Background The correlation between noise exposure and negative emotions of noise-exposed workers has received increasing attention and related studies have been reported. However, there is a lack of research on the path and effect analysis of the relationship between noise exposure and negative emotions, which will contribute to a more comprehensive understanding of the health damage characteristics of noise in addition to hearing loss.

Objective To explore the path and effects of cumulative noise exposure, tested hearing thresholds, and conscious hearing level of noise-exposed workers on negative emotions.

Methods Using stratified random sampling, 312 noise-exposed workers from a machinery and equipment manufacturing enterprise were selected. Occupational history, negative emotions (including the feelings of stress, anxiety, and depression), and conscious hearing level of the workers were investigated using the Depression-Anxiety-Stress Scale (DASS-21) and a self-made questionnaire. The hearing threshold of the workers was measured by pure tone air conduction audiometry. Sound level meter was used to measure noise equivalent sound level at selected work sites. Individual cumulative noise exposure was estimated based on work site noise level and personal noise exposure history. Path analysis was used to analyze potential mediating effects of workers' hearing thresholds and conscious hearing levels on the relationship between noise exposure and negative emotions (including stress, anxiety, and depression).

Results The positive rates of negative emotions among the 312 noise-exposed workers were 18.27% (57/312) for stress, 46.79% (146/312) for anxiety, and 28.53% (89/312) for depression; the cumulative noise exposure ranged from 101.0 to 136.1 dB(A)·d, with an average of 125.69 dB(A)·d. The distributions of tested hearing thresholds and conscious hearing levels among the workers exposed to noise were significantly inconsistent (P<0.001), with both unweighted and weighted Kappa values less than 0.4. The percentage of workers with conscious hearing levels higher than their hearing threshold levels was 16.0%, and the percentage of workers with conscious hearing levels lower than conscious hearing levels was 38.7%. The path analysis results showed that tested hearing thresholds had no mediating effect on the relationship between cumulative noise exposure and negative emotions. There was a partial mediating effect of conscious hearing level on the relationship between cumulative noise exposure and negative emotions, with a mediating effect value of 0.06 (95%CI: 0.03, 0.11) and a mediating effect ratio of 28.57%.

Conclusion Conscious hearing plays a partial mediating role in the relationship between cumulative noise exposure and negative emotions of noise-exposed workers, while tested hearing thresholds do not.