[Liver impairment status toward workers exposed to vinyl chloride under different techniques].

OBJECTIVE: To analyse potential differences towards liver impairment status on vinyl chloride monomer(VCM) exposed population from technique under acetylene hydrochlorination to the one of ethylene oxychlorination respectively and to explore the possible reasons, which will pave the way for occupational health promotion in terms of hazard reduction. METHODS: a cross-sectional study was initiated between June and September in 2022 towards 2 groups of VCM exposed population from the facility of acetylene hydrochlorination(n=78) and the one of ethylene oxychlorination(n=69) in a PVC petrochemical complex enterprise(abbreviation of H) in Tianjin City. The demographic information concerning age, gender, messages on occupational history, field investigation were inquired through questionnaire interview. Then, venous blood(4 mL/person) and urine(10-50 mL/person) were collected during the physical exam phase and indices of 8-hydroxy-2 deoxyguanosine(8-OHdG) in blood and thiodiglycolic acid(TDGA) in urine were detected through ELISA and solid phase extraction-ion chromatography respectively. RESULTS: The 2 groups of population were matched well in terms of average age distribution and gender composition ratio, with significant differences on population composition ratio were found on variables of working years, alcohol consumption and daily sleeping duration(P<0.01 or P<0.05). It was found that the average content of TDGA in acetylene hydrochlorination group was(0.81±0.05)mg/L while the content in ethylene oxychlorination group reached to(0.83±0.06)mg/L, noteworthy differences were only found among 6 posts in the acetylene hydrochlorination group and 5 others in the ethylene oxychlorination group after classification for specific posts, however, the average concentration of 8-OHdG in acetylene hydrochlorination group(122(78.3, 168.8) µg/m~3) was different from the one in ethylene oxychlorination group(101.7(79.6, 149.7) µg/m~3)(Z=6.82, P<0.05). Moreover, a series of positive correlations in moderate intensity between 8-OHdG concentration and TDGA content were observed among posts of polymerization cleaners(r=0.53), aggregation operators(r=0.47), maintenance repairers(r=0.45), sampling operators(r=0.41) in acetylene hydrochlorination group(P<0.05) and posts of cracking reactants(r=0.64), DCS operators(r=0.51), oxychlorination operators(r=0.50) and chemical loaders(r=0.44) in ethylene oxychlorination group(P<0.05). Liver function indices such as content on ALT(χ~2=15.41, P<0.01), AST(χ~2=9.95, P<0.01) and ALP(χ~2=3.79, P<0.01) were different in the 2 groups population with statistical significance, then proportions on population composition ratio that exceeded normal ranges of indices on ALT, AST, AST/ALT ratio, ALP and Alb/Glb ratio were higher in acetylene hydrochlorination group than ones in ethylene oxychlorination group with great significance(P<0.05), so as to the abnormalities in liver B altrosonography test between groups(χ~2=17.33, P<0.01). Binary logistic regression model indicated that 8-OHdG concentration in blood that exceed 90 µg/m~3, TDGA content in urine that exceed 0.60 mg/L, working years that were over 10a, alcohol consumption, sleeping duration less than 6 h per day and male workers were potential risky factors for liver impairment(P<0.05). CONCLUSION: The degree on liver impairment status was higher in acetylene hydrochlorination group than ones in in ethylene oxychlorination group under the same PVC factory, which might be associated with the oxidative stress injury induced from the combination of higher VCM concentration at workplaces, longer cumulative exposure time, longer working years, alcohol consumption habits and sleep shortage caused by shift work patterns.

Impacts of inflammatory cytokines on depression: a cohort study.

BACKGROUND: Inflammatory factors are associated with depression. We seek to investigate the correlation between inflammatory cytokines and prognosis of depression or suicidal ideation and behavior at 3 months in depression patients. METHODS: Eighty-two depressed outpatients were recruited and treated as usual. Plasma cytokines were measured at baseline. Patients were followed up with Patient Health Questionnaire-9 and suicidal ideation and behavior according to the item 3 of Hamilton depression scale for 3 months. RESULTS: Compared to the depression patients with low level of interleukin-1ß, the high one had severe depressive symptoms at month 2 and 3 (B 0.92, P < 0.01; B 0.86, P = 0.02; respectively). The incidence of suicidal ideation or behavior was 18.3% at 3 months. Depression patients with high levels of tumor necrosis factor-α showed high risk of suicidal ideation and behavior than the low one (OR 2.16, 95% CI 1.00-4.65, P = 0.04). CONCLUSIONS: High levels of interleukin-1ß and tumor necrosis factor-α were predictive of middle-term severe depressive symptoms and suicidal ideation and behavior respectively.

