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ABSTRACT: To explore the risk factors of low back pain among the Chinese occupational population in several major industries.
A total of 7200 subjects (3600 cases and 3600 controls) were randomly sampled from a cross-sectional study, and they were investigated for individual and occupational factors of low back pain. The potential risk factors were first selected by using chi-square tests. Secondly, collinearity diagnosis proceeded by using the Kendall's rank correlation. Finally, binary logistic regression model was used for multi-factor analysis.
Collinearity diagnosis showed that there was a severe collinearity problem among the potential risk factors of low back pain. Logistic regression model included 20 variables with statistical significance. Bending neck forward or holding neck in a forward posture for long periods (OR=1.408) was the most important risk factor inducing low back pain in this study, followed by bending heavily with the trunk (OR=1.402), carrying out identical work almost for the whole day (OR=1.340). Additionally, sufficient normal break was a protective factor of low back pain.
Low back pain among the Chinese occupational population was associated with body height, occupation, work organization, physical work, working posture, and others. All these risk factors could be regarded as the indicators of low back pain, and some relevant preventive measures should be taken to reduce low back pain risk.
Biomedical and Environmental Sciences 08/2012; 25(4):421-9. · 1.35 Impact Factor
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ABSTRACT: To investigate and analyze the occupational hazards of ultraviolet radiation, protective measures and related factors for typical symptoms among workers in electric welding, and to provide basic information for revision of the occupational standards of UV.
Questionnaires and physical examinations were used in this investigation. A total of 828 workers from four vehicle manufacturers in Beijing and Guangdong Province were selected. Corresponding analyses were conducted with SPSS 16.0 statistic software.
The top three injuries of faces and hands were burning tingling (48.7% & 41.3%), itch of skin (39% & 34.9%) and pigmentation (31.9% & 24.5%).The major injuries of eyes were ophthalmodynia (61.5%) , photophobia and tearing (61.4%), and blurred vision (50.2%). The incidences of facial and hands burning tingling, hands flushing, hands macula and papula were significantly different between the welders and auxiliary workers (P<0.05). The differences of facial and hands burning tingling, flushing, facial disesthesia and anaesthesia, symptoms and signs of eyes were significant in different working years groups (P<0.05). The top three usages of protective measures were welding masks (87.2%), gloves (84.3%) and glasses (65.9%). Except for UV cut cream, the usages of other protective equipments in the auxiliary workers were significantly lower than those in the welders (P<0.05). The logistic regression analysis showed that prolonged exposure to arc welding, using argon arc welding and CO(2) gas shielded arc welding, not wearing welding masks, and not using UV cut cream was significantly associated with the increased risk of face burning tingling, and the ORs were 3.894 (6 h to 8 h), 2.665 (4 h to 6 h), 2.052, 1.765, 1.759, 1.833, respectively; working years might be a protective factor, and the OR was 0.440, respectively.
The study suggested that the UV radiation produced during welding operations not only caused harm to welders, but also to the auxiliary workers. Protection should be strengthened,for example, wearing welding masks, glasses, etc. Meanwhile automatic welding machines should be adopted by the factories to reduce the exposure time for workers.
Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences 06/2012; 44(3):448-53.
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Wei-wei Du,
Sheng Wang,
Jian-xin Wang, Li-hua He,
Shan-shan Wu,
Jing-yun Li,
Lei Yang,
Shan-fa Yu,
Zhao-lin Xia,
Ling-ping Li,
An-ping Zhu,
Xiao-feng Liu,
Zi-hua Zhu
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ABSTRACT: To evaluate the reliability and validity of musculoskeletal questionnaire.
A self-administered modified musculoskeletal questionnaire was used to investigate 12 098 workers from eight occupations, i.e. coal mining, petroleum, metallurgical, mechanical manufacturing, chemical, garment and railroad transportation industries and education. The Cronbach's α coefficient, analysis of covariance and multiple logistic regression were used to assess the reliability and validity of musculoskeletal questionnaire.
The consistent test between total items of Musculoskeletal Questionnaire and each factor showed that the range of Cronbach's α was 0.52 ∼ 0.92, except from vibration factor, other Cronbach's α was more than 0.7. All 55 items of Musculoskeletal Questionnaire were subjected to factor analysis, and ten latent factors were identified, which explained 55.17% of the total variance. The potentially hazardous working conditions could be categorized into seven dimensions (force, dynamic load, static load, repetitive load, climate factors, vibration exposure and environmental ergonomic factor), which consisted with the theory model. The results of covariance analysis indicated that there were significant difference among 7 dimension indices in different jobs (P < 0.01).
