[The dose-response relationship of chrysotile asbestos exposure and lung cancer in cohort study].

OBJECTIVE: To clarify the dose-response relationship between asbestos dust exposure and lung cancer incidence in chrysotile asbestos miners by fixed cohort study and to investigate the incidence rates of lung cancer in exposure to different concentrations of asbestos dust. METHODS: A retrospective cohort study was conducted in 1932 asbestos miners who registered from January 1, 1981 to December 31, 1988, had worked for at least 1 year, and had no obvious cardiopulmonary diseases; the cohort study began in July 2009 and covered a time span of 29 years (1981 - 2009). The personal information, occupational history, disease history, and health data of these miners were recorded, and the monitoring data on dust concentrations in the mine over the years were collected. The dose-response relationship between asbestos dust concentration and lung cancer incidence was established by the method of life table; a regression equation was fitted to predict the excess incidence rates of lung cancer under the conditions of different working years and dust concentrations. RESULTS: A significant dose-response relationship was observed between cumulative exposure (Ce) and cumulative probability (Px) of lung cancer incidence, and the smokers hada higher Px than nonsmokers. When Ce was less than 2000 mg/m(3)·each year, Px reached 6.58/10000; when Ce was not less than 2000 mg/m(3)·and less than 3000 mg/m(3)·each year, Px reached 91.72/10000; when Ce was more than 5000 mg/m(3)·each year, Px was as high as 141.02/10000. The three models were fitted to obtain the optimal regression equation: Px = -0.0004Ce(2) + 0.0052Ce - 0.0011 (r(2) = 0.9387). In the workshop of asbestos mine in this study, the average dust concentration was 85 times higher than the limit in 2009, so the excess incidence rate of lung cancer was 112.598/10000 if the miners worked under this condition for 40 years, according to the equation. CONCLUSION: There is a significant dose-response relationship between cumulative asbestos exposure and lung cancer incidence in chrysotile asbestos miners. The risk for lung cancer rises as asbestos exposure increases.

[Study on mental workload of teachers in primary schools].

OBJECTIVE: To investigate the distribution characteristics and influencing factors of mental workload of teachers in primary schools. METHODS: National Aeronautics and Space Administration-Task Load Index (NASA-TLX) was used to assess the mental workload levels for 397 teachers of primary schools in a city. RESULTS: The mental workload (64.34+10.56) of female teachers was significantly higher than that (61.73+ 9.77) of male teachers (P<0.05). The mental workload (65.66+10.42) of "-35" years old group was the highest. When age of teachers was younger than 35 years old, there was a positive correlation between the mental workload and age (r=0.146, P<0.05). When age of teachers was older than 35 years old, there was a negative correlation between the mental workload and age (r=-0.190, P<0.05). The teachers with higher education level felt higher mental workload (unstandardized coefficients B=1.524, standardized coefficients /=0.111, P<0.05). There was a positive correlation between the mental workload and working hours per day (unstandardized coefficients B =4.659, standardized coefficients/3 =0.223, P<0.001). CONCLUSION: Mental workload of the teachers in primary schools is closely related to age, educational level and work hours per day. Work hours per day is an important risk factor for mental workload. Reducing work hours per day (8 hours) is an effective measure of alleviating the mental workload of teachers in primary schools.

[A survey report on dermatitis patients in hospital in Baoan district of shenzhen city from 1992 to 2006].

OBJECTIVE: To analyse the epidemiological distribution of dermatitis patients in hospital and provide basis for studying the basic conditions and the prevention of dermatitis especially TCE-induced dermatitis in Baoan District of Shenzhen City. METHODS: All dermatitis patients in hospital in Baoan District from 1992 to 2006 were descriptively analysed. RESULTS: There were 645 dermatitis patients in hospital in Baoan District. The total number of patients is tended to rise in recent years. The main age group of 16 approximately years old, followed by 26 approximately years old, the majority are workers. The clinical diagnosis are allergic dermatitis, drug-induced dermatitis, TCE-induced dermatitis. Compared with other dermatitis, women are more than men in TCE-induced dermatitis (P < 0.05). The risk of hepatic dysfunction in TCE-induced dermatitis was significantly greater than other dermatitis (P < 0.05). It is mainly distributed in electronic, metal, electroplating industry. CONCLUSION: The TCE-induced dermatitis was one of the main occupational hazards in Baoan district. To strengthen self-protection awareness of workers, pay more attention to early work observed and occupational screening in key industries and trades workers, reduce opportunities for occupational exposure, all above can effectively reduce the occurrence of TCE-induced dermatitis.

