[Research progress in genetics of noise-induced hearing loss]

Noise-induced hearing loss（NIHL） is an acquired sensorineural hearing loss induced by long-term noise exposure. The susceptibility of exposed people may vary even in the same noise environment. With the development of sequencing techniques, genes related to oxidative stress, immunoinflammatory, ion homeostasis, energy metabolism, DNA damage repair and other mechanisms in NIHL have been reported continuously. And some genes may interact with noise exposure indexes. In this article, population studies on NIHL-related gene polymorphisms and gene-environment interactions in the past 20 years are reviewed, aimed to providing evidence for the construction of NIHL-related risk prediction models and the formulation of individualized interventions.

An updated job-exposure matrix for occupational noise: development and validation

OBJECTIVES

The aim of this study was to create a quantitative job-exposure matrix (JEM) for noise including a large set of measurements for the Swedish workforce, a detailed exposure-level assessment, spanning over an extensive time period from 1970 to 2014.

METHODS

The JEM was developed by 2 teams, each with an experienced occupational hygienist and an occupational safety engineer. Each pair assessed the exposure using measurements performed and reported by occupational hygienists, occupational safety engineers, or similar, from 1970 to 2014. The measurements included either the original LAeq(8h) measurements or an LAeq(8h) levels calculated from partial measurements of the working day, provided that the measurement targeted a regular task usually performed during a full workday. The collection of measurement reports was done in 2008 and 2012 by contacting clinics working in the area of occupational health or occupational safety engineers and their submitted reports were added to our own material. Noise exposure assessments were inserted at the appropriate time period for the relevant job family. The final matrix was developed in a consensus procedure and the validity was investigated by comparison of the 2 team's individual results.

RESULTS

The noise JEM contains 321 job families with information regarding occupational noise from 1970 to 2014. The time-period label has a 5-yr scale starting in 1970. The estimated average 8 h (TWA) noise level in decibels [dB(A)] for every job family and 5-yr period was coded as 1: <70 dB(A), 2: 70 to 74 dB(A), 3: 75 to 79 dB(A), 4: 80 to 84 dB(A) or 5: 85(+) dB(A). The validation showed no systematic difference in relative position and very high agreement in the ordering of paired ordinal classifications. The JEM has also successfully been applied in several epidemiological studies.

CONCLUSIONS

We present a JEM for occupational noise using Swedish data from 1970 to 2014 with a higher degree of sensitivity in assessed noise exposure compared with the previously existing version. Repeated application of the JEM, in epidemiological studies, has shown consistent results and contributed to yielding important findings.

Interactions of genetic variations in FAS, GJB2 and PTPRN2 are associated with noise-induced hearing loss: a case-control study in China

BACKGROUND

This study aimed to screen and validate noise-induced hearing loss (NIHL) associated single nucleotide polymorphisms (SNPs), construct genetic risk prediction models, and evaluate higher-order gene-gene, gene-environment interactions for NIHL in Chinese population.

METHODS

First, 83 cases and 83 controls were recruited and 60 candidate SNPs were genotyped. Then SNPs with promising results were validated in another case-control study (153 cases and 252 controls). NIHL-associated SNPs were identified by logistic regression analysis, and a genetic risk model was constructed based on the genetic risk score (GRS), and classification and regression tree (CART) analysis was used to evaluate interactions among gene-gene and gene-environment.

RESULTS

Six SNPs in five genes were significantly associated with NIHL risk (p < 0.05). A positive dose-response relationship was found between GRS values and NIHL risk. CART analysis indicated that strongest interaction was among subjects with age ≥ 45 years and cumulative noise exposure ≥ 95 [dB(A)·years], without personal protective equipment, and carried GJB2 rs3751385 (AA/AB) and FAS rs1468063 (AA/AB) (OR = 10.038, 95% CI = 2.770, 47.792), compared with the referent group. CDH23, FAS, GJB2, PTPRN2 and SIK3 may be NIHL susceptibility genes.

CONCLUSION

GRS values may be utilized in the evaluation of the cumulative effect of genetic risk for NIHL based on NIHL-associated SNPs. Gene-gene, gene-environment interaction patterns play an important role in the incidence of NIHL.

Implication of noise exposure on hearing with emphasis to hOGG1 and GPx-1 polymorphisms and HO-1 protein among textile workers

Noise exposure is a health hazard in the textile industry. In cochlear hair cells, DNA damage caused by 8-oxoguanine (8-oxo G) can result in noise-induced hearing loss. Human 8-hydroxyguanine glycosylase (hOGG1) is a DNA repair enzyme that excises (8-oxo G) in the DNA and repairs DNA damage. Glutathione peroxidase-1 (GPx) is a crucial antioxidant enzyme that aids in limiting cochlear damages. Heme oxygenase-1 (HO-1) is a stress-inducible protein with a high fold change in the hair cells of the cochlea. The study aimed to investigate the association of either hOGG1 and GPx-1 polymorphisms with audiometric notches and HO-1 protein among textile workers. hOGG1 and GPx genotypes were analyzed by PCR-RFLP, and HO-1 levels were measured by ELISA in 115 male textile workers. Blood pressure and audiogram were performed. Results recorded the relation between audiometric notches and ear complaints among workers. Older age workers showed audiometric notches at > 25 dB with a significant decrease in HO-1 levels and higher levels in workers with normal audiogram. Ser/Cys genotype of hOGG1 gene was associated with age and work duration while CC genotype of GPx is associated with HO-1 levels and diastolic pressure. Ser/Cys genotype of hOGG1 gene was associated with age while Cys/Cys genotype was associated with work duration among workers. CC genotype of GPx gene was associated with higher HO-1 levels and TT genotype was associated with high diastolic pressure. Finally, hearing impairment was dependent on the duration of exposure to noise, older age, and the presence of heterozygote TC genotype of GPx gene among textile workers.

Comparative transcriptome profiling reveals RNA splicing alterations and biological function in patients exposed to occupational noise

Genetic factors play an important role in susceptibility to noise-induced hearing loss (NIHL). Alternative splicing (AS) is an essential mechanism affecting gene expression associated with disease pathogenesis at the post-transcriptional level, but has rarely been studied in NIHL. To explore the role of AS in the development of NIHL, we performed a comprehensive analysis of RNA splicing alterations by comparing the RNA-seq data from blood samples from NIHL patients and subjects with normal hearing who were exposed to the same noise environment. A total of 356 differentially expressed genes, including 23 transcription factors, were identified between the two groups. Of particular note was the identification of 56 aberrant alternative splicing events generated by 41 differentially expressed genes between the two groups, with exon skipping events accounting for 54% of all the differentially alternative splicing (DAS) events. The results of functional enrichment analysis showed that these intersecting DAS genes and differentially expressed genes were significantly enriched in autophagy and mitochondria-related pathways. Together, our findings provide insights into the role of AS events in susceptibility and pathogenesis of NIHL.

The relationship between extended high-frequency hearing and the binaural spatial advantage in young to middle-aged firefightersa)

Relationships between extended high-frequency (EHF) thresholds and speech-in-spatialized noise were examined in firefighters with a history of occupational noise and airborne toxin exposure. Speech recognition thresholds were measured for co-located and spatially separated (±90° azimuth) sentences in a competing signal using the Listening in Spatialized Noise-Sentences test. EHF hearing was significantly correlated with the spatial advantage, indicating that firefighters with poorer EHF thresholds experienced less benefit from spatial separation. The correlation between EHF thresholds and spatial hearing remained significant after controlling for age. Deficits in EHF and spatial hearing suggest firefighters may experience compromised speech understanding in job-related complex acoustic environments.

[Investigation and analysis of occupational hazard factors in different industries in Tongliao City]

Objective: To investigate the occupational hazard factors of different industries in Tongliao City, and to provide scientific basis for the prevention and control of occupational disease in Tongliao City. Methods: In July 2021, the detection data of coal dust, silica dust, cement dust, benzene, noise and other occupational hazard factors, as well as the occupational health examination data of workers in various positions of 104 enterprises in different industries in Tongliao City were cllected and anylazed. χ(2) test was used to analyze the results of chest radiography of workers in different age groups. Results: A total of 104 enterprises were investigated, and the median time-weighted average concentration (C(TWA)) of coal dust, silic a dust, cement dust and benzene in contact with test posts were 0.94, 0.30, 0.70 and 0.95 mg/m(3), respectively. The median 8 h equivalent sound level (L(EX, 8 h)) of noise was 74.1 dB (A) . The over standard rates of silica dust, cement dust and noise contact positions were 10.83% (16/240) , 7.14% (2/28) and 0.48% (3/628) , respectively. The differences of chest X-ray examination of coal dust and silica dust workers in different working ages were statistically significant (χ(2)=218.50, 531.80, P<0.001) . The difference of hearing threshold of noise workers with different working age was statistically significant (χ(2)=1290.00, P<0.001) . The rates of leukopenia and neutropenia were 41.90% (44/105) and 20.95% (22/105) in benzene exposed workers. The positive rate of brucella exposure workers was 1.33% (1/75) for tiger red plate agglutination test and 3.23% (3/93) for tube agglutination test. Conclusion: Silica dust, cement dust and noise exceed the standard in some posts and places in the Tongliao City, and some workers are infected with Brucella. In the future, we can focus on monitoring noise-generating posts, strengthen supervision and implement prevention and control measures to reduce the incidence of occupational diseases.

