Occupational Noise-induced Hearing Loss Research Articles

Hearing Difficulties Among Farmworkers in the México-US Southwest Border Region.

Migrant and seasonal farmworkers are a vulnerable population with a potentially high risk for hearing loss due to farm-related noise exposures. Occupational noise-induced hearing loss (NIHL) is permanent, and it is associated with an increased risk for injuries on the job, as well as communication difficulties, isolation, and depression. The México/US border region is one of the most productive agricultural regions in the country, however, no known studies have explored hearing loss among farmworkers in this area. This pilot study was a first step toward measuring and addressing hearing loss and noise exposure among this region's farmworkers. We conducted a cross-sectional survey to estimate the prevalence of subjective hearing difficulties among Yuma County, Arizona farmworkers. Survey interviews took place during a late-night farmworker health fair from 2am to 6 am to accommodate local farms' labor schedules. Multivariable regression adjusted for demographic and work covariates estimated subjective hearing loss prevalence ratios. Among 132 farmworker participants, 36% reported they have or might have hearing loss, and 62% reported no hearing loss. Subjective hearing loss prevalence was lower in farmworkers who report not working in noise compared to prevalence in farmworkers who work in noise [prevalence ratio, 0.44 (95% CI 0.23-0.82)]. This report contributes to understanding the perception of hearing-related health and occupational exposures among farmworkers in the México-US Southwest border region. The information from this line of research will inform appropriate safety measures known to lower the risk of experiencing occupational NIHL.

Bridging the gap: addressing occupational noiseinduced hearing loss in India

Bridging the gap: addressing occupational noiseinduced hearing loss in India

The Burden of Occupational Noise-Induced Hearing Loss From 1990 to 2019: An Analysis of Global Burden of Disease Data.

The relationship between long-term exposure to occupational noise and hearing loss has been extensively documented. We aimed to assess spatial and temporal changes in the burden of occupational noise-induced hearing loss (ONIHL) in 204 countries and territories with varying socio-demographic indexes (SDI) from 1990 to 2019. Temporal and spatial trends in age-standardized disability-adjusted life year rates (ASDR) for ONIHL were estimated by sex, age, SDI level, country, and geographic region from 1990 to 2019. We used the Joinpoint model to calculate annual average percentage changes to assess such trends and projected trends in ASDR for ONIHL globally and across different income regions from 2020 to 2044 using an age-period-cohort model. We fitted the relationship between ASDR and SDI, ASDR and healthcare access and quality index, respectively. Overall, the global burden of ONIHL has decreased since 1990, especially in middle and lower SDI regions. In 2019, the global ASDR for ONIHL was 84.23 (95% confidence interval: 57.46 to 120.52) per 100,000 population. From 1990 to 2019, the global ASDR for ONIHL decreased by 1.72% (annual average percentage change = -0.05, 95% confidence interval: -0.07 to -0.03). Our projections showed a decreasing trend in the global ONIHL burden until 2044. ASDR and SDI (R = -0.8, p < 0.05), ASDR and healthcare access and quality index (R = -0.75, p < 0.05) showed significant negative correlations. The global ONIHL burden has decreased over the past three decades, especially in regions with middle and lower SDI levels. However, the global ONIHL burden still remained severe in 2019, notably among males, the middle-aged and elderly, and regions with lower SDI levels.

Time Trend of Occupational Noise-induced Hearing Loss in a Metallurgical Plant With a Hearing Conservation Program

BackgroundThis study aimed to analyze the trend of occupational noise-induced hearing loss (ONIHL) in Brazilian workers at a metallurgical plant with a hearing conservation program (HCP), which has been addressed in a previous study. MethodsAll 152 workers in this time series (2003–2018) participated in the HCP and used personal protective equipment. All annual audiometry records in the company's software were collected from the electronic database. The trend of ONIHL was analyzed with the joinpoint regression model. The hearing thresholds of ONIHL cases at the end of the series were compared with those found in a national reference study. ResultsThe binaural mean hearing thresholds at 3, 4, and 6 kHz at the end of the series were higher for ages ≥50 years, exposures ≥85 dB (A), time since admission >20 years, and maintenance workers. Significance was found only in the group divided by age. There was an increasing time trend of ONIHL, though with a low percentage variation for the period (AAPC = 3.5%; p = 0.01). Hearing thresholds in this study differed from the reference one. ConclusionDespite the unmet expectation of a stationary trend in the study period, the time pace of ONIHL evolution did not follow what was expected for a population exposed to noise. These findings signal to the scientific community and public authorities that good ONIHL control is possible when HCP is well implemented.

