Characteristics and influencing factors of hearing loss among noise-exposed workers in a large machinery maintenance enterprise / 环境与职业医学

Background The current increasing trend of new cases of occupational noise-induced deafness indicates that the hearing loss of occupational population has not been effectively controlled in China. It is of great significance to study the characteristics of hearing loss among noise-exposed workers and its related factors. Objective To investigate characteristics and influencing factors of hearing loss among occupational noise-exposed workers in a large machinery maintenance enterprise, and to provide a scientific basis to prevent and control noise-induced hearing loss. Methods A cross-sectional survey was conducted to investigate male Han occupational noise-exposed workers in a large mechanical maintenance enterprise. We acquired demographic characteristics, occupational exposure history, and individual life behavior characteristics of the workers through questionnaires, collected occupational exposure level data from annual occupational disease hazard factor surveillance reports, obtained pure tone hearing threshold test data through occupational health examinations, and estimated individual noise exposure levels using cumulative noise exposure (CNE). According to the results of pure tone air conduction hearing threshold test, the workers were divided into a hearing loss group and a normal hearing group. The chi-square test was employed to compare the occupational exposure characteristics and individual life behavior characteristics between the two groups. Additionally, the trend chi-square test was utilized to analyze the changing trends of age, length of service, CNE, and hearing loss rate within the two groups. The relationship between high-frequency hearing loss in both ears and its related influencing factors was assessed by a multiple logistic regression model. Results The M (P25, P75) of CNE for the 2531 occupational noise-exposed workers was 97.51 (95.39, 99.96) dB(A)·year. The incidence of hearing anomaly, binaural high-frequency hearing anomaly, random ear high-frequency hearing anomaly, binaural low-frequency hearing anomaly, and random ear low-frequency hearing anomaly were 22.48%, 16.59%, 22.13%, 2.77%, and 3.52%, respectively. High-frequency hearing threshold increase was the main reason for hearing anomaly (98.42%). In comparison to the CNE ≤ 97 dB(A)·year group, the 97 dB(A)·year<CNE≤ 100 dB(A)·year group and the CNE>100 dB(A)·year group experienced a 36.4% and 52.3% increase in the risk of bilateral high-frequency hearing loss, respectively. The smoking group exhibited a 43.5% elevated risk of bilateral high-frequency hearing loss when compared to the non-smoking group. Conversely, the group frequently wearing hearing protection equipment demonstrated a 23.6% lower risk of bilateral high-frequency hearing loss in comparison to the group occasionally wearing protective equipment. The data suggested that CNE＞97 dB(A)·year and smoking might be independent risk factors for bilateral high-frequency hearing loss, and frequently wearing hearing protection equipment might be an important protective factor. Conclusion Increased CNE and smoking can elevate the risk of high-frequency hearing loss, while personal hearing protection can effectively reduce the risk of hearing loss.

Occupational health risk assessment of noise in a coal mining enterprise in Shaanxi Province / 公共卫生与预防医学

Objective To evaluate the noise hazard level of a coal mining enterprise, and identify high-risk operation types and people, and to provide a basis for preventing and controlling the health damage caused by noise. Methods A large coal mining enterprise in Shaanxi Province was selected as the research object. The noise monitoring data of the coal mine over the years was used to calculate the noise exposure matrix of each post in the enterprise, and the classification of occupational hazards at workplaces (GBZ/T 229.4-2012) was used to assess the occupational health risk levels. Results Among the 22 noise-exposed positions in the enterprise, the 8-hour working day equivalent sound level in positions of shearer driver, horseshoe driver, crusher driver, shuttle driver, relaxation screen driver, and grading screen driver were all higher than the occupational exposure limit of noise. In 2021, the noise exposure levels of shearer drivers, crusher drivers, and coal-selecting workers were all higher than 90 dB (A), and the occupational hazard level was moderate hazard level. In addition, the noise exposure levels of most other jobs also exceeded the occupational exposure limit. Conclusion The noise hazards in the coal mine industry are mainly concentrated in the posts of the coal mining system, tunneling system, and screening workshop. Among them, the shearer driver, the crusher driver, and the coal preparation workers have higher noise exposure levels. It is recommended to take corresponding noise reduction measures and strengthen the protection level to reduce the noise exposure risk of workers.