Risk perception or hazard perception? Examining misperceptions of miners' personal exposures to noise

While perceptions of risk have been examined in the workplace to understand safety behavior, hazard perception has been overlooked, particularly for chemical, physical, and biological agents. This study sought to establish the prevalence of one type of mismatch in hazard perception, - noise misperception - among miners, to examine whether different types of noisy environments (e.g., continuous, highly variable, etc.) alter workers' misperception of their noise exposures, and to evaluate whether noise misperception is associated with hearing protection device (HPD) use behavior. In this cross-sectional study across 10 surface mines in the USA, 135 normal-hearing participants were surveyed on their perceptions of exposure to noise at work and were monitored for three shifts, each with personal noise dosimetry, to examine which workers had a mismatch in perceived versus true noise exposure by 8-hr, time-weighted average, NIOSH exposure limits (TWANIOSH). Mixed effects logistic regression and probit Bayesian Kernel Machine Regression (BKMR) models examining on the odds of noise misperception associated with four different noise metrics (kurtosis, crest factor, variability, and number of peaks >135 dB) were used to determine which types of noisy environments may influence noise misperception. The relationship between noise misperception and odds of not wearing HPDs during a work shift was further examined. Our findings showed that nearly 1 in 3 workers underestimated their exposure to noise when their true exposure was in fact hazardous (TWANIOSH≥85 dBA) for at least one shift, and 6% misperceived hazardous exposures for all shifts. Work shifts with highly kurtotic noise distributions (>3) had 3.1 (95% CI: 1.1 to 8.4) times significantly higher odds of resulting in misperceived noise; no other noise metric was significantly associated with noise misperception. BKMR modeling provided further evidence that kurtosis dominates this relationship, with an IQR increase in kurtosis significantly associated with 1.68 (95% CI: 1.13 to 2.50) higher odds of noise misperception. Although not statistically significant, misperception of hazardous noise exposure was associated with 3.2 (95% CI: 0.8 to 12.5) times higher odds of not using earplugs during a work shift. Misperception of noise occurs in the workplace, and likely occurs for other physical, chemical, and biological exposures. This hazard misperception may influence risk perceptions and worker behavior and reduce the effectiveness of behavior-related training. Elimination, substitution, or engineering controls of exposures is the best way to prevent hazard misperceptions and exposure-related diseases.

Association between occupational noise exposure duration and heart rate variability among Chinese adults: The role of plasma miRNAs

We aimed to explore the association between occupational noise exposure duration and heart rate variability (HRV) and the underlying mechanism. A total of 449 subjects in a manufacturing company in Wuhan, China were included in our study and six candidate miRNAs (miR-200a-3p, miR-200b-3p, miR-200c-3p, miR-1-3p, miR-92a-3p and miR-21-5p) were tested among 200 individuals. Information combining the work histories and the occupational noise monitoring records were used to calculate the exposure of occupational noise, HRV indices were measured by using 3-channel digital Holter monitors, including the standard deviation of all normal R-R intervals (SDNN), the root mean of the square of successive differences between adjacent normal NN intervals (r-MSSD), SDNN index, low-frequency power (LF), high-frequency power (HF) and TP (total power). We found a significant linear negative dose-response relationship between occupational noise exposure duration and HRV indices (P for overall <0.05, P for nonlinear >0.05), including SDNN, r-MSSD, SDNN index, LF and HF. In the continuous models, the β (95% CIs) for each 1-year occupational noise exposure were -0.002 (-0.004, -0.001) for SDNN, -0.002 (-0.004, -0.001) for r-MSSD, -0.002 (-0.004, -0.001) for SDNN index, and -0.006 (-0.012, -0.001) for HF. Meanwhile, we also found that occupational noise exposure duration was significantly associated with lower expression of five miRNAs, when adjusting for other covariates. The β (95% CIs) were -0.039 (-0.067, -0.011) for miRNA-200c-3p, -0.053 (-0.083, -0.022) for miRNA-200a-3p, -0.044 (-0.070, -0.019) for miRNA-200b-3p, -0.032 (-0.048, -0.017) for miRNA-92a-3p, and -0.063 (-0.089, -0.038) for miRNA-21-5p in the continuous models. In addition, we found a positive association between miRNA-1-3p and LF (β = 0.039, 95% CI = 0.002, 0.080). Our study suggests that occupational noise exposure duration is associated with cardiac autonomic dysfunction, and the role of miRNAs in noise induced HRV reduction needs to be confirmed in future studies.

Prevalence of Hearing Loss and Perceptions of Hearing Health and Protection among Florida Firefighters

Firefighters are exposed to extensive hazardous noise while on the job, both during routine tasks at the station and when responding to calls. However, little is known about firefighters' occupational noise hazards. This study employed mixed methods, including focus groups, a survey, and audiometric testing, to identify sources of noise in the firefighters' work environment, determine hearing protective strategies, discern firefighters' perceptions of occupational noise exposure and impacts to their health, and quantify the prevalence of hearing loss among South Florida firefighters. A total of 6 senior officers served in an expert panel, 12 participated in focus groups, 300 completed the survey, and 214 received audiometric tests. Most firefighters were unaware of the risk and their departments' policies, and did not participate in hearing protection practices and avoided using hearing protection devices, which they believed impede team communication and situational awareness. Nearly 30% of participating firefighters showed mild to profound hearing loss, a prevalence that is considerably worse than expected by normal aging alone. Educating firefighters about noise-induced hearing loss early in their careers may have significant health implications for their future. These findings provide insights for developing technologies and programs to mitigate the effects of noise exposure in the firefighting population.

Association of Occupational Stress With Tinnitus Among Career Firefighters in the United States

OBJECTIVE

This study explores the relationship between occupational stress and tinnitus among firefighters, a group often exposed to two tinnitus risk factors: high stress and noise.

METHODS

This cross-sectional study includes 240 firefighters in the United States. Data describing demographic characteristics, occupational stress, noise exposure, and tinnitus were collected by survey. Occupational stress was measured using the short version of the Effort-Reward Imbalance Questionnaire.

RESULTS

Forty-three percent of participants reported experiencing tinnitus within the past month. For occupational stress, higher effort (odds ratio, 1.25; 95% confidence interval, 1.05 to 1.49) and higher effort-reward ratio (odds ratio, 12.28; 95% confidence interval, 3.08 to 48.86) were associated with increased odds of tinnitus, after adjustment for demographic characteristics and noise exposure.

CONCLUSIONS

Occupational stress may increase the likelihood of tinnitus for firefighters, an already at-risk group of workers. Health providers should incorporate stress assessment into tinnitus management programs.

The effects of hearing protection devices on spatial awareness in complex listening environments

Hearing protection devices (HPDs) remain the first line of defense against hazardous noise exposure and noise-induced hearing loss (NIHL). Despite the increased awareness of NIHL as a major occupational health hazard, implementation of effective hearing protection interventions remains challenging in at-risk occupational groups including those in public safety that provide fire, emergency medical, or law enforcement services. A reduction of situational awareness has been reported as a primary barrier to including HPDs as routine personal protective equipment. This study examined the effects of hearing protection and simulated NIHL on spatial awareness in ten normal hearing subjects. In a sound-attenuating booth and using a head-orientation tracker, speech intelligibility and localization accuracy were collected from these subjects under multiple listening conditions. Results demonstrate that the use of HPDs disrupts spatial hearing as expected, specifically localization performance and monitoring of speech signals. There was a significant interaction between hemifield and signal-to-noise ratio (SNR), with speech intelligibility significantly affected when signals were presented from behind at reduced SNR. Results also suggest greater spatial hearing disruption using over-the-ear HPDs when compared to the removal of high frequency cues typically associated with NIHL through low-pass filtering. These results are consistent with reduced situational awareness as a self-reported barrier to routine HPD use, and was evidenced in our study by decreased ability to make accurate decisions about source location in a controlled dual-task localization experiment.

The association of noise exposure with stroke incidence and mortality: A systematic review and dose-response meta-analysis of cohort studies

BACKGROUND AND AIMS

Noise exposure is a major public health challenge with important implications for cardiovascular health. However, the association between noise exposure and stroke risk remains controversial. Therefore, we aimed to evaluate the role of noise exposure on stroke incidence and mortality by conducting a dose-response meta-analysis of cohort studies.