[Development and evaluation of Comprehensive Work Ability Index scales].

OBJECTIVE: To compile the instrument of comprehensive work ability evaluation-Comprehensive Work Ability Index (CWAI) scales. METHODS: One hundred and ninety-eight employees were selected with the random cluster sampling method from a factory. On the basis of the work ability theory, CWAI scales, a self-rating scales on work ability, was developed according to the standardized processes of scales compilation. Item differentiation analysis, principal component analysis and factor analysis as well as intra-item reliability were used for selecting the item of CWAI scales. RESULTS: Work ability was assessed with a comprehensive work ability index, which was a comprehensive indicator constructed on the basis of the responses to the scales. It was derived as the sum of the five items including self-rating work ability domain, physiological domain (disease, sick leave etc.), psychological domain (work satisfaction, mental state etc.), social functions dominant (social support, social flexibility etc.) and work ability prediction domain. CONCLUSION: CWAI scales correspond with the theoretical structure. However, the reliability and validity of CWAI scales must be assessed before the formal application.

[Reliability and validity of Comprehensive Work Ability Index scales].

OBJECTIVE: To test the reliability and the validity of Comprehensive Work Ability Index (CWAI) scales. METHODS: For evaluating the reliability and validity of CWAI scales, 1959 subjects employed in various kinds of occupations were selected with the random cluster sampling method. 245 subjects of them were retested at intervals of 2 to 4 weeks in order to assess the test-retest reliability. The sample for criterion validity consisted of 86 subjects. The inter-item consistency (Cronbach's alpha coefficient, Spearman-Brown coefficient, theta coefficient and Omega coefficient), test-retest reliability (intra-class correlation coefficient) and Pearson correlation were calculated to assess the reliability of CWAI scales. Pearson correlation analysis, and factor analysis were used to assess the validity of CWAI scales. RESULTS: The reliability analysis showed that CWAI was significantly correlated with the item scores (P < 0.01), and most of the correlation coefficients were higher than 0.30. Generally speaking, Cronbach's alpha coefficients (ranging from 0.701 to 0.808), theta coefficient (ranging from 0.703 to 0.845) and Omega coefficient (ranging from 0.802 to 0.942) and Spearman-Brown coefficient (0.860) conformed to the requirements of psychometric study. The intra-class correlation coefficient (ranging from 0.597 to 0.897) suggested that the test-retest consistency was good at intervals of 2 to 4 weeks. In point of the theoretic concept and development method, the content validity of CWAI scales was satisfactory. The intra-class correlation coefficient for the concurrent validity was 0.650 (P < 0.01) when WAI scales were taken as the criterion. Factor analysis revealed that when eight common factors were drawn from the 17 items of CWAI scales, the cumulative variance of eigenvalues amounted to 71.894%. Each item had communality over 0.60 and its factor loading (0.538 approximately 0.948) attached to the relevant common factor was over 0.40. The common factors with higher factor loading were basically consistent with the theoretic concept of CWAI scales. CONCLUSION: CWAI scales are reliable and valid.

Cancer mortality and asbestosis among workers in an asbestos plant in Chongqing, China.