Integrated mRNA and microRNA profiling in lung tissue and blood from human silicosis.

BACKGROUND: The overwhelming majority of subjects in the current silicosis mRNA and microRNA (miRNA) expression profile are of human blood, lung cells or a rat model, which puts limits on the understanding of silicosis pathogenesis and therapy. To address the limitations, our investigation was focused on differentially expressed mRNA and miRNA profiles in lung tissue from silicosis patients to explore potential biomarker for early detection of silicosis. METHODS: A transcriptome study was conducted based on lung tissue from 15 silicosis patients and eight normal people, and blood samples from 404 silicosis patients and 177 normal people. Three early stage silicosis, five advanced silicosis and four normal lung tissues were randomly selected for microarray processing and analyze. The differentially expressed mRNAs were further used to conduct Gene Ontology and pathway analyses. Series test of cluster was performed to explore possible changes in differentially expressed mRNA and miRNA expression patterns during the process of silicosis. The blood samples and remaining lung tissues were used in a quantitative real-time PCR (RT-qPCR) (RT-qPCR). RESULTS: In total, 1417 and 241 differentially expressed mRNAs and miRNAs were identified between lung tissue from silicosis patients and normal people (p < 0.05). However, there was no significant difference in most mRNA or miRNA expression between early stage and advanced stage silicosis lung tissues. RT-qPCR validation results in lung tissues showed expression of four mRNAs (HIF1A, SOCS3, GNAI3 and PTEN) and seven miRNAs was significantly down-regulated compared to those of control group. Nevertheless, PTEN and GNAI3 expression was significantly up-regulated (p < 0.001) in blood samples. The bisulfite sequencing PCR demonstrated that PTEN had significantly decreased the methylation rate in blood samples of silicosis patients. CONCLUSIONS: PTEN might be a potential biomarker for silicosis as a result of low methylation in the blood.

Improvements in protective measures in factories with acetylene hydrochlorination and ethylene oxychlorination techniques declined risk assessment levels and affected liver health status.

Acetylene hydrochlorination and ethylene oxychlorination are the two most common methods of producing vinyl chloride monomer (VCM), which has been linked to liver impairment, hepatocellular carcinoma (HCC), and angiosarcoma of the liver (ASL) in occupational settings. However, whether and how these impairments could be effectively improved from workplace root causes has yet to be discovered. This study aimed to evaluate whether improvements in protective measures in groups Y (408 subjects) and Z (349 subjects) could have an influential impact on the alleviation of liver impairment by comparing risk assessment levels under several semi-quantitative models and results from liver ultrasound detection and liver function tests before and after the improvement. Importantly, significant differences in constituent ratio involved in parameters among age, length of employment, weekly exposure time, smoking status, alcohol consumption, and sleeping quality were found between Y and Z before improvement took place in 2020 (P < 0.05 or P < 0.001), and population distribution by gender between Y and Z was in a large homogeneity with differences in age and length of employment. CSTE involves ore breaking, acetylene generation, steam stripping, outward processing, and welding maintenance, was disqualified in 2020 compared to OEL, and was said to have declined to meet OEL requirements by 2021. Further, a negative correction of fresh air requirement and ventilation air changing rate with ambient concentration toward hazards in Y was stronger in 2021 than in 2020. Significant differences in risk levels in Y between 2020 and 2021 were found as ore breaking, acetylene generation, steam stripping, outward processing, VCM polymerization, welding, and repairing, decreasing to relatively lower risk levels in 2021 from the original ones in 2020 only under the semi-quantitative comprehensive index model. Abnormal rates toward other hepatic symptoms decreased in the majority of positions after the improvement, as referred to by alterations such as ALT, AST, and GGT. Overall, the effect of improvements on protective measures effectively reduced positions' risk assessment levels through ventilation enhancement and airtight strengthening, which further affected abnormal rates toward other hepatic symptoms, and alterations such as ALT, AST, and GGT were much more significant in Y than effect in Z.

[Risk assessment of noise-induced hearing loss among workers in railway transportation equipment manufacturing enterprises].