METHODS

The relevant publications were retrieved via PubMed, Embase, Web of Science, and Scopus up to June 26, 2022. The potential linear and curve relationship between noise and stroke were fitted using the generalized least squares method and restricted cubic spline. We estimated the pooled relative risk (RR) with 95% confidence interval (CI) by random-effect models. The Grading of Recommendations Assessment Development and Evaluation (GRADE) approach was used to evaluate the strength of the results.

RESULTS

In total, 21 cohort studies with 16,075,204 participants and 311,878 cases were included in the analysis. The risk of stroke incidence increased up to 4% (95% CI:1.02-1.06) and stroke mortality increased up to 3% (95% CI:1.00-1.07), every 10 dB(A) increment in noise exposure. Moreover, each 10 dB(A) increment in noise exposure was associated with a 4% (95% CI:1.01-1.07) increase in ischemic stroke and a 2% (95% CI:1.00-1.04) increase in hemorrhagic stroke. According to GRADE criteria, the evidence level in this study was rated as moderate.

CONCLUSIONS

The current findings provide further evidence of a dose-response relationship between exposure to noise and the risk of stroke incidence and mortality. Additionally, we update and fill a knowledge gap that the statistically significant increase in stroke incidence when noise decibels are >65 dB(A).

Identification of Noise Levels for Skill Training Activities, Equipment, Machines and Power Tools at TVET Institutes in Malaysia

The use of various machines, equipment and power tools at TVET Institute causes the institute's environment to be exposed to noise hazards that are similar to the industry. However, not much data has been published regarding noise exposure at TVET institutes. This study was carried out to document the noise exposure of work activities training in public TVET institutes in Malaysia that implement skill training programs in metal fabrication, furniture manufacturing and automotive maintenance. The identification of excessive noise, task-based noise exposure monitoring and source measurement was conducted. The noise contribution from each work activity to the daily A-weighted noise exposure level and sound pressure level emitted by machines and equipment was documented. The findings of this study recorded 20 activities with task-based noise contribution to the daily A-weighted noise exposure level between 75.3 dB and 95 dB. Based on the findings, the training environment at the TVET institutes has a risk of operating with excessive noise. The documented data can be used in planning the implementation of suitable noise control measures in TVET institutes.

Proposal of Combined Noise and Hand-Arm Vibration Index for Occupational Exposure: Application to a Study Case in the Olive Sector

In many production and industrial sectors, workers are exposed to noise and hand-arm vibrations (HAV). European directives have established the maximum limit values or exposure action values for noise and vibration independently. However, in many cases, workers who endure hand-arm vibration also receive high noise levels. This research suggests a procedure to aid the establishment of precautionary measures for workers with simultaneous exposure to both physical agents. This procedure defines a combined index based on the energy doses for both noise and HAV. From this combined index, the suggested methodology allows a recommended exposure time for workers with simultaneous noise and HAV exposure to be calculated. This methodology can be adapted to tackle the relative importance assigned to both agents according to the safety manager and new knowledge on combined health effects. To test this method, a measurement campaign under real working conditions was conducted with workers from the olive fruit-harvesting sector, where a variety of hand-held machinery is used. The results of the study case show that the suggested procedure can obtain reliable exposure time recommendations for simultaneous noise and HAV exposures and is therefore a useful tool for establishing prevention measures.

Prevalence of Self-Reported Hearing Loss and Associated Risk Factors: Findings From the Survey of the Health of Wisconsin

PURPOSE

The purpose of this study was to determine the prevalence of self-reported hearing loss and associated risk factors in a representative population-based study of Wisconsin residents.

METHOD

Survey of the Health of Wisconsin participants with data on self-reported hearing loss were included. We reported prevalence of self-reported hearing loss with corresponding 95% confidence intervals (CIs), overall, and stratified by age and sex. Age- and sex-adjusted and multivariable logistic regression models were used to evaluate determinants of self-reported hearing loss, and results are presented as odds ratios with corresponding 95% CIs.

RESULTS

There were 2,767 participants (50.7% men) with a mean age of 46 years (range: 21-74) in this study. Prevalence of self-reported hearing loss was 26.8% (24.4, 28.4) and was higher in men (30.3% [27.1, 33.4]) than in women (22.5% [19.9, 25.0]). Prevalence increased with age. After multivariable adjustment, age (per +1 year increase; 1.05 [1.04, 1.06]), male sex (1.57 [1.18, 2.08]), having two chronic diseases (vs. 0; 1.93 [1.16, 3.23]), occupational (2.47 [1.91, 3.19]) and recreational (1.58 [1.22, 2.04]) noise exposure, and poor diet (1.88 [1.28, 2.78]) were associated with higher odds of self-reported hearing loss.

CONCLUSIONS

Hearing loss is a highly prevalent public health concern and may be at least partially modifiable via interventions to reduce noise exposure and promote health. Statewide prevalence and risk factor data can be used to inform public health practice and promote hearing loss prevention.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19661130.

Association between UBAC2 gene polymorphism and the risk of noise-induced hearing loss: a cross-sectional study

The purpose of this article was to investigate the association between the ubiquitin-associated domain-containing protein 2 (UBAC2) gene polymorphism and noise-induced hearing loss (NIHL) and to further explore the role of single-nucleotide polymorphism (SNP) in UBAC2 in NIHL. A case control study involving 660 NIHL cases and 581 controls was conducted in this research. After genotyping by multiplex polymerase chain reaction (PCR) with next-generation sequencing, the correlation between SNPs and NIHL was analyzed using logistic regression analysis. Haplotype analysis was performed by Haploview 4.1 software. Then luciferase reporter assays and siRNA were used to explore the mechanism of SNPs in UBAC2 affecting NIHL susceptibility. The correlation analysis showed that rs3825427 AA genotype, rs9517701 GG genotype, rs7999348 GG genotype, and rs2296860 AA genotype were all associated with increased risk of NIHL (P < 0.05). The haplotype AGGA (rs3825427-rs9517701-rs7999348-rs2296860) also had a higher risk of NIHL (OR = 1.314; 95% CI, 1.098-1.572; P = 0.003). The results of the luciferase reporter assays showed that the fluorescence intensity of CTCF-OE + UBAC2 WT + TK was significantly higher than that of CTCF-NC + UBAC2 WT + TK and CTCF-OE + UBAC2 MT + TK (all P < 0.01). In CTCF knockdown cells, the expression of UBAC2 was also significantly downregulated (P = 0.0038), indicating that the transcription factor CTCF positively regulated the expression of UBAC2 and the rs3825427 C allele acted as an enhancer, which can promote CTCF to bind to the promoter of UBAC2, thereby promoting transcription. UBAC2 gene polymorphism is related to NIHL susceptibility. The UBAC2 rs3825427 regulates the expression level of UBAC2 by affecting the combination of CTCF and DNA, thus affecting the susceptibility of NIHL.

Time-Trends of U.S. Occupational Noise Standard Violations by OSHA Region and Industry Type 1972 to 2019

OBJECTIVE

We examined time-trends in Occupational Noise Standard violations by OSHA region and industry type over 48 years.

METHODS

Along with descriptive analysis of original data, negative binomial regression and Poisson regression were applied to the analysis of 1972 to 2019 and 1972 to 2012 data, respectively.

RESULTS

A small annual decrease in violation units over the periods was revealed. The three analyses produced differing timetrends. The manufacturing industry had more violations, and Region 4 had the most violations. Regarding numbers of units, the 10 regions and 2 industries were jointly significant. Some interaction between regions and industry types appeared in both regressions.

CONCLUSIONS

OSHA should specify how many regions report noise violations each year to ensure accurate identification of noise-related health risks to American workers. Further time-trend studies are needed for specific regions and industry types.

