ABSTRACT
Objective: To analyze the current status of work-related musculoskeletal disorders (WMSDs), work fatigue and musculoskeletal pain in Chinese occupational population, and to study the relationship between work fatigue and musculoskeletal pain and WMSDs. Methods: A total of 66 961 employees from 323 enterprises in 15 key industries in China were selected as the study subjects using stratified cluster sampling method. The incidence of WMSDs in the past year was investigated using the Chinese version of the Musculoskeletal Disorders Questionnaire, and the work fatigue and musculoskeletal pain were investigated using Borg 6-20 Rating of Perceived Exertion Scale and visual analogue scale. The data were standardized using the age composition data of 18 to 60 years from the seventh national population census. Results: The standardized annual incidence of WMSDs was higher in the front-line workers than that in the administrative and other supportive staff (38.82% vs 36.30%). The detection rates of work fatigue and musculoskeletal pain in the study subjects were 44.54% and 63.08%, respectively. The result of S-curve fitting showed that the risk of WMSDs increased with the level of work fatigue (P<0.01). Among the front-line workers, the average of monthly fatigue frequency in the neck, shoulder, lower back, upper back, wrist/hand, foot and ankle, knee, leg, and elbow were higher in the group with WMSDs compared to those without WMSDs (all P<0.01). The pain degree of musculoskeletal pain was higher in all nine sites in the fatigued group than in the no-fatigue group (all P<0.01). The standardized detection rate of musculoskeletal pain was higher in the fatigued group than in the non-fatigued group (80.38% vs 25.71%). The work fatigue was moderate and positively correlated with musculoskeletal pain in all seven sites except the lower back and elbow, with Kendall Tau-b correlation coefficients ranging from 0.423 to 0.546 (all P<0.01). Conclusion: There is a good correlation between work fatigue and local musculoskeletal pain, work fatigue and WMSDs in Chinese occupational population. Implementing ergonomic interventions to control the development of work fatigue can be an effective measure for preventing WMSDs.
ABSTRACT
The National Disease Control and Prevention Bureau and the National Health Commission jointly issued an announcement on Notice on Carrying out Pilot Work of Occupational Health Classification Supervision and Law Enforcement, which presented a method of comprehensive risk assessment method of occupational disease hazards of employers. This method embraces relevant factors at full scale and is simple in operation, but its applicability and accuracy of assessment results need further practical study. Based on the steps of occupational health risk assessment and proven occupational health risk assessment methods available at home and abroad, this paper proposed improvements and discussed the comprehensive risk assessment method of occupational disease hazards of employers, so as to provide a technical basis to implement the occupational disease hazard classification management of employers for relevant government supervision departments.
ABSTRACT
In the face of a serious occupational disease prevention and control situation, the lack of efficient supervision and regulation methods has become a prominent contradiction. This paper reviewed the progress and application of occupational health grading and classification supervision methods for employers in China in recent years, and analyzed the characteristics and limitations of selected methods. The grading and classification supervision methods have gradually developed from considering only inherent health risk of occupational disease hazards, to considering both inherent attributes of occupational disease hazards and exposure duration. Some regional authorities introduced trial measures for grading and classification of occupational health supervision by embracing exposure level of an occupational disease hazard of interest, associated outcome severity, and occupational health management situation of targeted employers. In October 2022, the National Disease Control and Prevention Bureau issued the Notice on Carrying out Pilot Work of Occupational Health Classification Supervision and Law Enforcement, which further promoted the establishment of a differentiated occupational health supervision model. Grading and classification of occupational health supervision can improve the supervision efficiency of public health administration departments and promote employers to fulfill the main responsibility of occupational disease prevention and control.
ABSTRACT
This paper introduced concepts of occupational health risk grading and its development in China and abroad, reviewed the history of seeking occupational health classification supervision models, and explored the applicability and effectiveness of occupational health risk grading and assessment methods serving occupational health classified supervision on employers. These findings would provide a scientific basis for occupational health classification supervision and law enforcement.