Development of an artificial intelligence based occupational noise induced hearing loss early warning system for mine workers.

Occupational Noise Induced Hearing Loss (ONIHL) is one of the most prevalent conditions among mine workers globally. This reality is due to mine workers being exposed to noise produced by heavy machinery, rock drilling, blasting, and so on. This condition can be compounded by the fact that mine workers often work in confined workspaces for extended periods of time, where little to no attenuation of noise occurs. The objective of this research work is to present a preliminary study of the development of a hearing loss, early monitoring system for mine workers. The system consists of a smart watch and smart hearing muff equipped with sound sensors which collect noise intensity levels and the frequency of exposure. The collected information is transferred to a database where machine learning algorithms namely the logistic regression, support vector machines, decision tree and Random Forest Classifier are used to classify and cluster it into levels of priority. Feedback is then sent from the database to a mine worker smart watch based on priority level. In cases where the priority level is extreme, indicating high levels of noise, the smart watch vibrates to alert the miner. The developed system was tested in a mock mine environment consisting of a 67 metres tunnel located in the basement of a building whose roof top represents the "surface" of a mine. The mock-mine shape, size of the tunnel, steel-support infrastructure, and ventilation system are analogous to deep hard-rock mine. The wireless channel propagation of the mock-mine is statistically characterized in 2.4-2.5 GHz frequency band. Actual underground mine material was used to build the mock mine to ensure it mimics a real mine as close as possible. The system was tested by 50 participants both male and female ranging from ages of 18 to 60 years. Preliminary results of the system show decision tree had the highest accuracy compared to the other algorithms used. It has an average testing accuracy of 91.25% and average training accuracy of 99.79%. The system also showed a good response level in terms of detection of noise input levels of exposure, transmission of the information to the data base and communication of recommendations to the miner. The developed system is still undergoing further refinements and testing prior to being tested in an actual mine.

A risk model for occupational noise-induced hearing loss in workers.

Occupational hearing loss is one of the most common work-related diseases with various risk factors and considerable negative impacts on both physical and mental well-being of affected workers. Occupational noise-induced hearing loss (ONIHL) has a complex interaction with personal, environmental and occupational factors. This study aimed to develop a risk model for ONIHL in workers by identifying risk factors and their interactions. The subjects were 605 males in an industrial factory in Arak, Iran. The study took place between 2022 and 2023. The sociodemographic and occupational characteristics were collected by a health technician using questionnaires and medical records. Hearing status was assessed using audiometry by a qualified audiologist. Hearing loss was analyzed by univariate logistic analysis including age, smoking, medical history, type of occupation, and some workplace hazards. The risk model was generated by logistic regression. Hearing loss in the participants was 44.13% (n = 267). In univariate logistic analysis, age (OR: 2.93,95% CI: 1.848-4.656), smoking (OR: 1.80, 95% CI: 1.224-2.655), work experience (OR: 1.06, 95% CI: 1.016-1.107), previous exposure to noise (OR: 1.60, 95% CI: 1.112-2.312) or vibration (OR: 1.68, 95% CI: 1.150-2.475) and type of occupation (OR: 2.126, 95% CI: 1.055-4.285) were associated with an increased risk of ONIHL (P < 0.05). It was found that vibration exposure, work experience, previous noise exposure, type of occupation as well as age and smoking significantly affected the likelihood of developing ONIHL. This risk model could help management to prevent ONIHL and enhance application-oriented research on the condition.

