Objective: To get insight into the current practice of noise reduction effect of workers as they wore hearing protectors in different domestic enterprises and the possible affected factors. Methods: From October 2020 to April 2021, using a random sampling method, 1197 workers exposed to noise in petrochemical factories, textile factories, and parts manufacturing factories were selected as the study subjects. The noise reduction effect of hearing protectors worn by workers in daily use was tested using a hearing protector suitability testing system. The personal sound attenuation level (PAR) was compared among workers in three enterprises, Targeted intervention and repetitive testing were conducted for workers who did not meet the noise reduction effect required by the enterprise, and the changes in PAR of workers before and after the intervention were compared. The comparison of baseline PARs between two or more groups was performed using the Mann Whitney test, the comparison of baseline PARs with post intervention PARs was performed using the Wilcoxon signed rank sum test, and the comparison of qualitative data between two or more groups was performed using the Chi square test. Results: The median baseline PAR for all workers was 15 dB. Men, age<30 years old, education level at or above college level, working experience of 5 to 15 years, and those who used hearing protectors for 5 to 15 years had higher PARs, with statistically significant differences (P<0.05). The median difference in baseline PAR among workers from three enterprises was statistically significant (H=175.06, P<0.01). The median PAR of subjects who did not pass the baseline increased from 3 dB to 21 dB after intervention (Z=-27.92, P<0.01) . Conclusion: Some workers wearing hearing protectors do not meet the required PAR, and low PARs may be related to incorrect wearing methods and incorrect selection of hearing protectors. As a tool for testing, training, and assisting in selection, the hearing protector suitability testing system is of great significance for worker hearing protection.
Male ; Humans ; Adult ; Hearing Loss, Noise-Induced/prevention & control* ; Ear Protective Devices ; Noise, Occupational/prevention & control* ; Hearing ; Audiometry

China ; Hearing Loss, Noise-Induced ; prevention & control ; Hearing Tests ; standards ; Humans ; Noise, Occupational ; adverse effects ; legislation & jurisprudence ; prevention & control ; Occupational Diseases ; prevention & control

Adult ; China ; Hearing Loss, Noise-Induced ; etiology ; prevention & control ; Humans ; Middle Aged ; Noise, Occupational ; adverse effects ; prevention & control ; Occupational Exposure ; adverse effects ; prevention & control

PURPOSE: This study was done to identify the distribution and related factors for stage of change for wearing hearing protection devices (HPDs) by workers in environments with high noise. Predictors of Use of Hearing Protection Model and Trans-theoretical Model were tested. METHODS: The participants were 755 workers from 20 noisy work places in Busan and Gyeongnam. Data were collected from January to April 2008 using self-administered questionnaires, and analyzed using multiple logistic regression. RESULTS: There were significant differences in social mode (OR=1.35, 95% CI: 1.06-1.73) between precontemplation/contemplation and preparation stage, in males (OR=2.36, 95% CI: 1.24-4.51), workers with high school education or less (OR=1.39, 95% CI: 1.28-2.78), shift workers (OR=1.50, 95% CI: 1.02-2.21), workers who previously worked in noisy places (OR=1.39, 95% CI: 1.20-2.34), and workers who had previous hearing examinations (OR=1.89, 95% CI: 1.25-2.85), in the social model (OR=1.59, 95% CI: 1.42-1.78), and self-efficacy (OR=1.05, 95% CI: 1.02-1.08) between workers in preparation and action stages, in length of time working in noisy work places (OR=2.26, 95% CI: 1.17-4.39), social model (OR=1.66, 95% CI: 1.33-2.08), and perceived benefit (OR=0.95, 95% CI: 0.93-0.97) between action and maintenance stage. CONCLUSION: Social model was a common factor showing differences between two adjacent stages for wearing HPDs. The results provide data for developing programs to encourage workers to wear HPDs and application of these programs in work settings.
Adult ; Ear Protective Devices/*utilization ; Female ; Hearing Loss, Noise-Induced/*prevention & control ; Humans ; Male ; Middle Aged ; Noise, Occupational ; Occupational Exposure/prevention & control ; Questionnaires ; Self Efficacy ; Workplace

Ear Protective Devices ; Follow-Up Studies ; Hearing Loss, Noise-Induced ; prevention & control ; Humans ; Male ; Mining ; Noise, Occupational ; prevention & control ; Petroleum ; Retrospective Studies