ABSTRACT
Background Prolonged awkward postures during occupational activities can lead to excessive musculoskeletal load on the wrist of workers and symptoms such as wrist pain or discomfort. Objective To survey the prevalence of wrist pain among workers in 10 key industries and analyze its correlation with wrist working postures. Methods By using stratified cluster sampling method, workers from 10 key industries, such as footwear manufacturing industry, shipbuilding manufacturing industry, and automobile manufacturing industry, were selected from seven regions in North China, East China, Central China, South China, Southwest China, Northwest China, and Northeast China. The demographic information, wrist working postures, pain in wrist of the workers were collected through a cross-sectional survey. Pearson χ2 test was used to compare prevalence by selected factors, trend χ2 test for between group comparison, and unconditional logistic regression models for the association of wrist working postures with wrist pain. Results There were 64052 workers enrolled in this survey, and 56286 provided valid questionnaires (the effective rate was 87.8%). According to the survey, the prevalence of wrist pain was 23.3% (13112/56286), and the industries with higher prevalences were footwear manufacturing (27.1%, 1927/7106), automobile manufacturing (24.9%, 5378/21560), and shipbuilding and related equipment manufacturing (24.4%, 850/3488) industries. Finger pinching (OR=2.09, 95%CI: 1.95-2.24), frequent wrist bending (OR=2.03, 95%CI: 1.92-2.15), fixed wrist bending (OR=1.77, 95%CI: 1.69-1.85), wrist on hard edge (OR=1.34, 95%CI: 1.28-1.40), and arms over shoulders (OR=1.11, 95%CI: 1.05-1.17) increased the risk of reporting wrist pain. Conclusion Awkward postures are related to wrist pain among workers in selected 10 key industries. The related factors are wrist on hard edge, frequent wrist bending, finger pinching, fixed wrist bending, and arms over shoulders.
ABSTRACT
Background Non-Gaussian noise has become the dominant noise type in industry. However, the epidemiological characteristics of non-Gaussian noise exposure and associated noise-induced hearing loss (NIHL) are still unclear. Objective To summarize the epidemiological characteristics of NIHL associated with non-Gaussian noise in manufacturing industry in China and provide a basis for the early prevention and control of occupational hearing loss. Methods Chinese and English literature on hearing loss associated with non-Gaussian noise in China were retrieved. The overall prevalence was calculated based on the prevalence data provided by each included study. A meta-analysis of studies with Gaussian noise as a control group was also performed and the overall weighted odds ratio (OR) was calculated to compare the effects of non-Gaussian noise and Gaussian noise on hearing loss. Publication bias was evaluated by funnel plot and Egger regression, and a sensitivity analysis was performed by eliminating references in turn. Results A total of 37 cross-sectional studies involving 25 055 Chinese manufacturing workers exposed to non-Gaussian noise were included, 92.5% of whom were male. These workers aged (32.7±9.6) years were exposed to non-Gaussian noise at (87.0±4.2) dB(A) for (6.8±4.9) years. The mean cumulative noise exposure (CNE) was (95.9±8.0) dB(A)·year. The prevalence rate of high-frequency NIHL (HFNIHL) and speech-frequency NIHL (SFNIHL) were 29.0% and 14.2%, respectively. The results of the meta-analysis treating 19 cross-sectional studies with Gaussian noise as a control group showed that there were no significant differences in age, exposure duration, and equivalent continuous A-weighted sound pressure level (LAeq), and CNE between the non-Gaussian noise group and the Gaussian noise group. The overall weighted OR of HFNIHL was 1.87 (95%CI: 1.46−2.41), which was statistically significant. The funnel plot showed good symmetry and the result of Egger regression was t=−0.11, P=0.910 (>0.05), suggesting a low risk of publication bias in this meta-analysis. The sensitivity analysis showed no significant changes of results after eliminating references in turn, indicating that the results were robust. Conclusion Chinese manufacturing workers, mainly young adult males, are exposed to non-Gaussian noise at high levels for a long time and have a high prevalence of NIHL. Compared to workers exposed to Gaussian noise, those exposed to non-Gaussian noise suffer from more serious hearing loss.
