Characteristics at different frequencies of hearing loss in noise exposure workers of the automobile manufacturing industry

Abstract

Objective: To analyze the effects of noise exposure on the hearing at different frequencies in workers from the automobile manufacturing industry. Methods: A total of 4723 noise workers in a large automobile manufacturing company in Guangzhou were chosen as the research object by using judgment sampling method between April and July, 2018, and carried out 0.5, 1.0, 2.0, 3.0, 4.0 and 6.0 kHz pure tone audiometry threshold to analyze the characteristics of the status of hearing loss at different frequencies and its relationship with the noise exposure time. Results: The detection rate of hearing loss in noise-exposed workers was 29.8% (1406/4723) . Among them, the binaural hearing loss was 21.2% (999/4723) , and single unilateral hearing loss accounted for 8.6% (407/4723) . The hearing loss detection rate of right ear was higher than that of the left ear (P<0.05) , especially in the 6.0 kHz (P<0.001) . The detection rate of increased speech frequency hearing threshold was 1.9% (90/4723) , and the detection rate of increased high-frequency hearing threshold was 28.9% (1366/4723) . The detection rate of increased threshold in both the left and the right ear increased with the increase of frequency (P<0.001) , the increased hearing threshold was the highest at the frequency of 6.0 kHz. The auditory threshold of left ear in 0.5 kHz were higher than that of right ear at the same frequency (P<0.05) . The detection rate of hearing loss increased with the increase of noise exposure time (P<0.001) , and the increased threshold of 3.0, 4.0 and 6.0 kHz from workers increased with the increase of noise exposure time (P<0.001) . Conclusion: There is a significant increased threshold in workers exposed to noise frequency of 6.0 kHz, right ear is more easily damaged than left ear, there is a dose-response relationship for the noise exposure time and high-frequency hearing loss.