Document Type : Original Article


1 Research Center for Environmental Determinants of Health (RCEDH), Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran

2 Department of Occupational Medicine, Iran University of Medical Sciences, Tehran, Iran,

3 Occupational Medicine Research Center, Iran University of Medical Sciences, Tehran, Iran


BACKGROUND: Unwanted sound is recognized as the most extensive source of contaminant
in the workplace. Exposure to intense, continuous, and higher than 85 dB level noise can lead to
noise‑induced hearing loss.The aim of the present study was to determine the level of noise exposure
and its impact on hearing health among auto body workers.
MATERIALS AND METHODS: This descriptive‑analytic study was conducted in 2020 to investigate
the hearing health status of workers in auto body workshops. Sixty‑one participants were randomly
selected for audiometric testing. The equivalent sound level (Leq) of the workers was measured using
a Casella CEL‑320 noise dosimeter. Audiometric testing was performed using an AC40 audiometer.
The mean hearing threshold levels (HTLs) of both ears were calculated for different frequencies. The
results obtained were analyzed using SPSS v21.0 at a significance level of 95%.
RESULTS: The participants had an average age of 35.5 ± 11.8 years and an average work experience
of 16.5 ± 9.8 years. The mean Leq was 92.3 ± 4.7 dB. The mean HTLs for the right ear and left ear
were 20, 15, 17.6, 19.2 dB, respectively with the right ear suffering more loss. A significant relationship
was found between hearing loss in both ears (P < 0.001). The highest prevalence of hearing loss
in both ears was observed at a frequency of 4 kHz. About 73.8% of the subjects had a normal HTL,
23.3% had mild hearing loss, and 3.3% had severe hearing loss. With increasing work experience,
HTLs also increased significantly, particularly at 2–8 kHz.
CONCLUSIONS: Chronic exposure to noise pollution threatens hearing health. Therefore, it is
necessary to raise the level of awareness among workers in order to enable better hearing health
protection and also to promote the use of hearing protection devices.


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