ABSTRACT
Background Equivalent continuous A-weighted sound pressure level is not appropriate for evaluating the risk of non-steady noise exposure, and need to be corrected by noise time-domain structure, but the correction method and its applicability need to be discussed. Objective To validate the application of the kurtosis-adjusted normalization of equivalent continuous A-weighted sound pressure level to a normal 8 h working day ( LAeq,8 h) in assessing noise-induced hearing loss (NIHL), and to improve the methods for assessing occupational hearing loss associated with different types of noise. Methods Audiometric and shift-long noise exposure data were acquired from a population(n=2 466) of screened workers exposed to noise between 70 dB(A) and 95 dB(A) from 6 industries in China. The cohort data were collapsed into 1 dB(A) bins, and the average kurtosis and noise-induced permanent threshold shifts at 3 kHz, 4 kHz, and 6 kHz (NIPTS346) within 1 dB(A) were calculated respectively. According to the existing correction method, the adjustment coefficient λ was calculated by multiple regression, and LAeq,8 h was corrected by λ (L'Aeq,8 h). The entire cohort was divided into K1 (≤10; steady noise), K2 (10~50; non-steady noise), and K3 (＞50; non-steady noise) groups based on mean kurtosis levels. Predicted NIPTS346 was calculated using the ISO 1999 model for each participant and the actual measured NIPTS346 was corrected for age and gender. The underestimated NIPTS346 was the difference between the values of estimated NIPTS346 and the corresponding actual NIPTS346. To validate the applicability of L′Aeq,8 h in evaluating NIHL, the correlation between L′Aeq,8 h and HFNIHL, and the mean difference between real NIPTS346 and estimated NIPTS346 were analyzed. Results The adjustment coefficient λ was determined at 5.43. The results of multiple logistic regression analysis showed that the relationship between L'Aeq,8 h and HFNIHL increased from 6.6% to 9.6% after the kurtosis adjustment. The DRR of LAeq,8 h and HFNIHL showed that the percentage of HFNIHL decreased after the adjustment of kurtosis in the non-steady noise groups, and the regression lines of the non-steady noise groups approached that of the steady noise group. The R2 of the K2 group increased from 0.935 3 to 0.986 3, and the R 2 of the K3 group increased from 0.905 6 to 0.951 6. Under the un-adjusted condition, the NIPTS346 underestimation for the K3 group was significantly higher than that for the steady noise group (t=−3.23, P=0.001). After the LAeq,8 h was adjusted by kurtosis, the NIPTS346 underestimation decreased significantly in the three kurtosis groups (K1: t=6.78, P＜0.001; K2: t=14.31, P＜0.001; K3: t=11.06, P＜0.001). There was no significant difference in the degree of underestimation between the three kurtosis groups (K1 vs K2: t=−0.22, P=0.830; K1 vs K3: t=−1.40, P=0.205) as the curves of the three kurtosis groups were nearly overlapped. Conclusion The kurtosis-adjusted LAeq,8 h can effectively estimate the hearing loss associated with non-steady state noise.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
Background Occupational hearing loss associated with noise is becoming more and more serious, and occupational noise-induced deafness has become the second most frequently reported occupational disease in China. Objective To characterize occupational hearing loss in Zhejiang Province so as to provide a basis for the formulation of hearing protection strategies and measures. Methods Through the occupational diseases reporting system, the data of new cases of occupational noise-induced deafness in Zhejiang Province from 2006 to 2020 and the audiometry results of laborers who were exposed to occupational noise and participated in physical examinations from 2015 to 2020 were collected. The distribution of new cases of occupational noise-induced deafness were described in categories of region, year, industry, enterprise scale, age, onset age, and length of work, as