Occupational noise-induced hearing loss (ONIHL) is the most prevalent occupational disease in the world. The goal of this study was to review the epidemiology, pathogenesis, and preventive measures of ONIHL among workers and provide evidence for the implementation of control measures. Literature studies were identified from the MEDLINE, PubMed, Embase, Web of Science, and Google Scholar using the search terms "noise-induced hearing loss" "prevalence", "pathogenesis", and "preventive measures". The articles reviewed in this report were limited from 2000 to 2020. Articles that were not published in the English language, manuscripts without an abstract, and opinion articles were excluded. After a preliminary screening, all of the articles were reviewed and synthesized to provide an overview of the current status of ONIHL among workers. The mechanism of ONIHL among workers is a complex interaction between environmental and host factors (both genetic and acquired factors). The outcomes of noise exposure are different among individual subjects. Clinical trials are currently underway to evaluate the treatment effect of antioxidants on ONIHL. Noise exposure may contribute to temporary or permanent threshold shifts; however, even temporary threshold shifts may predispose an individual to eventual permanent hearing loss. Noise prevention programs are an important preventive measure in reducing the morbidity of ONIHL among workers.
Adult ; Aged ; Female ; Hearing Loss, Noise-Induced/prevention & control* ; Humans ; Male ; Middle Aged ; Noise ; Occupational Diseases/prevention & control* ; Prevalence ; Young Adult

OBJECTIVE: To evaluate the protective effects of oral administration of N-acetyl-cysteine (NAC) on noise-induced hearing loss. METHOD: Three hundred sixty three volunteers were recruited and randomly divided into two groups: experimental group (n=223) and control group (n=140). The subjects had received oral administration of NAC in the experimental group and placebo in the control group before noise exposure. The routine audiometric evaluation and ABR testing were performed and recorded pre- and post-noise exposure. The statistical analysis was carried out on the data obtained from two groups with SPSS 11.0. RESULT: The hearings of all the participatory were changed after noise exposure, but there were statistically significant differences between two groups. CONCLUSION The protective effects of NAC were prominent on the noise-induced hearing loss.
Acetylcysteine ; administration & dosage ; therapeutic use ; Adult ; Hearing Loss, Noise-Induced ; drug therapy ; prevention & control ; Humans ; Male ; Military Personnel ; Young Adult

OBJECTIVETo investigate the prophylactic effect of low calcium concentration perilymph on noise-induced hearing loss.

METHODSForty guinea pigs with normal hearing weighing 250-350 g were assigned to five groups (8 in each group): (1) Ca(2+)-deficient perilymph perfusion (CDP) for 2 h; (2) white noise (120 dB SPL) exposure (WNE) only for 1 h, (3) combination of calcium-deficient perilymph perfusion and white noise (120 dB SPL) exposure (WNE + CDP); (4) normal artificial perilymph (NAP) perfusion for 2 h; and (5) white noise exposure + normal artificial perilymph perfusion (WNE + NAP) for 2 h. Compound action potentials (CAP) evoked by click was recorded from round window every 15 min. The cochleae from 5 animals in each group were examined with scanning electron microscope.

RESULTSThe CAP for group 1 experienced a threshold shift (TS) of 15-26 dB, while group 2 yielded a 46-59 dB TS and group 3 a 37-45 dB TS; no threshold shift occurred in group 4. The CAP TS in group 5 was 33-64 dB. The CAP TS of group 3 was less than that of group 2. After one hour of noise exposure, the CAP TS of group 3 were 45.92 +/- 2.90 dB and 59.30 +/- 3.95 dB in group 2. There were significant differences (P < 0.05) between groups 3 and 2. The CAP TS of group 3 was less than that of group 5 at the points of 1, 1.5 and 2 h after noise exposure. There was a significant difference between groups 3 and 5 (P < 0.01). Stereocilia of 89 OHC(3) were in disarray in five cochleae after noise exposure in group 2. The cuticular plates of 8 OHC(2),3 sank and the stereocilia became fused in only one animal cochlea after noise exposure in group 3 combined with low calcium perilymph perfusion.

CONCLUSIONSLow calcium concentration appears to participate in preventing noise-induced hearing loss and the rising of calcium concentrations in inner hair cells after noise exposure, which may have been due to the opening of calcium channels in inner hair cells during noise exposure. The mechanism of the prophylactic effect might be caused by a lower calcium concentration in inner hair cells in the cochlea attenuating the influence of noise exposure on hearing loss; calcium deficient perilymph perfusion prevented calcium accumulation in inner hair cells of the cochlea. The motility of the OHCs might be partially inhibited by low calcium concentration that reduced noise-induced hearing loss in turn.

