Hearing difficulty and tinnitus among U.S. workers and non-workers in 2007

Hazardous exposures and engineering controls in the landscaping services industry

Landscapers are exposed to noise, carbon monoxide (CO), respirable dust, and respirable crystalline silica (RCS) generated from the tools they use. Although engineering controls are available to reduce these exposures, no previous study has evaluated chronic exposures to landscapers in different work settings and compared exposures from landscaping tools with and without engineering controls. This field study of workers in the landscaping services industry documented the occupational exposures of 80 participants at 11 varied worksites to noise, CO, respirable dust, and RCS using personal breathing zone sampling. Results were analyzed using SAS/STAT 14.1. Analysis of variance was used for normally distributed data; otherwise, nonparametric methods were used. Most workers were overexposed to noise, with 94 of the 119 8-hr time-weighted average (TWA) noise exposures at or above the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit (REL) of 85 dBA. There were no statistically significant differences among different locations or occupations. No 8-hr TWA exposures to CO above the NIOSH REL were measured. Overexposures to RCS were measured at all locations where hardscaping (installing or maintaining non-living aspects of the landscape) was taking place. This is the first known field study of this type to include hardscapers. The use of engineering controls such as dust capture or wet methods would reduce RCS exposures, but respiratory protection may still be needed. Task-based analysis of noise and CO exposure revealed that the loudest landscaping tools used in this study were hardscaping table saws, gas chainsaws, gas leaf blowers, chipper/shredders, gas string trimmers, and fuel mowers. Workers were exposed to significantly more noise and CO when using fuel-powered versions compared to battery-powered versions of leaf blowers, string trimmers, and chainsaws.

Associations Between Noise Exposure Level, Noise Kurtosis, and Distortion Product Otoacoustic Emissions in Young Workers With Normal Hearing

OBJECTIVES

Growing evidence has suggested that, in addition to noise exposure level, noise temporal structure (i.e., kurtosis) plays an important role in the development of noise-induced hearing loss, while most of the relevant research has been on the results of pure-tone audiometry. This study focuses on the combined effect of noise exposure level and noise kurtosis on distortion product otoacoustic emissions (DPOAEs) in young workers with normal hearing.

DESIGN

A cross-sectional study among young workers in manufacturing industries was conducted in Zhejiang Province, China. Individual noise exposure measurements were performed on participants to obtain an A-weighted noise exposure level normalized to 8 hr ( LAeq, 8hr ), cumulative noise exposure (CNE), kurtosis, and kurtosis-adjusted CNE (CNE-K). The DPOAE test was performed on the participants and DPOAE levels were obtained. The relationships between noise exposure level, kurtosis, and DPOAE levels were explored by univariate analyses. Furthermore, multivariate regression models were conducted to estimate the combined effects of exposure level and kurtosis after adjusting for age, gender, and use of hearing protection devices.

RESULTS

The overall DPOAE curves across frequency bands presented a fluctuating downward trend with increasing frequency. Both exposure level and kurtosis were found to be associated with decreases in DPOAE levels. The multivariate regression model including CNE-K as a joint indicator of complex noise showed an increased R2 compared with the model including CNE. After adjustment for age, gender, and the use of hearing protection devices, significant effects of CNE-K on DPOAE levels were observed at 3, 4, and 5 kHz frequencies, with maximum effect presented at 4 kHz.

CONCLUSIONS

DPOAE is a sensitive test that can detect cochlear damage in limited areas that cannot be detected by conventional audiometry. The present study provided a more comprehensive understanding of the impact of complex noise on the DPOAE levels. It also suggested that CNE-K was an effective metric in assessing DPOAE levels associated with complex noise.

Prevalence of hearing loss among noise-exposed U.S. workers within the Construction sector, 2010-2019

BACKGROUND

The purpose of this cross-sectional study is to estimate the prevalence of hearing loss among noise-exposed U.S. workers during 2010-2019 within the Construction sector.

METHODS

Audiograms for 26,653 workers at 833 Construction companies (and for 1.3 million other workers) were examined. Period prevalence and adjusted risk for hearing loss as compared with a reference industry (Couriers and Messengers) were estimated for the Construction sector and sub-sectors, and all industries combined.

RESULTS

The prevalence of hearing loss within the Construction sector was 23% compared to 20% for all industries combined. Several sub-sectors exceeded the overall prevalence and all but two had adjusted risks significantly higher than the reference industry. The sub-sectors with the highest prevalences for hearing loss were: Highway, Street, and Bridge Construction (28%), Site Preparation Contractors (26%), New Single-Family Housing Construction (except Operative Builders) (25%), Oil and Gas Pipeline and Related Structures Construction (25%), and Other Building Finishing Contractors (25%). The sub-sectors with the highest adjusted risks were Industrial Building Construction; Other Heavy and Civil Engineering Construction; Oil and Gas Pipeline and Related Structures Construction; Finish Carpentry Contractors; and Site Preparation Contractors; with risks 62%, 61%, 60%, 59% and 58% higher than the reference industry, respectively.

CONCLUSIONS

Hearing loss continues to be a significant issue within Construction. Reducing noise exposure is critical, including buying quieter equipment, keeping moving parts oiled and well-maintained, enclosing noise sources, and employing administrative controls to reduce the number of workers in noisy areas. Barriers to workers consistently and correctly wearing their hearing protection also need to be addressed.

PRACTICAL APPLICATIONS

Within Construction, hazardous noise is common and the risk of hearing loss is high. This study identified the Construction sub-sectors with the highest prevalences and risks to guide interventions toward workers most in need of prevention and described strategies for reducing exposures.

Noise characteristics and its influence analysis of the waiting areas in a Chinese children's hospital

Compared to the general hospital, the children's hospital has significantly higher noise levels. This seriously influences hospital environment quality and medical service level. The noise characteristic and its influence were studied with field measurements and questionnaire surveys conducted in Kunming Children's Hospital. A-weighted equivalent continuous sound level (LAeq), percentile sound pressure levels, loudness and sharpness in waiting areas of cardiology, internal medicine, stomatology, intravenous blood collection and VIP departments were acquired and analyzed. Results showed that LAeq variation was consistent with the medical service schedule. The children's cries and the broadcast system were regarded as the main noise sources and their suddenness characteristic for a single event were analyzed. Questionnaire survey results revealed that more staff than patients in the waiting areas considered the sound environmental noisy. The ordered logit model analysis showed the subjective noisy evaluation of staff was significantly associated with ten percentile sound level (L10) and five percentile loudness (N5).

The Global Prevalence of Noise Induced Hearing Impairment Among Industrial Workers: A Systematic Review and Meta-Analysis

Noise is one of the harmful health factors in industrial sites. Hearing impairments are one of the most common occupational diseases in a wide range of industries. The aim of this study is to determine the general prevalence of noise-induced hearing disorders among industrial workers and to homogenize the results of different studies in this field. In this systematic review and meta-analysis study, the keywords of Occupational Noise, Hearing Impairment, Workers, Industry in Science Direct, PubMed, Scopus, Web of Science and Google Scholar databases without any lower time limit and until March 2022. Details of the identified studies were then transferred into the EndNote reference management software. Subsequently, duplicate studies were eliminated, and the remaining studies were evaluated in accordance with the inclusion and exclusion criteria and through the three remaining phases of PRISMA i.e., screening, eligibility, and inclusion. To analyze the eligible studies, the random effects model was used, and the heterogeneity of the studies was assessed using the I2 index. In a review of 69 studies with a sample size of 3,552,888 people, the overall prevalence of hearing impairment among industrial workers was 28.8% (95% CI 26.2%-31.6%). The highest prevalence of hearing impairments was reported among agricultural and fishery workers with 45.7% (95% CI 35.1%-56.7%), and the highest prevalence of hearing impairment among industrial workers was found in the continent of Africa with 46.2% (95% CI 37.4%-55.2%). Due to the higher prevalence of hearing impairments among men, the elderly and in developing countries, it is necessary to establish pertinent laws and regulations in order for workers to use appropriate personal protective equipment (PPE) and mandate employers to provide hearing protection programs.

Calcitriol alleviates noise-induced hearing loss by regulating the ATF3/DUSP1 signalling pathway

BACKGROUND

Calcitriol (Cal) is the most active metabolite of vitamin D and has antioxidant and anti-inflammatory properties. The aim of this study was to investigate the role of Cal in noise-induced hearing loss (NIHL) to further elucidate the mechanism of noise-induced oxidative stress in the mouse cochlea.

METHODS

C57BL/6 J mice were given six intraperitoneal injections of Cal (500 ng/kg/d). After 14 days of noise exposure, auditory brainstem response (ABR) thresholds, and the cochlear outer hair cell loss rate were analysed to evaluate auditory function. Real-time fluorescence quantitative PCR, immunofluorescence and western blotting were performed in vitro after the treatment of cochlear explants with 100 µM tert-butyl hydroperoxide (TBHP) for 2.5 h and HEI-OC1 cells with 250 µM TBHP for 1.5 h.

