Effect of psychological capital and social support on job satisfaction among workers in a natural gas field / 中国职业医学

@#To explore the effects of psychological capital social support and their interaction on job satisfaction in Methods natural gas field workers. A total of 1 473 workers from a natural gas field were selected as the research subjects ， using convenient sampling method. Job Satisfaction Questionnaire Psychological Capital Questionnaire and Social Support ， Results Scale were used to investigate the scores of job satisfaction psychological capital and social support level. The ， ， detection rates of job satisfaction psychological capital and social support in the high level group were 55.9% 52.5% and ， 48.1% respectively. The detection rates of job satisfaction of workers in the high level psychological capital group and high level （ social support group were higher than those in the low level psychological capital group and low level social support group 67.4% vs ， vs ， P ） 43.3% 71.9% 41.2% all <0.01 . The results of multivariate logistic regression analysis showed that psychological capital ［ （CI） （ - ） and social support had positive effects on job satisfaction odds ratio and 95% confidence interval were 1.58 1.17 2.41 （ - ）， ， P ］ ， and 2.53 1.82 3.52 respectively all <0.01 . Moreover the psychological capital and social support had additive effect on ［ CI （ - ）， CI job satisfaction relative excess risk of interaction and 95% was 3.07 1.02 5.12 attributable proportion and 95% was （ - ）， CI （ - ）］， 0.48 0.35 0.61 synergy index and 95% was 2.34 1.72 3.16 but there was no multiplication interaction between （P ）Conclusion psychological capital and social support >0.05 . Psychological capital and social support can positively affect job satisfaction of natural gas workers. There is an additive interaction between psychological capital and social support on job ， satisfaction but no multiplicative interaction is found. Keywords: ； ； ； ； ； Psychological capital Social support Job satisfaction Interaction Natural gas Worker

The Effect of PCDH15 Gene Variations on the Risk of Noise-induced Hearing Loss in a Chinese Population.

Noise-induced hearing loss (NIHL) is a complex disease caused by interactions between environmental and genetic factors. This study investigated whether genetic variability in protocadherin related 15 (PCDH15) underlies an increased susceptibility to the development of NIHL in a Chinese population. The results showed that compared with the TT genotype of rs11004085, CT/CC genotypes were associated with an increased risk of NIHL [adjusted odds ratio (OR) = 2.64; 95% confidence interval (CI): 1.14-6.11, P = 0.024]. Additionally, significant interactions between the rs11004085 and rs978842 genetic variations and noise exposure were observed in the high-level exposure groups (P < 0.05). Furthermore, the risk haplotype TAGCC was observed when combined with higher levels of noise exposure (P < 0.05). Thus, our study confirms that genetic variations in PCDH15 modify the susceptibility to NIHL development in humans.

Long-term exposure to diesel engine exhaust induced lung function decline in a cross sectional study.

To clarify the effects of lung function following exposure to diesel engine exhaust (DEE), we recruited 137 diesel engine testing workers exposed to DEE and 127 non-DEE-exposed workers as study subjects. We performed lung function tests and measured cytokinesis-block micronucleus (CBMN) cytome index and levels of urinary polycyclic aromatic hydrocarbons (PAHs) metabolites. There was a significant decrease of forced expiratory volume in 1 second (FEV1), ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/ FVC), maximal mid expiratory flow curve (MMF), forced expiratory flow at 50% of FVC (FEF50%), and forced expiratory flow at 75% of FVC (FEF75%) in the DEE-exposed workers than non-DEE-exposed workers (all p<0.05). Among all study subjects, the decreases of FEF75% were associated with the increasing levels of PAHs meta-bolites (p<0.05), and there were negative correlations between FEV1, FEV1/FVC, MMF, FEF50%, and FEF75% with CBMN cytome index (all p<0.05). Our results show that long-term exposure to DEE can induce lung function decline which shows mainly obstructive changes and influence of small airways function. The decreased lung function is associated with internal dosage of DEE exposure, and accompany with the increasing CBMN cytome index.

Development of Job Burden-capital Model of Occupational Stress: An Exploratory Study.

This study proposes a new framework as job burden-capital model for comprehensive assessment on occupational stress. 1618 valid samples were recruited from electronic manufacturing service industry in Hunan province by self-rated questionnaires after written consent. Structural equation model analysis was employed to verify the model by the data collected. The final fitting model has satisfactory fitting goodness (CMIN/DF=5.78, AGFI=0.937, NNFI=0.960, IFI=0.968, RMSEA=0.054). Both of the measurement model and structural model have acceptable path loadings. Job burden and capital could either directly affect occupational outcomes or indirectly influence them through personality. Multi-group structural equation model analyses indicate general applicability of the model to the basic features of such population. The job burden-capital model opens up new horizons for more in-depth study on occupational stress.