OBJECTIVE: To analyze the noise exposure and hearing loss of workers in railway transportation equipment manufacturing enterprises, and to assess the risk of hearing loss caused by noise. METHODS: From 2018 to 2020, an investigation was carried out on 3 railway transportation equipment manufacturing enterprises in Hubei Province and Hunan Province. A total of 840 noise-exposed workers were selected, the individual noise exposure level(L_(Aeq·8 h)) and hearing loss level were measured, the cumulative noise exposure(CNE) was calculated, and the relationship between hearing loss and technological process, working time and CNE were analyzed. ISO1999:2013 was used to calculate the change of hearing threshold and the risk of noise-induced hearing loss after 40 years old. RESULTS: The median age of workers was 32 years old, and the median working age for noise exposure was 10 years. The distribution of positions is mainly welding, machining, assembly and painting.79.5%(120/151) of the individual noise exposure doses exceeded 85 dB(A), and the average L_(Aeq.8 h) was 89.9(A). There were significant differences in the proportion of hearing loss among workers in different process units(χ~2= 29.597, P<0.001), and the proportion of hearing loss in the preparation and steel structure units was higher. The proportion of hearing loss showed an upward trend with the increase of working years(χ~2=164.462, P<0.001), and the high-frequency combined speech-frequency hearing loss(26.7%) increased significantly after working for more than 20 years. With the increase of CNE, the proportion of high-frequency hearing loss and the proportion of high-frequency combined speech-frequency hearing loss increased accordingly(χ~2=192.544, P<0.001). The proportion of high frequency combined speech frequency hearing loss increased significantly in the group with CNE greater than 105 dB(A)·years. It is predicted that the risk of hearing loss caused by noise in assemblers appears earliest and the risk is the greatest. The risk of high noise-induced frequency hearing loss of assemblers was 3.6%-8.6% at the age of 40, 20.2% at the age of 50, 22.0% at the age of 60. The risk of high-frequency combined speech-frequency hearing loss of assemblers was 1.2%-6.2% at the age of 50 and 8.6% at the age of 60. CONCLUSION: The noise hazard is serious and widely distributed in railway transportation equipment manufacturing enterprises, and the proportion of hearing loss increases with the increase of working time and CNE. Although ISO1999:2013 predicts that there may be an underestimation of noise-induced hearing loss in workers, it can be used as an early warning of hearing loss to identify the potential risk of hearing loss in the population.

[Risk assessment of hearing loss of noise workers in three petrochemical enterprises].

OBJECTIVE: To evaluate the risk of noise induced hearing loss among workers in petrochemical enterprises. METHODS: Number of workers exposed to noise were recruited from three petrochemical enterprises. The noise exposure level(L_(EX, W)) of the research objects was measured, their occupational history was investigated, and the audiometric testing was carried out. The ISO 1999:2013 model was used to calculate the change of hearing threshold level and the risk of hearing loss in each post, and compared the result of model with the result of the audiometric testing. RESULTS: The median of L_(EX, W) is range from 79.8 to 85.0 dB(A). L_(EX, W) among all posts were greater than 80 dB(A) except naphtha processing operators. The result of pure tone hearing threshold test showed that the prevalence of high-frequency hearing loss among workers exposed to noise was 12.8%. According to the classification of noise operation according to the maximum value of L_(EX, W), the operator for styrene dry gas combined unit is the only post that is extremely dangerous in the department of chemical, the other posts in the department of chemical and all posts in the department of public works are exposed to light and medium noise hazards, and 62.5% the external operators of the oil refining department are under heavy and extremely hazardous. According to the evaluation result of ISO 1999:2013, the risk of high-frequency hearing loss among workers in crude distillation unit, hydrogen production unit and the electricians of electrical system is high. The measured median of noise-induced pernament threshold shift(NIPTS) among male workers in different workstation was higher than the predicted median of NIPTS of ISO 1999, and the difference was statistically significant(P<0.01), and the predicted values for four-fifths of positions were more than 10 dB lower than the measured value. CONCLUSION: The risk of noise induced hearing loss of workers in petrochemical enterprises is high.

[Application of ISO 1999:2013 (E) model in risk assessment of hearing loss caused by industrial noise].