RESULTS

In vivo experiments confirmed that Cal pretreatment mitigated NIHL and outer hair cell death. The in vitro results demonstrated that Cal significantly reduced TBHP-induced cochlear auditory nerve fibre degradation and spiral ganglion neuron damage. Moreover, treatment with Cal inhibited the expression of oxidative stress-related factors (3-NT and 4-HNE) and DNA damage-related factors (γ-H2A.X) and attenuated TBHP-induced apoptosis in cochlear explants and HEI-OC1 cells. A total of 1479 upregulated genes and 1443 downregulated genes were screened in cochlear tissue 1 h after noise exposure. The level of transcription factor 3 (ATF3) was significantly elevated in HEI-OC1 cells after TBHP stimulation. Gene Transcription Regulation Database （GTRD）and Cistrome database analyses revealed that the downstream target gene of ATF3 is dual specificity phosphatase 1 (DUSP1). Cistrome DB Toolkit database results showed that the transcription factor of DUSP1 was ATF3. In addition, the ChIP-PCR results indicated that ATF3 might be a direct transcription factor of DUSP1.

CONCLUSION

The results of our study suggest that Cal attenuates NIHL and inhibits noise-induced apoptosis by regulating the ATF3/DUSP1 signalling pathway.

DNA Methylation Patterns Associated with Tinnitus in Young Adults-A Pilot Study

PURPOSE

Tinnitus, the perception of sound without any external sound source, is a prevalent hearing health concern. Mounting evidence suggests that a confluence of genetic, environmental, and lifestyle factors can influence the pathogenesis of tinnitus. We hypothesized that alteration in DNA methylation, an epigenetic modification that occurs at cytosines of cytosine-phosphate-guanine (CpG) dinucleotide sites, where a methyl group from S-adenyl methionine gets transferred to the fifth carbon of the cytosine, could contribute to tinnitus. DNA methylation patterns are tissue-specific, but the tissues involved in tinnitus are not easily accessible in humans. This pilot study used saliva as a surrogate tissue to identify differentially methylated CpG regions (DMRs) associated with tinnitus. The study was conducted on healthy young adults reporting bilateral continuous chronic tinnitus to limit the influence of age-related confounding factors and health-related comorbidities.

METHODS

The present study evaluated the genome-wide methylation levels from saliva-derived DNA samples from 24 healthy young adults with bilateral continuous chronic tinnitus (> 1 year) and 24 age, sex, and ethnicity-matched controls with no tinnitus. Genome-wide DNA methylation was evaluated for > 850,000 CpG sites using the Infinium Human Methylation EPIC BeadChip. The association analysis used the Bumphunter algorithm on 23 cases and 20 controls meeting the quality control standards. The methylation level was expressed as the area under the curve of CpG sites within DMRs.The FDR-adjusted p-value threshold of 0.05 was used to identify statistically significant DMRs associated with tinnitus.

RESULTS

We obtained 25 differentially methylated regions (DMRs) associated with tinnitus. Genes within or in the proximity of the hypermethylated DMRs related to tinnitus included LCLAT1, RUNX1, RUFY1, NUDT12, TTC23, SLC43A2, C4orf27 (STPG2), and EFCAB4B. Genes within or in the proximity of hypomethylated DMRs associated with tinnitus included HLA-DPB2, PM20D1, TMEM18, SNTG2, MUC4, MIR886, MIR596, TXNRD1, EID3, SDHAP3, HLA-DPB2, LASS3 (CERS3), C10orf11 (LRMDA), HLA-DQB1, NADK, SZRD1, MFAP2, NUP210L, TPM3, INTS9, and SLC2A14. The burden of genetic variation could explain the differences in the methylation levels for DMRs involving HLA-DPB2, HLA-DQB1, and MUC4, indicating the need for replication in large independent cohorts.

CONCLUSION

Consistent with the literature on comorbidities associated with tinnitus, we identified genes within or close to DMRs involved in auditory functions, chemical dependency, cardiovascular diseases, psychiatric conditions, immune disorders, and metabolic syndromes. These results indicate that epigenetic mechanisms could influence tinnitus, and saliva can be a good surrogate for identifying the epigenetic underpinnings of tinnitus in humans. Further research with a larger sample size is needed to identify epigenetic biomarkers and investigate their influence on the phenotypic expression of tinnitus.

Music therapy for tinnitus: A systematic review and meta-analysis

OBJECTIVE

To evaluate the clinical efficacy of music therapy in the treatment of tinnitus.

METHODS

Three English databases (PUBMED, Embase, Web of Science) and three Chinese databases (CNKI, VIP, and Wanfang) were searched, and eligible articles were selected according to the set inclusion criteria. Clinical efficacy was used as the primary outcome, and each score was used as the secondary outcome. Using RevMan5.3 software for statistical analysis.

RESULTS

A total of 14 studies involving 1239 tinnitus patients were included. The results of the meta-analysis showed that music therapy had a certain clinical efficacy in the treatment of tinnitus, but there was no significant difference compared with the control group (OR = 1.00, 95%CI =0.83-1.22; P = 1.00). However, music therapy significantly improved THI score (MD = -6.77, 95 % CI = -9.62 to -3.92; P < 0.00001), TSQ (MD = -2.80, 95 % CI = -3.23 to -2.36; P < 0.00001), tinnitus loudness (MD = -3.90, 95 % CI = -6.58 to -1.23; P = 0.004), VAS score (MD = -1.11, 95 % CI = -2.11 to -0.11; P = 0.03) and TQ score (MD = -8.36, 95 % CI = -11.10 to -5.62; P < 0.001).

CONCLUSION

Music therapy is an effective method for the treatment of tinnitus, which can improve the THI score, tinnitus severity, VAS score, and TQ score and reduce the loudness of tinnitus. Due to the low quality of the included literature, the current conclusions need to be further verified by more and higher-quality studies.

Hearing protection field attenuation estimation systems and associated training for reducing workers' exposure to noise

BACKGROUND

Global Burden of Disease studies identify hearing loss as the third leading cause of years lived with a disability. Their estimates point to large societal and individual costs from unaddressed hearing difficulties. Workplace noise is an important modifiable risk factor; if addressed, it could significantly reduce the global burden of disease. In practice, providing hearing protection devices (HPDs) is the most common intervention to reduce noise exposure at work. However, lack of fit of HPDs, especially earplugs, can greatly limit their effectiveness. This may be the case for 40% of users. Testing the fit and providing instructions to improve noise attenuation might be effective. In the past two decades, hearing protection fit-test systems have been developed and evaluated in the field. They are called field attenuation estimation systems. They measure the noise attenuation obtained by individual workers using HPDs. If there is a lack of fit, instruction for better fit is provided, and may lead to better noise attenuation obtained by HPDs.

OBJECTIVES

To assess: (1) the effects of field attenuation estimation systems and associated training on the noise attenuation obtained by HPDs compared to no instruction or to less instruction in workers exposed to noise; and (2) whether these interventions promote adherence to HPD use.

SEARCH METHODS

We used CENTRAL, MEDLINE, five other databases, and two trial registers, together with reference checking, citation searching, and contact with study authors to identify studies. We imposed no language or date restrictions. The latest search date was February 2024.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), cluster-RCTs, controlled before-after studies (CBAs), and interrupted time-series studies (ITSs) exploring HPD fit testing in workers exposed to noise levels of more than 80 A-weighted decibels (or dBA) who use hearing protection devices. The unit 'dBA' reports on the use of a frequency-weighting filter to adjust sound measurement results to better reflect how human ears process sound. The outcome noise attenuation had to be measured either as a personal attenuation rating (PAR), PAR pass rate, or both. PAR pass rate is the percentage of workers who passed a pre-established level of sufficient attenuation from their HPDs, identified on the basis of their individual noise exposure.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, risk of bias, and extracted data. We categorised interventions as fit testing of HPDs with instructions at different levels (no instructions, simple instructions, and extensive instructions).

MAIN RESULTS

We included three RCTs (756 participants). We did not find any studies that examined whether fit testing and training contributed to hearing protector use, nor any studies that examined whether age, gender, or HPD experience influenced attenuation. We would have included any adverse effects if mentioned by the trial authors, but none reported them. None of the included studies blinded participants; two studies blinded those who delivered the intervention. Effects of fit testing of HPDs with instructions (simple or extensive) versus fit testing of HPDs without instructions Testing the fit of foam and premoulded earplugs accompanied by simple instructions probably does not improve their noise attenuation in the short term after the test (1-month follow-up: mean difference (MD) 1.62 decibels (dB), 95% confidence interval (CI) -0.93 to 4.17; 1 study, 209 participants; 4-month follow-up: MD 0.40 dB, 95% CI -2.28 to 3.08; 1 study, 197 participants; both moderate-certainty evidence). The intervention probably does not improve noise attenuation in the long term (MD 0.15 dB, 95% CI -3.44 to 3.74; 1 study, 103 participants; moderate-certainty evidence). Fit testing of premoulded earplugs with extensive instructions on the fit of the earplugs may improve their noise attenuation at the immediate retest when compared to fit testing without instructions (MD 8.34 dB, 95% CI 7.32 to 9.36; 1 study, 100 participants; low-certainty evidence). Effects of fit testing of HPDs with extensive instructions versus fit testing of HPDs with simple instructions Fit testing of foam earplugs with extensive instructions probably improves their attenuation (MD 8.62 dB, 95% CI 6.31 to 10.93; 1 study, 321 participants; moderate-certainty evidence) and also the pass rate of sufficient attenuation (risk ratio (RR) 1.75, 95% CI 1.44 to 2.11; 1 study, 321 participants; moderate-certainty evidence) when compared to fit testing with simple instructions immediately after the test. This is significant because every 3 dB decrease in noise exposure level halves the sound energy entering the ear. No RCTs reported on the long-term effectiveness of the HPD fit testing with extensive instructions.