Self-Reported Voice-Related Quality of Life in Cochlear Implant Users

Objective: The aim of this study was to identify if cochlear implant (CI) users are perceiving a decrease in life quality due to voice problems. This study evaluated 43 CI user's perception of their voice and how it affects their quality of life through a survey. Approach: Forty-three CI users responded to a survey regarding their demographics, details about their CI, the Hearing Health Quick Test (HHQT), the Voice Related Quality of Life (V-RQOL), and the Voice Handicap Index-10 (VHI-10). The survey responses were analyzed using univariate linear regression analysis. Results: Few of the CI users scored below the cut off for normal voice related quality of life. CI users averaged 93.4 out of 100 on the V-RQOL and only four scored abnormally for the VHI-10. Lower scores on the V-RQOL were correlated with the participants having an associate degree and with participants visiting friends, family, and neighbors less often due to hearing loss. The VHI-10 scores were correlated with gender, education levels, difficulty in social situations due to hearing loss, noise exposure, and tinnitus. Limitations of the study: The small n was the primary limitation of this study. Originality: This study was one of the first to examine the voice-related quality of life in CI users. Conclusions: Overall, respondents did not perceive much voice-related difficulty. However, they were more likely to perceive voice-related difficulty if they experienced difficulty hearing in noise and avoided social situations due to hearing loss.

Objetivo: Este estudio identificó si los usuarios de implantes cocleares (IC) están percibiendo una disminución en la calidad de su vida debido a problemas de voz. Además, evaluó la percepción de la voz de 43 usuarios de IC y cómo afecta su calidad de vida a través de una encuesta. Enfoque: Cuarenta y tres usuarios de IC respondieron a una encuesta sobre su demografía, detalles sobre su IC, la Hearing Health Quick Test (HHQT), la Voice Related Quality of Life (V-RQOL) y el Voice Handicap Index-10 (VHI-10). Las respuestas de la encuesta se analizaron mediante un análisis de regresión lineal univariado. Resultados: Pocos usuarios de IC puntuaron por debajo del límite para calidad de vida relacionada con la voz. El promedio V-RQOL fue de 93,4/100; solo 4 participantes tuvieron puntuación anormal en VHI-10. Las bajas puntuaciones en V-RQOL se correlacionaron con título de asociado y menos visitas por pérdida auditiva; las puntuaciones VHI-10, con sexo, educación, dificultad en situaciones sociales, exposición al ruido y tinnitus. Limitaciones del estudio: La pequeña n fue la principal limitación de este estudio. Originalidad: Este estudio fue uno de los primeros en examinar la calidad de vida relacionada con la voz en usuarios de CI. Conclusiones: En general, los encuestados no percibieron mucha dificultad relacionada con la voz. Sin embargo, era más probable que percibieran dificultades relacionadas con la voz si tenían dificultades para oír en ruido y evitaban situaciones sociales debido a la pérdida auditiva.

Presenteeism and noise perception at work: a cross-sectional study using association analysis

ABSTRACT BACKGROUND: Presenteeism refers to the presence of a worker at work with reduced performance due to illness, and it is a common public health problem. Exposure to noise during production processes brings risk to workers' health. OBJECTIVE: To analyze the health profile of workers in the automotive industry and identify the association between noise perception and presenteeism among workers in the Brazilian automotive industry. DESIGN AND SETTING: This was a cross-sectional study utilizing a case study design analyzing the automotive industry in the interior of São Paulo state, Brazil. METHODS: This study included 306 workers using the Presenteeism Work Limitations Questionnaire protocol. Multiple logistic regression was used for data analysis. RESULTS: Male workers with reports of headache, tension, and limited well-being at work, having perceived that noise exposure interferes with productivity, showed a positive association with the occurrence of presenteeism. Physical demand had the highest score in terms of interfering with the presenteeism index. CONCLUSION: Workers' perceptions of noise were associated with presenteeism.

Prevalence of tinnitus in noise-exposed workers and its influencing factors / 环境与职业医学