OBJECTIVE: To assess the risk of hearing loss caused by industrial noise exposure of welders and assemblers in a mechanical equipment manufacturing enterprise, and to explore the practical application and possible underestimation of ISO 1999∶2013(E) model. METHODS: A total of 829 noise-exposed male workers from a mechanical equipment manufacturing enterprise were selected as study subjects. The questionnaire survey was administered, and individual noise exposure level(L_(Aeq.8 h)) and hearing loss level were measured. The risk assessment method of ISO 1999∶2013(E) was used to calculate the change of hearing threshold level and the risk of noise-induced hearing loss. By comparing the median of permanent hearing threshold shift caused by actual noise with the median of ISO1999 predicted value, the reason of the difference between the predicted value of ISO 1999∶2013(E) model and the actual value was analyzed. RESULTS: The L_(Aeq.8 h )was 89.5 dB(A), 77.4%(n=62)of the individual noise exposure levels exceeded 85 dB(A), and 24.6% of the participants(n=829) had different degrees of hearing loss. There was significant difference in hearing loss rate between welding and assembly positions(χ~2=10.07, P<0.01). The risk of noise-induced high-frequency hearing loss of 90% welders was 11.2% at the age of 50, and 14.0% at the age of 60. The risk of noise-induced deafness of 90% welders was 4.3% at the age of 60. The risk of high noise-induced frequency hearing loss of 90% assemblers was at the range of 4.0%-9.0% at the age of 40, 20.8% at the age of 50, and 22.5% at the age of 60. The risk of noise-induced deafness of 90% assemblers was at the range of 1.4%-6.4% at the age of 50, and 9.0% at the age of 60. Compared with actual median of permanent hearing threshold shift, ISO1999∶2013(E) predictions underestimated the median of permanent hearing threshold shift at 10.7 dB. CONCLUSION: The noise hazards of welding and assembly positions in mechanical equipment manufacturing enterprises are high relatively. ISO1999∶2013(E) can be used to predict the risk of noise-induced hearing loss in workers, but attention should be paid to the risk underestimation of this model.

Epidemiological Characteristics of Occupational Cancers Reported - China, 2006-2020.

Introduction: Occupational cancers are a major threat to workers' health in China. The latest version of the Classification and Catalogue of the Occupational Diseases includes 11 occupational cancers. This study analyzed the epidemiological characteristics of occupational cancers in China reported to the National Occupational Disease Reporting System during 2006-2020. Methods: Occupational cancers reported during 2016-2020 were obtained from the National Occupational Disease Reporting System. Epidemiological characteristics were analyzed by year, region, industry, gender, age at diagnosis, and exposure duration to occupational hazards. Results: Overall, a total of 1,116 cases of occupational cancers were reported between 2006 and 2020. The main types reported were leukemia caused by benzene exposure (511, 45.79%), lung cancer caused by coke oven exhaust exposure (266, 23.84%), and lung cancer and mesothelioma caused by asbestos exposure (226, 20.25%). There were 6 provincial-level administrative divisions (PLADs) that had reported over 50 new cases in the last 15 years. Most cases (913, 81.18%) were distributed in the manufacturing industry. There were 870 (77.96%) male cases and 246 (22.04%) female cases. The average age at diagnosis of all reported cases was 51.91±15.85 years, and the median exposure duration to occupational hazards was 12 (5.29-23.25) years. Conclusions: There is a large discrepancy between the high morbidity of occupational cancers and a low number of cases diagnosed and reported cases. Occupational cancers in China may be underestimated, and comprehensive measures should be taken to improve the diagnosis and reporting of occupational cancers.

Trend Analysis of Occupational Lung Cancer from Coke Oven Emission Exposure - China, 2008-2019.

What is already known about this topic?: Coke oven emissions are a complex mixture of particulate matter and gases, some with carcinogenicity, released during coke production. Lung cancer caused by coke oven emissions has been listed as a statutory occupational cancer in China and many countries. What is added by this report?: In this study, coke oven emissions-induced lung cancer was mainly found in the manufacturing industries. Coke oven workers exposed to higher levels of polycyclic aromatic hydrocarbons in different workplaces had a high risk of occupational lung cancer. What are the implications for public health practice?: It is necessary to take efforts to greatly reduce emissions from coke production and effectively monitor the health of workers.

Estimation of Occupational Noise-Induced Hearing Loss Using Kurtosis-Adjusted Noise Exposure Levels.