Evaluation of Digits-in-Noise Test and Hearing Handicap Inventory for Adults Screening in Patients with Occupational Noise-Induced Hearing Loss

Objective: To explore the clinical evaluation role of the Digits-in-Noise (DIN) test and Hearing Handicap Inventory for Adults Screening (HHIA-S) for patients with occupational noise-induced hearing loss and to observe and analyze their application values. Methods: Fifty patients with suspected occupational noise-induced hearing loss were randomly selected from the Department of Otolaryngology at the hospital as the research target. The collection period for the research cases spanned from January 2022 to November 2023, and all patients had a history of noise exposure. The DIN test and HHIA-S were used for hearing examinations, with clinical, comprehensive diagnosis serving as the gold standard to study their diagnostic performance. Results: The compliance rate of the DIN test was 88.00%, the HHIA-S’s compliance rate was 80.00%, and the combined compliance rate was 94.00%. The compliance rate of the DIN test and the combined compliance rates of the patients were statistically significant compared to the clinical gold standard data (P &lt; 0.05), while there was no difference between the compliance rate of the HHIA-S and the gold standard (P &gt; 0.05). The data shows that the sensitivity of the combined diagnosis is significantly higher than the sensitivity data of the DIN test and HHIA-S examination alone (P &lt; 0.05). Its specificity is 100.00%, and the accuracy data of the joint diagnosis in the degree were higher than those of the DIN test alone (P &gt; 0.05) and the HHIA-S alone (P &lt; 0.05). Conclusion: For patients with occupational noise-induced hearing loss, the joint evaluation of the DIN test and HHIA-S can significantly improve their diagnostic value with high sensitivity and accuracy.

Alterations of resting-state functional network connectivity in patients with noise-induced hearing loss: A study based on independent component analysis.

Functional reorganization is a response to auditory deficits or deprivation, and less is known about the overall brain network alterations involving resting-state networks (RSNs) and multiple functional networks in patients with occupational noise-induced hearing loss (NIHL). So this study evaluated resting-state functional network connectivity (FNC) alterations in occupational NIHL using an independent component analysis (ICA). In total, 79 mild NIHL patients (MP), 32 relatively severe NIHL patients (RSP), and 84 age- and education- matched healthy controls (HC) were recruited. All subjects were tested using the Mini-mental State Examination scale, the tinnitus Handicap Inventory scale, the Hamilton Anxiety scale (HAMA) and scanned by T1-3DFSPGR, resting-state functional magnetic resonance imaging sequence in 3.0 T and analysed by the ICA. Seven RSNs were identified, compared with the HC, the MP showed increased FNC within the executive control network (ECN) and enhanced FNC within the default mode network (DMN) and the visual network (VN); compared with the HC, the RSP showed decreased FNC within the ECN and auditory network (AUN), DMN and VN; no significant changes in FNC were found in the MP compared with the RSP. Furthermore, the correlation analysis between the noise exposure time and hearing loss level, HAMA were both negative, and there were no significant correlations between the abnormal RSNs and the hearing level, noise exposure time and HAMA. These findings indicate that different degrees of NIHL involve different alterations in RSNs connectivity and may reveal the neural mechanisms related to emotion-related features and functional abnormalities following long-term NIHL.

Addressing underreported occupational noise-induced hearing loss: the experience of an educational workshop on local occupational health planning and program

Resumo Introdução: a subnotificação da Perda Auditiva Induzida por Ruído (Pair) relacionada ao trabalho é um problema que contribui para a invisibilidade e falta de prioridade deste agravo nos programas de Saúde do Trabalhador (ST). Logo, ações de educação permanente voltadas ao planejamento estratégico-situacional podem contribuir para o enfrentamento desta realidade. Objetivo: apresentar e discutir a experiência de uma intervenção educativa com técnicos da ST de uma macrorregião de saúde do estado da Bahia, Brasil, sobre o uso do Planejamento e Programação Local em Saúde (PPLS) como ferramenta para ampliação da notificação da Pair relacionada ao trabalho Métodos: a intervenção consistiu em uma oficina estruturada em cinco etapas, as quais proporcionaram discussão sobre a Pair, conhecimento do PPLS, prática do PPLS, socialização dos resultados e avaliação do evento. Resultados: a prática do PPLS, a partir de um problema real, viabilizou o delineamento de ações concretas de enfrentamento da subnotificação da Pair a serem implementadas nos Centros de Referência em Saúde do Trabalhador (Cerest) e no estado como um todo. Conclusão: a experiência mostrou-se bem-sucedida ao fomentar a tomada de consciência e mobilização dos técnicos para enfrentamento da subnotificação da Pair, ao tempo que propiciou qualificação em PPLS dos participantes.