Establishment of a reference value for chromium in the blood for biological monitoring among occupational chromium workers.

The concentration of chromium in the blood (CrB) has been confirmed as a biomarker for occupational chromium exposure, but its biological exposure indices (BEIs) are still unclear, so we collected data from the years 2006 and 2008 (Shandong Province, China) to analyze the relationship between the concentration of chromium in the air (CrA) of the workplaces and CrB to establish a reference value of CrB for biological monitoring of occupational workers. The levels of the indicators for nasal injury, kidney (ß2 microglobulin (ß2-MG)), and genetic damages (8-hydroxy-deoxyguanosine (8-OHdG) and micronucleus (MN)) were measured in all subjects of the year 2011 (Henan Province, China) to verify the protective effect in this reference value of CrB. Compared with the control groups, the concentrations of CrA and CrB in chromium exposed groups were significantly higher (P < 0.05). Positive correlations were found between CrA and CrB in chromium exposed groups (r 2006 = 0.60, r 2008 = 0.35) in the years 2006 and 2008. According to the occupational exposure limitation of CrA (50 µg/m(3), China), the reference value of CrB was recommended to 20 µg/L. The levels of nasal injury, ß2-MG, 8-OhdG, and MN were not significantly different between the low chromium exposed group (CrB ≤ 20 µg/L) and the control group, while the levels of ß2-MG, 8-OHdG, and MN were statistically different in the high chromium exposed group than that in the control group. This research proved that only in occupational workers, CrB could be used as a biomarker to show chromium exposure in the environment. The recommended reference value of CrB was 20 µg/L.

How Work Organization Affects the Prevalence of WMSDs: A Case-control Study.

OBJECTIVE: In this study, we aimed at exploring the association between work-related musculoskeletal disorders (WMSDs) and work organization based on a case-control study. METHODS: A total of 1938 workers who claimed to suffer from WMSDs were selected from Beijing, Henan, Hubei, and the Guangdong province. The control group consisted of 2009 workers employed in similar industries without severe disease or musculoskeletal discomforts. We used a modified version of the questionnaire developed by the NMQ and the DMQ to investigate individual and work-related factors. RESULTS: A total of 13 variables (P<0.1) were selected by the chi-square test and finally, 7 variables entered into the equation, with 6 variables reaching statistical significance (P<0.05). The odds ratios (OR) of 'work changing with season' and 'sufficient rest time' did not reach 1 (0.749 and 0.441, respectively). In addition, 'sufficient rest time' seemed to be the stronger protective factor according to its higher standardized coefficient. And 'repetitive work every minute', 'constantly repetitive work' (every day), 'shortage of site personnel', and 'often switching shifts with others' seemed to be the risk factors. CONCLUSION: Work organization may have comprehensive effects on the occurrence of WMSDs. This pattern of associations suggests that further investigation into the mechanism of how work organization affects the prevalence of WMSDs is required.

Biomarkers for lung epithelium injury in occupational hexavalent chromium-exposed workers.

OBJECTIVE: To evaluate whether Club (Clara) cell protein (CC16) and surfactant-associated protein D (SP-D) can be used as biomarkers for lung injury caused by chromium exposure. METHODS: The concentrations of chromium in the air (CrA), chromium in the blood (CrB), lung function, CC16, SP-D, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were detected in 91 chromium-exposed workers and 38 controls. RESULTS: In chromium-exposed group, the levels of CrA, CrB, SP-D, TNF-α, and IL-6 were significantly higher, whereas forced expiratory volume in one second (FEV1), FEV1/FVC, maximal expiratory flow (MEF), maximum ventilation volume (MVV), CC16, and CC16/SP-D were lower. Negative correlations were shown between CC16, SP-D or CC16/SP-D, and CrB or inflammatory cytokines (TNF-α and IL-6). Positive relationships were shown between CC16 or CC16/SP-D with indicators of lung function. Tobacco smoking and chromium exposure had synergic effects on lung injury. CONCLUSIONS: CC16, as an immunosuppressive protein, and CC16/SP-D can be used as sensitive and noninvasive biomarkers for lung injury. Smoking should be banned in chromium workplaces.

Association of folate deficiency and selected tumor marker concentrations in long-term hexavalent chromium exposed population.