[Analysis on the diagnosis of suspected occupational diseases in Guangzhou from 2014 to 2019]

Objective: To understand the diagnosis of suspected occupational diseases reported in Guangzhou from 2014 to 2019, so as to provide theoretical basis and technical support for the supervision of suspected occupational disease reports. Methods: By cluster sampling, the suspected occupational disease report card, occupational disease report card and pneumoconiosis report card reported by Guangzhou from January 1, 2014 to December 31, 2019 in the occupational disease and occupational health information monitoring system were collected for matching analysis to understand the diagnosis of suspected occupational disease patients. Results: From 2014 to 2019, a total of 1426 suspected occupational cases in 7 categories and 32 species were reported in Guangzhou. The average number of reported cases per year was about 240. The main diseases of suspected occupational diseases were suspected occupational noise deafness (68.44%, 976/1426) , suspected occupational chronic benzene poisoning (16.48%, 235/1426) , suspected occupational other pneumoconiosis (4.84%, 69/1426) , suspected occupational silicosis (3.23%, 46/1426) and suspected occupational welder pneumoconiosis (1.82%, 26/1426) . The diagnostic rate required to enter the occupational disease diagnostic program is 36.61% (522/1426) , and the diagnostic rate is 59.20% (309/522) . In 2019, the diagnosis rate of suspected occupational diseases was the lowest (23.92%, 61/255) , Huadu District was the lowest (8.33%, 9/108) , suspected occupational pneumoconiosis was the lowest (28.03%, 44/157) , the diagnosis rate of suspected occupational diseases reported by the Centers for Disease control and prevention was the lowest (17.43%, 19/109) , and the diagnosis rate of suspected occupational diseases reported by outpatient treatment was the lowest (22.22%, 2/9) . The suspected occupational diseases reported by institutions outside Guangzhou did not enter the occupational disease diagnosis procedure. Suspected occupational skin diseases, suspected occupational diseases caused by physical factors and suspected occupational tumors were diagnosed, and the diagnosis rate of occupational disease prevention and control institutions was the highest (94.87%, 37/39) . Conclusion: The main types of suspected occupational diseases reported during these six years are noise deafness, chronic benzene poisoning and pneumoconiosis. The overall diagnosis rate and diagnosis rate of suspected occupational diseases are not high. It is suggested to improve the network direct reporting system of suspected occupational diseases and strengthen the follow-up management and supervision of suspected occupational diseases.

The impact of operating room noise levels on stress and work efficiency of the operating room team: A protocol for systematic review and meta-analysis

BACKGROUND

There is no high-quality meta-analysis in the literature to determine the noise level in the operating room. Therefore, the aim of this study is to systematically review the available evidence in the literature to elucidate the impact of operating room noise levels on stress and work efficiency of the operating room team.

METHODS

Two individual researchers will conduct the platform searches on the PubMed, Cochrane Library, and Embase databases from inception to June 1, 2022. The cohort studies assessing the impact of operating room noise levels on stress and work efficiency of the operating room team will be included. The outcomes include total workload level, stress scores, anxiety scores, operation time. We will collect data according to the guidelines in the Cochrane Handbook for Systematic Reviews of Interventions. The Meta analysis will be performed using Review Manager version 5.3 provided by the Cochrane Collaboration. Risk bias analysis of the studies will be performed independently by two reviewers using the Cochrane Risk of Bias Assessment Tool.

RESULTS

The review will add to the existing literature by showing compelling evidence and improved guidance in clinic settings.

REGISTRATION NUMBER

10.17605/OSF.IO/7N8RY.

OUP accepted manuscript

Introduction

Cardiovascular diseases (CVDs) are the number one cause of death, and there is evidence that work exposures could be associated with their development. This study aimed to systematically review observational studies of adults exposed to job strain, effort–reward imbalance, long working hours, job insecurity, shift work, and occupational noise, and assess the association of those work exposures with CVDs.

Methods

The Navigation Guide framework was applied. The population were adults of working age (18–65), and cohort and case–control studies were included. The work exposures were job strain, effort–reward imbalance, long working hours, job insecurity, shift work, and occupational noise. The outcomes were cerebrovascular diseases, ischaemic heart disease, and hypertensive diseases. The selection, data extraction, risk of bias assessment, and quality assessment were carried out by two reviewers independently and disagreements were solved by a third reviewer or by consensus. The synthesis of the results was done by applying the ‘vote counting based on direction’ method, and the results were summarized in an effect direction plot. The strength of the evidence for every risk factor and CVD was defined by consensus.

Results

A total of 17 643 papers were initially identified in the literature search, but after applying the filters by title and abstract, and full text, 86 studies were finally included. From the included studies, sufficient evidence was found of the harmfulness of job strain for cerebrovascular disease and ischemic heart disease. Furthermore, there was sufficient evidence of the harmfulness of shift work for ischemic heart disease. Evidence of no relationship was found between long working hours and shift work with ischaemic heart disease and hypertensive disease, respectively. The other associations of work exposures and CVDs had limited or inadequate evidence of harmfulness.

Conclusions

In this comprehensive review, there was sufficient evidence of a harmful relationship between job strain, shift work, and CVDs. For the other work exposures, more high-quality studies are needed. In order to improve current prevention strategies for CVDs, the findings of this review imply that job strain and shift work are work exposures that constitute additional risk factors that could be approached as targets for worksite interventions.

Systematic review registration

PROSPERO CRD42020179972.

Too Loud for Comfort: A Simulated Evaluation of Cast Saw Noise

BACKGROUND

Orthopaedic cast saws are an integral component to a pediatric orthopaedic practice but can also be associated with patient anxiety and noise exposure for patient. Although previous studies have deemed the noise generation from orthopaedic cast saws to be within safe occupational exposure levels, no study to date has compared the noise generation from a cast saw used in various exam room settings.

METHODS

A simulated fiberglass cast model was used. Noise generation was assessed using calibrated sound level meters with measurements performed at 18 inches, 36 inches, and 6 ft measured from the cast saw. Measurements were performed in 1 of 2 clinical settings: (1) an open bay setting and (2) an enclosed exam room. In the enclosed exam room, the 6-foot measurement was performed behind the closed exam door. An orthopaedic cast saw with built-in vacuum was used to continuously cut the fiberglass model for 1 minute with measurements of peak and mean sound generation, recorded in decibels (dB), a logarithmic scale. Three measurements were recorded at each distance. Between group comparisons were performed with statistical significance set at P=0.05.

RESULTS

Baseline sound levels were similar between cohorts with progressive decreases in mean sound with increasing distance from the saw. Mean sound levels were significantly higher in the enclosed room setting at 18 inches (92.8 dB, 95% confidence interval (CI): 91.72-93.88 vs. 90.6 dB, 95% CI: 89.91-91.29; P=0.043] and 36 inches (90.3 dB, 95% CI: 89.9-90.7 vs. 86.0 dB, 95% CI: 85.18-86.82; P=0.017). At 6-ft distance, however, the enclosed room demonstrated a 13.8-fold sound reduction compared with the open bay (72.0 dB, 95% CI: 71.59-72.4 vs. 83.4 dB, 83.14-83.72; P<0.001).

CONCLUSION

By closing the exam door, a 13-fold reduction in noise exposure can be achieved for adjacent patients and personnel. Consideration should be given for using orthopaedic cast saws in an enclosed exam room to prevent unnecessary noise exposure with hearing protection of cast saw operators and treated patients.

CLINICAL RELEVANCE

Orthopaedic cast removal.

Psychophysiological responses to potentially annoying heating, ventilation, and air conditioning noise during mentally demanding work

Exposure to noise-or unwanted sound-is considered a major public health issue in the United States and internationally. Previous work has shown that even acute noise exposure can influence physiological response in humans and that individuals differ markedly in their susceptibility to noise. Recent research also suggests that specific acoustic properties of noise may have distinct effects on human physiological response. Much of the existing research on physiological response to noise consists of laboratory studies using very simple acoustic stimuli-like white noise or tone bursts-or field studies of longer-term workplace noise exposure that may neglect acoustic properties of the noise entirely. By using laboratory exposure to realistic heating, ventilation, and air conditioning (HVAC) noise, the current study explores the interaction between acoustic properties of annoying noise and individual response to working in occupational noise. This study assessed autonomic response to two acoustically distinct noises while participants performed cognitively demanding work. Results showed that the two HVAC noises affected physiological arousal in different ways. Individual differences in physiological response to noise as a function of noise sensitivity were also observed. Further research is necessary to link specific acoustic characteristics with differential physiological responses in humans.

Occupational Noise Exposure and Incidence of High Fasting Blood Glucose: A 3-Year, Multicenter, Retrospective Study

The role of hazardous occupational noise exposure on the development of prediabetes is not well researched. We aimed to elucidate exposure to hazardous occupational noise as an independent risk factor for high fasting blood glucose (FBG). Participants exposed/non-exposed to occupational noise were recruited from the Common Data Model cohorts of 2013/2014 from two centers and were followed-up for 3 years. Multivariate time-dependent Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) and were adjusted for various covariates. Pooled HRs were calculated. Among the 43,858 participants of this retrospective cohort study, 37.64% developed high FBG. The mean (standard deviation) age in the cohort was 40.91 (9.71) years. In the fully adjusted models, the HRs of high FBG in the two centers were 1.35 (95% CI: 1.24-1.48) and 1.22 (95% CI: 1.17-1.28), and the pooled HR was 1.28 (95% CI: 1.16-1.41). A Kaplan-Meier plot of high FBG incidence by occupational noise exposure showed significant results (p < 0.001). We found that occupational noise exposure is significantly associated with high FBG. Preventing exposure to hazardous noise in the work environment may help reduce the risk for prediabetes among workers.