The modified Musculoskeletal Questionnaire is a valid and reliable tool for measuring musculoskeletal workload.
Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 05/2012; 30(5):335-8.
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Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 03/2012; 30(3):230-2.
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ABSTRACT: To establish and evaluate a real-time PCR assay to detect Mycoplasma pneumoniae (M.pneumoniae) in clinical specimens.
By analysing the whole p1 gene sequence of 60 M.pneumoniae clinical isolates in Beijing of China, an optimized real-time PCR assay (MpP1) using p1 gene conserved region was designed. The specificity and sensitivity of this assay were evaluated and compared with other two reported assays (RepMp1 and Mp181) using 40 positive and 100 negative clinical specimens.
The detection limit of the new assay was 8.1 fg (about 1∼3CFU) M.pneumoniae DNA. The sensitivity of MpP1, RepMp1, and Mp181 assays appeared to be 100%, 100%, and 85%, respectively.
MpP1 assay is suitable for the detection of M.pneumoniae in Chinese clinical specimens.
Biomedical and Environmental Sciences 02/2012; 25(1):77-81. · 1.35 Impact Factor
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Shan-shan Wu, Li-hua He,
Sheng Wang,
Jian-xin Wang,
Jing-yun Li,
Lei Cao,
Wei-wei Du,
Lei Yang,
Shan-fa Yu,
Yan Zhang,
Chang-yun Zhang
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ABSTRACT: To develop a draft questionnaire (China Musculoskeletal Questionnaire, CMQ) for evaluating of musculoskeletal workload and associated potential hazardous working conditions as well as musculoskeletal symptoms of workers in Sitting Posture.
Multi-methods, which include the reviewing references, the summarizing results of preliminary studies, the reviewing ergonomic tools, the consulting experts and occupational health workers and the interviewing or discussing with individual workers in sitting posture, were used in developing item pool. The experts and epidemiologists of occupational health scored the importance of every single item in the item pool, and then the survey and sampling were carried out in 325 workers of sitting posture who completed the questionnaire. On the basis of these data, the methods including experts scoring, item analysis, Cronbach's α analysis and factor analysis were synthetically used to select the reliable items which consisted of the formal questionnaire.
The standard of the CMQ, which consists of 34 items on musculoskeletal workload and associated potentially hazardous working conditions, can be divided into nine indices (dynamic loads, static loads, repetitive loads, forces-exertion, prolong time, climatic factors, vibration, position and ergonomic environmental factors).
The CMQ possesses good content validity, and the items of CMQ are divergent, reliable and typical. However, the reliability and validity of CMQ should be validated.
Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 12/2011; 29(12):908-12.
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ABSTRACT: Work-related musculoskeletal disorders (WMSDs) have high prevalence in sewing machine operators employed in the garment industry. Long work duration, sustained low level work and precise hand work are the main risk factors of neck-shoulder disorders for sewing machine operators. Surface electromyogram (sEMG) offers a valuable tool to determine muscle activity (internal exposure) and quantify muscular load (external exposure). During sustained and/or repetitive muscle contractions, typical changes of muscle fatigue in sEMG, as an increase in amplitude or a decrease as a shift in spectrum towards lower frequencies, can be observed. In this paper, we measured and quantified the muscle load and muscular activity patterns of neck-shoulder muscles in female sewing machine operators during sustained sewing machine operating tasks using sEMG.
A total of 18 healthy women sewing machine operators volunteered to participate in this study. Before their daily sewing machine operating task, we measured the maximal voluntary contractions (MVC) and 20%MVC of bilateral cervical erector spinae (CES) and upper trapezius (UT) respectively, then the sEMG signals of bilateral UT and CES were monitored and recorded continuously during 200 minutes of sustained sewing machine operating simultaneously which equals to 20 time windows with 10 minutes as one time window. After 200 minutes' work, we retest 20%MVC of four neck-shoulder muscles and recorded the sEMG signals. Linear analysis, including amplitude probability distribution frequency (APDF), amplitude analysis parameters such as roof mean square (RMS) and spectrum analysis parameter as median frequency (MF), were used to calculate and indicate muscle load and muscular activity of bilateral CES and UT.