Background Tinnitus is a common symptom in workers exposed to noise, and no specific treatment is available yet. Paying attention to the influencing factors of tinnitus is very important to prevent tinnitus. Objective To investigate the situation of tinnitus among noise-exposed workers and its influencing factors. Methods Using a cross-sectional study design, 1011 noise-exposed male workers in Hangzhou were studied. Tinnitus status, age, education, personal protection, smoking history, drinking history, and family history of the participants were surveyed by questionnaires. Binaural pure tone hearing threshold test was performed on all study subjects. The environmental noise in the workplace was measured. The relationships of tinnitus with noise exposure intensity, noise exposure time, noise exposure category, cumulative noise exposure, and wearing hearing protectors among the noise-exposed workers were analyzed by logistic regression. Results The prevalence of tinnitus among the noise-exposed workers was 36.1%. The mean hearing thresholds at 500, 3000, 4000, and 6000 Hz in the right and left ears were higher in the tinnitus group than in the non-tinnitus group (P<0.05); the hearing threshold at 2000 Hz in the right ear was higher in the tinnitus group than in the non-tinnitus group (P<0.05). There was no statistically significant difference between the two groups in the prevalence of monaural speech-frequency hearing loss or monaural high-frequency hearing loss (P>0.05). The on-site noise intensity was divided into three groups: ＜85, 85-＜95, and ≥95 dB(A); the prevalence of tinnitus in the three groups was 19.6%, 40.5%, and 66.7% respectively. The years of noise exposure was divided into three groups: ＜1, 1-＜5, and ≥5 years; the prevalence of tinnitus in the three groups was 17.9%, 34.0%, and 45.4% respectively. The cumulative noise exposure was divided into six groups: ＜80, 80-＜85, 85-＜90, 90-＜95, 95-＜100, and ≥100 dB(A)·year; the prevalence of tinnitus in the six groups was 6.8%, 25.0%, 31.0%, 39.6%, 43.1%, and 46.7% respectively. The prevalence of tinnitus was higher in the non-stationary noise group (42.5%) than in the stationary noise group (26.8%) (χ2=26.18, P<0.01), and the prevalence in the group without or with hearing protection was 39.7% and 35.5% respectively. The results of logistic regression showed that workers exposed to higher intensity, longer noise exposure, higher cumulative noise exposure, and non-stationary noise (reference: stationary noise) resulted in a higher risk of tinnitus (Ptrend<0.01 or P<0.01); workers wearing of hearing protection device versus those not showed a lower risk of tinnitus (P<0.05). Conclusion Higher intensity, longer exposure to noise, and more cumulative noise exposure associate with a higher risk of tinnitus. Wearing hearing protective device can reduce the risk of tinnitus. Tinnitus in noise-exposed workers can precede the presentation of abnormal hearing loss.

Path analysis on relationship among tested hearing thresholds, conscious hearing, and negative emotions in noise-exposed workers / 环境与职业医学

Background The correlation between noise exposure and negative emotions of noise-exposed workers has received increasing attention and related studies have been reported. However, there is a lack of research on the path and effect analysis of the relationship between noise exposure and negative emotions, which will contribute to a more comprehensive understanding of the health damage characteristics of noise in addition to hearing loss. Objective To explore the path and effects of cumulative noise exposure, tested hearing thresholds, and conscious hearing level of noise-exposed workers on negative emotions. Methods Using stratified random sampling, 312 noise-exposed workers from a machinery and equipment manufacturing enterprise were selected. Occupational history, negative emotions (including the feelings of stress, anxiety, and depression), and conscious hearing level of the workers were investigated using the Depression-Anxiety-Stress Scale (DASS-21) and a self-made questionnaire. The hearing threshold of the workers was measured by pure tone air conduction audiometry. Sound level meter was used to measure noise equivalent sound level at selected work sites. Individual cumulative noise exposure was estimated based on work site noise level and personal noise exposure history. Path analysis was used to analyze potential mediating effects of workers' hearing thresholds and conscious hearing levels on the relationship between noise exposure and negative emotions (including stress, anxiety, and depression). Results The positive rates of negative emotions among the 312 noise-exposed workers were 18.27% (57/312) for stress, 46.79% (146/312) for anxiety, and 28.53% (89/312) for depression; the cumulative noise exposure ranged from 101.0 to 136.1 dB(A)·d, with an average of 125.69 dB(A)·d. The distributions of tested hearing thresholds and conscious hearing levels among the workers exposed to noise were significantly inconsistent (P<0.001), with both unweighted and weighted Kappa values less than 0.4. The percentage of workers with conscious hearing levels higher than their hearing threshold levels was 16.0%, and the percentage of workers with conscious hearing levels lower than conscious hearing levels was 38.7%. The path analysis results showed that tested hearing thresholds had no mediating effect on the relationship between cumulative noise exposure and negative emotions. There was a partial mediating effect of conscious hearing level on the relationship between cumulative noise exposure and negative emotions, with a mediating effect value of 0.06 (95%CI: 0.03, 0.11) and a mediating effect ratio of 28.57%. Conclusion Conscious hearing plays a partial mediating role in the relationship between cumulative noise exposure and negative emotions of noise-exposed workers, while tested hearing thresholds do not.