Audiometric assessment of hearing loss sustained during military service

An analysis is presented of the audiograms, obtained using Telephonics TDH39 headphones (Huntington, NY), of 80 men claiming compensation for noise-induced hearing loss (NIHL) sustained during military service. A comparison with an independent database of audiograms collected using other headphones suggested that no adjustment was needed to the hearing threshold levels (HTLs) at 6 kHz to allow for the use of TDH39 headphones. The method of Moore [(2020). J. Acoust. Soc. Am. 148, 884-894] for diagnosing military noise-induced hearing loss (M-NIHL) gave a positive diagnosis for 92.5% of right ears and 97.5% of left ears. The mean HTLs were maximal and similar at 4, 6, and 8 kHz but with considerable individual variability. A comparison with age-expected HTLs showed that M-NIHL was typically greatest at 3, 4, 6, or 8 kHz but with considerable individual variability. M-NIHL values were positive from 0.5 to 8 kHz. The HTLs were significantly higher for the left than for the right ears, but the asymmetry varied across individuals and could usually be ascribed to specific features of the noise exposure. The asymmetry existed over the range from 0.5 to 8 kHz, supporting the idea that M-NIHL occurs over a wide frequency range. Tinnitus was reported by 76 of the 80 men.

A functional SNP in miR-625-5p binding site of AKT2 3'UTR is associated with noise-induced hearing loss susceptibility in the Chinese population

The purposes of the current study were to investigate the association of a few of single nucleotide polymorphisms (SNPs) within the AKT2 gene and noise-induced hearing loss (NIHL) susceptibility and explore the potential mechanism underlying NIHL. Three SNPs (rs2304186, rs41275750, and rs76524493) were genotyped in a Chinese population which consists of 690 NIHL patients and 650 normal hearing controls. Bioinformatic analysis was conducted to predict the potential miRNA-binding site of SNPs. Plasmid construction, cell transfection, and dual-luciferase reporter assay were performed to investigate the potential molecular mechanism of SNPs involving in NIHL. The results revealed that rs2304186 GT genotype (OR = 1.41; 95% CI = 1.09-1.83) and TT genotype (OR = 1.51; 95% CI = 1.08-2.10) imparted increased risk of NIHL, and the increased risk could also be found in a dominant model (OR = 1.44; 95% CI = 1.12-1.84). The stratification analysis showed that rs2304186 GT/TT conferred a higher risk for NIHL, especially in subgroups of male, age (35-45 and > 45 years), noise exposure time (> 16 years), and noise exposure level (≤ 85 and ≥ 92 dB), when GG genotype as a reference. Furthermore, the haplotype TCCTACT (rs2304186-rs41275750-rs76524493) was found to be significantly associated with a high risk of NIHL (OR = 1.19; 95% CI = 1.02-1.40). Functional experiments showed that rs2304186 G allele combined with hsa-miR-625-5p mimics could significantly decrease the luciferase activity compared with T allele, indicating that rs2304186 altered the binding affinity of hsa-miR-625-5p to SNP rs2304186 mutation region, thus directly targeting AKT2 gene. In conclusion, our study provides evidence for the first time that SNP rs2304186 of AKT2 3'UTR might affect NIHL susceptibility by altering the binding affinity of has-miR-625-5p to mutation region in an allele-specific manner and it may act as a potential biomarker of NIHL susceptibility.

A deep neural-network classifier for photograph-based estimation of hearing protection attenuation and fit

Occupational and recreational acoustic noise exposure is known to cause permanent hearing damage and reduced quality of life, which indicates the importance of noise controls including hearing protection devices (HPDs) in situations where high noise levels exist. While HPDs can provide adequate protection for many noise exposures, it is often a challenge to properly train HPD users and maintain compliance with usage guidelines. HPD fit-testing systems are commercially available to ensure proper attenuation is achieved, but they often require specific facilities designed for hearing testing (e.g., a quiet room or an audiometric booth) or special equipment (e.g., modified HPDs designed specifically for fit testing). In this study, we explored using visual information from a photograph of an HPD inserted into the ear to estimate hearing protector attenuation. Our dataset consists of 960 unique photographs from four types of hearing protectors across 160 individuals. We achieved 73% classification accuracy in predicting if the fit was greater or less than the median measured attenuation (29 dB at 1 kHz) using a deep neural network. Ultimately, the fit-test technique developed in this research could be used for training as well as for automated compliance monitoring in noisy environments to prevent hearing loss.

Genetic association study between TAB2 polymorphisms and noise-induced-hearing-loss in a Han Chinese population

Noise-induced-hearing-loss(NIHL) is a common occupational disease caused by various environmental and biological factors. To investigate the association between TAB2 and the susceptibility of NIHL of people exposed to occupational environments, a genetic association study was performed on selected companies with 588 cases and 537 healthy control subjects. Five selected single nucleotide polymorphisms (SNPs) in TAB2,incoluding rs2744434, rs521845, rs652921, rs7896, rs9485372, were genotyped after a collection of DNA samples. Evident differences in participants between the case group and the control group reveals the result that people with the TAB2 has a high probability of getting NIHL. The results show that rs521845 is deeply associated with the risk of NIHL and is available for the diagnosis in the future.

Development of an ultrasound level meter for use in occupational safety and health

The widespread use of ultrasound techniques throughout industry causes many workers to be exposed to airborne ultrasound at their workplaces. To measure and assess the exposure to airborne ultrasound at these workplaces, devices are required that allow reliable measurements of ultrasound levels and support occupational safety and health measures. However, the sound level meters available to date do not meet these requirements. Therefore, a research prototype of a sound level meter covering audible and ultrasonic frequencies was developed, paying particular attention to the suitability of the components in terms of their acoustical characteristics (such as directional patterns) in the ultrasonic frequency range. The prototype was tested based on the international standard for sound level meters IEC 61672-1, with extensions regarding the signal frequencies used. The results revealed that the sound level meter developed is suitable for application at most workplaces exposed to ultrasound, as reflected by, e.g., its frequency range (at least up to 47 kHz), upper level limits (up to 160 dB SPL), and measurement uncertainty (k = 2, GUM) of 1.15 dB. The prototype developed allows measurement and assessment of exposure at workplaces for occupational safety and health purposes. Moreover, it can serve as a basis for future developments of commercial ultrasound level meters.

Analysis of correlation between window duration for kurtosis computation and accuracy of noise-induced hearing loss prediction

Kurtosis is considered an important metric for evaluating noise-induced hearing loss (NIHL). However, how to select window duration to calculate kurtosis remains unsolved. In this study, two algorithms were designed to investigate the correlation between window duration for kurtosis computation and the accuracy of NIHL prediction using a Chinese industrial database. Pure-tone hearing threshold levels (HTLs) and full-shift noise were recorded from each subject. In the statistical comparison, subjects were divided into high- and low-kurtosis groups based on kurtosis values computed over different window durations. Mann-Whitney U test was used to compare the difference in group HTLs to find the optimal window duration to best distinguish these two groups. In the support vector machine NIHL prediction model, kurtosis obtained from different window durations was used as a feature of the model for NIHL evaluation. The area under the curve was used to evaluate the performances of models. Fourteen window durations were tested for each algorithm. Results showed that 60 s was an optimal window duration that allows for both efficient computation and high accuracy for NIHL evaluation at test frequencies of 3, 4 and 6 kHz, and the geometric mean of kurtosis sequence was the best metric in NIHL evaluation.

Assessment of occupational personal sound exposures for music instructors

Daily activities performed by music instructors generate high sound levels that could potentially lead to overexposure. Adverse outcomes associated with high-exposure to sound, such as hearing loss and tinnitus, can be especially devastating to music instructors as hearing is essential to both job performance and career reward. The primary objective of this study was to compare sound exposures of music instructors to recommended exposure limits. Secondary objectives were to identify high-exposure activities and to evaluate potential similar exposure groups by examining between- and within-worker exposure variability. Personal sound exposure measurements from music instructors were collected using dosimeters during full workdays for up to 4 weeks over multiple semesters at a university's school of music. Study participants completed an activity log to record work-related activities throughout each day of sampling. Dosimeters logged 1-sec sound equivalent levels in A-weighted decibels. These data were used to calculate 8-hr time-weighted averages, daily dose, and activity-specific contributions to that dose to determine if daily exposures exceeded the recommended limit of 85 dBA and to identify high-exposure activities that could be targeted for future intervention. Seventeen participants were sampled for a total of 200 days. Approximately one-third of daily exposures exceeded recommended limits. The groups with the highest exposures were brass and conducting instructors. Conductors experienced the highest between-day variability in daily exposures. Activities that contributed the most to daily dose included group rehearsals, personal practice sessions, and performances, while classes and administrative work did not substantially contribute to daily dose. Daily exposures were highly variable, ranging from 60-95 dBA (mean = 81 dBA, sd = 8 dBA), and were influenced by instructional area and musical activity. Future exposure assessments for music instructors should include sampling for multiple days, and those above-recommended limits should be placed into hearing conservation programs.