AUTHORS' CONCLUSIONS

HPD fit testing accompanied by simple instructions probably does not improve noise attenuation from foam and premoulded earplugs. Testing the fit of foam and premoulded earplugs with extensive instructions probably improves attenuation and PAR pass rate immediately after the test. The effects of fit testing associated with training to improve attenuation may vary with types of HPDs and training methods. Better-designed trials with larger sample sizes are required to increase the certainty of the evidence.

Study on impact of robotic-assisted orthopaedic industrial noise (SIREN)

INTRODUCTION

The aim of this study was to evaluate noise exposure to the operating room staff consisting of the surgeon, assistant, anaesthetist and Mako Product Specialist (MPS) during Mako robotic-arm assisted total knee arthroplasty (TKA) and total hip arthroplasty (THA). We aimed to determine whether employees were exposed to noise at or above a lower exposure action value (LEAV) set out by the Noise at Work Regulations 2005, Health and Safety Executive (HSE), UK.

MATERIALS AND METHODS

We prospectively recorded intra-operative noise levels in Mako robotic-arm assisted TKA and THA over a period of two months using the MicW i436 connected to an iOS device (Apple), using the Sound Level Meter App (iOS) by the National Institute for Occupation Safety and Health (NIOSH). Data obtained was then used to calculate "worst case" daily exposure value to assess if sound levels were compliant with UK guidelines. Comparison between operating room staff groups was performed with ANOVA testing.

RESULTS

A total of 19 TKA and 11 THA operations were recorded. During TKA, for the primary surgeon and the assistant, the equivalent continuous sound pressure level (LAeq) was over 80 dB, exceeding the LEAV set out by the Noise at Work Regulations by HSE. During THA, the average LAeq and peak sound pressure levels did not exceed the LEAV. The calculated daily exposure for the primary surgeon in TKA was 82 dB. A Tukey post hoc test revealed that LAeq was statistically significantly lower in the anaesthetist and MPS (p < .001) compared to the primary surgeon and assistant in both TKA and THA.

CONCLUSIONS

Operating room staff, particularly the primary surgeon and assistant are exposed to significant levels of noise during Mako robotic-arm assisted TKA and THA. Formal assessments should be performed to further assess the risk of noise induced hearing loss in robotic-arm assisted arthroplasty.

Systemic health effects of noise exposure

Noise, any unwanted sound, is pervasive and impacts large populations worldwide. Investigators suggested that noise exposure not only induces auditory damage but also produces various organ system dysfunctions. Although previous reviews primarily focused on noise-induced cardiovascular and cerebral dysfunctions, this narrow focus has unintentionally led the research community to disregard the importance of other vital organs. Indeed, limited studies revealed that noise exposure impacts other organs including the liver, kidneys, pancreas, lung, and gastrointestinal tract. Therefore, the aim of this review was to examine the effects of noise on both the extensively studied organs, the brain and heart, but also determine noise impact on other vital organs. The goal was to illustrate a comprehensive understanding of the systemic effects of noise. These systemic effects may guide future clinical research and epidemiological endpoints, emphasizing the importance of considering noise exposure history in diagnosing various systemic diseases.

Preventing Occupational Hearing Loss: 50 Years of Research and Recommendations from the National Institute for Occupational Safety and Health

For more than 50 years, the National Institute for Occupational Safety and Health (NIOSH), part of the United States (U.S.) Centers for Disease Control and Prevention (CDC), has been actively working to reduce the effects of noise and ototoxic chemicals on worker hearing. NIOSH has pioneered basic and applied research on occupational hearing risks and preventive measures. The Institute has issued recommendations and promoted effective interventions through mechanisms ranging from formal criteria documents to blogs and social media. NIOSH has conducted surveillance and published statistics to guide policy and target prevention efforts. Over the past five decades, substantial progress has been made in raising awareness of noise as a hazard, reducing the risk of occupational hearing loss, improving the use of hearing protection, and advancing measurement and control technologies. Nevertheless, noise remains a prevalent workplace hazard and occupational hearing loss is still one of the most common work-related conditions. NIOSH continues to work toward preventing the effects of noise and ototoxicants at work and has many resources to assist audiologists in their hearing loss prevention efforts.

The Associations Between Workplace Noise, Ototoxic Chemicals, and Tinnitus

OBJECTIVE

To investigate the occupational risk factors associated with tinnitus in the Australian working population.

DESIGN

The research was conducted using data collected from the Australian Workplace Exposure Survey-Hearing, a national cross-sectional study of 4970 workers conducted in 2016 to 2017. Workers were asked if they experienced tinnitus and if they answered affirmatively, they were asked about the frequency and length of the presentations. Based on their answers, each worker was categorized as having no tinnitus or any tinnitus, with an additional group of workers with any tinnitus subcategorized as having constant tinnitus. Exposure assessment was conducted using an automated expert assessment method. Exposures included daily noise (L Aeq,8h ), hand-arm vibration (A(8)), impulse noise, smoking status, styrene, trichloroethylene, toluene, n-hexane, p-xylene, ethylbenzene, lead, and carbon monoxide. Univariate and multivariate logistic regression models were used to examine the associations between workplace exposures and tinnitus.

RESULTS

Workers with an estimated noise exposure above the workplace limit (L Aeq,8h > 85 dBA) had 1.73 (95% confidence interval [CI]: 1.42 to 2.11) increased odds of any tinnitus and 2.15 (95% CI: 1.60 to 2.89) odds of constant tinnitus. The odds of workers having any tinnitus increased with increasing noise exposure levels in a dose-response relationship that strengthened when considering only those with constant tinnitus. In the fully adjusted model, statistically significant associations were seen for lead exposure with both any and constant tinnitus, toluene exposure with constant tinnitus, and carbon monoxide exposure with any tinnitus.

CONCLUSIONS

These results suggest that, in addition to workplace noise, occupational exposures to lead, toluene, and carbon monoxide are associated with tinnitus.

Workers' Compensation Costs for Occupational Hearing Loss Claims in the United States, 2009-2013

This study estimated the average annual number of U.S. workers' compensation (WC) claims for occupational hearing loss (OHL) and their associated cost and identified the industry/occupation classifications with the highest numbers of OHL claims. The most recent U.S. cost estimate ($242 million) was based on data from one state in 1 year (1991). WC data from the National Council on Compensation Insurance, Inc. (35 states) and two additional individual states were examined, incorporating data from 37 states and the District of Columbia. Costs and numbers of claims were estimated for the 13 missing states to develop estimates for the United States. Sensitivity analyses were also performed to develop ranges for the point estimates. The estimated U.S. average annual OHL claim cost fell within the range of $49 to $67 million during 2009-2013, with a point estimate of $60 million (2013 dollars). The estimated average annual number of OHL claims ranged from 4,114 to 5,986, with a point estimate of 4,965 claims. Based on data available from 36 states and DC, 18 of the 40 industry/occupation classifications with ≥50 OHL claims were in the manufacturing sector. WC data underestimate the true burden of OHL. Most OHL cases are not compensated. WC laws, industry composition and other factors vary widely by state, so estimates must employ data for many states. This study incorporated data from most states and utilized sensitivity and comparative analyses to obtain estimates. Workers in a wide range of industry/occupation classifications need special attention to prevent OHL.

Noise Exposure and Hearing Loss among Workers at a Hammer Forge Company

The National Institute for Occupational Safety and Health (NIOSH) evaluated continuous and impact noise exposures and hearing loss among workers at a hammer forge company. Full-shift personal noise exposure measurements were collected on forge workers across 15 different job titles; impact noise characteristics and one-third octave band noise levels were assessed at the forge hammers; and 4,750 historic audiometric test records for 483 workers were evaluated for hearing loss trends. Nearly all workers' noise exposures exceeded regulatory and/or recommended exposure limits. Workers working in jobs at or near the hammers had full-shift time-weighted average noise exposures above 100 decibels, A-weighted. Impact noise at the hammers reached up to 148 decibels. Analysis of audiometric test records showed that 82% of workers had experienced a significant threshold shift, as defined by NIOSH, and 63% had experienced a standard threshold shift, as defined by the Occupational Safety and Health Administration (OSHA). All workers with an OSHA standard threshold shift had a preceding NIOSH significant threshold shift which occurred, on average, about 7 years prior. This evaluation highlights forge workers' exposures to high levels of noise, including impact noise, and how their hearing worsened with age and length of employment.

