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Background The influencing factors of noise hazards in the automotive manufacturing industry are complex, diverse, and mutually correlated, resulting in significant health impacts on workers. Objective To explore the application of generalized estimating equations (GEE) to analyze the factors affecting high-frequency hearing loss among noise-exposed workers in an automotive manufacturing company, guiding enterprises to scientifically carry out employee hearing protection programs. Methods The data of occupational health field evaluation and occupational health surveillance of an automobile manufacturing company for five consecutive years from 2018 to 2022 were collected, and 806 noise-exposed workers with pure tone hearing test results for all five consecutive years were selected as study participants. The retrieved indicators were gender, physical examination year, noise intensity, blood pressure, white blood cell counts, red blood cell counts, platelet counts, concentrations of hemoglobin, alanine transaminase, aspartate aminotransferase, smoking, drinking, etc. Gender, noise intensity, blood pressure, white blood cell counts, red blood cell counts, concentrations of hemoglobin, platelet counts, glutamate aminotransferase, glutamate aminotransferase, smoking, and drinking were set as independent variables, and occurrence of high-frequency hearing loss was set as a dependent variable, and GEE were constructed by using the statistical software of SPSS 20.0 to analyze the influencing factors of high-frequency hearing loss. Results Of the 806 workers, 698 were male (86.6%) and 108 were female (13.4%). The detection rates of high-frequency hearing loss in each year from 2018 to 2022 were 66.4% (535/806), 69.8% (563/806), 70.0% (564/806), 68.9% (555/806), and 68.2% (550/806), respectively. The detection rate of high-frequency hearing loss in the company was varied significantly by gender, lowered white blood cell counts, lowered red blood cell counts, lowered platelet counts, smoking, and drinking (P<0.05). The results of GEE analysis showed that after adjusting for selected confounding factors and excluding interaction effects, the risk of high-frequency hearing loss was higher in men than in women (P=0.001; OR=1.907, 95%CI: 1.286, 2.829); it was higher in workplace with disqualified noise intensity than in those without (P=0.043; OR=1.289, 95%CI: 1.009, 1.648); it was also higher in smokers than in non-smokers (P=0.004; OR=1.507, 95%CI: 1.137, 1.999). Conclusion Gender, noise intensity, and smoking are the main influencing factors of high-frequency hearing loss in noise-exposed workers in this automobile manufacturing company. Controlling smoking and reducing noise exposure intensity may reduce the occurrence of high-frequency hearing loss in workers.
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Background Tinnitus is a common symptom in workers exposed to noise, and no specific treatment is available yet. Paying attention to the influencing factors of tinnitus is very important to prevent tinnitus. Objective To investigate the situation of tinnitus among noise-exposed workers and its influencing factors. Methods Using a cross-sectional study design, 1011 noise-exposed male workers in Hangzhou were studied. Tinnitus status, age, education, personal protection, smoking history, drinking history, and family history of the participants were surveyed by questionnaires. Binaural pure tone hearing threshold test was performed on all study subjects. The environmental noise in the workplace was measured. The relationships of tinnitus with noise exposure intensity, noise exposure time, noise exposure category, cumulative noise exposure, and wearing hearing protectors among the noise-exposed workers were analyzed by logistic regression. Results The prevalence of tinnitus among the noise-exposed workers was 36.1%. The mean hearing thresholds at 500, 3000, 4000, and 6000 Hz in the right and left ears were higher in the tinnitus group than in the non-tinnitus group (P<0.05); the hearing threshold at 2000 Hz in the right ear was higher in the tinnitus group than in the non-tinnitus group (P<0.05). There was no statistically significant difference between the two groups in the prevalence of monaural speech-frequency hearing loss or monaural high-frequency hearing loss (P>0.05). The on-site noise intensity was divided into three groups: ＜85, 85-＜95, and ≥95 dB(A); the prevalence of tinnitus in the three groups was 19.6%, 40.5%, and 66.7% respectively. The years of noise exposure was divided into three groups: ＜1, 1-＜5, and ≥5 years; the prevalence of tinnitus in the three groups was 17.9%, 34.0%, and 45.4% respectively. The cumulative noise exposure was divided into six groups: ＜80, 80-＜85, 85-＜90, 90-＜95, 95-＜100, and ≥100 dB(A)·year; the prevalence of tinnitus in the six groups was 6.8%, 25.0%, 31.0%, 39.6%, 43.1%, and 46.7% respectively. The prevalence of tinnitus was higher in the non-stationary noise group (42.5%) than in the stationary noise group (26.8%) (χ2=26.18, P<0.01), and the prevalence in the group without or with hearing protection was 39.7% and 35.5% respectively. The results of logistic regression showed that workers exposed to higher intensity, longer noise exposure, higher cumulative noise exposure, and non-stationary noise (reference: stationary noise) resulted in a higher risk of tinnitus (Ptrend<0.01 or P<0.01); workers wearing of hearing protection device versus those not showed a lower risk of tinnitus (P<0.05). Conclusion Higher intensity, longer exposure to noise, and more cumulative noise exposure associate with a higher risk of tinnitus. Wearing hearing protective device can reduce the risk of tinnitus. Tinnitus in noise-exposed workers can precede the presentation of abnormal hearing loss.
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Objective: To understand the harm degree of underground noise and provide basis for noise control. Methods: In November 2019, 13 typical coal mines in Sichuan Province were selected as the research objects, and a total of 1203 sites and 609 jobs of noise exposure were investigated. Results: The noise intensity P75 >80 dB (A) was measured. The noise intensity of the inspection place of the air compressor is >86 dB (A) , the noise intensity of the inspection place of the gas drainage and the operation place of the main fan is between 80-85 dB (A) . Conclusion: Besides the harm of dust, noise exposure should also be paid attention to, and the measures of sound absorption and sound insulation should be taken or personal protection should be strengthened.