OBJECTIVES: Studies have shown that in addition to energy, kurtosis plays an important role in the assessment of hearing loss caused by complex noise. The objective of this study was to investigate how to use noise recordings and audiometry collected from workers in industrial environments to find an optimal kurtosis-adjusted algorithm to better evaluate hearing loss caused by both continuous noise and complex noise. DESIGN: In this study, the combined effects of energy and kurtosis on noise-induced hearing loss (NIHL) were investigated using data collected from 2601 Chinese workers exposed to various industrial noises. The cohort was divided into three subgroups based on three kurtosis (ß) levels (K 1 : 3 ≤ ß ≤ 10, K 2 : 10 <ß ≤ 50, and K 3 : ß > 50). Noise-induced permanent threshold shift at test frequencies 3, 4, and 6 kHz (NIPTS 346 ) was used as the indicator of NIHL. Predicted NIPTS 346 was calculated using the ISO 1999 model for each participant, and the actual NIPTS was obtained by correcting for age and sex using non-noise-exposed Chinese workers (n = 1297). A kurtosis-adjusted A-weighted sound pressure level normalized to a nominal 8-hour working day (L Aeq,8h ) was developed based on the kurtosis categorized group data sets using multiple linear regression. Using the NIPTS 346 and the L Aeq.8h metric, a dose-response relationship for three kurtosis groups was constructed, and the combined effect of noise level and kurtosis on NIHL was investigated. RESULTS: An optimal kurtosis-adjusted L Aeq,8h formula with a kurtosis adjustment coefficient of 6.5 was established by using the worker data. The kurtosis-adjusted L Aeq,8h better estimated hearing loss caused by various complex noises. The analysis of the dose-response relationships among the three kurtosis groups showed that the NIPTS of K 2 and K 3 groups was significantly higher than that of K 1 group in the range of 70 dBA ≤ L Aeq,8h < 85 dBA. For 85 dBA ≤ L Aeq,8h ≤ 95 dBA, the NIPTS 346 of the three groups showed an obvious K 3 > K 2 > K 1 . For L Aeq,8h >95 dBA, the NIPTS 346 of the K 2 group tended to be consistent with that of the K 1 group, while the NIPTS 346 of the K 3 group was significantly larger than that of the K 1 and K 2 groups. When L Aeq,8h is below 70 dBA, neither continuous noise nor complex noise produced significant NIPTS 346 . CONCLUSIONS: Because non-Gaussian complex noise is ubiquitous in many industries, the temporal characteristics of noise (i.e., kurtosis) must be taken into account in evaluating occupational NIHL. A kurtosis-adjusted L Aeq,8h with an adjustment coefficient of 6.5 allows a more accurate prediction of high-frequency NIHL. Relying on a single value (i.e., 85 dBA) as a recommended exposure limit does not appear to be sufficient to protect the hearing of workers exposed to complex noise.

Occupational Dust Hazards and Risk Assessment of Coal-Fired Thermal Power Plants of Different Capacities - China, 2017-2019.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Silica dust and coal dust are the main occupational hazards in coal-fired thermal power plants, which mainly exist in coal transportation workplaces, combustion milling workplaces, and ash removal workplaces. WHAT IS ADDED BY THIS REPORT?: The overall environmental and personal dust exposure levels decrease with an increase in the capacity of coal-fired thermal power plants, the overall dust hazard risk level of the workforce in coal-fired is Medium. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: Dust management should be conducted in the coal-fired thermal power plant in 300 million watt units because it has the highest dust exposure level, and ash removal workplaces and combustion milling workplaces are key control points for dust hazards.

Surveillance of Noise Exposure Level in the Manufacturing Industry - China, 2020.

INTRODUCTION: Occupational noise exposure is a widespread issue in the manufacturing industry in China. Since 2019, the National Surveillance System for Occupational Hazards in the workplace was established to understand different occupational hazards, especially occupational noise, in workplaces in China. METHODS: Both environmental and individual noise exposure levels were measured for 19,378 enterprises according to the Work Plan for Surveillance of Occupational Hazards in the Workplace (2020) issued by National Health Commission of the People's Republic of China. Median and interquartile range (IQR) were calculated to describe the distribution of the noise exposure level by industry classification, enterprise-scale, and ownership type of the enterprise. RESULTS: Overall, 25.14% of the individual noise exposure samples exceeded the Chinese national standard among the selected enterprises. The overall median of environmental noise exposure level was 82.8 dB(A) in selected enterprises, while the median of individual noise exposure level was 81.3 dB(A). The individual noise exposure level in the manufacture of metal products, manufacture of motor vehicles, mini-sized enterprises, collective enterprises and private enterprises was relatively high. CONCLUSION: Occupational noise is still one of the occupational hazards that cannot be ignored in the manufacturing industry, especially in mini-sized and private enterprises. The risk of noise exposure in the target industry is still high and will pose a threat to the health of workers.