Noise Exposure Among Motorcycle Riders: A Scoping Review

@#This scoping review aimed to determine the dosage of noise exposure among motorcycle riders and the sources contributing to a rider’s noise exposure. A systematic search of several scientific databases was conducted from 1981 until 2021. Eligible articles were included into the defined criteria. The dosage of noise exposure, sources, and standardization method were extracted. A total of 37 studies were included. There was scarce publication regarding the exact level of noise exposure experienced by the riders. There was, however, abundant evidence on indirect sources of noise exposure for riders, which requires further critical analysis. The dosage of noise exposure among riders was significantly higher than the recommended level. Seven sources were determined to generate noise which could potentially affect the riders, presented in this paper along with their respective evidence.

Relationship between occupational noise exposure and renal function impairment in oil workers / 环境与职业医学

Background The current oil production determines oil workers’ occupational noise exposure. Without effective protection, noise will affect various aspects of worker’s body functions, including acting on the adrenal cortex system and resulting in renal function damage. Objective To evaluate the associations of noise exposure and its cumulative exposure level with renal function impairment of oil workers. Methods Oil workers from a collective medical examination in a hospital were selected as the study subjects. In accordance with the national standard Measurement of Physical Agents in the Workplace Part 8: Noise (GBZ/T 189.8—2007), noise exposure was measured three times at the oil workers' work site, and their average value was calculated to obtain the cumulative noise exposure (CNE). A questionnaire survey was conducted to collect general information such as socio-demographic characteristics, family history, lifestyles, and occupational history. All blood biochemical indicators were measured in the fasting state. Renal function impairment was judged based on the glomerular filtration rate. The relationship between CNE and renal function was analyzed using receiver operating characteristic curve (ROC) for workers with noise exposure. Results A total of 2 917 subjects were included in the study and their prevalence of renal function impairment was 14.2%. The univariate analysis results suggested statistically significant differences in the prevalence of renal function impairment among the oil workers grouped by having hypertension or not, gender, age, marital status, marital status, smoking, and alcohol consumption (P＜0.05); the prevalence of renal impairment was significantly higher in those with abnormal values of uric acid, total cholesterol, triglycerides, high-density lipoprotein, and fasting glucose than in those with normal values (P＜0.05); the oil workers with noise exposure [n=1565, 53.7%, equivalent sound level ≥80 dB(A)] showed a higher prevalence of renal function impairment than those without (P＜0.05). The results of multiple logistic regression analysis showed that being female (OR=2.811, 95%CI: 1.960-4.030), age at 31 years and above (OR31-40=3.502, 95%CI: 1.402-8.751; OR41-50=4.255, 95%CI: 1.759-10.291; OR≥51=7.179, 95%CI: 2.864-17.996), showing abnormal uric acid (OR=5.932, 95%CI: 4.486-7.843), having hypertension (OR=1.593, 95%CI: 1.230-2.063), alcohol consumption (OR=2.648, 95%CI: 1.346-5.212), and smoking (OR=1.816, 95%CI: 1.133-2.911) had higher risks of developing renal function impairment; besides, those exposed to noise had 1.351 times (95%CI: 1.073-1.702) higher risks of developing renal function impairment than non-exposed individuals. Noise-exposed oil workers in the renal impairment group had higher noise exposure intensity and CNE compared to the noise-exposed oil workers in the normal renal function group (P＜0.05), and the workers had an increased risk of renal function impairment when the CNE was >95.85 dB(A)·year versus CNE ≤ 95.85 dB(A)·year (OR=2.583, 95%CI: 1.956-3.411). Conclusion Exposure to noise, higher noise exposure intensity, and higher level of CNE may be associated with developing renal function impairment in oil workers. Oil workers with CNE above 95.85 dB(A)·year are at an increased risk of renal impairment.

