A review of occupational noise-induced hearing loss: focus on mechanisms and preventive measures

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.

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.

Although the effect of hearing loss on years lived with disability (YLD) is quite substantial, occupational hearing loss among migrant workers is significantly under-studied. In Kuwait, where nearly two-thirds of the population are migrant workers, the burden of occupational noise-induced hearing loss (ONIHL) is unknown. The objective of the study was to assess the prevalence of ONIHL among migrant workers in Kuwait and explore workplace and individual risk factors that are associated with ONIHL. We obtained data of annual physical exams for the year 2018 conducted by the Shuaiba Industrial Medical Center (SIMC) for all industrial workers in the area. We applied univariate and multivariate logistic regression models to estimate the effects of individual and occupational characteristics on ONIHL. A total of 3474 industrial workers visited the SIMC for an annual exam. The vast majority were men (99%) and non-Kuwaitis (98%) with a median age of 38 years. A total of 710 workers were diagnosed with ONIHL with a prevalence of 20.4%. Age, years of experience, and self-reported exposure to noise were associated with statistically significant higher odds of ONIHL. When adjusted for age, years of experience, and other individual level factors, type of industry was not a statistically significant predictor of ONIHL. The study uncovers the significant burden of hearing loss among the migrant worker subpopulation in Kuwait, an area of occupational health that is often underestimated or unrecognized. Although laws and regulations are in place to prevent and control noise in the workplace, the onus is on local authorities to ensure the necessary training and controls aimed to reduce noise exposure.

Occupational hearing loss (OHL) is known to be one of the most common occupational diseases. Common causes are being exposed to workplace hazardous noise levels, ototoxic chemicals, head injuries and barotrauma. Occupational noise-induced hearing loss is mostly due to the death or damage of hair cells in our ear, which do not grow back. On the other hand, ototoxic chemicals affect the structures in cochlear and auditory neurological pathways leading to hearing loss. In occupational head trauma, the parts of the ear that are damaged are the tympanic membrane, middle ear and cochlea which leads to hearing disability. Huge changes in pressure on the outside and the inside of the ear leads to barotrauma causing potential hearing loss. Many of the research available are regarding noise-induced OHL or chemicals causing OHL followed by barotrauma. More studies on OHL due to workplace head trauma should be conducted. Preventative measures should be taken by the worker’s supervisors or the government to implement safety measures to prevent and reduce OHL. This can be done via providing equipment and facilities that prevent hearing loss and education on OHL.

A large portion of Iranian Working Population (IWP) is becoming at risk of Occupational Noise-Induced Hearing Loss (ONIHL). Several primary studies have evaluated the prevalence of ONIHL in Iran with a variety of prevalence rates. We aimed to estimate the prevalence of ONIHL in the IWP using data from relevant studies. The present study is a meta-analysis and systematic review of previously published studies on ONIHL in Iran. Accordingly, the relevant articles published until Sep 1, 2021 were searched through Pub-Med, Scopus, and Google Scholar, together with Iranian scientific electronic databases. Heterogeneity between among the studies and data analysis was assessed using the I2 test and Random-Effect Model (REM) respectively. Having performed a quality assessment, the meta-analysis was performed on the data from twenty-six studies involving a total of 85685 participants. The prevalence of ONIHL was observed to range from 12.9% to 60.5% in the reviewed studies. Moreover, after combining the results from the primary research by the Random Effects Model (REM) approach, the prevalence of ONIHL among IWP was estimated to be 34.69% (95% CI: 29.10, 40.28). ONIHL is a significant concern with regard to public and occupational health in Iran. The results also highlighted the urgent need for taking appropriate preventive and control measures in the work-places; particularly by encouraging the employers and health-related policymakers to focus on preventive noise control techniques along with administrative and legislative approaches to mitigate the risk of developing ONIHL.