well as the detection of increased high-frequency hearing threshold of workers who ordered occupational health examination in each year. Results A total of 575 cases of occupational noise-induced deafness were reported in Zhejiang Province from 2006 to 2020, of which 526 cases were male and 49 were female. The mean onset age of patients with noise-induced deafness was (44.8±8.0) years. There was a significant difference in mean onset age between male and female (t=3.420, Ρ=0.001). The median length of work [M (P25, P75)] at the time of onset was 9.0 (5.5, 13.2) years. The number of cases of noise-induced deafness and its proportion to the total number of occupational diseases in a year showed an increasing trend from 2006 to 2020 and the average annual growth rate was 22.11%. The patients were mainly distributed in the Hangzhou, Ningbo, and Jiaxing, and the number of cases were 194, 140, and 112, respectively, accounting for 77.5% of the total cases in Zhejiang Province. Manufacturing industry was dominant one in terms of the number of cases, which accounted for 89.6% (515 cases). Private economic enterprise, in terms of economic type, accounted for 57.4% (330 cases). There were significant differences in the length of work at the time of onset among different economic types of enterprises (H=29.081, Ρ<0.001). There were 215 cases in the medium-sized enterprises and 265 in the small- and micro-sized enterprises, respectively, accounting for 83.5% of the the total number of cases. Conclusions From 2006 to 2020, the cases of occupational noise-induced deafness in Zhejiang Province present an increasing trend, with a relatively short length of work at the time of onset, and regional and industrial agglomeration.
ABSTRACT
Complex noise is the dominant type of noise in workplaces. It can cause more serious hearing loss than steady-state noise. The existing noise measurement and evaluation standards based on the "equal energy hypothesis" are not completely suitable for complex noise. This paper introduced the status quo of workplace noise measurement and assessment techniques, and the research progress of workplace complex noise measurement and assessment techniques. In terms of future research in this area, four proposals were made, including to improve associated population database, develop and revise noise-related standards, establish methodology of kurtosis adjustment, and identify the incidence characteristics of kurtosis-related occupational hearing loss. The paper also introduced the special column "Measurement and assessment techniques of complex noise in the workplace".
ABSTRACT
Objective:To investigate and analyze the radioactivity level of 90Sr in offshore seawater and seafood therein around Sanmen nuclear power plant (NPP) and to estimate the annual committed effective dose to local population from ingestion of 90Sr in seafood from 2015 to 2019. Methods:From 2015 to 2019, the offshore seawater and 3 kinds of marine products grown locally in Sanmen and consumed by local residents were collected for measurement of the level of 90Sr radioactivity. The committed effective doses to the local population were estimated based on monitoring result and consumption data on seafood in Zhejiang offshore. Results:The radioactivity concentrations of 90Sr ranged from 2.4 to 4.1 mBq/L in the seawater, close to the natural radioacrive background level and from 6.7×10 -2 to 1.3 Bq/kg in seafood, lower than the standard values specified in the "Limited concentrations of radioactive materials in foods" (GB 14882-94). Annual committed effective dose to the local population from 90Sr attributable to consumption of seafood in Sanmen County from 2015 to 2019 were 2.2×10 -4-4.2×10 -4mSv, respectively, far lower than the worldwide committed effective dose result ing from internal exposure. Conclusions:From 2015 to 2019, the radioactivity concentration of 90Sr in seawater and seafood are stable, with neglectable dose burden to the local population.