The Role of the Kurtosis Metric in Evaluating the Risk of Occupational Hearing Loss Associated with Complex Noise - Zhejiang Province, China, 2010-2019.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Occupational noise-induced hearing loss (NIHL) has been the second most common occupational disease in China. Noise energy is the main risk factor for occupational NIHL. Evidence shows the temporal structure of noise (as indicated by kurtosis metric) contribute to the development of NIHL. However, the role of the kurtosis metric in evaluating the risk of occupational NIHL associated with complex noise has been rarely reported. WHAT IS ADDED BY THIS REPORT?: Noise temporal structure (as indicated by kurtosis) is an important risk factor for occupational NIHL in addition to noise energy. Kurtosis can be used to quantify complex noise exposure. A combination of noise kurtosis and noise energy can effectively evaluate the risk of occupational hearing loss associated with complex noise. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: Considering the effect of noise temporal structure on occupational NIHL, the existing international noise exposure standards (e.g. measurement method and noise exposure limit) for complex noise should be modified based on noise temporal structure. More effort is needed to reduce noise exposure, improve health screening, and monitor occupational NIHL.

Applying Kurtosis as an Indirect Metric of Noise Temporal Structure in the Assessment of Hearing Loss Associated With Occupational Complex Noise Exposure.

OBJECTIVE: The association of occupational noise-induced hearing loss (NIHL) with noise energy was well documented, but the relationship between occupational noise and noise temporal structure is rarely reported. The objective of this study was to investigate the principal characteristics of the relationship between occupational NIHL and the temporal structure of noise. METHODS: Audiometric and shift-long noise exposure data were collected from 3102 Chinese manufacturing workers from six typical industries through a cross-sectional survey. In data analysis, A-weighted 8-h equivalent SPL (LAeq.8h), peak SPL, and cumulative noise exposure (CNE) were used as noise energy indicators, while kurtosis (ß) was used as the indicator of noise temporal structure. Two NIHL were defined: (1) high-frequency noise-induced hearing loss (HFNIHL) and (2) noise-induced permanent threshold shift at test frequencies of 3, 4, and 6 kHz (noise-induced permanent threshold shift [NIPTS346]). The noise characteristics of different types of work and the relationship between these characteristics and the prevalence of NIHL were analyzed. RESULTS: The noise waveform shape, with a specific noise kurtosis, was unique to each type of work. Approximately 27.92% of manufacturing workers suffered from HFNIHL, with a mean NIPTS346 of 24.16 ± 14.13 dB HL. The Spearman correlation analysis showed that the kurtosis value was significantly correlated with the difference of peak SPL minus its LAeq.8h across different types of work (p < 0.01). For a kurtosis-adjusted CNE, the linear regression equation between HFNIHL% and CNE for complex noise almost overlapped with Gaussian noise. Binary logistic regression analysis showed that LAeq.8h, kurtosis, and exposure duration were the key factors influencing HFNIHL% (p < 0.01). The notching extent in NIPTS at 4 kHz became deeper with the increase in LAeq.8h and kurtosis. HFNIHL% increased most rapidly during the first 10 years of exposure. HFNIHL% with ß ≥ 10 was significantly higher than that with ß < 10 (p < 0.05), and it increased with increasing kurtosis across different CNE or LAeq.8h levels. When LAeq.8h was 80 to 85 dB(A), the HFNIHL% at ß ≥ 100 was significantly higher than that at 10 ≤ ß < 100 or ß < 10 (p < 0.05 and p < 0.01, respectively). CONCLUSIONS: In the evaluation of hearing loss caused by complex noise, not only noise energy but also the temporal structure of noise must be considered. Kurtosis of noise is an indirect metric that is sensitive to the presence of impulsive components in complex noise exposure, and thus, it could be useful for quantifying the risk for NIHL. It is necessary to re-evaluate the safety of permissible exposure limit of 85 dB(A) as noise with a high kurtosis value can aggravate or accelerate early NIHL.