An MR spectroscopy study of temporal areas excluding primary auditory cortex and frontal regions in subjective bilateral and unilateral tinnitus

Previous studies indicate changes in neurotransmission along the auditory pathway in subjective tinnitus. Most authors, however, investigated brain regions including the primary auditory cortex, whose physiology can be affected by concurrent hearing deficits. In the present MR spectroscopy study we assumed increased levels of glutamate and glutamine (Glx), and other Central Nervous System metabolites in the temporal lobe outside the primary auditory cortex, in a region involved in conscious auditory perception and memory. We studied 52 participants with unilateral (n = 24) and bilateral (n = 28) tinnitus, and a control group without tinnitus (n = 25), all with no severe hearing losses and a similar hearing profile. None of the metabolite levels in the temporal regions of interest were found related to tinnitus status or laterality. Unexpectedly, we found a tendency of increased concentration of Glx in the control left medial frontal region in bilateral vs unilateral tinnitus. Slightly elevated depressive and anxiety symptoms were also shown in participants with tinnitus, as compared to healthy individuals, with the bilateral tinnitus group marginally more affected. We discuss no apparent effect in the temporal lobes, as well as the role of frontal brain areas, with respect to hearing loss, attention and psychological well-being in chronic tinnitus. We furthermore elaborate on the design-related and technical obstacles of MR spectroscopy.

The relationship between hearing status, listening effort, and the need for recovery in employees of a manufacturing company

OBJECTIVE

Hearing screening can be used to detect hearing loss, but its value for identifying employees with work functioning difficulties is unclear. The objective of this study was to assess the association between the hearing status measured with an occupational hearing-in-noise screening test, Listening Effort (LE), and Need For Recovery (NFR) in employees of a manufacturing company, and to examine whether these associations depend on the perceived noise level at the workplace.

METHODS

Employees of coatings and paints manufacturing company were included. Their hearing status was assessed with an occupational hearing-in-noise screening test. An online survey was used to assess their LE, NFR, and the perceived noise level at the workplace. Responses from 143 employees were analyzed (mean age = 53 years) using hierarchical multiple regression analysis with the outcomes LE and NFR.

RESULTS

Regression analysis-with adjustments for gender, age, educational level, health status, pace/amount of work, job variety, and work pleasure-revealed that hearing status was significantly associated with LE, but the interaction between hearing status and the perceived noise level was not. Hearing status nor the interaction between hearing status and the perceived noise level was significantly associated with NFR.

CONCLUSION

The results confirm that poorer hearing is associated with higher LE, but not with higher NFR. These associations were unrelated to the perceived noise level at the workplace. Therefore, the value of occupational hearing screening appears to be early identification of hearing loss in employees, but not identification of work functioning difficulties.

Music as a unique source of noise-induced hearing loss

Music is among the most important artistic, cultural, and entertainment modalities in any society. With the proliferation of music genres and the technological advances that allow people to consume music in any location and at any time, music over-exposure has become a significant public health issue. Music-induced hearing loss has a great deal in common with noise-induced hearing loss. However, there are important differences that make music a unique insult to the auditory system and a unique threat to public health. Its unique properties also make it a potentially valuable asset in sound conditioning paradigms. This review discusses hearing loss from noise and music, comparing and contrasting the two. Recent research on music-induced hearing loss is reviewed, followed by discussion of the differences in music-induced hearing loss between performers and consumers. The review concludes with a discussion of the potential of music as a sound conditioning stimulus to protect against acquired hearing loss.

Noise Exposure in Palestinian Workers Without a Diagnosis of Hearing Impairment: Relations to Speech-Perception-in-Noise Difficulties, Tinnitus, and Hyperacusis

PURPOSE

Many workers in developing countries are exposed to unsafe occupational noise due to inadequate health and safety practices. We tested the hypotheses that occupational noise exposure and aging affect speech-perception-in-noise (SPiN) thresholds, self-reported hearing ability, tinnitus presence, and hyperacusis severity among Palestinian workers.

METHOD

Palestinian workers (N = 251, aged 18-70 years) without diagnosed hearing or memory impairments completed online instruments including a noise exposure questionnaire; forward and backward digit span tests; hyperacusis questionnaire; the short-form Speech, Spatial and Qualities of Hearing Scale (SSQ12); the Tinnitus Handicap Inventory; and a digits-in-noise (DIN) test. Hypotheses were tested via multiple linear and logistic regression models, including age and occupational noise exposure as predictors, and with sex, recreational noise exposure, cognitive ability, and academic attainment as covariates. Familywise error rate was controlled across all 16 comparisons using the Bonferroni-Holm method. Exploratory analyses evaluated effects on tinnitus handicap. A comprehensive study protocol was preregistered.

RESULTS

Nonsignificant trends of poorer SPiN performance, poorer self-reported hearing ability, greater prevalence of tinnitus, greater tinnitus handicap, and greater severity of hyperacusis as a function of higher occupational noise exposure were observed. Greater hyperacusis severity was significantly predicted by higher occupational noise exposure. Aging was significantly associated with higher DIN thresholds and lower SSQ12 scores, but not with tinnitus presence, tinnitus handicap, or hyperacusis severity.

CONCLUSIONS

Workers in Palestine may suffer from auditory effects of occupational noise and aging despite no formal diagnosis. These findings highlight the importance of occupational noise monitoring and hearing-related health and safety practices in developing countries.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.22056701.

The experience of noise in communication-intense workplaces: A qualitative study

OBJECTIVE

The aim of the study was to explore and describe how workers in communication-intense workplaces in health care and preschools experience the sound environment. The dependence on vocal communication and social interaction poses a challenge using hearing protection in these working environments.

METHOD

A qualitative method was used, more specifically inductive thematic analysis was used, as this approach was deemed suitable to explore the staff's experiences of the sound environment. Data were collected by interviews and to increase trustworthiness, several researchers were involved in the data collection and analysis.

STUDY SAMPLE

Workers from two preschools, one obstetrics ward and one intensive care unit took part in the study.

RESULTS

Four main themes emerged from the thematic analysis: A challenging and harmful sound environment; Health-related effects of a challenging and harmful sound environment; A good sound environment is not prioritised; and Resourceful and motivated staff.

CONCLUSIONS

Workers in communication-intense workplaces in preschools, obstetrics care and intensive care reported that there was a relationship between the sound environment and negative health effects. In addition, the results suggests that the high motivation for change among staff should be utilised together with an increased prioritization from the management to reach innovative context specific improvements to the sound environment in communication intense working environments.

Effect of minocycline and its nano-formulation on central auditory system in blast-induced hearing loss rat model

Blast injuries are common among the military service members and veterans. One of the devastating effects of blast wave induced TBI is either temporary or permanent hearing loss. Treating hearing loss using minocycline is restricted by optimal drug concentration, route of administration, and its half-life. Therefore, therapeutic approach using novel therapeutic delivery method is in great need. Among the different delivery methods, nanotechnology-based drug delivery is desirable, which can achieve longer systemic circulation, pass through some biological barriers and specifically targets desired sites. The current study aimed to examine therapeutic effect of minocycline and its nanoparticle formulation in moderate blast induced hearing loss rat model through central auditory system. The I.v. administered nanoparticle at reduced dose and frequency than regularly administered toxic dose. After moderate blast exposure, rats had hearing impairment as determined by ABR at 7- and 30-days post exposure. In chronic condition, free minocycline also showed the significant reduction in ABR threshold. In central auditory system, it is found in this study that minocycline nanoparticles ameliorate excitation in inferior colliculus; and astrocytes and microglia activation after the blast exposure is reduced by minocycline nanoparticles administration. The study demonstrated that in moderate blast induced hearing loss, minocycline and its nanoparticle formulation exhibited the optimal therapeutic effect on the recovery of the ABR impairment and a protective effect through central auditory system. In conclusion, targeted and non-targeted nanoparticle formulation have therapeutic effect on blast induced hearing loss.

Sex-Linked Biology and Gender-Related Research Is Essential to Advancing Hearing Health

There is robust evidence that sex (biological) and gender (behavioral/social) differences influence hearing loss risk and outcomes. These differences are noted for animals and humans-in the occurrence of hearing loss, hearing loss progression, and response to interventions. Nevertheless, many studies have not reported or disaggregated data by sex or gender. This article describes the influence of sex-linked biology (specifically sex-linked hormones) and gender on hearing and hearing interventions, including the role of sex-linked biology and gender in modifying the association between risk factors and hearing loss, and the effects of hearing loss on quality of life and functioning. Most prevalence studies indicate that hearing loss begins earlier and is more common and severe among men than women. Intrinsic sex-linked biological differences in the auditory system may account, in part, for the predominance of hearing loss in males. Sex- and gender-related differences in the effects of noise exposure or cardiovascular disease on the auditory system may help explain some of these differences in the prevalence of hearing loss. Further still, differences in hearing aid use and uptake, and the effects of hearing loss on health may also vary by sex and gender. Recognizing that sex-linked biology and gender are key determinants of hearing health, the present review concludes by emphasizing the importance of a well-developed research platform that proactively measures and assesses sex- and gender-related differences in hearing, including in understudied populations. Such research focus is necessary to advance the field of hearing science and benefit all members of society.