Effect of noise on morphological structure and functions of rat liver / 环境与职业医学

Background Noise can cause not only auditory system injury, but also liver damage. However, the biomarkers and pathological mechanism of noise-induced liver injury are not clear yet. Objective To observe the effect of noise on the morphological structure and functions of rat liver. Methods A total of 30 Wistar rats were randomly divided into a normal control group, a low noise exposure group [(95 dB sound pressure level (SPL)], and a high noise exposure group (105 dB SPL). After 30 days of noise exposure, blood was collected, and livers were harvested and fixed. The pathological changes of livers were observed. The levels of biochemical indicators of liver function, blood glucose, and blood lipid were measured. Serum metabolites were detected by ultra-high-pressure liquid chromatography-tandem quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS). Differential metabolite markers and metabolic pathways were identified. Results Compared with the control group, the body weight gain decreased in the low noise group and the high noise group after noise exposure (P<0.001, P<0.05). The pathological results showed that noise caused the rat livers’ morphological and structural damage at various degrees, and damage of the high noise exposure group was more serious. Compared with the control group, the serum levels of aspartate aminotransferase, albumin, and glycosylated serum protein in the low noise exposure group were increased (P<0.05), but the total bile acid level was decreased (P<0.05). The serum levels of alanine aminotransferase, aspartate aminotransferase, albumin, triglyceride, low density lipoprotein, and glycosylated serum protein in the high noise group exposure were increased (P<0.05), but the glucose level was decreased (P<0.05). In the serum metabolomics analysis, 11 differential metabolites were screened out in the low noise exposure group, which were mainly enriched in 3 pathways (thiamine metabolism, primary bile acid biosynthesis, and bile secretion) related to liver metabolism. Four differential metabolites were screened out in the high exposure noise group, which were mainly enriched in four significantly different metabolic pathways (insulin signaling pathway, non-alcoholic fatty liver disease, bile secretion, and insulin secretion). All the metabolic pathways involved in bile acid secretion and metabolism. Conclusion Nosie exposure can not only damage the liver structure of rats, but also affects the metabolism functions of liver. The mechanism may be related to bile acid secretion metabolic pathway.

Applying kurtosis-adjusted cumulative noise exposure to assess occupational hearing loss among furniture manufacturing workers / 环境与职业医学

Background Occupational noise-induced hearing loss (NIHL) is one of the most prevalent occupational diseases in the world. With the development of industry, noise sources in the workplace have become increasingly complex. Objective To apply kurtosis-adjusted cumulative noise exposure (CNE) to assess the occupational hearing loss among furniture manufacturing workers, and to provide a basis for revising noise measurement methods and occupational exposure limits in China. Methods A cross-sectional survey was conducted to select 694 manufacturing workers, including 542 furniture manufacturing workers exposed to non-Gaussian noise, and 152 textile manufacturing workers and paper manufacturing workers exposed to Gaussian noise. The job titles involving non-Gaussian noise were gunning and nailing, and woodworking, while those involving Gaussian noise were weaving, spinning, and pulping. High frequency noise-induced hearing loss (HFNIHL) and noise exposure data were collected for each study subject. Noise energy metrics included eight-hour equivalent continuous A-weighted sound pressure level (LAeq,8 h) and CNE. Kurtosis was a noise temporal structure metric. Kurtosis-adjusted CNE was a combined indicator of noise energy and temporal structure. Results The age of the study subjects was (35.64±10.35) years, the exposure duration was (6.71±6.44) years, and the proportion of males was 75.50%. The LAeq,8 h was (89.43±6.01) dB(A). About 81.42% of the study subjects were exposed to noise levels above 85 dB(A), the CNE was (95.85±7.32) dB(A)·year, with a kurtosis of 99.34 ± 139.19, and the prevalence rate of HFNIHL was 35.59%. The mean kurtosis of the non-Gaussian noise group was higher than that of the Gaussian noise group (125.33±147.17 vs. 5.86±1.94, t=−21.04, P<0.05). The results of binary logistic regression analysis showed that kurtosis was an influential factor of workers' HFNIHL after correcting for age, exposure duration, and LAeq,8 h (OR=1.49, P<0.05). The results of multiple linear regression analysis showed that the effects of age, exposure duration, LAeq,8 h, and kurtosis on noise-induced permanent threshold shift at frequencies of 3, 4, and 6 kHz of the poor hearing ear were statistically significant (all P<0.05). The results of chi-square trend analysis showed that when CNE ≥ 90 dB(A)·year, the HFNIHL prevalence rate elevated with increasing kurtosis (P<0.05). The mean HFNIHL prevalence rate was higher in the non-Gaussian noise group than in the Gaussian noise group (31.7% vs. 22.0%, P<0.05). After applying kurtosis-adjusted CNE, the linear equation between CNE and HFNIHL prevalence rate for the non-Gaussian noise group almost overlapped with that for the Gaussian noise group, and the mean difference in HFNIHL prevalence rate between the two groups decreased from 9.7% to 1.4% (P<0.05). Conclusion Noise kurtosis is an effective metric for NIHL evaluation. Kurtosis-adjusted CNE can effectively evaluate occupational hearing loss due to non-Gaussian noise exposure in furniture manufacturing workers, and is expected to be a new indicator of non-Gaussian noise measurement and assessment.