During 200 minutes of sewing machine operating, the median load for the left cervical erector spinae (LCES), right cervical erector spinae (RCES), left upper trapezius (LUT) and right upper trapezius (RUT) were 6.78%MVE, 6.94%MVE, 6.47%MVE and 5.68%MVE, respectively. Work load of right muscles are significantly higher than that of the left muscles (P < 0.05); sEMG signal analysis of isometric contractions indicated that the amplitude value before operating was significantly higher than that of after work (P < 0.01), and the spectrum value of bilateral CES and UT were significantly lower than those of after work (P < 0.01); according to the sEMG signal data of 20 time windows, with operating time pass by, the muscle activity patterns of bilateral CES and UT showed dynamic changes, the maximal amplitude of LCES, RCES, LUT occurred at the 20th time window, RUT at 16th time window, spectrum analysis showed that the lower value happened at 7th, 16th, 20th time windows.
Female sewing machine operators were exposed to high sustained static load on bilateral neck-shoulder muscles; left neck and shoulder muscles were held in more static positions; the 7th, 16th, and 20th time windows were muscle fatigue period that ergonomics intervention can protocol at these periods.
Chinese medical journal 11/2011; 124(22):3731-7. · 0.86 Impact Factor
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ABSTRACT: As the widespread use of electric devices in modern life, human are exposed to extremely low frequency magnetic fields (ELF MF) much more frequently than ever. Over the past decades, a substantial number of epidemiological and experimental studies have demonstrated that ELF MF (50 Hz) exposure is associated with increased risk of various health effects. The present study examined the effects of chronic exposure to ELF MF on anxiety level and spatial memory of adult rats.
The 50-Hz ELF MF was used during the whole experimental procedures and the value of magnetic field (MF) was set to 2 mT. Adult rats were divided randomly to control, MF 1 hour and MF 4 hours group. Anxiety-related behaviors were examined in the open field test and the elevated plus maze; changes in spatial learning and memory were determined in Morris water maze after 4 weeks of daily exposure.
Rats in MF 4 hours group had increased anxiety-like behaviors with unaltered locomotor activity. In the Morris water maze test, rats had reduced latency to find the hidden platform and improved long-term memory of former location of platform without changes in short-term memory and locomotor activity.
Chronic ELF MF exposure has anxiogenic effect on rats, and the promoting effects on spatial learning and long-term retention of spatial memory.
Chinese medical journal 10/2011; 124(20):3362-6. · 0.86 Impact Factor
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Xin-ning Yang,
Yan Xu,
Wei-wei DU,
Lei Cao,
Sheng Wang,
Xue-mei Dong,
Hou-han Lu,
Song-gen Chen,
Xiao-ou Cao,
Long-lian Zhang, Li-hua He
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ABSTRACT: To investigate and analyze present conditions of the assembling line illumination in our country, and to set the recommended values of illuminance standard.
Questionnaires and field surveys were used in this investigation. A total of 752 workers from seven factories in textile, shoes and electronics industries were selected for the questionnaire survey and site measurement, and corresponding analyses made with SPSS 13.0 statistic software.
Uniformity of illumination, definition in working face, general satisfactory degrees, asthenopia were significantly correlated with each other. Assembly line illuminances for five different visual characteristics were recommended in this paper. The illuminances were 500-1 000-1 500 lx, 300-500-1 000 lx, 200-300-750 lx, 100-300-500 lx, 50-100-200 lx, respectively.
Present conditions of the assembling line illumination are less than satisfactory, uniformity of illumination is on the low side, and there is no assembling line illuminance standard for general satisfactory degrees and asthenopia of workers. The related work should be further improved.
Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences 06/2011; 43(3):370-4.
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ABSTRACT: To investigate the morbidity and influence factors of work-related musculoskeletal disorders (WMSD) in oil drillers.
The modified Nordic Standardized Questionnaire for WMSD was used to perform the epidemiological investigation in 860 oil drillers.
The predominant sites of WMSD in the oil drillers were waist (50.6%), neck (29.8%) and shoulder (23.4%), respectively. There were significant differences of the WMSD morbidities in all body sites except for wrist and hip among groups with different working years (P < 0.05 of P < 0.01). The WMSD morbidities in the neck, shoulder, back and waist of oil drillers working for more than 40h a week were significantly higher than those of oil drillers working for less than 40 ha week (P < 0.05). The results of logistic regression analysis revealed that some occupational factors, i.e. keeping stoop and stand for long time, repeating trunk bend, keeping awkward lift posture and lifting the heave objects, were the risk factors for WMSD at waist (P < 0.05), also some management factors, i.e. overtime work and inadequate rest, were the risk factors for WMSD at waist (P < 0.05).