ABSTRACT
Objective@#To pre-assess the occupational hazards in a waste ecological landfill project using comprehensive exposure index with analogy method,and to provide reference for improvement of protective measures and prevention of occupational diseases. @*Methods@#Some enterprises which were comparable with the project in landfill storage capacity,disposal scale,techniques,occupational hazards and occupational health management were selected to carry out on-site occupational health survey,and were evaluated by occupational exposure limits（OEL）. The risk of occupational hazards of the project was assessed by analogy and comprehensive index method.@*Results@#The occupational hazards of analogous enterprises were hydrogen sulfide,ammonia,other dust and noise in ash solidification workshop,paving post in landfill area,spraying post and inspection post in sewage disposal area;manganese and its inorganic compounds,welding fume and arc light in welding post. Except for the noise intensity of spraying post exceeding the national OEL,the other items were qualified. The results of the pre-assessment of the project showed that in the posts with vacant OEL,the hazards of paving compaction post exposed to high temperature in summer,spraying post exposed to high temperature in summer,cypermethrin and machine repairing post exposed to heat,ozone and noise were at moderate risk;in the posts qualified by OEL,the hazards of paving compaction and sewage disposal posts exposed to noise were neglectable,paving compaction and transportation post exposed to other dust were at low risk,others were at moderate risk;unqualified spraying post exposed to noise was at moderate risk. @*Conclusion@#Medium-risk occupational hazards exist in paving compaction,spraying,sewage disposal and machine repairing posts. Comprehensive index method combined with analogy method can comprehensively achieve the occupational hazard pre-assessment of a proposed project.
ABSTRACT
Objective@#To study the effect of p-phenylenediamine (PPD) on liver and kidney function in occupational exposed workers.@*Methods@#Workers in a hair dye production enterprise which used p-phenylenediamine as a raw material for production were selected as the main research population. Then we conducted a questionnaire survey on the basic conditions of workers and conducted occupational health checkups on general health status, liver and kidney function. Occupational health examination assessment results were tested in Taizhou Cancer Hospital. All data was built using EpiData 3.1 software, and statistical analysis was performed using software SPSS 20.0.@*Results@#The liver function indicators including direct bilirubin, prealbumin, total protein, and white protein, globulin, aspartate aminotransferase, glutamyl transpeptidase, and total bilirubin in the workers exposed to high concentration of PPD were at high normal values, and these indicators were significantly different from low PPD concentration group (P<0.05) . The serum creatinine and serum uric acid in the renal function index were significantly higher in workers exposed to PPD than in workers exposed to low concentrations and in the control group (P<0.05) .@*Conclusion@#Occupational exposed to PPD may have a hazard to the workers’ liver and kidney function. Long-term occupational exposure to PPD may lead to increased cumulative exposure of workers, which may cause potential chronic liver and kidney damage in occupationally exposed populations.
ABSTRACT
Objective@#To study the effects p-phenylenediamine (PPD) on lung function and health-related quality of life of occupational exposed workers.@*Methods@#This study was based on data from a company that produce hair dye containing PPD in China. Workers who exposed to PPD were selected as the study group, and workers un-exposed to PPD were selected as the control group. Questionnaires on health-related quality of life of workers using the 36-item Short Form Health Survey (SF-36) . Occupational health examination assessment results were tested in Taizhou Cancer Hospital. The lung function test includes forced vital capacity (FVC) , forced expiratory volume in one second (FEV1.0) , and ratio of FEV1.0 to FVC (FEV1.0/FVC) .@*Results@#The difference in systolic blood pressure between the PPD exposed group and the control group was statistically significant (P<0.05) . FVC, FEV1.0, and FEV1.0/FVC of the lung function indexes in the exposed group were lower than those in the control group (P<0.05) . In the health-related quality of life, body pain (P=0.002) , general health (P=0.029) , vitality (P=0.038) , and mental health (P=0.003) were lower in the exposed group than in the control group.@*Conclusion@#Occupational exposed to PPD may induce hazard to the workers’lung function and may cause detrimental effect on workers’ health-related quality of life.