Purpose: to analyze the impact of a Hearing Conservation Program on occupational noise-induced hearing loss in a metallurgical plant. Methods: a longitudinal case study (2003-2018) was carried out and a Hearing Conservation Program assessed with interviews and document verification. The assessment also included 2,350 audiometric examinations and occupational noise exposure of 152 Hearing Conservation Program - participating employees, collecting the data from the company’s database. Results: high compliance indices regarding occupational noise -induced hearing loss - prevention Hearing Conservation Program practices were found between 2003 and 2018. The comparison between 2018 and 2003 showed a reduced number of workers exposed to noise at 85 dB(A) or above. The final prevalence of audiometric changes suggestive of occupational noise-induced hearing loss that remained in degree I differed from the initial one in the period. The high Hearing Conservation Program percentages and low occupational noise-induced hearing loss indicators point to an inverse relationship between them. Conclusion: the results suggest a positive impact of a Hearing Conservation Program on occupational noise-induced hearing loss in this metallurgical plant, in the period studied.

Objective: To analyze the literature of related research reports on occupational hearing loss (ONIHL) , study the characteristics of the subject and determine the research hotspots. Methods: In December 2020, PubMed database was searched by bibliometrics for ONIHL published in PubMed database from January 1971 to December 2020. Bicomb 2.03 software was used to extract the subject. The publication year, publication country, source magazine and subject words were summarized and analyzed. Results: A total of 1 473 papers were included in this study, and the number of papers was 66 from 1971 to 1980, and 628 from 2011 to 2020, an increase of nearly 10 times. The top three countries were the United States, China and Germany, with 31.5% (464/1473) , 11.5% (171/1473) and 6.2% (91/1473) ; The cross-sectional study was the most applied type; The top five words for 2011-2020: Mental Illness, polymorphism, cardiovascular disease, high frequency hearing impairment and standards and regulations. Conclusion: Susceptibility Genes, Psychological Disorders, Cardiovascular Diseases and Risk Assessment are hot areas in ONIHL at present. Researchers should focus on major fields and grasp future trends as a whole.

BackgroundOccupational noise is a global issue that widely affects workers’ physical health and quality of life. This study aimed to illustrate the trends and spatiotemporal patterns of occupational noise-induced hearing loss (ONIHL) burden from 1990 to 2021 and project future trends.MethodsUtilizing the Global Burden of Disease Study (GBD) 2021 data, we calculated ONIHL disability-adjusted life years (DALYs), age-standardized DALY rates (ASDRs), and summary exposure values (SEVs) by age, sex, and the Socio-demographic Index (SDI). Inequality and decomposition analyses were used to quantify health inequalities and identify the drivers of the ONIHL burden, respectively. The autoregressive integrated moving average (ARIMA) model was used to project the disease burden until 2040.ResultsIn 2021, the global burden of ONIHL remained substantial, with a total of 7,847,444.59 DALYs (95% uncertainty intervals [UI]: 5,313,648.10–10,980,789.34), indicating a 104.46% increase compared with that in 1990. The ASDR for ONIHL in 2021 was 91.12 per 100,000 individuals (95% UI: 61.98–127.20). The ASDRs and SEVs showed remarkable growth in high-middle SDI regions, especially for females. Regionally, East Asia, South Asia, Southeast Asia, and Eastern Sub-Saharan Africa experienced the greatest ONIHL burden in the world. Spearman correlation analysis revealed a significant negative correlation between the ASDR and SDI across 21 GBD regions and 204 countries and territories. ONIHL DALYs occurred mainly in middle-aged and older adults, and men consistently presented higher DALYs and ASDRs than females. The ONIHL burden was greater in lower-SDI regions, but cross-country health inequalities did not improve. Decomposition analysis revealed population growth as the main driver. By 2040, ONIHL DALYs are predicted to increase, whereas the ASDR is projected to decrease; however, the disease burden among females will rise significantly.ConclusionThe ONIHL burden is characterized by global growth, regional divergence, and widening disparities in sex trends. Targeted actions like bolstering occupational safety in lower SDI regions, adopting gender-responsive policies for female workers in high-noise industries, and prioritizing early hearing screening and long-term monitoring of noise hazards are key to tackling the burden of ONIHL worldwide.