The WMSD appears to be a serious ergonomic problem in oil drillers, it is necessary to correct working posture, reduce working load, improve organizational management, and encourage a workplace health program with regular work and rest.
Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 03/2011; 29(3):163-6.
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ABSTRACT: To investigate the recovery duration of manual lifting tasks.
30 college student volunteers with gender equally distributed were involved in the simulated stoop-, squart- and semisquart-lifting tasks in the laboratory. Signals of electromyography (EMG) at the back muscles (left and right thorax m. erector spinae, LT(10) and RT(10); left and right lumbar m. erector spinae, LL(3) and RL(3)) and electrocardiography (ECG) were recorded during the rest intervals. The percentage of maximum voluntary electrical activation (MVE%), EMG median frequency (MF), and heart rate (HR) were analyzed to predict the recovery time required.
During the break, MVE% at 4 back muscles of all the male subjects were recovered to resting level within 5 minutes and 91.8% were within 2 minutes. Except for RL(3) after squat- and stoop-lifting task, the MVE% of female subjects went back to resting level within 3 minutes and 67.8% were within 2 minutes. The MF of male subjects were recovered in 10 minutes and 74.9% within 2 minutes, with the exception of RL(3) after stoop- and squat-lifting tasks. All the female MF were recovered in 8 minutes and 83.4% were within 2 minutes. However, during the last 20 minute break after the lifting tasks, the MVE% and MF of all male and female subjects were recovered, while HR came back to resting level within 14 and 5 minutes, respectively.
For the three manual lifting tasks with 25% MVC workload lasting for 4.5 min, a break of 15 minutes is sufficient for most erectors spinae to recover from local muscle load. However, in terms of the HR, a break of 15 minutes is enough for the recovery of systematic load.
Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 03/2011; 29(3):167-70.
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ABSTRACT: To study neck and shoulder work-related muscle fatigue of female sewing machine operators.
18 health female sewing machine operators without musculoskeletal disorders work in Beijing garment industry factory as volunteers in participate of this study. The maximal voluntary contraction (MVC) and 20% MVC of bilateral upper trapezium and cervical erectors spinae was tested before sewing operations, then the whole 20 time windows (1 time window = 10 min) sewing machine operations was monitored and the surface electromyography (sEMG) signals simultaneously was recorded after monitoring the 20%MVC was tested. Use amplitude analysis method to reduction recorded EMG signals.
During work, the median load for the left cervical erector spinae (LCES), right cervical erector spinae (RCES), left upper trapezium (LUT) and right upper trapezium (RUT) respectively was 6.78 ± 1.05, 6.94 ± 1.12, 5.68 ± 2.56 and 6.47 ± 3.22, work load of right is higher than the left; static load analysis indicated the value of RMS(20%MVC) before work was higher than that value after work, the increase of right CES and UT RMS(20%MVC) was more; the largest 20%MVE of bilateral CES occurred at 20th time window, and that of bilateral UT happened at 16th.
The work load of female sewing machine operators is sustained "static" load, and work load of right neck-shoulder is higher than left, right neck-shoulder muscle is more fatigable and much serious once fatigued.
Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 03/2011; 29(3):171-5.
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ABSTRACT: To investigate the interactive effect of job task and psychosocial factors on the outcomes of musculoskeletal disorders.
653 workers from different type of manufacturing industries and administration office recruited in a cross-sectional epidemiological survey. The Quick Exposure Check (QEC) was applied to assess the ergonomic load of job task, Job Content Questionnaire (JCQ) for identifying psychological characteristics, and Nordic Standardized Questionnaire for investigating outcomes of WMSDs.
The prevalence of WMSD in shoulder, upper back, lower back and hand/wrist were significantly different under a variety of combined job task and psychosocial characteristics (P < 0.05 or P < 0.01). The more physical and psychological loads, the higher prevalence of WMSDs were revealed. By using multivariate analyses, a potential interactive effect was found in terms of the WMSDs symptoms in hand/wrist, shoulder, upper back and lower back after adjusted by work year, age, and gender.
Higher physical load and greater psychosocial risk are more frequent self-reported symptoms of WMSDs than those of lower exposures. Ergonomic intervention strategies aimed at reducing the incidence of WMSDs should not only be focused on control of physical work factors but also psychosocial risks of relevance.
Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 03/2011; 29(3):176-9.
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ABSTRACT: To study the prevalence of occupational musculoskeletal disorders (OMSDs) in a shipyard and explore the relationship between type of work, age, length of service and OMSDs by cross sectional epidemiological survey.
1570 workers from a shipyard were selected as survey objects, and a revised Northern Europe Standardized Questionnaire was used to investigate OMSDs. 253 technicians and clerks in the shipyard were selected as controls.
OMSDs in these workers primarily located in waist, neck and shoulder, prevalence were 58.0%, 54.6% and 44.3% respectively; There were significant differences among workers of different types of work (P < 0.05) in prevalence and the cumulative parts number of OMSDs. The control group in this study also showed a higher prevalence of neck, shoulder and waist OMSDs. Female workers had higher prevalence of OMSDs in neck and shoulder compared with male workers (P < 0.05). As well there was significant correlation between age and OMSDs prevalence except the wrist and ankle disorders (P < 0.05), OMSDs prevalence increased with years. In addition, there was correlation between length of service and OMSDs prevalence, the group of ≤ 5 years had the lowest prevalence and the prevalence of low-back, neck and shoulder increased with service years.
The OMSDs in workers engaged in shipyard are serious, the length of service, age, gender and type of work seem to be the risk factors, and it seems reasonable that the ergonomics intervention in the above aspects should be necessary for the prevention of OMSDs.
Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 03/2011; 29(3):180-3.
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ABSTRACT: To analyze the distribution of the musculoskeletal disorders, work load and working postures in different factories, gender, education levels, age and working years among manufacturing workers.
In a cross-sectional study of 5134 manufacturing workers in 12 factories, the morbidities for musculoskeletal disorders in one year period were measured with questionnaires.
The morbidities for musculoskeletal disorders in body sites: waist, neck, shoulder, wrist, ankle/feet, knee, hip/buttocks and elbows were 59.7%, 47.9%, 38.1%, 33.7%, 26.9%, 25.4%, 15.2%, and 14.9%, respectively in one year period. There were significant differences of morbidities for musculoskeletal symptoms in body sites of workers among different factories (P < 0.05 or P < 0.01). The morbidities of musculoskeletal symptoms in elbows, waist, wrists and ankle/feet of the workers in refractory material and chemical fiber factories were higher than those in other factories, the morbidities for musculoskeletal symptoms of workers in garments and diamond factories were lower than those in other factories. The morbidities for musculoskeletal symptoms in neck, shoulders and wrists of female workers were significantly higher than those of male workers (P < 0.01). There were significant differences of the morbidities for musculoskeletal symptoms in body sites among workers with different educational levels (P < 0.05 or P < 0.01). There were significant differences of the morbidities for musculoskeletal symptoms in neck, shoulders, wrists, hip/buttocks and knee among groups with different age or different working years (P < 0.01), and the morbidities for musculoskeletal symptoms increased with age and working years. The proportions of unhealthy working postures and high working load among workers in refractory material and chemical fiber factories were higher; but those in garments and diamond factories were lower.
The morbidities for musculoskeletal symptoms in waist, neck, shoulder and wrists of workers in manufacturing workers were higher; the gender, education level, age and working years could influenced the morbidities for musculoskeletal disorders.
Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 03/2011; 29(3):184-9.
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Jing-zhi Sun,
Rui-jie Ling,
Zheng-lun Wang,
Ting-bo Song,
Biao Chen,
Lei Wu,
Jia-bing Wu,
Qiu-ling Yang, Li-hua He,
Sheng Wang,
Lei Yang
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ABSTRACT: To study the main risk factors of low back pain of workers ina foundry factory of the automobile company using cross sectional epidemiological investigation, and to provide scientific base for preventing the disorder.
The low back pain and work loads of 1340 workers in a foundry factory of the automobile company were investigated using questionnaire, and logistic regression analysis was used to analyze the risk factors.
The one-year morbidity of low back pain in workers was 58.9% the morbidities of low back pain in workers engaged in foundry, transportation and modeling were 64.6%, 64.6% and 62.5%, respectively. The lifting with squat postures, bending trunk heavily, bending trunk with twisting and moving the heavy objects were found to be the most dominant risk factors for low-back pain, the OR values were 2.085, 1.961, 1.967 and 1.956, respectively. The distributions of risk factors were different among the different jobs. The logistic regression analysis showed that moving the heavy objects, lifting with squat postures, bending trunk heavily, bending trunk with twisting existed simultaneously, also the work years and gender were the risk factors.
