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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.
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{L-End}Objective To study the situation of occupational noise exposure and hearing loss in workers in petrochemical enterprises. {L-End}Methods A total of 2 052 workers from four large-scale petrochemical enterprises in China were selected as the research subjects using convenience sampling method. The noise-exposed level of job position was detected by individual noise dosimeters, and pure-tone audiometry of the workers was conducted. {L-End}Results The noise-exposed levels at various job positions in the workplace of the enterprises ranged from 83.2 to 86.7 dB(A), and 61.1% of the job positions had a cumulative noise exposure (CNE) > 95.0 dB(A) per year. The detection rate of high-frequency hearing loss was 12.6%(259/2 052) among the research subjects. The detection rate of speech frequency hearing loss was 5.5%(112/2 052) among the research subjects. The result of CNE stratified analysis showed that the detection rate of hearing loss at frequencies of 2.0, 3.0, 4.0, and 6.0 kHz, as well as high frequencies, gradually increased with increasing CNE (all P<0.05). {L-End}Conclusion The noise hazard in petrochemical enterprises is severe, and long-term occupational noise exposure can increase the risk of hearing loss among workers. Efforts should be made to strengthen noise control and hearing protection measures.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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Cholesterol , Cholesterol, LDL , Linear Models , Lipoproteins , Myocardial Ischemia , Noise , Noise, Occupational , Risk Factors , Steel , TriglyceridesABSTRACT
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.
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OBJECTIVE: To analyze the relationship between the cumulative noise exposure( CNE) and prevalence of hypertension in iron and steel production workers. METHODS: By convenience sampling method,2 253 workers,whose workplace in an iron and steel enterprise with wet bulb globe temperature index less than 25. 0 ℃,were selected as study subjects. The blood pressure and workplace noise exposure level were measured. According to the equal energy principle,the normalized continuous A-weighted sound pressure level equivalent to an 8 h-working-day and workers' length of service were used to calculate the CNE level. The workers with CNE≥75 d B( A) ·year were regarded as the exposure group,and those with CNE < 75 d B( A) ·year were deemed as the control group. RESULTS: The prevalence rate of hypertension in the exposure group was higher than that of the control group( 32. 3% vs 21. 5%,P < 0. 01). With the increased CNE level,the prevalence rate of hypertension increased( P < 0. 01). The multiple logistic regression analysis results showed that the prevalence risk of hypertension disputed an upward trend of the dose-response relationship following the increasing CNE among the iron and steel production workers( P < 0. 01) after controlling the confounding factors of age,body mass index,educational background,family history of hypertension,smoking,alcohol drinking,salt intake,fried barbecue food intake and so on. CONCLUSION: CNE is a vital factor which influences hypertension prevalence in iron and steel production workers. Strengthen the noise protection is helpful for the prevention and treatment of hypertension in the steel workers.
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OBJECTIVES: The association of workplace cumulative noise exposure and blood pressure was investigated in this study using cross-sectional design. METHODS: The study population comprised 852 manufacturing male workers of whom occupational health examination data, questionnaire and personnel records were available. Workplace ambient noise monitoring data was used for calculating individual cumulative noise exposure level. Mean of each systolic and diastolic blood pressure of occupational health examination data was used for individual systolic and diastolic blood pressure level. Possible confounding variables including family history of hypertension, smoking habit, alcohol drinking habit were collected by questionnaire. On the basis of job location and duration of work at the location, a cumulative time-weighted average noise level was calculated for each workers. According to this cumulative noise exposure level, each study subject was categorized as low noise exposure group, moderate noise exposure group, high noise exposure group, very high noise exposure group. Among noise exposure groups, mean of systolic and diastolic blood pressure was compared after adjusting possible confounding variables such as age, body mass index, serum cholesterol level, family history of hypertension, smoking history, alcohol drinking habit. RESULTS: After adjusting possible confounding variables, noise exposure group was significant explanatory variables for both systolic and diastolic blood pressure, and mean of both systolic and diastolic blood pressure of very high exposure group was higher than that of low exposure group. CONCLUSIONS: These findings suggested that the high cumulative noise exposure might elevate the blood pressure.