Sensitivity and specificity of a method for diagnosis of military noise-induced hearing loss

Moore [(2020). J. Acoust. Soc. Am. 148, 884-894] proposed a method for the diagnosis of hearing loss produced by noise exposure during military service (denoted M-NIHL) based on the audiogram. This letter characterizes the sensitivity and specificity of the method, based on 116 ears of men claiming compensation for M-NIHL and 244 ears of an age-matched non-noise-exposed control group of men screened to match the noise-exposed group in age, absence of conductive hearing loss, no history of ear diseases, and asymmetry across ears ≤10 dB. The sensitivity was 0.97 and the specificity was 0.67, giving a discriminability index d' of 2.3.

Noise exposure assessment of occupational health and safety (OHS) consultants: A preliminary study

No published noise exposure assessment of occupational health and safety (OHS) consultants exists. An assessment was performed to quantify the noise level of OHS consultants while they were on site at a client's facility. OHS consultants wore a dosimeter set to A-weighting, slow response, 60 s log interval and a criterion level of 85dBA with a 3 dB exchange rate. Both the projected time-weighted average (TWA) and projected dose were recorded. Of the 32 noise assessments collected, three had projected TWAs that exceeded the occupational exposure limit of 85 dBA. Nearly 75% of the projected TWA measurements were equal or greater than the Action Level of 80 dBA. According to best practices, occupational noise levels greater than 80 dBA present a risk for noise-induced hearing loss and, therefore, a hearing loss prevention program should be implemented.

[Experimental measurement of the real reduction (PAR) of seven ear plugs]

The study aimed to evaluate, through the use of the EA-RfitTM Validation System, the real reduction (PAR) for the right ear (AuD), for the left ear (AuS) and biaural reduction related to each of the seven earplugs currently produced by 3M. In addition, we wanted to verify any difference between the aforementioned PARs in consideration of the tendency to predominantly use the right hand (right-handed) or the left hand (left-handed) and in relation to gender. Finally, for each insert and for each subject, an audiometric examination was conducted with the insert worn, to compare the average PAR value obtained by the EA-RfitTM system for each of the seven inserts and for all selected subjects, with the determined abatement curve through the audiometric measurement of the hearing threshold with the insert worn. The use of the E-ARfitTM system for the choice of the ear insert leads to important advantages in the protection of all workers. Moldable acoustic PPE generally proved to be more efficient than non-moldable, so much so that the higher SNRs (provided by the manufacturer), especially when referring to non-moldable inserts, were found to be misleading as to the real personal abatement capacity of the inserts. The average audiometric curves, obtained with the different inserts worn, confirmed that all of them guarantee a higher reduction for high frequencies than for "social" ones.

Physical and psychosocial work factors as explanations for social inequalities in self-rated health

OBJECTIVE

We investigated the contribution of physical and psychosocial work factors to social inequalities in self-rated health (SRH) in a sample of Danish 40 and 50 years old occupationally active women and men.

METHODS

In this longitudinal study, the study population consisted of 3338 Danish women and men. Data were collected by postal questionnaires in 2000 (baseline) and 2006 (follow-up). The independent variable, socioeconomic position (SEP), was assessed by the highest achieved educational level at baseline. We conducted gender-stratified parallel multiple mediation analyses. In the mediation analyses, SEP was categorised as SEP I, II, III, VI and V among men. Among women, SEP was dichotomised into SEP I-IV and V. The outcome, SRH, was assessed at baseline and follow-up. A wide range of physical and psychosocial work factors were included as potential mediators.

RESULTS

We found a social gradient in SRH across all levels of SEP among men. Among women, we only found a poorer SRH among those with the lowest SEP. Mediation analyses showed that work factors together accounted for 56% of the social inequalities in SRH among men and 44% among women. In both genders, ergonomic exposures and job insecurity seemed to play the major role for social inequalities in SRH. For women only, we also found noise to contribute to the social inequalities in SRH.

CONCLUSION

Physical and psychosocial work factors partially explained social inequalities in SRH among both genders. Improvement of the working environment can potentially contribute to the reduction of social inequalities in health.

Individual Fit Testing of Hearing-Protection Devices Based on Microphones in Real Ears among Workers in Industries with High-Noise-Level Manufacturing

Hearing-protection devices (HPDs) are particularly important in protecting the hearing of workers. The aim of this study was to prevent hearing damage in workplaces in Taiwan. It was conducted to determine the actual sound attenuation of the personal attenuation rating (PAR) values when wearing HPDs via measurements from field microphones in workers’ real ears (F-MIRE). Across 105 measurement trials for the Classic™ roll-down foam earplug HPDs worn by the workers, there were 23 cases of ineffective protection (including caution and fail); the proportion was 20% (including the first measurement and re-wear of HPDs after education and training). In addition, re-education and training in how to wear the HPDs was provided, improving wearing skills. A total of 29 testees wearing the Classic™ roll-down foam earplug HPDs failed to meet the pass standard for the first PAR test, and 6 of them improved and subsequently passed the PAR test. The improvement rate was 20%. These 23 testees switched to another HPD, namely Kneading-Free Push-Ins™ earplugs. From this group, 16 effective sound attenuation values were obtained, with an improvement rate of 70%. However, seven testees failed to pass the PAR test, and after education, training, and replacement of HPDs with different types, they still could not pass the PAR test. At that time, even if the UltraFit™ pre-molded earplugs were adopted again for wear and replacement, they were still unable to pass the PAR test. This HPD was eventually replaced with the PELTOR X4A Earmuff HPD and then tested again, with these HPDs finally passing the PAR test. In Taiwan, the use of fit testing has been increasing but it is not a common practice, and few studies on hearing-protection fit testing have been conducted in this country. The goal of this study was to gain more insight into the current hearing protection situation, including field attenuation of HPDs obtained by workers, the effects of training on improving the attenuation of HPDs after F-MIRE measurements, and the awareness of hearing health and motivation on the use of HPDs in a high-noise-level environment.

[Relationship between occupational noise exposure and hypertension in male steel workers]

OBJECTIVE

To analyze the effect of occupational noise exposure on hypertension in male steel workers.

METHODS

The general information, noise exposure and blood pressure were collected through questionnaires and physical examinations. Chi-square test was used to investigate the prevalence of hypertension under different cumulative noise exposure, and the effect of noise exposure and other factors on hypertension was analyzed by the restrictive cubic spline(RCS) combined with multivariatenon-condition Logistic regression model.

RESULTS

The prevalence of hypertension in noise exposure group was higher than that in noise non-exposure group(P&lt;0. 001). After adjusting for multiple factors, the restricted cubic spline model showed a dose-response relationship between cumulative noise exposure(CNE) and hypertension(overall correlation χ~2=75. 76, P&lt;0. 001, and nonlinear χ~2=24. 17, P&lt;0. 001). Compared with the steel workers exposure to lowest dose, the risk of hypertension of steel workers exposure to 82-94 and 95-107 dB(A) in group was 1. 81(95%CI 1. 31-2. 52) times and 2. 60(95%CI 1. 84-3. 68) times.

CONCLUSION

There is a non-linear dose-response relationship between cumulative noise exposure and hypertension.

The insertion loss distribution function of an ear plug, and its implications for the ear plug acceptability

INTRODUCTION

In order to establish the acceptability of a hearing protector device (HPD) used in a given noisy environment, two key elements must be known with the highest possible accuracy: the insertion loss of the HPD and the associated variability. Methods leading to objective field measurements of insertion loss have become widely available in the last decade and have started to replace the traditional subjective "Real-Ear Attenuation at Threshold" (REAT) laboratory measurements. The latter have long been known to provide a gross overestimate of the attenuation, thus leading to a strong underestimate of the worker's exposure to noise.

METHODS

In this work we present objective measurements of the insertion loss of an ear plug, carried out using the E-A-Rfit procedure by 3M on a large sample of 36 female and 64 male subjects. This large number of independent measurements has been exploited to calculate the distribution function of effective noise levels, that is noise levels that take into account the use of the HPD. The knowledge of the distribution function has in its turn allowed the calculation of the uncertainty on the effective noise levels.

RESULTS

This new estimate of uncertainty (6 to 7 dB) is significantly larger than most previous estimates, which range between 4 and 5 dB when using objective data but with an improper uncertainty propagation, and around 3 dB when using REAT subjective data. We show that the revised new estimate of uncertainty is much more realistic as it includes contributions that are missed by the other methods.