A genome-wide association study of tinnitus reveals shared genetic links to neuropsychiatric disorders

Tinnitus, a phantom perception of sound in the absence of any external sound source, is a prevalent health condition often accompanied by psychiatric comorbidities. Recent genome-wide association studies (GWAS) highlighted a polygenic nature of tinnitus susceptibility. A shared genetic component between tinnitus and psychiatric conditions remains elusive. Here we present a GWAS using the UK Biobank to investigate the genetic processes linked to tinnitus and tinnitus-related distress, followed by gene-set enrichment analyses. The UK Biobank sample comprised 132,438 individuals with tinnitus and genotype data. Among the study sample, 38,525 individuals reported tinnitus, and 26,889 participants mentioned they experienced tinnitus-related distress in daily living. The genome-wide association analyses were conducted on tinnitus and tinnitus-related distress. We conducted enrichment analyses using FUMA to further understand the genetic processes linked to tinnitus and tinnitus-related distress. A genome-wide significant locus (lead SNP: rs71595470) for tinnitus was obtained in the vicinity of GPM6A. Nineteen independent loci reached suggestive association with tinnitus. Fifteen independent loci reached suggestive association with tinnitus-related distress. The enrichment analysis revealed a shared genetic component between tinnitus and psychiatric traits, such as bipolar disorder, feeling worried, cognitive ability, fast beta electroencephalogram, and sensation seeking. Metabolic, cardiovascular, hematological, and pharmacological gene sets revealed a significant association with tinnitus. Anxiety and stress-related gene sets revealed a significant association with tinnitus-related distress. The GWAS signals for tinnitus were enriched in the hippocampus and cortex, and for tinnitus-related distress were enriched in the brain and spinal cord. This study provides novel insights into genetic processes associated with tinnitus and tinnitus-related distress and demonstrates a shared genetic component underlying tinnitus and psychiatric conditions. Further collaborative attempts are necessary to identify genetic components underlying the phenotypic heterogeneity in tinnitus and provide biological insight into the etiology.

Development of an audiological assessment and diagnostic model for high occupational noise exposure

PURPOSE

To explore the diagnostic auditory indicators of high noise exposure and combine them into a diagnostic model of high noise exposure and possible development of hidden hearing loss (HHL).

METHODS

We recruited 101 young adult subjects and divided them according to noise exposure history into high-risk and low-risk groups. All subjects completed demographic characteristic collection (including age, noise exposure, self-reported hearing status, and headset use) and related hearing examination.

RESULTS

The 8 kHz (P = 0.039) and 10 kHz (P = 0.005) distortion product otoacoustic emission amplitudes (DPOAE) (DPs) in the high-risk group were lower than those in the low-risk group. The amplitudes of the summating potential (SP) (P = 0.017) and action potential (AP) (P = 0.012) of the electrocochleography (ECochG) in the high-risk group were smaller than those in the low-risk group. The auditory brainstem response (ABR) wave III amplitude in the high-risk group was higher than that in the low-risk group. When SNR = - 7.5 dB (P = 0.030) and - 5 dB (P = 0.000), the high-risk group had a lower speech discrimination score than that of the low-risk group. The 10 kHz DPOAE DP, ABR wave III amplitude and speech discrimination score under noise with SNR = - 5 dB were combined to construct a combination diagnostic indicator. The area under the ROC curve was 0.804 (95% CI 0.713-0.876), the sensitivity was 80.39%, and the specificity was 68.00%.

CONCLUSIONS

We expect that high noise exposure can be detected early with this combined diagnostic indicator to prevent HHL or sensorineural hearing loss (SNHL).

TRIAL REGISTRATION NUMBER/DATE OF REGISTRATION

ChiCTR2200057989, 2022/3/25.

Encouraging Hearing Loss Prevention in Music Listeners Using Personalized Technology: Questionnaire Study

Background

Noise-induced hearing loss (NIHL) affects millions of people despite being almost completely preventable. For recreational music listening through personal listening equipment (such as earbuds), it seems that listeners do not yet have a way to accurately assess their risk of developing hearing loss and prevent it accordingly.

Objective

The aim of this study is to analyze the perceived utility of a hypothetical device that encourages NIHL prevention based on listeners’ exposure to noise and to determine the most effective methods of such encouragement. Here, we describe 3 different potential NIHL risk notification method types, as follows: auditory, external visual, and visual.

Methods

An open, web-based survey was created on Google Forms, and the link was posted to Amazon’s Mechanical Turk as well as music-related Reddit communities. The survey was designed to gauge each respondent’s self-assessed NIHL awareness, willingness to lower their audio if reminded, and NIHL risk notification type preference. The likelihood of a specific notification type to encourage NIHL prevention among its users was based on the average of each user’s responses to 2 survey questions. Data collection started on July 13, 2020, and ended on July 17, 2020.

Results

Of the 116 respondents, 92 (79.3%) reported having prior awareness about NIHL; however, 60 (51.7%) described doing nothing to prevent it despite 96 (82.8%) feeling a moderate, high, or extreme risk of developing NIHL. Of those who already prevented NIHL, 96% (53.5/56) described using estimates to guide their prevention instead of using data. A Kruskal-Wallis test corrected for ties showed that despite the visual NIHL risk notification type being selected by the highest number of participants (84/116, 72.4%), the auditory type had a significantly higher (H1=6.848; P=.03) average percentage likelihood of encouraging NIHL prevention (62%, SD 24%) among the 40 respondents who chose it, with a median likelihood of 56% (95% CI 50%-75%). The visual type’s average likelihood was 50% (SD 28.1%), with a median of 50% (95% CI 37.5%-56.3%). Regardless of the NIHL risk notification type, 69% (80/116) of respondents were not opposed to using NIHL risk notifications and lowering their audio volume accordingly.

Conclusions

The hypothetical device detailed here was thought to be useful because most respondents (82.8%, 96/116) felt an extreme to moderate risk of developing NIHL and such a device could provide accurate data to those who currently use estimates to prevent NIHL, and most respondents were willing to act on NIHL risk notifications. The most effective NIHL risk notification type seemed to be the auditory type, but many aspects of this study need further research to determine which implementation method should reach the public.

Hearing impairment and tinnitus among older construction workers employed at DOE facilities

BACKGROUND

Few studies have defined the risk of hearing impairment and tinnitus after retirement. This report measures hearing impairment and tinnitus prevalence among older construction trades workers.

METHODS

The study cohort included 21,340 participants in a national medical screening program (www.btmed.org). Audiometric hearing impairment was classified according to the Global Burden of Disease Study. Tinnitus was determined by self-report. An internal subcohort of nonconstruction trades workers served as a reference group. Stratified analyses and multivariate analyses were used to measure the prevalence of hearing impairment and tinnitus by age, sex, and job category.

RESULTS

Prevalence of any hearing impairment was 55.2% (males, 57.7%; females, 26.8%) and increased rapidly with age. Construction trades workers were 40% more likely to have hearing impairment than the reference group. The overall prevalence of tinnitus was 46.52% and followed patterns similar to hearing impairment. Workers with hearing impairment were more likely to also have tinnitus, but tinnitus was frequently reported in the absence of measured hearing impairment.

CONCLUSIONS

Hearing impairment and tinnitus prevalence were much higher in this study than in previous research. A significant reason for the difference is that BTMed follows participants after they have retired. To draw conclusions about the risk for work-related chronic diseases and disorders it is important to monitor workers through their lifetimes. Also, tinnitus by itself should be given greater significance. These findings reinforce the need to promote noise reduction and hearing conservation in construction.

The Variability in Potential Biomarkers for Cochlear Synaptopathy After Recreational Noise Exposure

PURPOSE

Speech-in-noise tests and suprathreshold auditory evoked potentials are promising biomarkers to diagnose cochlear synaptopathy (CS) in humans. This study investigated whether these biomarkers changed after recreational noise exposure.

METHOD

The baseline auditory status of 19 normal-hearing young adults was analyzed using questionnaires, pure-tone audiometry, speech audiometry, and auditory evoked potentials. Nineteen subjects attended a music festival and completed the same tests again at Day 1, Day 3, and Day 5 after the music festival.

RESULTS

No significant relations were found between lifetime noise-exposure history and the hearing tests. Changes in biomarkers from the first session to the follow-up sessions were nonsignificant, except for speech audiometry, which showed a significant learning effect (performance improvement).

CONCLUSIONS

Despite the individual variability in prefestival biomarkers, we did not observe changes related to the noise-exposure dose caused by the attended event. This can indicate the absence of noise exposure-driven CS in the study cohort, or reflect that biomarkers were not sensitive enough to detect mild CS. Future research should include a more diverse study cohort, dosimetry, and results from test-retest reliability studies to provide more insight into the relationship between recreational noise exposure and CS. Supplemental Material https://doi.org/10.23641/asha.16821283.

Estimated Prevalence of Functional Hearing Difficulties in Blast-Exposed Service Members With Normal to Near-Normal-Hearing Thresholds

OBJECTIVES

Over the past decade, U.S. Department of Defense and Veterans Affairs audiologists have reported large numbers of relatively young adult patients who have normal to near-normal audiometric thresholds but who report difficulty understanding speech in noisy environments. Many of these service members also reported having experienced exposure to explosive blasts as part of their military service. Recent studies suggest that some blast-exposed patients with normal to near-normal-hearing thresholds not only have an awareness of increased hearing difficulties, but also poor performance on various auditory tasks (sound source localization, speech recognition in noise, binaural integration, gap detection in noise, etc.). The purpose of this study was to determine the prevalence of functional hearing and communication deficits (FHCD) among healthy Active-Duty service men and women with normal to near-normal audiometric thresholds.