Measuring method of occupational non-Gaussian noise exposure based on kurtosis adjustment / 环境与职业医学

The existing measuring methods of noise exposure on the basis of equal energy hypothesis are applicable to Gaussian noise while not fully applicable to non-Gaussian noise. Studies have shown that temporal structure (kurtosis) combined with noise energy has the potential to quantify non-Gaussian noise exposure effectively. However, there is no unified measuring method adopting this joint metric. In this paper, the measuring method of non-Gaussian noise exposure based on kurtosis adjustment was introduced, detailing measurement indicators, adjustment schemes, applicable objects, instrument requirements, and measurement steps. Adjusting the exposure duration of cumulative noise exposure (CNE) by kurtosis or adjusting the equivalent continuous A-weighted sound pressure level (LAeq) by an adjustment coefficient based on animal or population studies can more accurately quantify workers' exposure to non-Gaussian noise and improve the underestimation of hearing loss caused by non-Gaussian noise. A large number of population studies are warranted in the future to verify the effectiveness of these two adjustment schemes.

Application of two occupational risk assessment methods in noise assessment of a beer manufacturing enterprise / 公共卫生与预防医学

Objective To study the applicability of two different occupational health risk assessment methods for noise positions in a beer manufacturing enterprise. Methods An occupational health investigation along with the detection of occupational hazard factors were carried out in the workplace of a beer manufacturing enterprise in Wuhan. Workers with 8-hour working day equivalent sound level (LEX,8 h) ≥ 80 dB (A) were selected as research subjects. The “Guidelines for Noise Occupational Disease Risk Management” method and occupational hazard risk index method were used to assess the risk of noise jobs in the beer manufacturing company. The assessment results of the two methods were compared. Results The noise exposure level of the enterprise was between 81.2 and 91.2dB(A). The guideline method predicted that the risk of high-frequency hearing loss and noise deafness for wine bottling workers and labelers on the bottling production line was high after 35 years exposure to noise. Washing，inspection and boxing on the bottling production line and bottling up on the canning production line were at medium risk, and others were at low risk. The evaluation results of the occupational hazard risk index method showed that the bottlers, bottling workers, wine inspectors, labelers and boxers on the bottling production line were at medium risk, and other positions were at low risk. Conclusion The occupational hazard risk index method is more comprehensive to consider all the factors of health risk, and the evaluation results are close to the “Guidelines for Noise Occupational Disease Risk Management” method. The guideline method can quantitatively predict the risk of high-frequency hearing loss and noise deafness, and the risk of hearing loss increases with the extension of years of noise exposure.

Application of temporal kurtosis index in assessing hearing loss caused by complex noise / 中国职业医学

Complex noise with impulse or impact property is common in workplace, and its damage on the auditory system is greater than that of steady-state noise. At present, the noise exposure measurement and evaluation indicators widely used in the world mainly include the equivalent continuous sound level and the cumulative noise exposure, both are based on the equal energy hypothesis(EEH). EEH only considered the damage of noise energy on the auditory system, but ignored the effect of temporal characteristics of noise, and underestimated the degree of hearing loss associated with complex noise. This paper first introduced the limitations of current noise exposure assessment standards at home and abroad, then introduced the definition of temporal kurtosis and the calculation method of its related energy indexes(such as cumulative noise exposure and equivalent continuous A-weighted sound pressure level), and further summarized the effectiveness of temporal kurtosis as an auxiliary parameter of noise energy in assessing the risk of hearing loss caused by complex noise, providing a rationale to supplement the existing noise assessment standards.

Analysis of factors affecting the noise-induced high frequency hearing loss of male workers in a vehicle manufacturing enterprise / 中华劳动卫生职业病杂志

Objective@#To analyze the relationships between the exposure of occupational noise and the occurrence of noise-induced high frequency hearing loss in automobile manufacturing industry.@*Methods@#From June to November 2017, 1579 male workers were selected for exposure to noise hazards in the automobile manufacturing industry in Guangzhou for more than one year (including one year) using the convenient sampling method. According to the hearing test results, 276 people in the high frequency hearing loss group and 1303 in the normal hearing group were surveyed, occupational health tests were conducted, and the noise intensity in the workplace was measured. The cumulative noise exposure (CNE) was calculated. The relationship between shift work and high frequency hearing loss of noise work is analyzed.@*Results@#Compared with the normal hearing group, the noise exposure intensity, age, length of service, marital status, working system, and physical exercise of the high frequency hearing loss group were statistically significant (P<0.05). Through logistic regression analysis, after correcting the effects of organic solvent contact, marital status, and physical exercise, CNE, age, and shift operations (double-shift operations, three-shift operations) are the risk factors for high frequency hearing loss to occur.@*Conclusion@#The risk of hearing loss of workers exposed to noise in the whole vehicle manufacturing industry may be related to CNE, age, and shift work. Two-shift and three-shift work are possible risk factors for noise-induced high frequency hearing loss.