Background: Occupational noise-induced hearing loss (ONIHL) is one of the most common yet preventable occupational diseases. The aim of this study was to estimate the economic burden of ONIHL in the Australian working population by quantifying and monetising ONIHL—related loss of Quality Adjusted Life Years (QALY) and Productivity Adjusted Life Years (PALYs). Methods: We simulated the number of moderate-to-severe ONIHL by multiplying the age-specific prevalence of occupational noise exposure by the excess risks of ONIHL. Life table modelling was applied to workers with ONIHL. The QALY and PALY weights attributable to hearing loss were sourced from published data. The 2016 Gross Domestic Product per full-time equivalent worker in Australia was used to estimate the cost of productivity loss due to ONIHL. The cost due to the loss of well-being was quantified using willingness to pay thresholds derived from an Australian longitudinal study. Results: Under current occupational noise exposure levels in Australia, we estimated that over 80,000 male workers and over 31,000 female workers would develop ONIHL over 10 years of exposure. Following this cohort until the age of 65 years, the estimated loss of QALYs and PALYs were 62,218 and 135,561 respectively, with a projected loss of AUD 5.5 billion and AUD 21.3 billion due to well-being and productivity loss, respectively. Reducing noise exposure at work would substantially reduce the economic burden of ONIHL. Conclusion: ONIHL imposes substantial burden on Australian economy. Interventions to reduce occupational noise exposure are warranted.

This study aimed to characterize trends in occupational noise-induced hearing loss (ONIHL) incidence and to assess noise exposure levels and changes in audiometric thresholds among workers. This retrospective study analyzed audiometric data from 72,952 workers between 1980 and 2019. Incidence rates of ONIHL were calculated. The first and last audiograms for each worker were compared, and noise exposure levels were analyzed. The final cohort included 36,984 workers. ONIHL incidence fluctuated between 4.0% and 7.0%, with a slight upward trend from 2000 to 2019. Noise exposure exceeded 85 dBA for 69.3% of workers with available measurements. Audiometric thresholds significantly worsened from the first to the last audiogram. Between 1980 and 2019, ONIHL incidence showed a slight increase. Ongoing monitoring of ONIHL trends and enhanced prevention initiatives are critical for mitigating future risks.

The aim of the study was to investigate the occupational epidemiological characteristics of hearing loss among noise-exposed workers through a cross-sectional study and to explore the impact of combined noise and dust exposure on workers' hearing loss through a longitudinal study. This cross-sectional study revealed that the risk of speech-frequency hearing loss increases with age (OR = 1.096, 95%CI = 1.081-1.111). Independent factors influencing high-frequency hearing loss include sex, age, hazardous factors, industry category, and enterprise size. Scientific research and technical services (OR = 1.607, 95%CI = 1.111-2.324), wholesale and retail (OR = 2.144, 95%CI = 1.479-3.107), manufacturing (OR = 1.907, 95%CI = 1.429-2.545), and other industries (OR = 1.583, 95%CI = 1.002-2.502) are risk factors for high-frequency hearing loss, whereas being female (OR = 0.297, 95%CI = 0.236-0.373) is a protective factor against high-frequency hearing loss. Independent factors influencing occupational noise-induced hearing loss include sex, working age, hazardous factors, industry category, smoking, and drinking, with the risk of occupational noise-induced hearing loss increasing with working age (OR = 1.045, 95%CI = 1.031-1.058). Noise and dust work (OR = 1.271, 95%CI = 1.011-1.597), other work (OR = 0.619, 95%CI = 0.479-0.800), manufacturing (OR = 2.085, 95%CI = 1.336-3.254), other industries (OR = 2.063, 95%CI = 1.060-4.012), occasional smokers (OR = 0.863, 95%CI = 0.652-1.142), regular smokers (OR = 1.216, 95% CI = 0.987-1.497), and excessive drinkers (OR = 2.171, 95%CI = 1.476-3.193) are risk factors for occupational noise-induced hearing loss, whereas being female (OR = 0.496, 95%CI = 0.347-0.709) is a protective factor against occupational noise-induced hearing loss. The longitudinal study revealed differences in pure-tone hearing threshold test results at 500 Hz, 1,000 Hz, 3,000 Hz, 4,000 Hz, and 6,000 Hz in both ears before and after enrollment among noise-exposed workers (p < 0.05). Combined noise and dust exposure (OR = 4.660, 95%CI = 1.584-13.711), 1st year (OR = 1.540, 95%CI = 1.128-2.103), 2nd year (OR = 1.994, 95%CI = 1.409-2.821), and 3rd year (OR = 1.628, 95%CI = 1.170-2.264) were risk factors for high-frequency hearing loss. Combined noise and dust exposure is a risk factor for occupational noise-induced hearing loss. Additionally, occupational noise-induced hearing loss is influenced by gender, working age, enterprise industry category, smoking, and drinking. Employers should enhance occupational health management and improve workers' occupational health literacy, with a particular focus on older male workers of long working age, and those with unhealthy habits. Combined exposure to noise and dust may have a synergistic effect on causing high-frequency hearing loss, and comprehensive protective measures should be implemented for workers exposed to both.