DESIGN

To estimate the prevalence of such FHCD in the overall military population, performance of roughly 3400 Active-Duty service members with hearing thresholds mostly within the normal range were measured on 4 hearing tests and a brief 6-question survey to assess FHCD. Subjects were subdivided into 6 groups depending on the severity of the blast exposure (3 levels: none, far away, or close enough to feel heat or pressure) and hearing thresholds (2 levels: audiometric thresholds of 20 dB HL or better, slight elevation in 1 or more thresholds between 500 and 4000 Hz in either ear).

RESULTS

While the probability of having hearing difficulty was low (≈4.2%) for the overall population tested, that probability increased by 2 to 3 times if the service member was blast-exposed from a close distance or had slightly elevated hearing thresholds (>20 dB HL). Service members having both blast exposure and mildly elevated hearing thresholds exhibited up to 4 times higher risk for performing abnormally on auditory tasks and more than 5 times higher risk for reporting abnormally low ratings on the subjective questionnaire, compared with service members with no history of blast exposure and audiometric thresholds ≤20 dB HL. Blast-exposed listeners were roughly 2.5 times more likely to experience subjective or objective hearing deficits than those with no-blast history.

CONCLUSIONS

These elevated rates of abnormal performance suggest that roughly 33.6% of Active-Duty service members (or approximately 423,000) with normal to near-normal-hearing thresholds (i.e., H1 profile) are at some risk for FHCD, and about 5.7% (approximately 72,000) are at high risk, but are currently untested and undetected within the current fitness-for-duty standards. Service members identified as "at risk" for FHCD according to the metrics used in the present study, in spite of their excellent hearing thresholds, require further testing to determine whether they have sustained damage to peripheral and early-stage auditory processing (bottom-up processing), damage to cognitive processes for speech (top-down processing), or both. Understanding the extent of damage due to noise and blast exposures and the balance between bottom-up processing deficits and top-down deficits will likely lead to better therapeutic strategies.

Effects of hearing protection field attenuation estimation systems and associated training on the level of noise attenuation in workers exposed to noise

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

The first objective of this review is to assess the effects of field attenuation estimation systems and associated training on noise exposure at the ear and adherence to hearing protection use. A secondary objective is to assess whether the effects of field attenuation estimation systems differ according to age, gender, earplug type, and HPD use experience. 

[Self-reported hearing impairment and occupational exposure to hazardous noise and ototoxic agents: a population-based study]

This study's objective was to estimate the association between self-reported hearing impairment and occupational exposure to hazardous noise and ototoxic agents in Brazilian workers. This was a cross-sectional study with data from the Brazilian National Health Survey (PNS-2013). The dependent variable was self-reported hearing impairment, and three principal exposures were analyzed: noise, industrial dust, and chemical substances. Logistic regression was performed, estimating crude and adjusted odds ratios (OR) with 95% confidence intervals (95%CI). The principal exposure variables were adjusted for each other and by covariables sex, age, workplace, time on the job, and hypertension. 36,442 workers participated in the study. Higher prevalence of hearing impairment was seen in workers exposed to industrial dust (9.9%) (p < 0.001). The older the worker and the longer the time on the job, the higher the prevalence of hearing impairment (p < 0.001). In the adjusted analysis, workers exposed to noise showed 1.65 higher odds of reporting difficulty hearing, when compared to unexposed individuals (p < 0.001). The same was true for workers exposed to industrial dust (OR = 1.36) (p = 0.012). No association was observed between the outcome and exposure to chemical substances (p = 0.120). There was an association between hearing impairment and occupational exposure to noise and industrial dust in Brazilian workers. This emphasizes the importance of strengthening public policies for hearing health and the development of measures for prevention and auditory monitoring in the workplace.

Association Analysis of Candidate Gene Polymorphisms and Tinnitus in Young Musicians

INTRODUCTION

Subjective tinnitus, a perception of phantom sound, is a common otological condition that affects almost 15% of the general population. It is known that noise-induced hearing loss (NIHL) and tinnitus exhibit a high level of comorbidity in individuals exposed to intense noise and music. However, the influence of genetic variants associated with NIHL on tinnitus remains elusive. We hypothesized that young musicians carrying genetic variants associated with NIHL would exhibit a higher prevalence of tinnitus than their counterparts.

METHODS

To test this hypothesis, we analyzed the database by Bhatt et al. (2020) (originally developed by Phillips et al., 2015) that investigated the genetic links to NIHL in young college-aged musicians. The present study identified 186 participants (average age = 20.3 yrs, range = 18-25 yrs) with normal tympanometry and otoscopic findings and with no missing data. We included 19 single nucleotide polymorphisms in 13 cochlear genes that were previously associated with NIHL. The candidate genes include: KCNE1, KCNQ1, CDH23, GJB2, GJB4, KCNJ10, CAT, HSP70, PCDH70, MYH14, GRM7, PON2, and ESRRB.

RESULTS

We find that individuals with at least one minor allele of rs163171 (C > T) in KCNQ1 exhibit significantly higher odds of reporting tinnitus compared to individuals carrying the major allele of rs163171. KCNE1 rs2070358 revealed a suggestive association (p = 0.049) with tinnitus, but the FDR corrected p-value did not achieve statistical significance (p < 0.05). A history of ear infection and sound level tolerance showed a statistically significant association with tinnitus. Music exposure showed a suggestive association trend with tinnitus. Biological sex revealed a statistically significant association with distortion product otoacoustic emissions SNR measures.

CONCLUSIONS

We concluded that KCNQ1/KCNE1 voltage-gated potassium ion channel plays a critical role in the pathogenesis of NIHL and tinnitus. Further research is required to construct clinical tools for identifying genetically predisposed individuals well before they acquire NIHL and tinnitus.

Modifiable lifestyle-related risk factors for tinnitus in the general population: An overview of smoking, alcohol, body mass index and caffeine intake

INTRODUCTION

Tinnitus is a symptom and not a disease in its own right. A number of medical conditions are known to increase the risk of developing tinnitus. Most known risk factors are otological or neurological, but general health and lifestyle can also precipitate the condition. Understanding these modifiable risk factors can help to identify vulnerable groups and can inform preventive actions to reduce likelihood of developing tinnitus. Smoking, alcohol consumption, body mass index (BMI) and caffeine intake are all lifestyle risk factors hypothesized to be related to tinnitus. Nonetheless, research findings in support of those relationships are somewhat mixed.

METHODS

A systematic review was conducted to identify all relevant studies on the specific risk factors. Findings were summarized using a narrative synthesis and meta-analysis, where possible.

RESULTS

Overall 384 studies were included, mostly using cross-sectional designs. Findings indicated significantly increased risk of tinnitus among current (based on 26 studies) and ever smokers (based on 16 studies) and among obese people (based on seven studies), but no effect of alcohol consumption (based on 11 studies). With respect to caffeine intake or coffee drinking, only three studies examined this risk factor and so we were unable to draw conclusions.

CONCLUSION

Our results contribute to quantifying the relationship between tinnitus and specific lifestyle-related risk factors, and we highlight some of the gaps and inconsistencies across published studies.

Noise Evaluation of Arthroplasty Theaters: Results From the NEAT Study

AIMS

The aim of this study was to define the levels of noise exposure for the surgeon, assistant, scrub nurse, and anesthetist during total hip and knee arthroplasty surgery. In addition, we sought to determine whether the noise exposure during these procedures reaches or exceeds the action values set out by the U.K. Noise at Work Regulations (2005).

MATERIALS AND METHODS

Individual noise exposure during arthroplasty hip and knee surgery was recorded using a personal noise Dosemeter System model 22 (DM22) (Pulsar instruments, Filey, U.K.). Recordings were taken in real-time during five separate theater sessions. Each theater session included two arthroplasty procedures and lasted approximately 4 hrs. Personal noise exposure was expressed in terms of peak sound pressure and an average noise exposure over an 8-hour time-period to reflect the noise experienced by the ear over a working day.

RESULTS

In all three sessions involving total hip replacement surgery, the peak sound pressure, for the operating surgeon exceeded the exposure action values set out by the U.K. Noise at Work Regulations. Theater sessions involving total knee replacement surgery did not exceed any exposure action values for LCPeak or LEPd.

CONCLUSION

Arthroplasty surgery is a working environment with significant noise exposure. We recommend any surgeon or theater member who is concerned about the noise generated in their theater to have noise levels formally assessed using appropriately positioned recording devices.

Occupational Noise: Auditory and Non-Auditory Consequences

Occupational noise exposure accounts for approximately 16% of all disabling hearing losses, but the true value and societal costs may be grossly underestimated because current regulations only identify hearing impairments in the workplace if exposures result in audiometric threshold shifts within a limited frequency region. Research over the past several decades indicates that occupational noise exposures can cause other serious auditory deficits such as tinnitus, hyperacusis, extended high-frequency hearing loss, and poor speech perception in noise. Beyond the audiogram, there is growing awareness that hearing loss is a significant risk factor for other debilitating and potentially life-threatening disorders such as cardiovascular disease and dementia. This review discusses some of the shortcomings and limitations of current noise regulations in the United States and Europe.