Effect of cumulated noise exposure on the intima-media thickness of carotid artery in steel workers / 中国职业医学

OBJECTIVE: To explore the effects of cumulative noise exposure(CNE) on the intima-media thickness(IMT) of carotid artery in steel workers. METHODS: A cluster random sampling method was used to select 1 437 noise exposed workers in a steel company as study subjects. The CNE was calculated according to the noise intensity of the workplace, and the occupational health check was carried out to construct the structural equation model of noise to IMT. RESULTS: The detection rate of carotid atherosclerosis(CAS) in these 1 437 subjects was 38.3%. The CAS detection rates of steel workers increased with the increasing CNE(P<0.01). The structural equation model had good fitting effect. Path analysis showed CNE can indirectly affect IMT through blood pressure, triglycerides, fasting blood glucose, homocysteine, high-density lipoprotein & apolipoprotein A, low-density lipoprotein & apolipoprotein B. The total effects were-0.375, 0.337, 0.248, 0.117, 0.056, 0.056 and 0.018 respectively. CONCLUSION: CNE can indirectly increase the IMT of steel workers by acting on the proximal cause.

Occupational noise exposure of traffic enforcers in selected streets in the City of Manila

@#<p style="text-align: justify;"><strong>OBJECTIVE:</strong> The study aimed to evaluate the sound pressure levels of selected traffic enforcer sites in the City of Manila.</p><p style="text-align: justify;"><strong>METHODOLOGY:</strong> A Brüel & Kjær Integrating Sound Level Meter type 2225 was used to measure sound pressure levels in dB(A) to estimate personal noise exposure of traffic enforcers designated at Quezon Boulevard near Quiapo Church and Recto - Rizal Avenue on a weekday and a weekend. Graphs were generated while appropriate measures were calculated for the noise exposure levels. The mean exposure levels were compared with the Philippine Occupational Safety and Health standards by computing the corresponding permissible exposure limit for each work shift using the Equal Energy Principle.17</p><p style="text-align: justify;"><strong>RESULTS:</strong> Noise exposure levels at Quezon Boulevard ranged from 75.0 dB(A) to 91.5 dB(A) with mean noise exposure level of 84.3 ± 3.7 dB(A) and 82.5 ± 2.6 dB(A) for the weekday AM and PM shift, respectively. The mean noise exposure level at Quezon Boulevard for the weekend AM shift was 82.4 ± 2.6, whereas 80.4 ± 2.8 for the PM shift. The noise exposure levels at Recto - Rizal Avenue ranged from 81.5 dB(A) to 99.3 dB(A) with mean noise exposure level of 86.7 ± 2.6 dB(A) and 86.0 ± 2.1 dB(A) for the weekday AM and PM shift, respectively. The mean noise exposure level at Recto - Rizal Avenue for the weekend AM shift was 86.7 ± 2.3, whereas 89.0 ± 4.0 for the PM shift.</p><p style="text-align: justify;"><strong>CONCLUSION:</strong> The study showed that traffic enforcers designated at Quezon Boulevard and Recto - Rizal Avenue are exposed to noise levels that do not exceed the Philippine Occupational Safety and Health standards.</p>

Analysis on hearing status and related influencing factors in workers exposed to noise in an automobile manufacture enterprise / 中华劳动卫生职业病杂志

Objective@#To study the hearing status and analyze the related influencing factors in noise-exposed workers in an automobile manufacture enterprise, and put forward suggestions for prevention of noise-induced hearing loss.@*Methods@#Noise exposure level testing, audiometry testing and questionnaires were performed for noise exposed workers in the automobile manufacture enterprise. To analyze the relationship between different factors and noise-induced hearing loss by cumulative noise exposure(CNE) calculated 8-hour continuous A-weighted equivalent noise level and seniority.@*Results@#The detection rate of hearing loss in noise-exposed workers was 22.8%. The noise exposure intensity of stamping workshop is higher than other workshop, and the hearing loss detection rate of stamping workshop workers is higher than other workshop workers. The detection rate of hearing loss has significant difference in LAeq·8 h, seniority, CNE, age, high temperature and wearing earplugs (P<0.05). The results of logistic regression analysis showed that CNE, age and high-temperature were risk factors for noise-induced hearing loss (P<0.05 and OR>1) and there was an increasing tendency of hearing loss with increase in length of service and CNE, while using of earplugs was a protective factor (P<0.05 and OR<1). With the increase of CNE, the incidence of hearing loss is the rising trend.@*Conclusion@#It is suggested to strengthen the noise control and individual protection and improve the high-temperature working environment, which plays an important role in reducing the occurrence of noise-induced hearing loss.