Both hexavalent chromium [Cr (VI)] exposure and folate deficiency have been associated with increased cancer risks. Our previous studies have found folate deficiency in Cr (VI) exposed population. Here the relationship between some tumor markers and folate status in long-term Cr (VI) exposure was investigated carefully to show the multiple aspects of Cr (VI) carcinogenesis. A group of 115 workers occupationally exposed to chromate and 60 matched, unexposed controls in Shandong province of China were recruited. Environmental and biological exposure assessments including personal exposure to airborne Cr and Cr contents in erythrocytes were performed. Serum folate, plasma total homocysteine (tHcy) and plasma carcinoembryonic antigen (CEA), neuron specific enolase (NSE), squamous cell carcinoma antigen (SCC), cytokeratin fragment antigen 21-1 (CYFRA 21-1), cancer antigen 72-4 (CA72-4), as well as α-fetoprotein (AFP) were measured. Smoking index (SI) was also calculated to discriminate possible confounding effects of smoking status. Serum folate level decreased significantly, while plasma tHcy, CEA, NSE, SCC, CYFRA21-1, CA72-4 and AFP concentrations increased significantly after Cr (VI) exposure. Meanwhile, plasma CEA, NSE and SCC were negatively correlated with serum folate. SI was negatively correlated with serum folate but positively correlated with plasma tHcy, CEA and NSE levels. Present study suggests that folate deficiency was associated with increased cancer risks and might be affected by smoking in Cr (VI) exposed population. Folate might play a key role in Cr (VI) carcinogenesis although further detailed investigations are needed to clarify the mechanism of this process.

[Evidence-based study of chromate exposed workers' health surveillance indexes].

OBJECTIVE: The health surveillance proposal for chromate exposed workers was provided and analyzed on the evidence-based study and then to be improved. METHOD: Firstly, the related literatures were searched about liver damage, micronuclei, urinary chromium and hexavalent chromium exposure in Evidence Based Medicine Reviews such as Cochran library, OVID Medline, Web of knowledge in December 2011; and then, these literatures were reviewed in according to inclusion and exclusion criteria; 22 articles totally were retrieved, evaluated and classified in according to the grading standard by Oxford Centre for Evidence-based Medicine.Finally, field epidemiological investigation was further adopted to confirm the efficiency and feasibility of this proposal, combined with cost-effectiveness analysis:the ratio of total cost divided survival years was used to express the cost-effectiveness. RESULT: Only the glutamic pyruvic transaminase test could not reflect liver damage caused by chromate exposure well; Urinary chromium correlated well with the index reflecting body damage caused by chromate exposure; Binucleated cells micronucleus index in peripheral blood lymphocyte could reflect the genetic damage caused by chromate exposure. As for health economic evaluation of chromate lung cancer, the value of cost/effectiveness was ¥42 321.61 per year that was far below the value of common people (¥252 868.97 per year) . CONCLUSION: It was suggested that serum glutamic pyruvic transaminase test should be replaced by liver function test, urinary chromium should be classified as a compulsory index and binucleated cells micronucleus index in peripheral blood lymphocyte should be supplied as a recommended index.

Co-effect of Demand-control-support model and effort-reward imbalance model on depression risk estimation in humans: findings from Henan Province of China.

OBJECTIVE: To investigate the co-effect of Demand-control-support (DCS) model and Effort-reward Imbalance (ERI) model on the risk estimation of depression in humans in comparison with the effects when they are used respectively. METHODS: A total of 3 632 males and 1 706 females from 13 factories and companies in Henan province were recruited in this cross-sectional study. Perceived job stress was evaluated with the Job Content Questionnaire and Effort-Reward Imbalance Questionnaire (Chinese version). Depressive symptoms were assessed by using the Center for Epidemiological Studies Depression Scale (CES-D). RESULTS: DC (demands/job control ratio) and ERI were shown to be independently associated with depressive symptoms. The outcome of low social support and overcommitment were similar. High DC and low social support (SS), high ERI and high overcommitment, and high DC and high ERI posed greater risks of depressive symptoms than each of them did alone. ERI model and SS model seem to be effective in estimating the risk of depressive symptoms if they are used respectively. CONCLUSION: The DC had better performance when it was used in combination with low SS. The effect on physical demands was better than on psychological demands. The combination of DCS and ERI models could improve the risk estimate of depressive symptoms in humans.

[Distribution of chromium in whole blood and urine among general population in China between year 2009 and 2010].

