)...16-17



Appendix A: Tables...22-23

Appendix B: Figures...24

Appendix C: Self-reported employee medical questionnaire form...25


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