OBJECTIVE: To investigate whether asbestosis is a risk factor for mortality of lung cancer. METHODS: A fixed cohort study was established in an asbestos plant in Chongqing, China, and followed up for 30 years from the beginning of 1972. Basic personal information on life state, cause of death, and diagnosis of asbestosis was collected. Multiple logistic regressions were applied to analyze risk factors. RESULTS: During the 30-year follow-up, 584 male workers constituting a total of 14,664 person-years were monitored and data were analyzed. Among them, 203 (34.8%) died and the mortality rate was 13.8 per 1000 person-years, cancer accounting for 37.4%. Excess risks were observed for lung cancer (OR = 3.72) and nonmalignant respiratory diseases (OR = 2.73) among workers with asbestosis. High-exposure level was another risk factor for lung cancer (OR = 3.20). Workers with category II of asbestosis demonstrated a higher OR of both lung cancer and nonmalignant respiratory diseases than those with category I of asbestosis. CONCLUSION: High asbestos exposure level and asbestosis were the risk factors for death of lung cancer and nonmalignant respiratory diseases. Asbestosis is an independent risk factor for lung cancer among Chinese workers exposed to chrysotile, the risk increases with the increasing profusion of opacities of lung.

[Development of safety climate measurement at workplace: validity and reliability assessment].

OBJECTIVE: To develop a measurement of safety climate at workplace and assess its validity and reliability. METHODS: According to the theory of preventive safety culture model, a scale including 7 dimensions of 27 items was developed. 342 workers were selected from among all workers of an artificial board factory and were investigated with the developed scale. Occupational accidents were recorded during the past year. Factor analysis, association validation and inter-item consistency test were applied to assess the scale validity and reliability. RESULTS: After the deletion of 6 items, 21 items composed the safety climate scale, which was loaded on 7 common factors: safety competence and consciousness, safety communication, organizational environment, management support, danger judgment, safety control measure and safety training. The cumulative contribution reached to 70.50%. All item communities (common factor variance) were above 0.6 except one item was 0.595. ANOVA showed that occupational accidents were associated with the safety climate score on total, danger judgment and safety control measure dimension (P < 0.05). There existed significant correlation between the safety climate total score and dimension scores (P < 0.01), the correlation coefficients were 0.700, 0.728, 0.705, 0.703, 0.354, 0.571 and 0.485 respectively. The safety climate scale total Cronbach's alpha coefficient, half-split Spearman-Brown coefficient, theta coefficient and omega coefficient indicated that the safety climate scale had good inter-item consistency among items. CONCLUSION: The measurement of safety climate at workplace is developed. It has good reliability and valid.

[Nested case-control study of chrysotile and lung cancer].

OBJECTIVE: To investigate the relationship between simple exposure to chrysotile and lung cancer. METHODS: The nested case-control study method was used. All of lung cancer cases collected from a male fixed prospective cohort with follow-up of 30 years served as cases and a 1:4 matched proportion was used to select non-cancer case as controls. Controls matched for sex age (+/-5 years old), work time (+/-5 years) and smoking were collected in the same cohort. RESULTS: Forty cases died of lung cancer in the study cohort, and the incidence was higher than the average incidence (SMR =1.77). The top four work types of death density were raw material (741.5), combing and spinning (424.3), weaving (365.0), and repairing (285.5), which was consistent with exposed level. According to the exposed level of chrysotile, the research objects were divided into the high level group and the low level group. The result demonstrated that lung cancer incidence of the high exposed level group of chrysotile was higher (OR = 3.7 95% CI 2.30 approximately 8.16), compared with the low exposed level group. CONCLUSION: Simple exposure to chrysotile can increase the risk of lung cancer for workers who are exposed to chrysotile.

[Paired-control study on the effect of vanadium on neurobehavioral functions].

OBJECTIVE: To investigate the change of neurobehavioral functions of workers with long term exposure to vanadium. METHODS: A total of 106 workers with exposure to vanadium were paired with workers without exposure to vanadium. The WHO-NCTB was employed to assess the neurobehavioral functions. RESULTS: The exposure group had lower scores in the domains measuring positive moods and higher scores in the domains measuring negative moods. The exposure group had poorer performance in Santa Ana dexterity, Benton visual retention and pursuit aiming II than the control group. CONCLUSION: Exposure to vanadium can adversely affect neurobehavioral functions of workers. Workers exposed to vanadium may show mood disorders, decreased vision-memory, and declined motor speed and accuracy.