The prevalence of occupational exposure to noise: A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury.

BACKGROUND: The World Health Organization (WHO) and the International Labour Organization (ILO) are developing joint estimates of the work-related burden of disease and injury (WHO/ILO Joint Estimates), with contributions from a large network of individual experts. Evidence from mechanistic and human data suggests that occupational exposure to noise may cause cardiovascular disease. In this paper, we present a systematic review and meta-analysis of the prevalence of occupational exposure to noise for estimating (if feasible) the number of deaths and disability-adjusted life years from cardiovascular disease that are attributable to exposure to this risk factor, for the development of the WHO/ILO Joint Estimates. OBJECTIVES: We aimed to systematically review and meta-analyse estimates of the prevalence of occupational exposure to noise. DATA SOURCES: We searched electronic academic databases for potentially relevant records from published and unpublished studies, including Ovid Medline, PubMed, EMBASE, and CISDOC. We also searched electronic grey literature databases, Internet search engines, and organizational websites; hand-searched reference list of previous systematic reviews and included study records; and consulted additional experts. STUDY ELIGIBILITY AND CRITERIA: We included working-age (≥15 years) workers in the formal and informal economies in any WHO Member and/or ILO member State, but excluded children (<15 years) and unpaid domestic workers. We included all study types with an estimate of the prevalence of occupational exposure to noise, categorized into two levels: no (low) occupational exposure to noise (<85dBA) and any (high) occupational exposure to noise (≥85dBA). STUDY APPRAISAL AND SYNTHESIS METHODS: At least two review authors independently screened titles and abstracts against the eligibility criteria at a first stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. We combined prevalence estimates using random-effect meta-analysis. Two or more review authors assessed the risk of bias and the quality of evidence, using the RoB-SPEO tool and QoE-SPEO approach developed specifically for the WHO/ILO Joint Estimates. RESULTS: Sixty-five studies (56 cross-sectional studies and nine cohort studies) met the inclusion criteria, comprising 157,370 participants (15,369 females) across 28 countries and all six WHO regions (Africa, Americas, Eastern Mediterranean, Europe, South-East Asia, and Western Pacific). For the main analyses, we prioritized the four included studies that surveyed national probability samples of general populations of workers over the 58 studies of workers in industrial sectors and/or occupations with relatively high occupational exposure to noise. The exposure was generally assessed with dosimetry, sound level meter, or official or company records; in the population-based studies, it was assessed with validated questions. Estimates of the prevalence of occupational exposure to noise are presented for all 65 included studies, by country, sex, 5-year age group, industrial sector, and occupation where feasible. The pooled prevalence of any (high) occupational exposure to noise (≥85dBA) among the general population of workers was 0.17 (95% confidence interval 0.16 to 0.19, 4 studies, 108,256 participants, 38 countries, two WHO regions, I2 98%, low quality of evidence). Subgroup analyses showed that pooled prevalence differed substantially by WHO region, sex, industrial sector, and occupation. CONCLUSIONS: Our systematic review and meta-analysis found that occupational exposure to noise is prevalent among general populations of workers. The current body of evidence is, however, of low quality, due to serious concerns for risk of bias and indirectness. Producing estimates of occupational exposure to noise nevertheless appears evidence-based, and the pooled effect estimates presented in this systematic review are suitable as input data for the WHO/ILO Joint Estimates (if feasible). Protocol identifier: 10.1016/j.envint.2018.09.040 PROSPERO registration number: CRD42018092272.

New Metrics Needed in the Evaluation of Hearing Hazard Associated With Industrial Noise Exposure.