Occupational Noise Induced Hearing Loss in Motor Boat Fisherman

Introduction: Noise Induced Hearing Loss is a person's hearing loss either partially or completely which is permanent and can affect one or both ears caused by continuous exposure to noise in the work environment. One of the causes of Noise Induced Hearing Loss (NIHL) is working as a motorboat fisherman.&#x0D; Content: NIHL can arise as a result of the interaction between genetic factors and environmental factors with the role of internal and external risk factors. The diagnosis of NIHL can be established through history taking, physical examination such as otoscopy and tuning fork tests, as well as supporting examinations in the form of pure tone audiometry.&#x0D; Conclusion: NIHL will produce the impression of sensorineural deafness with a permanent nature so that the only treatment that can be given is supportive and preventive management.&#x0D; Keywords: Noisy; noise-induced hearing loss; motorboat fisherman

Necessity of Hearing Conservation Program in India: A Systematic Review

Abstract: Background: Noise-induced hearing loss (NIHL) is a significant public health concern in India. Occupational noise exposure is prevalent in various industries and poses a significant risk to workers' hearing health. Implementing effective hearing conservation programs (HCPs) is essential for preventing and managing NIHL. This systematic review aims to assess the necessity of hearing conservation programs in India and explore their potential impact on occupational noise-induced hearing loss. Methods: A comprehensive literature search was conducted across major electronic databases, including PubMed, Google Scholar, Science Direct, ProQuest and Psynet. Studies published between 2009 to 2023 were included if they focused on hearing conservation programs, NIHL prevalence, awareness, or interventions in the Indian context. Relevant articles were selected, and their quality was assessed using with Preferred reporting Items for systematic review and meta-analysis (PRISMA) Results: The initial search yielded 3102 articles, of which 12 met the inclusion criteria. The included studies highlighted the alarming prevalence of NIHL among Indian workers, particularly in industries such as manufacturing, construction, and textiles. Moreover, they emphasized the lack of awareness and inadequate implementation of hearing conservation programs across various sectors. However, a limited number of studies evaluated the effectiveness and outcomes of existing programs. Conclusion: The findings of this systematic review underscore the urgent need for comprehensive hearing conservation programs in India. The prevalence of noise-induced hearing loss among workers indicates a significant occupational health challenge. Strengthening awareness campaigns, implementing preventive measures, such as engineering controls and personal protective equipment, and regular audiometric monitoring are crucial for reducing the burden of NIHL

Association between occupational noise-induced hearing loss and genotoxicity among textile factory workers

Background/aimHearing loss caused by exposure to noise is still among the most prevalent health risks for industrial workers. This study aims to evaluate the relationship between Shebien El-kom textile factory workers’ occupational noise exposure, genotoxicity, and noise-induced hearing loss.MethodsThis cross-sectional case–control study was performed in a textile industry in Shebin Elkom, Egypt. The participants of this work were 36 exposed male workers from the spinning section of the textile factory and 36 subjects as the control male group from administrative staff in the same factory, in the age range of 25–45 years. A pure-tone audiometer and portable sound level meter were utilized for the measurement of hearing threshold and noise level, respectively. Genotoxicity was assessed using the Comet assay technique.ResultsThere was no significant difference between both groups regarding age and the mean duration of work was 18.94 ± 4.88 for exposed workers. The average level of noise was 95–105 dB (A). The exposed workers’ mean hearing thresholds for the left and right ears at frequencies between 2000 and 8000 Hz were substantially greater than those of the control group (P < 0.05). In the exposed workers, there was not a marked variation between the hearing thresholds of the left and right ears (p > 0.05). The exposed workers’ percentage of DNA damage was substantially greater than that of the control group (p < 0.001). Among exposed workers, a positive correlation between DNA damage, the degree of hearing loss, and the duration of time exposed to noise was demonstrated.ConclusionThe majority of exposed workers suffered from occupational noise-induced hearing loss. A positive correlation was found between the percentage of DNA damage, duration of exposure to noise, and hearing threshold in exposed workers.