Hearing Difficulties and Tinnitus in Construction, Agricultural, Music, and Finance Industries: Contributions of Demographic, Health, and Lifestyle Factors

High levels of occupational noise exposure increase the risk of hearing difficulties and tinnitus. However, differences in demographic, health, and lifestyle factors could also contribute to high levels of hearing difficulties and tinnitus in some industries. Data from a subsample (n = 22,936) of the U.K. Biobank were analyzed to determine to what extent differences in levels of hearing difficulties and tinnitus in high-risk industries (construction, agricultural, and music) compared with low-risk industries (finance) could be attributable to demographic, health, and lifestyle factors, rather than occupational noise exposure. Hearing difficulties were identified using a digits-in-noise speech recognition test. Tinnitus was identified based on self-report. Logistic regression analyses showed that occupational noise exposure partially accounted for higher levels of hearing difficulties in the agricultural industry compared with finance, and occupational noise exposure, older age, low socioeconomic status, and non-White ethnic background partially accounted for higher levels of hearing difficulties in the construction industry. However, the factors assessed in the model did not fully account for the increased likelihood of hearing difficulties in high-risk industries, suggesting that there are additional unknown factors which impact on hearing or that there was insufficient measurement of factors included in the model. The levels of tinnitus were greatest for music and construction industries compared with finance, and these differences were accounted for by occupational and music noise exposure, as well as older age. These findings emphasize the need to promote hearing conservation in occupational and music settings, with a particular focus on high-risk demographic subgroups.

Drug development for noise-induced hearing loss

INTRODUCTION

Excessive exposure to noise is a common occurrence that contributes to approximately 50% of the non-genetic hearing loss cases. Researchers need to develop standardized preclinical models and identify molecular targets to effectively develop prevention and curative therapies.

AREAS COVERED

In this review, the authors discuss the many facets of human noise-induced pathology, and the primary experimental models for studying the basic mechanisms of noise-induced damage, making connections and inferences among basic science studies, preclinical proofs of concept and clinical trials.

EXPERT OPINION

Whilst experimental research in animal models has helped to unravel the mechanisms of noise-induced hearing loss, there are often methodological variations and conflicting results between animal and human studies which make it difficult to integrate data and translate basic outcomes to clinical practice. Standardization of exposure paradigms and application of -omic technologies will contribute to improving the effectiveness of transferring newly gained knowledge to clinical practice.

Acupuncture for tinnitus: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the efficacy/effectiveness of acupuncture for the treatment of tinnitus.

METHODS

Four English and four Chinese databases were searched for randomized controlled trials (RCTs) of acupuncture for tinnitus published before 30 September 2018. RCTs applying acupuncture alone compared with conventional treatments, sham acupuncture, or no treatment, as well as acupuncture plus conventional treatments compared with conventional treatments alone, were included. The primary outcome was the visual analogue scale (VAS). Secondary outcomes included tinnitus handicap inventory (THI) and tinnitus severity index (TSI) scores. Meta-analysis was conducted using RevMan V5.3 software. The protocol was registered in the PROSPERO database (ref. CRD42018108692).

RESULTS

Eight studies involving 504 participants were included. Meta-analysis showed no significant differences in the VAS score (mean difference (MD) = -1.81, 95% confidence interval (CI) = -3.69 to 0.07; p = 0.06) between the acupuncture and control groups. However, favorable effects of acupuncture on changes in THI score (MD = -10.11, 95% CI = -12.74 to -7.48; p < 0.001) and TSI score (MD = -8.36, 95% CI = -8.87 to -7.86; p < 0.001) were found.

CONCLUSION

Acupuncture had no significant effect on the primary outcome of VAS score compared with control treatment; however, positive effects on secondary outcomes (THI and TSI score) were observed in acupuncture versus control groups. Due to the low quality and small sample size of the included trials, the level of evidence was insufficient to draw any definitive conclusions. Further rigorous and high-quality studies with larger sample sizes should be conducted to confirm the efficacy/effectiveness of acupuncture for tinnitus.

Prevalence of hearing loss among noise-exposed workers within the services sector, 2006-2015

OBJECTIVE

The purpose of this study is to estimate the prevalence of hearing loss among noise-exposed U.S. workers within the Services sector.

METHODS

Audiograms for 1.9 million workers (158,436 within Services) from 2006 to 2015 were examined. Prevalence and adjusted risk for hearing loss as compared with a reference industry were estimated for the Services sector/sub-sectors, and all industries combined.

RESULTS

The prevalence of hearing loss within Services was 17 compared to 16% for all industries combined. However, many sub-sectors greatly exceeded the overall prevalence (10-33% higher) and/or had adjusted risks significantly higher than the reference industry. Workers in Administration of Urban Planning and Community and Rural Development had the highest prevalence (50%), and workers in Solid Waste Combustors and Incinerators had more than double the risk, the highest of any sub-sector. Some sub-sectors traditionally viewed as 'low-risk' also had high prevalences and risks.

CONCLUSIONS

Large numbers of workers within Services have an elevated risk of hearing loss and need immediate hearing conservation efforts. Additional research and surveillance are needed for sub-sectors for which there is low awareness of hearing hazards or a lack of hearing data.

Factors influencing the need for recovery in employees with hearing loss: a cross-sectional study of health administrative data

Objective

Need for recovery is a predictor of work stress and health problems, but its underlying factors are not yet well understood. We aimed to identify hearing-related, work-related, and personal factors influencing need for recovery in hearing-impaired employees.

Methods

We retrospectively identified hearing-impaired employees (N = 294) that were referred to the Amsterdam University Medical Center between 2004 and 2019. Routinely obtained healthcare data were used, including a survey and hearing assessments. A directed acyclic graph was constructed, revealing the hypothesized structure of factors influencing need for recovery as well as the minimal set of factors needed for multiple regression analysis.

Results

Four variables were included in the regression analysis. In total, 46.1% of the variance in need for recovery was explained by the factors feeling that something should change at work (B = 19.01, p < 0.001), self-perceived listening effort (B = 1.84, p < 0.001), personal adaptations scale score (B = − 0.34, p < .001), and having a moderate/poor general health condition (B = 20.06, p < 0.001). Although degree of hearing loss was associated with self-perceived listening effort, the direct association between degree of hearing loss and need for recovery was not significant.

Conclusions

The results suggest that the way employees perceive their hearing loss and how they cope with it directly influence need for recovery, rather than their measured degree of hearing loss. Additionally, general health condition was found to be an independent factor for need for recovery. The results should be confirmed by future, longitudinal research.

Epidemiology of Clinically Significant Tinnitus: A 10-Year Trend From Nationwide Health Claims Data in South Korea

OBJECTIVES

Prevalence of tinnitus has been reported to vary according to the target population and definition of tinnitus. To improve the understanding of tinnitus, authors used the nation-wide health claim data to study the tinnitus in the entire population of South Korea.

STUDY DESIGN

Retrospective big data review.

SETTING

Analysis of big data from the National Health Information Database.

PATIENTS

Patients diagnosed with tinnitus according to International Classification of Diseases code 10th edition (ICD-10) and requested to receive National Health Insurance claim at least once from January 2006 to December 2015.

INTERVENTION

None.

MAIN OUTCOME MEASURE

Epidemiologic data, association of tinnitus with the otologic and systemic diseases.

RESULTS

The number of patients who received medical care because of tinnitus was 1.44% (0.78 million per 51 million) in 2015. There was a higher prevalence of tinnitus in women, and the overall prevalence increased with increasing age of patients and peaked at patients in their 70s (4.43%). The prevalence of tinnitus among patients aged 10 to 30 years, showed a tendency to increase during study period. In the regional analysis, highest prevalence was observed in Gwangju (2.02%). In comparison with the control group, the patients with tinnitus showed a higher frequency in otologic and systemic disease. Especially, noise induced hearing loss (adjusted odds ratio [AOR] = 82.1, 95% confidence interval [95% CI] = 74.8-90.2) and sudden sensorineueal hearing loss (AOR = 49.7, 95% CI = 48.4-51.0) showed high frequency in tinnitus patient group.

CONCLUSIONS

The prevalence and incidence of tinnitus in this study for entire nation were lower than previously reported studies. These results have limitation because the study only covered patient using the medical service for tinnitus and missed tinnitus sufferers not seeking medical service. However, this study is meaningful in that it was targeting entire nation, reflected the characteristics of clinically significant tinnitus patient enough to visit medical service.

Occupational noise exposure: A review of its effects, epidemiology, and impact with recommendations for reducing its burden

Exposure to hazardous noise is one of the most common occupational risks, both in the U.S. and worldwide. Repeated overexposure to noise at or above 85 dBA can cause permanent hearing loss, tinnitus, and difficulty understanding speech in noise. It is also associated with cardiovascular disease, depression, balance problems, and lower income. About 22 million U.S. workers are currently exposed to hazardous occupational noise. Approximately 33% of working-age adults with a history of occupational noise exposure have audiometric evidence of noise-induced hearing damage, and 16% of noise-exposed workers have material hearing impairment. While the Mining, Construction, and Manufacturing sectors typically have the highest prevalence of noise exposure and hearing loss, there are noise-exposed workers in every sector and every sector has workers with hearing loss. Noise-induced hearing loss is preventable. Increased understanding of the biological processes underlying noise damage may lead to protective pharmacologic or genetic therapies. For now, an integrated public health approach that (1) emphasizes noise control over reliance on hearing protection, (2) illustrates the full impact of hearing loss on quality of life, and (3) challenges the cultural acceptance of loud noise can substantially reduce the impact of noise on worker health.