[Factors affecting workers' compliance to occupational health and safety management system manuals].

OBJECTIVE: To identify the factors that affect the implementation of workers' manuals of occupational health and safety management system (OHSMS). METHODS: A self-designed questionnaire, which contained 23 items, was used to investigate workers' knowledge, responsibility and supporting environment of the OHSMS. The Logistic Regression Model was developed to identify factors that affect the implementation of the OHSMS. RESULTS: Demographic characteristics did not affect the implementation of the OHSMS manual. Knowledge (six out of seven items), responsibility and supporting environment had significant impact on the implementation of the OHSMS manuals. CONCLUSION: A variety of factors affect workers' compliance to the OHSMS manuals and need to be better controlled.

[Study on the relationship between workplace violence and work ability among health care professionals in Shangqiu City].

OBJECTIVE: To study the relationship between workplace violence and work ability and to provide evidence for preventing workplace violence and improving work ability among health care professionals. METHODS: A test of the workplace violence and work ability was carried out with workplace violence scale and work ability index, and Other information was investigated with questionnaire among 507 health care professionals in Shangqiu City of China. RESULTS: (1) The mean score of workplace violence was significantly higher in the group aged 30 - 44 than that of the group aged 45 - 59 (P < 0.05). (2) Among nurse group the mean score of workplace violence was higher than that of the doctor group and medical technician group (P < 0.05). (3) The mean score of WAI was lower in the group with primary educational level than that of other group (P < 0.05). (4) The workplace violence score correlated negatively to the WAI score (r = - 0.250, P < 0.01). (5) Logistic regression analysis showed that after controlling the other risk factors, workplace violence was an important risk factor of work ability ( OR = 8.44). CONCLUSION: Workplace violence has impact on work ability among health care professionals. Intervention measures should be taken to prevent workplace violence among health care professionals.

[Job burnout and contributing factors for nurses].

OBJECTIVE: To investigate the degree of job burnout and contributing factors for nurses. METHODS: A total of 495 nurses from three provincial hospitals were randomly selected. The MBI-GS, EPQ-RSC and OSI-R were administered to measure job burnout, personality traits and occupational stress, respectively. RESULTS: The medical and surgical nurses had significant greater scores of job burnout than others (P < 0.05). The poorer educational background was correlated with lower professional efficacy. The younger nurses had stronger feeling of job burnout. The scores of job burnout changed with different personality traits. The main contributing variables to exhaustion were overload, sense of responsibility, role insufficient and self-care (P < 0.05). The main contributing variables to cynicism were role insufficiency, role boundary, sense of responsibility and self-care (P < 0.05). The main contributing variables to professional inefficacy were role insufficiency, social support and rational/cognitive coping (P < 0.05). CONCLUSION: Job burnout for nurses can be prevented by reducing or keeping moderate professional duties and responsibility, making clearer job descriptions, promoting leisure activities, and enhancing self-care capabilities.

[Study of the intervention measures for the occupational stress to the teachers in the primary and secondary schools].

OBJECTIVE: To study the status of the occupational stress and the work ability of the teachers in the primary and secondary schools, then take some integrated intervention measures to reduce the occupational stress and improve their work ability, and evaluate the intervening efficacy. METHODS: The levels of stressor and strain was measured with the occupation stress inventory revised edition (OSI-R) and the work ability was measured with the work ability index (WAI) for the teachers in nine primary and secondary schools in Sichuan Province, then health educations about occupational stress were taken to the teachers in the study group, the same test was carried out after one year for the teachers in the nine schools to evaluate the effect of intervention measures. RESULTS: (1) After intervening, among the six items of occupational role questionnaire, the scores of role overload, role boundary, responsibility and physical environment of the teachers in the study group significantly decreased, compared with the teachers in the control group, the scores of the role overload, role boundary and physical environment were significantly lower (P < 0.05). (2) Among the four items of personal strain questionnaire, only the scores of interpersonal strain of the teachers in the study group significantly decreased (P < 0.05), compared with the teachers in the control group, the scores of the vocational strain and interpersonal strain were significantly lower (P < 0.05). (3) Among the four items of personal resources questionnaire, the scores of the recreation, self-care and rational cognitive coping of the teachers in the study group significantly raised and were significantly higher than those of the teachers in the control group (P < 0.05). (4) The score of WAI of the teachers in the study group significantly raised and was significantly higher than that of the teachers in the control group (P < 0.05). CONCLUSION: The intervention measures are efficient to reduce the occupational stress of teachers, strengthen their coping resource and improve their work ability.