Occupational Noise-Induced Hearing Loss in the City of Mosul: A Cross-sectional Study

Introduction: This study aimed to investigate the distribution of demographic characteristics and the prevalence of hearing loss among workers. Methods: The study sample consisted of 160 participants, and various demographic variables were examined. Data regarding age, gender, work experience, work hours, work nature, and work type were collected and analyzed. The degrees of hearing loss in the bilateral, left, and right ears were assessed, and the prevalence of hearing loss among different work types was examined. Audiograms were utilized to assess the degrees of hearing loss. The limitations of this study include a small sample size, and the cross-sectional design preventing causal relationships. Results: The majority of participants were male, and the age distribution showed a higher representation in the 30-49 years age range. The degrees of hearing loss were predominantly intermediate in the bilateral, left, and right ears. Military personnel had the highest prevalence of hearing loss, followed by builders, drivers, carpenters, and bakers. The logistic regression analysis indicated limited predictive power for age, diabetes mellitus (DM), years in the job, and years in the current job. However, the absence of formal training emerged as a significant factor associated with an increased likelihood of potential hearing loss. Conclusion: The findings highlight the importance of considering demographic characteristics and occupational factors in assessing the prevalence of hearing loss among workers. The results emphasize the need for occupational training programs and increased awareness of hearing protection measures in the workplace to mitigate the risk of hearing loss.

Prevalence of Hearing Loss among Noise Exposed Industrial Workers

Exposure to any type of noise has a potential risk. Higher the level of noise and longer duration of exposure, more the risk for hearing sensitivity and health as a whole. Occupational noise induced hearing loss (ONIHL) is a major cause of disability throughout the world. So this study was designed to know the prevalence of NIHL among the noise exposed industrial workers in Bangladesh. A prospective observational study of 377 People working at industrial environment in Jute mills at Faridpur region were studied between January 2021 to June 2021. Data collected from each respondent recorded on a predesigned data collection form. Pure tone audiometry was performed in both ears. Among 377 study population, 157(41.6%) subjects had hearing loss and 220 subjects (58.4%) had no loss. Among the workers with hearing loss, 98(62.4%) got hearing loss on both sides, 32(20.4%) on the right side and 27(17.2%) on the left side. Among them 83(52.9%) had mild hearing loss, 37(23.6%) had moderate hearing loss, 31(19.7%) had severe hearing loss and 6(3.8%) had profound hearing loss. The average duration of work in the industry was 6.94±5.64 years and majority (78.5%) had 8 hours working hour per day and 21.5% had more than 8 hours. The average sound intensity was 91.51±8.12 dB(A) with 10.9% exposed to &lt;_85 dB(A) and 89.1% to &gt;85 dB(A). This study shows Noise-induced hearing loss (NIHL)as highly prevalent among noise-exposed workers in Bangladesh. Age &gt;35 years, high noise level, exposure of more than 10 years, were significantly associated with increased risk of hearing loss. The local and national authority should focus on noise monitoring, engineering modifications of buildings and machinery, occupational safety policies, administrative controls, providing education on NIHL, periodic audiometric assessments and follow-up evaluation for hearing threshold shift. This study supported the elements for further research studies related to the employer compliance with occupational health and safety regulations to address awareness of their responsibility in minimizing hazards in workplaces.&#x0D; Bangabandhu Sheikh Mujib Med. Coll. J. 2022;1(1):90-95

The Effect of a Web-Based Occupational Noise-Induced Hearing Loss Prevention Program on Hearing Protection Device Behavior Among Thai Navy Officers: A Quasi-Experimental Study

        Navy officers working on the coastal guard vessels risk hearing loss due to repeated exposure to high noise levels from ship engines. Therefore, proper use of hearing protection devices is important. In this study, a web-based hearing loss prevention program was developed to promote the behavior of the use of hearing protection devices among Thai navy officers working on coastal guard vessels. In total, 152 navy personnel were recruited based on selection criteria and randomly assigned to the experimental (n = 76) and control groups (n = 76). The participants in the experimental group received the hearing loss prevention program via a website over four weeks. After completing the program, hearing protection device behavior was evaluated by a self-report questionnaire immediately after and at eight weeks follow-up.        The results showed significantly increasing scores of the use of hearing protection devices behavior within the experimental group, both immediately and eight weeks after the program completion. However, there were no significant differences in the scores when comparing between groups, even though the scores of the experimental group were better than those in the control group. The restrictions could be explained by some emerging events during the implementation period, including the COVID-19 pandemic followed by a massive oil spill incident at sea. These put an extra workload on the study participants. Most importantly, there was a problem with the network connection that might have affected the continuation of participant attention to the program. Although this study found no effective results of the developed program due to some limitations, nurses can adopt this protective intervention to reduce the risk of occupational noise-induced hearing loss among Navy officers. Therefore, a recommendation for further study is to develop an intervention program that considers both the working context of the coastal vessels and appropriate participation methods that require more challenging efforts.