Occupational noise-induced hearing loss (ONIHL) represents a prevalent occupational health condition, traditionally necessitating multiple pure-tone audiometry assessments. We have developed and validated a machine learning model leveraging routine haematological and biochemical parameters, thereby offering novel insights into the risk prediction of ONIHL. This study analysed data from 3297 noise-exposed workers in Shenzhen, including 160 ONIHL cases, with the data set divided into D1 (2868 samples, 107 ONIHL cases) and D2 (429 samples, 53 ONIHL cases). The inclusion criteria were formulated based on the GBZ49-2014 Diagnosis of Occupational Noise-Induced Hearing Loss. Model training was performed using D1, and model validation was conducted using D2. Routine blood and biochemical indicators were extracted from the case data, and a range of machine learning algorithms including extreme gradient boosting (XGBoost) were employed to construct predictive models. The model underwent refinement to identify the most representative variables, and decision curve analysis was conducted to evaluate the net benefit of the model across various threshold levels. Model creation data set and validation data sets: ONIHL. The prediction model, developed using XGBoost, demonstrated exceptional performance, achieving an area under the receiver operating characteristic curve (AUC) of 0.942, a sensitivity of 0.875 and a specificity of 0.936 on the validation data set. On the test data set, the model achieved an AUC of 0.990. After implementing feature selection, the model was refined to include only 16 features, while maintaining strong performance on a newly acquired independent data set, with an AUC of 0.872, a balanced accuracy of 0.798, a sensitivity of 0.755 and a specificity of 0.840. The analysis of feature importance revealed that serum albumin (ALB), platelet distribution width (PDW), coefficient of variation in red cell distribution width (RDW-CV), serum creatinine (Scr) and lymphocyte percentage (LYMPHP) are critical factors for risk stratification in patients with ONIHL. The analysis of feature importance identified ALB, PDW, RDW-CV, Scr and LYMPHP as pivotal factors for risk stratification in patients with ONIHL. The machine learning model, using XGBoost, effectively distinguishes patients with ONIHLamong individuals exposed to noise, thereby facilitating early diagnosis and intervention.

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.

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.

This study focuses on work-related injuries that required admission to hospital in a population of male workers exposed to occupational noise (≥80 dBA) which some displayed a hearing loss due to their exposure. The study population count 46 550 male workers, 1670 (3.6%) of whom incurred at least one work-related injury requiring admission to hospital within a period of 5 years following hearing tests conducted between 1987 and 2005. The noise exposure and hearing loss-related data were gathered during occupational noise-induced hearing loss (NIHL) screening. The hospital data were used to identify all members of the study population who were admitted, and the reason for admission. Finally, access to the death-related data made it possible to identify participants who died during the course of the study. Cox proportional hazards model taking into account hearing status, noise levels, age and cumulative duration of noise exposure at the time of the hearing test established the risk of work-related injuries leading to admission to hospital. For each dB of hearing loss, a statistically significant risk increase was observed (HR=1.01 dB 95% CI 1.006 to 1.01). An association (HR=2.36 95% CI 2.01 to 2.77) was also found between working in an occupational ambient noise ≥100 dBA and the risk of injury. From a safety perspective, this issue is highly relevant; especially when workers are exposed to intense ambient noise and NIHL.