CONCLUSIONS

By plugging this revised estimate of uncertainty into the criterion for checking the acceptability of the HPD, a better assessment of the actual protection provided by the HPD itself is possible.

Noise-induced hearing loss: Translating risk from animal models to real-world environments

Noise-induced hearing loss (NIHL) is a common injury for service members and civilians. Effective prevention of NIHL with drug agents would reduce the prevalence of NIHL. There are a host of challenges in translation of investigational new drug agents from animals into human clinical testing, however. Initial articles in this special issue describe common pre-clinical (animal) testing paradigms used to assess potential otoprotective drug agents and design-related factors that impact translation of promising agents into human clinical trials. Additional articles describe populations in which NIHL has a high incidence and factors that affect individual vulnerability. While otoprotective drugs will ultimately be developed for use by specific noise-exposed populations, there has been little effort to develop pre-clinical (animal) models that accurately model exposure hazards across diverse human populations. To facilitate advances in the translational framework for NIHL otoprotection in pre-clinical and clinical testing, the overarching goals of the current series are to (1) review the animal models that have been used, highlighting the relevance to the human populations of interest, (2) provide insight into the populations for whom pharmaceutical interventions might, or might not, be appropriate, and (3) highlight the factors that drive the significant individual variability observed in humans.

The inflammatory response to simulated day and night emergency alarm mobilisations

Purpose

Responding to emergency alarms is a daily occurrence for personnel in safety-critical occupations, and is associated with negative health outcomes in this population. The purpose of the present study was to determine the acute inflammatory response to an isolated emergency alarm mobilisation in both day and night conditions.

Methods

Sixteen healthy males (mean age 25 ± 4 years) spent four days and nights in a sleep laboratory and were required to mobilise to an emergency alarm either during the day (1558 h), or from nocturnal sleep (0358 h). Pro (TNF-α, IL-1β, IL-8, IL-6) and anti-inflammatory (IL-4 and IL-10) cytokine responses to each alarm mobilisation were compared to time-matched control conditions without the alarm and mobilisation stimulus.

Results

Analysis revealed no significant drift of cytokine levels at 1400 h across the study (P≥0.139). The plasma concentration of anti-inflammatory cytokine IL-4 was 84% greater in the 2-h sampling period following night alarm mobilisation compared to a night control of gentle awakening (P = 0.049), no other condition-by-time interactions were observed. The majority of inflammatory concentrations did not significantly change between alarm mobilisation and control conditions, in either day or night trials.

Conclusions

These findings may reflect the lack of a true emergency (and the perceived stress) for the alarm mobilisation, together with the neutralising effect of different circadian biorhythms on inflammatory cytokine concentrations.

Fight Song on Mute: University Pep Band Member Noise Dosages and Noise-Induced Hearing Loss Knowledge

The occurrence of noise-induced hearing loss (NIHL) can be detrimental to the future careers of student musicians. Few studies have focused on the noise exposure of student musicians within an indoor pep band as they performed during university basketball games. The purpose of this longitudinal study was to assess: (a) the status of noise dosages acquired via personal noise dosimeters from two pep band players as they performed over nine men's basketball games spanning three seasons, (b) perceived effectiveness of earplugs on the primary participants, and (c) the status of all band members' (n=72) knowledge of hearing loss and hearing loss prevention. The noise dosages accrued by primary participants in each game over the three seasons greatly exceeded the National Institute for Occupational Safety and Health's (NIOSH) recommendation regarding safe daily noise exposure time. Participants occasionally reported that the earplugs did not provide sufficient protection from noise or contributed to communication and intonation issues. Questionnaire responses from band members demonstrated a mild deficiency in hearing loss knowledge. Two-thirds of pep band members reported that they did not always wear hearing protection at pep band functions. Exceeding standard noise dosage recommendations without hearing protection potentially leaves these individuals at a high risk for permanent hearing loss.

Occupational noise exposure and hearing loss: A study of knowledge, attitude and practice among Tanzanian iron and steel workers

We assessed Knowledge Attitude and Practice (KAP) regarding occupational noise exposure, Noise-induced hearing loss, audiometry and use of hearing protection devices among iron and steel factory workers exposed to high noise level. A modified, validated, structured questionnaire was used to collect information from 253 male workers randomly selected from the four factories. The sum scores for each domain of KAP were computed. Scores above 75% were defined as good knowledge and positive attitude. For practice, scores of >50% were defined as good. Independent samples t-test and Chi-squared test were used to analyze association between KAP and continuous/categorical variables respectively. Majority of workers displayed poor knowledge and poor practice (94%), but 76% displayed a positive attitude. Most of the workers (86%) had never been provided with hearing protection devices. The mean scores for attitude and practice differed significantly between the four factories (one-way ANOVA, p < 0.001). Implementation of hearing conservation program with provision of hearing protection devices are suggested.

Prevalence of Noise-Induced Hearing Loss Among Tanzanian Iron and Steel Workers: A Cross-Sectional Study

Iron and steel factory workers in Tanzania are likely to develop noise-induced hearing loss (NIHL) due to exposure to high sound levels. Studies on hearing status in this population are lacking. The aims of this study were to determine prevalence of NIHL among iron and steel workers and compare hearing thresholds at different frequencies with a control group. We conducted a cross-sectional study among 221 iron and steel workers exposed to average noise level of 92 dB(A), compared with 107 primary school teachers recruited as controls and exposed to average noise level of 79.7 dB(A). We used a questionnaire-based interview to collect information on socio demographic characteristics and other confounding variables. Hearing loss was defined as hearing threshold levels ≥25 dB hearing loss in either ear at 3000, 4000 or 6000 Hz. The prevalence of hearing loss was significantly higher among the exposed group than among the controls, i.e. 48% and 31%, respectively. There were significant differences in hearing thresholds between the exposed and control groups at 3000, 4000, 6000, and 8000 Hz. Hearing loss was more frequent among workers exposed to higher noise levels than among the controls suggesting that iron and steel workers run a higher risk of developing hearing loss.

Mapping Occupational Hazards with a Multi-sensor Network in a Heavy-Vehicle Manufacturing Facility

Due to their small size, low-power demands, and customizability, low-cost sensors can be deployed in collections that are spatially distributed in the environment, known as sensor networks. The literature contains examples of such networks in the ambient environment; this article describes the development and deployment of a 40-node multi-hazard network, constructed with low-cost sensors for particulate matter (SHARP GP2Y1010AU0F), carbon monoxide (Alphasense CO-B4), oxidizing gases (Alphasense OX-B421), and noise (developed in-house) in a heavy-vehicle manufacturing facility. Network nodes communicated wirelessly with a central database in order to record hazard measurements at 5-min intervals. Here, we report on the temporal and spatial measurements from the network, precision of network measurements, and accuracy of network measurements with respect to field reference instruments through 8 months of continuous deployment. During typical production periods, 1-h mean hazard levels ± standard deviation across all monitors for particulate matter (PM), carbon monoxide (CO), oxidizing gases (OX), and noise were 0.62 ± 0.2 mg m-3, 7 ± 2 ppm, 155 ± 58 ppb, and 82 ± 1 dBA, respectively. We observed clear diurnal and weekly temporal patterns for all hazards and daily, hazard-specific spatial patterns attributable to general manufacturing processes in the facility. Processes associated with the highest hazard levels were machining and welding (PM and noise), staging (CO), and manual and robotic welding (OX). Network sensors exhibited varying degrees of precision with 95% of measurements among three collocated nodes within 0.21 mg m-3 for PM, 0.4 ppm for CO, 9 ppb for OX, and 1 dBA for noise of each other. The median percent bias with reference to direct-reading instruments was 27%, 11%, 45%, and 1%, for PM, CO, OX, and noise, respectively. This study demonstrates the successful long-term deployment of a multi-hazard sensor network in an industrial manufacturing setting and illustrates the high temporal and spatial resolution of hazard data that sensor and monitor networks are capable of. We show that network-derived hazard measurements offer rich datasets to comprehensively assess occupational hazards. Our network sets the stage for the characterization of occupational exposures on the individual level with wireless sensor networks.