Prevalence of hearing loss among noise-exposed workers within the Mining and Oil and Gas Extraction sectors, 2006-2015

BACKGROUND

The purpose of this study was to estimate the prevalence of hearing loss (HL) among noise-exposed US workers within the Mining, and Oil and Gas Extraction (OGE) sectors.

METHODS

Audiograms of 1.9 million workers across all industries (including 9389 in Mining and 1076 in OGE) from 2006 to 2015 were examined. Prevalence and adjusted risk as compared to a reference industry (Couriers and Messengers) were estimated for all industries combined and the Mining and OGE sectors and subsectors.

RESULTS

The prevalences of HL in Mining and OGE were 24% and 14%, respectively, compared with 16% for all industries combined. Many Mining and one OGE subsector exceeded these prevalences and most had an adjusted risk (prevalence ratio) significantly greater than the reference industry. Some subsectors, particularly in OGE, could not be examined due to low sample size. The prevalences in Construction Sand and Gravel Mining and Natural Gas Liquid Extraction were 36% and 28%, respectively. Workers within Support Activities for Coal Mining had double the risk of HL than workers in the reference industry.

CONCLUSIONS

The many subsectors identified with high prevalences and/or worker risks for HL well above risks in the reference industry need critical attention to conserve worker hearing and maintain worker quality of life. Administrative and engineering controls can reduce worker hazardous noise exposures. Noise and ototoxic chemical exposure information is needed for many subsectors, as is audiometric testing results for OGE workers. Additional research is also needed to further characterize exposures and improve hearing conservation measures.

Recent Advancements in Gene and Stem Cell-Based Treatment Modalities: Potential Implications in Noise-Induced Hearing Loss

Noise-induced hearing loss (NIHL) poses a significant burden on not only the economics of health care but also the quality of life of an individual, as we approach an unprecedented age of longevity. In this article, we will delineate the current landscape of management of NIHL. We discuss the most recent results from in vitro and in vivo studies that determine the effectiveness of established pharmacotherapy such as corticosteroid and potential emerging therapies like N-acetyl cysteine and neurotrophins (NTs), as well as highlight ongoing clinical trials for these therapeutic agents. We present an overview of how the recent advancements in the field of gene-based and stem cell-based therapies can help in developing effective therapeutic strategies for NIHL. Gene-based therapies have shown exciting results demonstrating cochlear cellular regeneration using Atoh1, NRF2 as well as NT gene therapy employing viral vectors. In addition, we will discuss the recent advancements in genome-editing technologies, such as CRISPR/Cas9, and its potential role in NIHL therapy. We will further discuss the current state of stem cell therapy as it pertains to treating neurodegenerative conditions including NIHL. Embryonic stem cells, adult-derived stem cells, and induced pluripotent stem cells all represent an enticing reservoir of replacing damaged cells as a result of NIHL. Finally, we will discuss the barriers that need to be overcome to translate these promising treatment modalities to the clinical practice in pursuit of improving quality of life of patients having NIHL. Anat Rec, 303:516-526, 2020. © 2019 American Association for Anatomy.

Auditory disorders and future therapies with delivery systems

Auditory function takes a major part in human life. While sensorineural hearing loss is related with many factors including genetic disorders, age and noise, the clear causes are not well understood. Even more, the currently available treatments with drugs cause side effects, which thus are considered suboptimal. Here, we communicate the delivery systems with biomaterials that can be possible therapeutic options to restore hearing and vestibular functions. We introduce briefly the various pathological factors related with hearing loss and the limitation of current therapies, detail the recent studies on delivery systems including nanoparticles and hydrogels and discuss future clinical availability.

Noise Exposure and Self-reported Hearing Impairment among Gas-fired Electric Plant Workers in Tanzania

Background:

Gas-fired electric plants are equipped with heavy machines, which produce hazards including noise pollution. Exposure to high level of noise of above 85dB(A) is known to bring about Noise-Induced Hearing Loss (NIHL). This study aimed to assess noise exposure level and reported prevalence of noise-induced hearing loss among workers in gas-fired electric plants.

Material and Methods:

This cross-sectional study was conducted in three gas-fired electric plants in Dar es Salaam (Plant A, Plant B and Plant C) from July to August 2017. A noise logging dosimeter was used to measure personal noise exposure level. A questionnaire was used to collect information on managerial factors, individual factors, socio-demographic factors and history of the participants. A short screening validated questionnaire was used to obtain noise exposure score. Frequency distribution, Chi-square test and Regression analyses were done using SPSS version 20.

Results:

One hundred and six participants were involved in the study. Noise exposure level among gas-fired electric plant workers was above 85dB(A), n = 37. The equivalent sound level (LAeq) measured over 8 hours was (98.6 ± 9.7) dB(A). The mean noise peak level was (139.5 ± 9.4) dB(A). Plant C had higher mean noise exposure level (TWA) of (96.9 ± 5.1) dB(A) compared to plant B 96.4 ± 3.7dB(A) and plant A 78.7 ± 11.9dB(A). Participants in both operation and maintenance had higher equivalent sound level (LAeq) measured over eight hours of 101.980 ± 3.6dB(A) compared to maintenance alone 98.5 ± 12.4dB (A) or operation 97.7 ± 8.8dB (A). Proportion of participants with reported hearing loss was 57(53.8%) where 44(41.5%) participants reported difficulty hearing people during conversations. Hearing protective devices (HPDs) were reported to be used by a majority, 101(95.3%).

Conclusion:

Workers in gas-fired plants are exposed to high noise levels that could damage their hearing. Hearing conservation programs should be established and maintained in this work environment.

Cardiovascular conditions, hearing difficulty, and occupational noise exposure within US industries and occupations

BACKGROUND

The purpose of this study was to estimate the prevalence of occupational noise exposure, hearing difficulty and cardiovascular conditions within US industries and occupations, and to examine any associations of these outcomes with occupational noise exposure.

METHODS

National Health Interview Survey data from 2014 were examined. Weighted prevalence and adjusted prevalence ratios of self-reported hearing difficulty, hypertension, elevated cholesterol, and coronary heart disease or stroke were estimated by level of occupational noise exposure, industry, and occupation.

RESULTS

Twenty-five percent of current workers had a history of occupational noise exposure (14% exposed in the last year), 12% had hearing difficulty, 24% had hypertension, 28% had elevated cholesterol; 58%, 14%, and 9% of these cases can be attributed to occupational noise exposure, respectively.

CONCLUSIONS

Hypertension, elevated cholesterol, and hearing difficulty are more prevalent among noise-exposed workers. Reducing workplace noise levels is critical. Workplace-based health and wellness programs should also be considered.

An inexpensive sensor for noise

Noise is a pervasive workplace hazard that varies spatially and temporally. The cost of direct-reading instruments for noise hampers their use in a network. The objectives for this work were to: (1) develop an inexpensive noise sensor (<$100) that measures A-weighted sound pressure levels within ±2 dBA of a Type 2 sound level meter (SLM; ∼$1,800); and (2) evaluate 50 noise sensors for use in an inexpensive sensor network. The inexpensive noise sensor consists of an electret condenser microphone, an amplifier circuit, and a microcontroller with a small form factor (28 mm by 47 mm by 9 mm) than can be operated as a stand-alone unit. Laboratory tests were conducted to evaluate 50 of the new sensors at 5 sound levels: (1) ambient sound in a quiet office; (2) 3 pink noise test signals from 65-85 dBA in 10 dBA increments; and (3) 94 dBA using a SLM calibrator. Ninety-four percent of the noise sensors (n = 46) were within ±2 dBA of the SLM for sound levels from 65-94 dBA. As sound level increased, bias decreased, ranging from 18.3% in the quiet office to 0.48% at 94 dBA. Overall bias of the sensors was 0.83% across the 75 dBA to 94 dBA range. These sensors are available for a variety of uses and can be customized for many applications, including incorporation into a stationary sensor network for continuous monitoring of noise in manufacturing environments.

Prevalence of hearing loss among noise-exposed workers within the agriculture, forestry, fishing, and hunting sector, 2003-2012

BACKGROUND

The purpose of this study was to estimate the prevalence of hearing loss among noise-exposed US workers within the Agriculture, Forestry, Fishing, and Hunting (AFFH) sector.

METHODS

Audiograms for 1.4 million workers (17 299 within AFFH) from 2003 to 2012 were examined. Prevalence, and the adjusted risk for hearing loss as compared with the reference industry (Couriers and Messengers), were estimated.

RESULTS

The overall AFFH sector prevalence was 15% compared to 19% for all industries combined, but many of the AFFH sub-sectors exceeded the overall prevalence. Forestry sub-sector prevalences were highest with Forest Nurseries and Gathering of Forest Products at 36% and Timber Tract Operations at 22%. The Aquaculture sub-sector had the highest adjusted risk of all AFFH sub-sectors (PR = 1.70; CI = 1.42-2.04).

CONCLUSIONS

High risk industries within the AFFH sector need continued hearing conservation efforts. Barriers to hearing loss prevention and early detection of hearing loss need to be recognized and addressed.