Analysis of polymorphic loci of candidate genes in patients with occupational diseases

Introduction. Development and progress features of vibration syndrome (VS) and noise-induced hearing loss (NIHL) are determined by genetic factors to a certain extent. The latter define the relevance of the search for individual approaches to  prevention and medical support of patients with these occupational diseases.&#x0D; The aim of the study was to investigate the genotypes distribution of polymorphic loci of candidate genes in patients with occupational diseases caused by vibration and noise impact.&#x0D; Materials and methods. Polymorphic variants of the HSPA1B (rs1061581), IL17A (rs2275913), IL10 (rs1800872), and TNF-α (rs1800629) genes of three hundred ninety eight males were studied using PCR-RFLP and real-time PCR methods, including 268  patients with VS divided into two groups: VShtv (n = 117) and VScomb (n = 151), in which VS was caused by exposure to hand-transmitted vibration (HTV) or combined exposure to HTV and whole-body vibration (COMB), respectively. The study also involved 96 patients with occupational NIHL diagnosis and 34 individuals of the comparison group without occupational contact with physical factors.&#x0D; Results. The increase in GG-HSPA1B (1267A/G) genotype frequency  (p=0.058) was found in VScomb patients compared with those from the VShtv group. There was a significant difference in carriers of the C/C genotype of the IL10 (rs1800872) polymorphic locus in the group of NIHL patients relative to the comparison group (p=0.036). The results of regression analysis indicate the carriage of the A allele to reduce the risk of NIHL development.&#x0D; Limitations. The limitations include the number of examined cases in all groups, especially in comparison group and the lack of groups of workers with no occupational exposure to a physical factor.  &#x0D; Conclusion. The obtained results expand the understanding of the genetic features able to determine sensitivity to the physical factors exposure that define the development of occupational pathology and the issues to be resolved at the next stage of research.

Description of the Sound Intensity of Smartphones Used by Students of SMAN 1 Permata Bener Meriah

Hearing aids/PLDs (Personal Listening Devices) such as earphones, headphones, or headsets are often used by people to listen to sound from smartphones in order to get a good sound experience. The recommended sound volume when using PLDs is no more than 60% of the maximum volume. The use of PLDs in intensities above 85 db and for a long period of time can cause non-NIHL (non occupational noise induced hearing loss). This study aims to determine the description of the sound intensity of smartphones used by students of SMAN 1 Permata bener Meriah in the academic year 2022/2023 The method used in this study is descriptive. This study uses a cross sectional approach, namely taking primary data through checking the sound intensity when using PLDs with SLM (sound level meter). From a total of 100 samples of students of SMAN 1 Permata bener Meriah in the 2022/2023 academic year, it was found that the average sound intensity heard using PLDs was 73.76 db with a minimum value of 63.1 db and a maximum of 89 db. The conclusion of this study is that students of SMAN 1 Permata bener Meriah use PLDs with sound intensity exceeding the recommended limit

The role of kurtosis and kurtosis-adjusted energy metric in occupational noise-induced hearing loss among metal manufacturing workers.

Noise energy has been well-established to increase the risk of occupational noise-induced hearing loss (NIHL). However, the role of noise temporal structure (expressed by kurtosis) or its combination with energy metrics (e.g., kurtosis-adjusted cumulative noise exposure, adj-CNE) in occupational NIHL was still unclear. A cross-sectional survey of 867 Chinese workers, including 678 metal manufacturing workers and 189 workers exposed to Gaussian noise, was conducted. Noise energy metrics, including LAeq,8h and CNE, kurtosis (β), and adj-CNE were used to quantify noise exposure levels. Noise-induced permanent threshold shift at frequencies 3, 4, and 6 kHz (NIPTS346) and the prevalence of high-frequency NIHL (HFNIHL%) were calculated for each participant. The dose-response relationship between kurtosis or adj-CNE and occupational NIHL was observed. Among 867 workers, different types of work had specific and independent noise energy and kurtosis values (p > 0.05). HFNIHL% increased with an increase in exposure duration (ED), LAeq,8h, CNE, or kurtosis (p < 0.01), and there were strong linear relationships between HFNIHL% and ED (coefficient of determination [R2] = 0.963), CNE (R2 = 0.976), or kurtosis (R2 = 0.938, when CNE < 100 dB(A)∙year). The "V" shape notching extent in NIPTS became deeper with increasing kurtosis when CNE < 100 dB(A)∙year and reached the notching bottom at the frequency of 4 or 6 kHz. The workers exposed to complex noise (β ≥ 10) had a higher risk of NIHL than those exposed to Gaussian noise (β < 10) at the frequencies of 3, 4, 6, and 8 kHz (OR > 2, p < 0.01). Moreover, HFNIHL% increased with adj-CNE (p < 0.001). There were strong linear relationships between NIHL and adj-CNE or CNE when β ≥ 10 (R2adj-CNE > R2CNE). After CNE was adjusted by kurtosis, average differences in NIPTS346 or HFNIHL% between the complex and Gaussian noise group were significantly reduced (p < 0.05). Kurtosis was a key factor influencing occupational NIHL among metal manufacturing workers, and its combination with energy metrics could assess the risk of NIHL more effectively than CNE alone.