The effect of noise exposure on insulin sensitivity in mice may be mediated by the JNK/IRS1 pathway

BACKGROUND@#Epidemiological studies have suggested that noise exposure may increase the risk of type 2 diabetes mellitus (T2DM), and experimental studies have demonstrated that noise exposure can induce insulin resistance in rodents. The aim of the present study was to explore noise-induced processes underlying impaired insulin sensitivity in mice.@*METHODS@#Male ICR mice were randomly divided into four groups: a control group without noise exposure and three noise groups exposed to white noise at a 95-dB sound pressure level for 4 h/day for 1, 10, or 20 days (N1D, N10D, and N20D, respectively). Systemic insulin sensitivity was evaluated at 1 day, 1 week, and 1 month post-noise exposure (1DPN, 1WPN, and 1MPN) via insulin tolerance tests (ITTs). Several insulin-related processes, including the phosphorylation of Akt, IRS1, and JNK in the animals' skeletal muscles, were examined using standard immunoblots. Biomarkers of inflammation (circulating levels of TNF-α and IL-6) and oxidative stress (SOD and CAT activities and MDA levels in skeletal muscles) were measured via chemical analyses.@*RESULTS@#The data obtained in this study showed the following: (1) The impairment of systemic insulin sensitivity was transient in the N1D group but prolonged in the N10D and N20D groups. (2) Noise exposure led to enhanced JNK phosphorylation and IRS1 serine phosphorylation as well as reduced Akt phosphorylation in skeletal muscles in response to exogenous insulin stimulation. (3) Plasma levels of TNF-α and IL-6, CAT activity, and MDA concentrations in skeletal muscles were elevated after 20 days of noise exposure.@*CONCLUSIONS@#Impaired insulin sensitivity in noise-exposed mice might be mediated by an enhancement of the JNK/IRS1 pathway. Inflammation and oxidative stress might contribute to insulin resistance after chronic noise exposure.

Effect of cumulative noise exposure on hypertension in automotive manufacturing workers / 中国职业医学

OBJECTIVE: To analyze the relationship between the cumulative noise exposure( CNE) and prevalence of hypertension in automotive manufacturing workers. METHODS: A total of 1 535 noise-exposed male workers with length of service ≥ 1. 0 year from automobile manufacturing industries in Guangzhou City was chosen as study subjects by convenience sampling method. The noise intensity in the workplace was measured, the CNE calculated, and the occupational health examination conducted. RESULTS: The prevalence of hypertension of the study subjects was 8. 1%( 125/1 535). The prevalence of hypertension showed an upward trend with the increase of CNE( P < 0. 01). The multivariate logistic regression analysis showed that the prevalence risk of hypertension increased with the increase of CNE after adjusting for confounding factors such as body mass index,smoking and wearing personal protective equipment in automobile manufacturing workers( P < 0. 01). CONCLUSION: There is a dose-effect relationship between prevalence of hypertension and CNE in automobile manufacturing workers who exposed to noise.

Occupational Noise Exposure and Serum Lipids in Manufacturing Company Workers

OBJECTIVE: The study aimed to examine the relationship between occupational cumulative noise exposure and serum lipids as risk factor of ischemic heart disease. METHODS: Participants (n=1,175) were workers of the steel product manufacturing factory exposed to more than 85 dB(A) of noise. We collected ambient noise and other materials monitoring data in workplace, laboratory test, and structured-questionnaires. Occupational noise exposure was defined as cumulative noise exposure calculated by duration of exposure and level of exposure. Serum lipids were total cholesterol, triglyceride, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and total cholesterol/HDL cholesterol. We examined the relationship between serum lipids and occupational noise exposure. RESULTS: In a noise exposure environment, 657 people (56.8%) worked for more than 10 years. Cumulative noise exposure increased significantly as exposure duration and noise level increased. Cumulative noise exposure were related to total cholesterol (P=0.001), LDL cholesterol (P=0.002), total cholesterol/HDL cholesterol (P=0.005) in correlation analysis. We conducted multiple linear regression analysis using the serum lipids and significant variables including cumulative noise exposure. We identified that total cholesterol was significantly related to cumulative noise exposure (β=0.072). CONCLUSION: We propose occupational cumulative noise exposure may be significantly related to total cholesterol.