Action Potentials ; Animals ; Calcium ; analysis ; physiology ; Cochlea ; pathology ; physiology ; Endolymph ; metabolism ; Guinea Pigs ; Hair Cells, Auditory ; metabolism ; Hearing Loss, Noise-Induced ; prevention & control ; Perilymph ; physiology

BACKGROUNDAntioxidants and the duration of treatment after noise exposure on hearing recovery are important. We investigated the protective effects of an antioxidant substance, edaravone, and its slow-release dosage form, edaravone solid lipid nanoparticles (SLNs), in steady noise-exposed guinea pigs.

METHODSSLNs loaded with edaravone were produced by an ultrasound technique. Edaravone solution or edaravone SLNs were administered by intratympanic or intravenous injection after the 1 st day of noise exposure. Guinea pigs were exposed to 110 dB sound pressure level (SPL) noise, centered at 0.25-4.0 kHz, for 4 days at 2 h/d. After noise exposure, the guinea pigs underwent auditory brainstem response (ABR) threshold measurements, reactive oxygen species (ROS) were detected in their cochleas with electron spin resonance (ESR), and outer hair cells (OHCs) were counted with silvernitrate (AgNO 3 ) staining at 1, 4, and 6 days.

RESULTSThe ultrasound technique was able to prepare adequate edaravone SLNs with a mean particle size of 93.6 nm and entrapment efficiency of 76.7%. Acoustic stress-induced ROS formation and edaravone exerted a protective effect on the cochlea. Comparisons of hearing thresholds and ROS changes in different animal groups showed that the threshold shift and ROS generation were significantly lower in treated animals than in those without treatment, especially in the edaravone SLN intratympanic injection group.

CONCLUSIONSEdaravone SLNs show noticeable slow-release effects and have certain protective effects against noise-induced hearing loss (NIHL).

Animals ; Antipyrine ; analogs & derivatives ; chemistry ; Ear, Inner ; drug effects ; injuries ; Female ; Guinea Pigs ; Hearing Loss, Noise-Induced ; prevention & control ; Lipids ; chemistry ; Nanoparticles ; chemistry ; Reactive Oxygen Species ; metabolism

The study was aimed at exploring the effect of noise on total antioxidant capacity (TAC) in serum, nitric oxide (NO) level in the cochlea and the protective action of alpha-lipoic acid against noise-induced hearing loss (NIHL). Sixty guinea pigs (350-400 g) were divided randomly into three groups (control group, noise+saline group and noise+alpha-lipoic acid group). Serum and cochlear tissue were treated immediately after noise exposure (4-kHz octave band, 115 dB SPL 5 h) to determine the level of TAC and NO, respectively. Auditory brainstem responses (ABRs) were measured before and immediately after exposure. The threshold of hearing in the control group was relatively stable, while the hearing threshold in the noise+saline group was significantly higher than those in the noise+alpha-lipoic acid group (P<0.05). TAC level of the noise+saline group was significantly lower than that of the control group P<0.05 . TAC level of the noise+alpha-lipoic acid group was significantly higher than that of the noise+saline group P<0.05 , while there was no significant difference in the levels between the noise+alpha-lipoic acid group and the control group (P>0.05). The NO level of the cochlear tissue in the noise+saline group was significantly higher than that of the control group (P<0.05). Cochlear NO level in the noise+alpha-lipoic acid group was significantly lower than that of the noise+saline group (P<0.05), while there was no significant difference in cochlear NO levels between the noise+alpha-lipoic acid group and the control group (P>0.05). The results obtained indicate that noise exposure causes a decrease in serum TAC and an increase in NO in cochlea. alpha-Lipoid acid exerts a protective effect against hearing loss in acoustic trauma through its antioxidant effects.
Animals ; Antioxidants ; pharmacology ; therapeutic use ; Cochlea ; metabolism ; Evoked Potentials, Auditory, Brain Stem ; Guinea Pigs ; Hearing Loss, Noise-Induced ; metabolism ; prevention & control ; Male ; Nitric Oxide ; metabolism ; Noise ; adverse effects ; Random Allocation ; Reactive Oxygen Species ; blood ; Thioctic Acid ; pharmacology ; therapeutic use