Prevalence and correlates of occupational noise-induced hearing loss among workers in the steel industry

BackgroundThe steel industry is one of the noisiest industries, which can predispose workers to hearing loss. In Egypt, the demand for steel is increasing due to the construction of new infrastructures as bridges, flyover roads, buildings, and towers; however, little is known about the prevalence of occupational noise-induced hearing loss (NIHL) among steel workers. Understanding the distribution of the affected workers is crucial for planning prevention strategies. This study aimed to estimate the prevalence of occupational NIHL among Egyptian steel workers and identify its correlates.MethodsThis study was conducted at two steel factories in Egypt in November 2021. It involved an initial retrospective review of the factory medical records of the latest periodic medical examination conducted on workers from July to September in the year 2021 representing workers’ health status in that year. Then, a case–control approach analysis was carried out. Eligible workers (n = 606) were enrolled and divided into two groups: noise-exposed workers (n = 396) and unexposed workers (n = 210). Univariate and multivariate regression analyses were performed.ResultsOccupational exposure to hazardous A-weighted equivalent noise level (> 85 dB) was associated with higher hearing thresholds at all frequencies (highest at 4 kHz followed by 6 kHz), particularly in younger workers below the age of 40 years. Nearly 71% of noise-exposed workers had hearing impairment, and 47% had NIHL compared with unexposed workers (45.7% and 11.9%, respectively). The probability of NIHL in noise-exposed workers was 6.55 times higher than that in unexposed workers (OR = 6.55, 95%CI = 4.13, 10.40; p < 0.001). In noise-exposed workers, age and tinnitus were independent predictors of hearing thresholds, while tinnitus was found to be an independent predictor of NIHL after adjusting for age and job duration (OR = 2.06, 95%CI = 1.01, 4.20; p = 0.045).ConclusionAlmost half of noise-exposed workers had NIHL. Tinnitus was found to be an independent predictor of NIHL. Decreasing noise exposure levels in steel plants is recommended to reduce hearing loss. Future research is required to study the effect of tinnitus on audiometry measurements among workers with NIHL.

Evaluating Earplug Performance over a 2-Hour Work Period with a Fit-Test System.

Workers rely on hearing protection devices to prevent occupational noise-induced hearing loss. This study aimed to evaluate changes in attenuation over time for properly fit devices when worn by workers exposed to hazardous noise. Earplug fit testing was accomplished on 30 workers at a brewery facility with three types of foam and three types of premolded earplugs. The personal attenuation ratings (PARs) were measured before and after a 2-hour work period while exposed to hazardous noise levels. The minimum acceptable initial PAR was 15 dB. Average decreases in PAR ranged from -0.7 to -2.6 dB across all six earplug types. Significant changes in PAR were observed for the Foam-1 ( p  = 0.009) and Premold-3 ( p  = 0.004) earplugs. A linear mixed regression model using HPD type and study year as fixed effects and subject as random effect was not significant for either fixed effect ( α  = 0.05). Ninety-five percent of the final PAR measurements maintained the target attenuation of 15 dB. Properly fitting earplugs can be effective at reducing worker's noise exposures over time. The potential for a decrease in attenuation during the work shift should be considered when training workers and establishing the adequacy of protection from hazardous noise exposures.