ABSTRACT
Objective@#To assess the occupational health risk level of a small-scale furniture manufacturer, and to explore the applicability of the Singapore-developed semi-quantitative occupational risk assessment model for chemical exposure (Singapore model) in small-scale furniture manufacturers, and to provide a basis for the continuous occupational health management of manufacturers.@*Methods@#A small-scale furniture manufacturer was selected as the study subject; an on-site occupational hygiene investigation was performed on the above manufacturer during April to June in 2017, and a risk assessment was carried out using the Singapore model.@*Results@#The assessment results of the Singapore model indicated that risk levels of occupational exposure to harmful chemicals for the key positions in the workplace were inconsistent between the actual exposure level method and the exposure index method except for the following: high risk for formaldehyde exposure (risk level: 3.5 and 4.1, respectively) during woodworking process, high risk for dimethyl benzene exposure (risk level: 3.5 and 3.5, respectively) during burnishing process, medium risk for methyl benzene and dimethyl benzene exposure (risk level: 3.0 and 3.4, respectively) as well as for dimethyl benzene exposure (risk level: 3.0 and 3.3, respectively) during primer coating process, medium risk for methyl benzene exposure (risk level: 3.0 and 3.4, respectively) during gel painting process, and medium risk for cyclohexanone exposure (risk level: 2.8 and 2.8, respectively) during oil polishing process. The exposure index method yielded a higher risk level than the actual exposure level method, especially in the risk level of benzene exposure, which was rated as "high" and "very high" by the former but "low" by the latter.@*Conclusion@#The Singapore model is suitable for risk assessment of occupational exposure to harmful chemicals in small-scale furniture manufacturers, which can provide a basis for further prevention and control measures taken by manufacturers.
ABSTRACT
Objective@#To investigate the quality of life of the visual display terminal (VDT) operators in Hangzhou Internet enterprises and to analyze its influencing factors. @*Methods@#Through cluster sampling,, 944 employees were investigated by demographic and general health questions and the MOS 36-Item Short Form Health Survey Questionnaire from October to November in 2016 and carried out statistical analysis. @*Results@#VDT operators’ physical functioning, role-physical, bodily pain, general health, vitality, social functioning, role-emotional, mental health, physical component summary and mental component summary scores were (86.3±17.0) , (82.5±30.3) , (80.6±16.1) , (56.8±18.6) , (53.7±15.6) , (78.5±17.8) , (81.2±31.9) , (48.8±19.3) , (51.1±8.9) , (43.8±9.1) . Except physical functioning, role-physical and physical component summary scores, the scores of other scales and mental component summary were lower than the norm (P<0.05) . Multivariable logistic regression showed that vegetable intake, sleeping and physical exercise had an impact on the physical component summary score. The influential factors of mental component summary score included marital status, education, neck pain and health concerns. @*Conclusion@#We should pay attention to the quality of life of VDT operators in Internet enterprises, especially their mental health.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the characteristics of exposure to iron oxide nanoparticles in workplace.</p><p><b>METHODS</b>The real-time particle number (NC), surface area (SAC), and mass (MC) concentrations of nanoparticles were measured in various locations of a selected workplace manufacturing iron oxide nanoparticles. The collected particles were analyzed for morphology and elemental composition.</p><p><b>RESULTS</b>The average NCs and SACs in milling site (16,566 pt/cm3, 106.082 µm2/cm3), packaging site (12,386 pt/cm3, 89.861 µm2/cm3), shipping site (13,808 pt/cm3, 102.071 µm2/cm3), and product storage room (17,192 pt/cm, 115.044 µm2/cm3) of the yellow powder (α-Fe2O3 . nH2O) were all significantly higher than the workplace background concentrations (11,420 pt/cm3, 85.026 µm2/cm3) (all P<0.05). The NC was highly correlated with the SAC (r= 0.784), while both NC and SAC were loosely correlated with the MC (r1=0.323, r2=0.331). Scanning electron microscopy revealed a spindle-like shape of the iron oxide nanoparticle; the chemical composition of the collected particles contained 19.33 weight percent iron (Fe).</p><p><b>CONCLUSION</b>The milling site and product storage room of the yellow powder are exposed to a higher concentration of nanoparticles, which are mainly composed of iron oxide nanoparticles. The NC is highly correlated with the SAC.</p>