[Occupational stress and job burnout in doctors].

OBJECTIVE: To investigate the status of job burnout in doctors and its relationship with occupational stress. METHODS: A total of 561 doctors from three provincial hospitals were randomly selected. The Maslach Burnout Inventory-General Survey (MBI-GS) was used to identify job burnout. The occupation stress inventory revised edition (OSI-R) was used to evaluate the level of occupational stress. RESULTS: Surgeon and doctors working in the internal medicine wards scored significantly higher in job burnout than their colleagues (P < 0.05). The 30-40 years of age group scored highest in exhaustion. The score of professional efficacy decreased with age and increased with educational levels. Role overload, responsibility, physical environment, reaction and self-care were major predictors for exhaustion. Role insufficiency, role overload and responsibility were major predictors for cynicism. Role insufficiency, social support and rational/cognitive were major predictors for professional efficacy. CONCLUSION: Maintaining moderate professional duty and responsibility, clearly defining job requirements, enriching leisure activities, and improving self-care ability are important measures to preventing job burnout.

[Evaluating training programs on occupational health and safety: questionnaire development].

OBJECTIVE: To develop a questionnaire to evaluate the quality of training programs on occupational health and safety. METHODS: A questionnaire comprising five subscales and 21 items was developed. The reliability and validity of the questionnaire was tested. Final validation of the questionnaire was undertaken in 700 workers in an oil refining company. RESULTS: The Cronbach's alpha coefficients of the five subscales ranged from 0.6194 to 0.6611. The subscale-scale Pearson correlation coefficients ranged from 0.568 to 0.834 . The theta coefficients of the five subscales were greater than 0.7. The factor loadings of the five subscales in the principal component analysis ranged from 0.731 to 0.855. Use of the questionnaire in the 700 workers produced a good discriminability, with excellent, good, fair and poor comprising 22.2%, 31.2%, 32.4% and 14.1 respectively. Given the fact that 18.7% of workers had never been trained and 29.7% of workers got one-off training only, the training program scored an average of 57.2. CONCLUSION: The questionnaire is suitable to be used in evaluating the quality of training programs on occupational health and safety. The oil refining company needs to improve training for their workers on occupational health and safety.

[Study on association of interleukin-1 receptor antagonist(RA) gene + 2018 locus mutation with silicosis].

OBJECTIVE: To approach whether + 2018 locus (T-- C) mutation within the interleukin- receptor antagonist (IL-1RA) gene promoter region are associated with susceptibility to silicosis in Southwest Chinese Han population. METHODS: 75 cases of silicosis and 137 silica-exposed workers(being employed) were selected as subjects.5ml peripheral vein blood was drawn from each subject. By real-time quantitative polymerase chain reaction and sequencing techniques, IL-1RA gene mutation of all subjects were analyzed. RESULTS: The frequency of IL-1RA + 2018C among the cases with silicosis was higher than that among the silica-exposed workers (controls) (28.0% versus 15.0% , Fisher' s exact P < 0.01 ). The frequency of allelic C was higher in cases with phase I silicosis than in controls(31.8% versus 15.0%, Fisher's exact P < 0.01 ). The frequency of allelic C was higher in cases with phase I and Ill silicosis than in controls, but which statistic difference being not significant(22.6% versus 15.0%, Fisher's exact P < 0.01). After adjusted for confounding factors, the frequency of IL-1RA + 2018C among silicoses and its subgroups was still higher than among controls, which statistic difference being significant (Fisher' s exact P < 0.01). CONCLUSION: IL-1RA gene polymorphisms played an important role in making the Han population of Southwest China susceptible to silicosis. IL-1RA might be took as a gene to be selected for studying the susceptibility of silicosis.