The manual moving heavy objects, awkward working posture or both were the most important risk factors for low-back pain. The intervene ergonomic study should be performed in future to reduce the morbidity of low-back pain.
Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 02/2011; 29(2):108-11.
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ABSTRACT: To investigate the usability of quick exposure check (Quick Exposure Check, QEC) for the field assessment of occupational musculoskeletal disorder risk factors.
In the shipyard and automobile manufacturing plants, QEC was used to observe the operations among workers with different jobs and to assess the work loads of workers. On the basis of results, the reliability of QEC was evaluated, and the correlation between QEC scores and morbidities of musculoskeletal disorders in workers was analyzed.
The inter-observer reliability (ICC) was in the range from 0.737 to 1.000, and intra-observer reliability (Spearman coefficient) was from 0.605 to 1.000. The order of exposure levels to risk factors of workers engaged in different jobs (QEC scores) in the shipyard factory was plumbers > assemblers > welders; The order of exposure levels to risk factors of workers engaged in different jobs (QEC scores) in the automobile factory was welders > punching workers > machinists > casters > assemblers. In different body parts, the exposure level at back and neck parts was the highest and the exposure level at the shoulder and wrist parts was the second. The regression analysis between QEC scores of body parts and the morbidities of musculoskeletal disorders showed that there was a good correlation between exposure levels and morbidities, the coefficients (r(2)) at the shoulder, wrist, and back (static work) were 0.670, 0.740 and 0.958, respectively (P < 0.05).
The QEC method is suitable and reliable as demonstrated by the field assessment on the exposure to risk factors in shipyard and automobile workers, and its results is correlated closely to the disease prevalence.
Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 02/2011; 29(2):112-5.
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Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 12/2010; 28(12):936-9.
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ABSTRACT: To observe the effect of chronic exposure to extremely low frequency magnetic field on neurobehavioral of adult rats.
Fifty Hz sinusoidal extremely low frequency magnetic field (ELF-MF) was used in this experimental procedure and the strength of magnetic field was fixed at 2 mT. Thirty male adult rats were divided randomly into 3 groups: (1) no ELF MF exposure (control group, n=10); (2) exposure to ELF MF 1 h/day (MF1h group, n=10); (3) exposure to ELF MF 4 h/day (MF4h group, n=10). The neurobehavioral changes of rats were detected by the open field test, elevated plus maze test and light/dark box test.
Compared with controls, no significant difference was found in rats of MF1h group in any test. Rats in MF4h group showed increased thigmotaxis, more grooming in the open field test; less time spent in open arms, central part and more time spent in closed arms. However, no significant difference was observed in the light/dark test in MF1h or MF4h group.
Chronic ELF MF exposure has an anxiogenic effect on rats, which is dependent on the daily exposure duration.
Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences 06/2010; 42(3):351-5.
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ABSTRACT: To study the characteristics of infrasound and its effects on the workers at power plants.
The audible noise and infrasound in three thermoelectricity plants were measured and by using Symptom Checklist 90 (SCL-90), the subjective sensation, and the physiological indices were compared between exposed workers and controls.
The infrasound levels were different at different measure sites of the three thermoelectricity works ranging from 40 to 98 dB. There was still 40 approximately 80 dB infrasound even when the soot blower stopped running. Different apparatus produced different infrasound levels with the highest ranging from 62 to 115 dB. A single frequency (16 Hz) infrasound was produced in certain department during working hour with sound pressure levels of 110 to 120 dB, but the audible noise sound pressure level was less than 70 dB. There was no significant difference in the indices representing vision fatigue and neurobehaviour function between exposed workers and controls. Workers at certain department experienced evident subjective sensation of neurobehavioral dysfunction, and the scores of somatization, depression, hostility, phobic anxiety, and psychotism in the SCL-90 were significantly higher in the exposed group than in the control and the norm in China (P < 0.05).
Infrasound is ubiquitous in the working environment, but usually, the noise levels are less than 120 dB. In some special production department, there is persistent infrasound above 110 to 120 dB. No obvious health effects are found among those who are exposed to infrasound below 100 dB. However, the workers who are chronically exposed to infrasound above 110 to 120 dB present notable subjective sensation of autonomic neurobehavioral dysfunction, and their psychological health status is not as good as those in the control and those in the domestic normal pattern.
Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 12/2008; 26(12):711-4.