OBJECTIVES: To evaluate (1) the accuracy of the International Organization for Standardization (ISO) standard ISO 1999 [(2013), International Organization for Standardization, Geneva, Switzerland] predictions of noise-induced permanent threshold shift (NIPTS) in workers exposed to various types of high-intensity noise levels, and (2) the role of the kurtosis metric in assessing noise-induced hearing loss (NIHL). DESIGN: Audiometric and shift-long noise exposure data were acquired from a population (N = 2,333) of screened workers from 34 industries in China. The entire cohort was exclusively divided into subgroups based on four noise exposure levels (85 ≤ LAeq.8h < 88, 88 ≤ LAeq.8h < 91, 91 ≤ LAeq.8h < 94, and 94 ≤ LAeq.8h ≤ 100 dBA), two exposure durations (D ≤ 10 years and D > 10 years), and four kurtosis categories (Gaussian, low-, medium-, and high-kurtosis). Predicted NIPTS was calculated using the ISO 1999 model for each participant and the actual measured NIPTS was corrected for age and sex also using ISO 1999. The prediction accuracy of the ISO 1999 model was evaluated by comparing the NIPTS predicted by ISO 1999 with the actual NIPTS. The relation between kurtosis and NIPTS was also investigated. RESULTS: Overall, using the average NIPTS value across the four audiometric test frequencies (2, 3, 4, and 6 kHz), the ISO 1999 predictions significantly (p < 0.001) underestimated the NIPTS by 7.5 dB on average in participants exposed to Gaussian noise and by 13.6 dB on average in participants exposed to non-Gaussian noise with high kurtosis. The extent of the underestimation of NIPTS by ISO 1999 increased with an increase in noise kurtosis value. For a fixed range of noise exposure level and duration, the actual measured NIPTS increased as the kurtosis of the noise increased. The noise with kurtosis greater than 75 produced the highest NIPTS. CONCLUSIONS: The applicability of the ISO 1999 prediction model to different types of noise exposures needs to be carefully reexamined. A better understanding of the role of the kurtosis metric in NIHL may lead to its incorporation into a new and more accurate model of hearing loss due to noise exposure.

Occupational exposure to silica and risk of heart disease: a systematic review with meta-analysis.

OBJECTIVE: To search for evidence of the relationship between occupational silica exposure and heart disease. DESIGN: A systematic review and meta-analysis. BACKGROUND: Growing evidence suggests a relationship between occupational silica exposure and heart disease; however, the link between them is less clear. DATA SOURCES: PubMed, ScienceDirect, Springer and EMBASE were searched for articles published between 1 January 1995 and 20 June 2019. Articles that investigated the effects of occupational silica exposure on the risk of heart disease were considered. STUDY SELECTION: We included cohort studies, including prospective, retrospective and retroprospective studies. DATA EXTRACTION AND SYNTHESIS: We extracted data using a piloted data collection form and conducted random-effects meta-analysis and exposure-response analysis. The meta-relative risk (meta-RR), a measure of the average ratio of heart disease rates in those with and without silica exposure, was used as an inverse variance-weighted average of relative risks from the individual studies. The Newcastle-Ottawa Quality Assessment Scale for cohort studies was used for study quality assessment. OUTCOME MEASURE: We calculated the risk of heart diseases such as pulmonary heart disease, ischaemic heart disease and others. RESULTS: Twenty cohort studies were included. The results suggest a significant increase in the risk of overall heart disease (meta-RR=1.08, 95% CI 1.03 to 1.13). Stronger evidence of association with pulmonary heart disease was found in the risk estimate of both categories of heart disease (meta-RR=1.24, 95% CI 1.08 to 1.43) and in the exposure-response analysis (meta-RR=1.39, 95% CI 1.19 to 1.62). Our subgroup analyses also revealed that the statistical heterogeneity among studies could be attributed mainly to the diversity in reference group, occupation and study quality score. CONCLUSIONS: Silica-exposed workers are at an increased risk for overall heart disease, especially pulmonary heart disease. Further research is needed to better clarify the relationship between occupational silica exposure and ischaemic heart disease. PROSPERO REGISTRATION NUMBER: CRD42019124673.

Noise Exposure Level of Coal-Fired Thermal Power Stations in Different Scales - China, 2017-2019.

What is already known about this topic? China is a country mainly based on thermal power generation. Noise is one of the most critical occupational hazards among thermal power stations. What is added by this report? The proportion of detected environmental noise that exceeded 85 dB(A) is 69.6%, and the median of its noise level was 88.4 dB(A). The proportion of detected individual noise that exceeded 85 dB(A) was 52.6%, and the median of its noise level was 85.4 dB(A). The overall environmental noise exposure levels rose with the increase in the scales of coal-fired thermal power stations, while the individual noise exposure levels were contrary. What are the implications for public health practice? Workers in coal-fired thermal power stations are exposed to noise at a significantly high level, more than half of the environmental and individual exposure level were above 85 dB(A), which could impair workers' hearing capacity. Specific intervention is required to protect workers from exposure to noise at the workplace and eliminate the adverse health effects.