[Path analysis on workplace violence affecting work ability, job satisfaction and turnover intent in health professionals in Shangqiu City].

OBJECTIVE: To explore the effects of workplace violence on work ability, work satisfaction and turnover intent based on the theory of occupational stress in health professionals and to provide evidence for evaluating the process and consequence of workplace violence. METHODS: Subjects of 483 health professionals from 5 hospitals in Shangqiu city of Hennan Province were selected with stratified cluster random sampling method. Workplace violence, violent fear at work, coping resources, work ability, job satisfaction and turnover intent were measured with questionnaires. Ordinal regression analysis and path analysis were applied to analyze the data. RESULTS: Workplace violence had direct or indirect effects on the work ability and job satisfaction through the fear of future violence at work. Workplace violence only had indirect effects on turnover intent through the fear and job satisfaction in health professionals. CONCLUSION: Workplace violence had direct and indirect effects on the work ability, job satisfaction and turnover intent. Measures should be taken to reduce workplace violence and it' s effects in health professionals.

[The relationship between the concentration of TGF-beta1 in serum and its gene polymorphisms in CWP].

OBJECTIVE: To study the relationship between the concentration of TGF-beta1, in serum and its gene polymorphisms in CWP. METHODS: 101 cases of coal worker's pneumoconiosis (CWP)were selected. And the peripheral vein blood samples were collected from them. The concentration of TGF-beta1 of their serum were detected with the TGF-beta1 ELISA kit. And their TGF-beta1 gene -509 site polymorphisms were analyzed with the polymerse chain reaction-restriction fragment length polymorphisms (PCR-RFLP) techniques. RESULTS: The mean value of TGF-beta1, concentration in serum of T/T, C/T and C/C gene type group were 90 ml, 60 ml and 55.960 +/- 28.833 ng/ ml respectively. Significant differences were observed within the three groups (P<0.05). The differences of the mean value of TGF-beta1, concentration in serum in various work years groups, age groups and in the groups with different stage of pneumoconiosis were not significant (P > 0.05). CONCLUSION: The correlative relationship between the concentration of transforming growth factor I (TGF-beta1) in serum and its gene -509 site polymorphisms might be occurring.

[On the association of tumor necrosis factor-alpha gene polymorphisms with the susceptibility to silicosis].

OBJECTIVE: To find out whether -308 and -238 locus (G --> A) mutation within the tumor necrosis factor-alpha gene (TNF-alpha) promoter region are associated with susceptibility to silicosis in the Han population of southwest China. METHODS: Governed by the principles of voluntatiness and cooperation, 75 patients with silicosis and 137 control with silica-exposure but without silicosis were recruited, and additionally, 140 elderly patients with silicosis and 135 healthy elderly (retired) controls were recruited in this case-control study. 5 ml peripheral vein blood was drawn from each subject. By means of polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) and sequencing techniques, TNF-alpha gene polymorphisms of all subjects were analyzed. RESULTS: The frequencies of TNF-alpha -308A and -238A in the 75 patients with silicosis were higher than those in the 137 controls (P < 0.01). After being adjusted for confounding factors, the -308A and the -238A were still associated with the presence of silicosis (P < 0.01). But the frequency of TNF-alpha -308A in the 140 elderly patients was significantly lower than that in the controls (P < 0.001). CONCLUSIONS: TNF-alpha gene -308 and -238 locus (G --> A) mutation might be related to the occurrence of silicosis and the severity of pulmonary fibrosis in silicosis among the Han population of southwest China, and TNF2 (-308A) allele might increase the risk of the disease.