Characteristics and Affecting Factors of Tinnitus in Noise Exposed Workers

Kim, Kyoo Sang; Chung, Ho Keun

Abstract

OBJECTIVES
Tinnitus is a relatively common complaint of workers who are exposed to noise. The aim of the study was to investigate the prevalence and characteristics of tinnitus as well as the factors related to the prevalence of tinnitus.
METHODS
A cross-sectional audiologic survey was combined with a questionnaire on tinnitus in a stratified random sample of 246 shipyard workers who had long-term exposure to noise.
RESULTS
Forty seven had tinnitus, giving a prevalence of 19.1 percent. The tinnitus was the here and now in 44.7 percent of cases, bilateral in 51.1 percent, and caused sleep disturbances in 12.8 percent. The prevalence of tinnitus was highest in shipfitters and those with longer exposure duration.The workers with tunnitus had consistently higher hearing thresholds at both high and low frequencies than those with no tinnitus.The workers with tinnitus had a significantly higher prevalence of hearing disorders such as conductive hearing loss, a C5-dip, and NIHL.Multivariative logistic regression indicated that past history of ear disease, working and military service exposure to noise were independently associated with tinnitus. The adjusted odds ratio estimates for tinnitus were 3.0 times greater (95%CI 1.4-6.4) for the group with a past history of ear diseases,2.3 times greater (95%CI 1.0-5.0) for the military noise exposed group,and 4.5 times greater (95%CI 1.8-11.1) for the working noise exposed group.
CONCLUSIONS
The results provide evidence that reports of tinnitus at the time of the annual audiometric testing may be useful in identifying workers at greater risk of developing significant shifts in their hearing thresholds. An awareness of the possible occurrence of tinnitus may encourage workers to cooperate more actively in a company's hearing conservation program.