Noise at sea: Characterization of extended shift noise exposures among U.S. Navy aircraft carrier support personnel

The purpose of this investigation was to characterize 12-hr on-duty, 12-hr off-duty, and 24-hr noise exposures among U.S. Navy aircraft carrier support personnel. Noise dosimetry samples were collected for 47 aircraft carrier support personnel while at sea during airwing carrier qualifications. L_eq measurements during 12-hr on-duty, 12-hr off-duty, and over 24-hr periods were compared to Threshold Limit Values. Four similar exposure groups (SEGs) were created based upon departmental assignment and similarity of work tasks: (1) Administration/Religious Ministries/Legal/Training, (2) Combat Systems/Operations, (3) Medical/Dental, and (4) Supply. Equivalent sound level (Leq) measurements in decibels "A" weighted (dBA) were compared to determine significant differences between each group according to 12-hr on-duty, 12-hr off-duty, and 24-hr periods. Mean 24-hr noise levels ranged from 69-88 dBA with 22% exceeding the 80 dBA Threshold Limit Value. Twelve-hr on-duty noise levels ranged from 71-90 dBA with 17% exceeding the 83 dBA 12-hr on-duty Threshold Limit Value. Twelve-hr off-duty noise exposure ranged from 68-84 dBA with 95% exceeding the 70 dBA American Conference of Governmental Industrial Hygienists threshold classified as effective quiet to allow for temporary threshold shift recovery. Welch Analysis of Variance and Dunnett T3 post hoc tests revealed SEG 2 had significantly higher 24-hr noise exposures than SEG 3 (p = 0.019) and SEG 4 (p = 0.045). SEG 2 had significantly higher 12-hr on-duty noise exposure than SEG 3 (p = 0.030). One Way Analysis of Variance revealed no significant differences between 12-hr off-duty noise exposures according to SEG (p = .096). Some aircraft carrier support personnel had 12-hr on-duty and 24-hr noise exposures exceeding Threshold Limit Values with a large proportion exceeding the 70 dBA effective quiet limit during 12-hr off-duty periods. Results suggest personnel that are typically considered low risk for hazardous noise exposure (<85 dBA) during 8-hr shifts may have a greater risk of noise exposure when considering full 12-hr and 24-hr shifts when working and living in close proximity.

Pneumatic rock drill vs. electric rotary hammer drill: Productivity, vibration, dust, and noise when drilling into concrete

OBJECTIVES

Both pneumatic rock drills and electric rotary hammer drills are used for drilling large holes (e.g., 10-20 mm diameter) into concrete for structural upgrades to buildings, highways, bridges, and airport tarmacs. However, little is known about the differences in productivity, and exposures to noise, handle vibration, and dust between the two types of drills. The aim of this study was to compare these outcomes with similar mass electric rotary and pneumatic rock drills drilling into concrete block on a test bench system.

METHOD

Three experiments were conducted on a test bench system to compare an electric (8.3 kg) and pneumatic drill (8.6 kg) on (1) noise and handle vibration, (2) respirable silica dust, and (3) drilling productivity. The test bench system repeatedly drilled 19 mm diameter x 100 mm depth holes into cured concrete block while the respective exposure levels were measured following ISO standards.

RESULTS

Productivity levels were similar between the electric and the pneumatic drill (9.09 mm/s vs. 8.69 mm/s ROP; p = 0.15). However, peak noise (L_Peak: 117.7 vs. 139.4 dBC; p = 0.001), weighted total handle vibration (a_hw: 7.15 vs. 39.14 m/s²; p = 0.002), and respirable silica dust levels (0.55 vs. 22.23 mg/m³; p = 0.003) were significantly lower for the electric than the pneumatic drill.

DISCUSSION

While there were no differences in drilling productivity between an electric and pneumatic drill of similar mass, there were substantial differences in exposure levels of noise, handle vibration, and respirable silica dust. Structural contractors should switch from pneumatic rock drills to electric rotary hammer drills for structural drilling into concrete in order to reduce worker exposures to the hazards of noise, hand vibration, and silica dust.

Sleep quality of offshore wind farm workers in the German exclusive economic zone: a cross-sectional study

OBJECTIVES

To assess the quality of sleep of employees in the German offshore wind industry and to explore factors associated with poor sleep quality.

DESIGN

Web-based cross-sectional survey.

SETTING

Offshore companies operating in wind farms within the German exclusive economic zone.

PARTICIPANTS

Workers with regular offshore commitments and at least 28 days spent offshore in the past year (n=268).

OUTCOME MEASURES

Sleep quality in the past 4 weeks, troubles falling asleep or sleeping through in the past 4 weeks, differences in sleep quality between offshore deployments and onshore leaves.

RESULTS

Having problems with sleep onset was reported by 9.5% of the respondents. 16.5% reported troubles with maintaining sleep three or more times per week. The overall quality of sleep was rated as very bad by only 1.7% of the participants. 47.9% of the workers reported their quality of sleep to be worse during offshore commitments than when being onshore. Higher levels of exposition to noise, vibrations and poor air quality were associated with sleeping troubles and poorer sleep quality. Sharing the sleep cabin with colleagues was associated with troubles sleeping through. No association was found for working in rotating shifts and for regularity of the offshore commitments.

CONCLUSIONS

Workers in our study showed frequent sleep problems and poorer sleep quality offshore than onshore. Our results indicate that higher degrees of exposure to noise, vibrations and artificial ventilation are associated with poor sleep quality rather than organisational factors such as shift-work and type of working schedule. In view of the high demands of the offshore workplace and the workers' particular recovery needs, addressing sleep disorders should be part of any health and safety management strategy for this workplace.

Efficiencies and noise levels of portable surgical smoke evacuation systems

Surgical smoke resulting from electrocauterization is a health risk for operating room personnel. The U.S. National Institute for Occupational Safety and Health recommends the use of local exhaust ventilation such as a portable smoke evacuation system to reduce surgical smoke, but its efficiency has never been assessed under experimental conditions. In this study, particle filtration efficiencies of five commercially available smoke evacuation systems were investigated in a model operating room. Two cutting angles, the devices' suction capacities, three unidirectional displacement flow rates, and the noise exposures were considered. Results demonstrated that portable smoke evacuation systems reduce surgical smoke up to 99% under optimal conditions. A cutting angle of 45°, the device's maximum suction capacity, and a unidirectional displacement flow rate of 10,500 m³/hr were advantageous. Sound levels ranged between 51-69 dBA and exceeded recommended threshold limits, if used with medium or maximum suction capacity. Hence, portable smoke evacuation systems are beneficial and are recommended. However, a combination with general unidirectional room ventilation and a strict limitation of the use of electrocauterization is strongly advised.

Imputation of missing values in a large job exposure matrix using hierarchical information

Job exposure matrices (JEMs) represent a useful and efficient approach for estimating occupational exposures. This study uses a large dataset of full-shift measurements and employs imputation strategies to develop noise exposure estimates for almost all broad level standard occupational classification (SOC) groups in the US. The JEM was constructed using 753,702 measurements from the government, private industry, and the published literature. Parametric Bayes imputation was used to take advantage of the hierarchical structure of the SOCs and the mean occupational noise exposures were estimated for all broad level SOCs, except those in major group 23-0000, for which no data were available. The estimated posterior mean for all broad SOCs was found to be 82.1 dBA with within- and between-major SOC variabilities of 22.1 and 13.8, respectively. Of the 443 broad SOCs, 85 were found to have an estimated mean exposure >85 dBA while 10 were >90 dBA. By taking advantage of the size and structure of the dataset, we were able to employ imputation techniques to estimate mean levels of noise exposure for nearly all SOCs in the US. Possible sources of errors in the estimates include misclassification of job titles due to limited data, temporal variations that were not accounted for, and variation in exposures within the same SOC. Our efforts have resulted in an almost completely populated noise JEM that provides a valuable tool for the assessment of occupational exposures to noise. Imputation techniques can lead to maximal use of available information that may be incomplete.

Status of Hearing Impairment among Handloom Workers in Tangail District of Bangladesh

Industrial noise is one of the major sources of noise pollution. Handloom industry is the biggest handicraft industry in our country; it is the second largest source of rural employment after agriculture. The workers of the handloom industry worked within excessive level of sound. This cross-sectional study was an attempt to see the status of hearing impairment among handloom worker at Tangail District, Bangladesh from August 2016 to December 2016. A total 180 handloom workers were included in this current study. All the respondents were male as handloom work is a strenuous work. The mean age of respondents was 38.18±11.529 years where most of the respondents were of middle age group (21-50) year's age group. Among the participants less than one-fourth was illiterate and rest had primary to secondary level of education. The average income of handloom workers was 13805.56±2764.696 BDT per month. Handloom workers spend average 10 hour for working per day. They were exposed to sound beyond NIOSH recommendation (70-83 dB around handloom machines and 80-90 dB around power loom machines). By self-assessment hearing impairment perception 76.7% participants reported that they had hearing problem. Based on the interpretation of Rinne, Webers and ABC test data indicate that among the respondents around 32.2% were identified with bilateral sensorineural hearing impairment and of them through Pure tone audiometry (PTA) around half were diagnosed as suffering from moderate to severe Noise induced hearing loss (NIHL). Using personal protective measure like ear muffle/ear musk has been recommended.