Subject(s)
Ferric Compounds , Metal Nanoparticles , Occupational Exposure , WorkplaceABSTRACT
<p><b>OBJECTIVE</b>To investigate the toxicity of intragastrically administered N, N-dimethylformamide (DMF) in female Wistar rats, and to provide experimental data for the overall evaluation of DMF toxicity under different ways of exposure.</p><p><b>METHODS</b>Forty female Wistar rats weighing 150∼180 g were randomly divided into four groups: control group (treated with water) and three DMF exposure groups with doses of 50 mg/kg, 100 mg/kg, and 200 mg/kg. After oral administration of DMF once a day for 14 consecutive days, the rats were weighed and sacrificed. The liver, kidney, brain, and uterus were weighed to calculate organ indices. The pathological changes in the liver were examined by HE staining. The protein expression of HSP70 in the liver, kidney, and brain was determined. Finally, peripheral lymphocytes were collected from the arteria cruralis to determine DNA damage by comet assay.</p><p><b>RESULTS</b>Fourteen days after DMF exposure, the body weight and organ indices of the kidney, brain, and uterus showed no significant changes. However, the liver index showed concentration-dependent increase in all DMF exposed groups (3.52±0.21, 3.55±0.13, and 3.88±0.22 in the low-, medium-, and high-dose groups, respectively), as compared with the control group (3.24±0.28) (P < 0.05 or P < 0.01). The pathological damage in the liver also showed a concentration-dependent manner. Inflammatory cell infiltration and granular degeneration in centrilobular hepatocytes were observed in the high-dose group. No significant change in protein expression of HSP70 was observed in the liver, kidney, or brain of DMF-exposed rats (P > 0.05). DNA damage was induced by DMF, and the DNA percentage of lymphocyte comet tail, average tail length, and tail moment in exposed groups were all significantly increased as compared with the control group (P < 0.05 or P < 0.01).</p><p><b>CONCLUSION</b>Gavaged DMF can induce liver injury and DNA damage in lymphocytes in rats 14 days after administration. There is no significant change in protein expression of HSP70 in the liver, brain, or kidney after DMF exposure.</p>
Subject(s)
Animals , Female , Rats , Brain , Pathology , DNA Damage , Dimethylformamide , Toxicity , Gastric Lavage , HSP70 Heat-Shock Proteins , Metabolism , Kidney , Pathology , Liver , Pathology , Lymphocytes , Rats, Wistar , Toxicity TestsABSTRACT
<p><b>OBJECTIVE</b>To study that low-intensity microwave whether or not enhances the genotoxic effects of mitomycin C(MMC) on human lymphocytes.</p><p><b>METHODS</b>Single strand DNA breaks and chromosomal aberrations were measured by comet assay and cytokinesis-blocked micronucleus(CBMN) test in vitro when human lymphocytes were exposed to 2,450-MHz microwave (5.0 mW/cm2) alone and in combination with mitomycin C.</p><p><b>RESULTS</b>In the comet assay, the average comet lengths of microwave group[(29.1 +/- 8.1) micron in male and (25.9 +/- 7.5) micron in female] were not significantly different from those of control groups [(26.3 +/- 6.6) and (24.1 +/- 4.3) micron respectively] (P > 0.05). The average comet lengths of MMC group(0.0125, 0.0250, 0.0500, 0.1000 microgram/ml) were significantly longer than those of control groups (P < 0.01) and were increased with the dose of MMC. The average comet lengths of microwave combined with MMC (MW + MMC) also were increased with the doses of MMC and were significantly longer than those of control groups (P < 0.01). When MMC was > or = 0.0250 microgram/ml, microwave and MMC synergistically increased the single strand DNA breaks. In the micronucleus test, the average micronucleus rates of microwave groups were not higher than those of control groups (P > 0.05). The average micronucleus rates of MMC groups and MW + MMC groups were significantly higher than those of control groups (P < 0.01) when MMC was > or = 0.0500 microgram/ml. The average micronucleus rates of MW + MMC groups seemed higher than those of corresponding MMC groups, however the difference was not significant (P > 0.05).</p><p><b>CONCLUSION</b>Low-intensity(2,450-MHz) microwave did not induce DNA and chromosome damages on human lymphocytes, but enhanced the effects of DNA breaks induced by MMC.</p>