OBJECTIVE: To evaluate the chromium (Cr) levels in blood and urine among general population in China between 2009 and 2010, and thereby to analyze its prevalent features. METHODS: From year 2009 to 2010, a total of 11 983 subjects of general population aged between 6 and 60 year-old were recruited from 24 districts in 8 provinces in eastern, central and western China mainland, by cluster random sampling method. The information about their living environment and health status were collected by questionnaire, and 11 983 blood samples and 11 853 urine samples were also collected. Inductively coupled plasma mass spectrometry (ICP-MS) was applied to test the Cr level both in blood and urine; and the Cr distribution in blood and urine among groups of population in different ages, genders and districts, were then analyzed. RESULTS: Among general population in China, the geometric mean (GM) of Cr concentration in blood was 1.19 µg/L, with median at 1.74 µg /L and 95% percentile at 5.59 µg/L. The Cr concentration in blood among males and females were separately 1.18 µg/L and 1.20 µg/L(P > 0.05); while its GM in the groups of population aged 6 - 12, 12 - 16, 16 - 20, 20 - 30, 30 - 45 and 45 - 60 years old were 1.00, 1.22, 1.01, 1.40, 1.27 and 1.30 µg/L (P < 0.01), respectively; and the figures in populations from eastern, central and western China were 1.00, 1.70 and 1.98 µg/L (P < 0.01), respectively. Among general population, the GM of Cr concentration in urine was 0.53 µg/L, with median was lower than 0.42 µg/L and 95% percentile at 3.53 µg/L. The Cr concentration in urine among males and females were separately 0.52 µg/L and 0.53 µg/L (P > 0.05);while its GM in the groups of population aged 6 - 12, 12 - 16, 16 - 20, 20 - 30, 30 - 45 and 45 - 60 years old were 0.56, 0.60, 0.52, 0.50, 0.52 and 0.46 µg/L (P < 0.01), respectively;and the figures in populations from eastern, central and western China were 0.58, < 0.42 and 0.60 µg/L (P < 0.01), respectively. CONCLUSION: The study reported the Cr levels in blood and urine among general population in China, and thereby provided basic data evidence for the following Cr biological monitoring studies in near future.

Risk factors of low back pain among the Chinese occupational population: a case-control study.

OBJECTIVE: To explore the risk factors of low back pain among the Chinese occupational population in several major industries. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

[The epidemiological characteristics and correlated factors of daily hassles for thermal power plant workers].

OBJECTIVE: This study aimed to investigate the epidemiological characteristics and correlated factors of daily hassles among thermal power plant workers. METHODS: A mass screening of daily hassles and correlated factors was conducted on 498 workers from a thermal power plant in Zhengzhou in July, 2008. The questionnaires included Daily Hassles Questionnaires, Work Roles Questionnaires, Job Content Questionnaires (Chinese version), Effort-Reward Imbalance (Chinese version), Work Locus of Control Scale and Type A Behavior Scale, with content covering demographic characters and occupational stress correlated factors among subjects. The daily hassles was divided into lower level and higher level according to scores, and the epidemiological characteristics and correlated factors of daily hassles were analyzed. RESULTS: A total of 446 qualified questionnaires were obtained, effective response rate was 89.6% (446/498). For respondents, the age was (36.96 ± 6.49) years old, working length of the current job was (12.05 ± 7.54) years, the daily hassles scores was (9.01 ± 2.50), and the prevalence rate of the higher level of daily hassles was 34.1% (152/446). The multiple non-conditional logistic regression analysis showed 5-14 years' working length of current job (OR = 0.451, 95%CI: 0.225 - 0.904), average income > 3000 yuan(OR = 0.372, 95%CI: 0.202 - 0.684), reward (OR = 0.557, 95%CI: 0.325 - 0.954) and coping strategy (OR = 0.552, 95%CI: 0.330 - 0.925) were negatively correlated with daily hassles, and shift-work (OR = 1.887, 95%CI: 1.108 - 3.215), effort (OR = 2.053, 95%CI: 1.198 - 3.519), psychological demand (OR = 1.797, 95%CI: 1.049 - 3.078), negative affectivity (OR = 3.421, 95%CI: 2.065 - 5.668) were positively correlated with daily hassles. CONCLUSION: The prevalence rate of the higher level of daily hassles was considerable high for thermal power plant workers. Its negative correlated factors included 5 - 14 years' working length of the current job, average income > 3000 yuan, reward and coping strategy and its positive corelated factors included shift-work, effort, psychological demand and negative affectivity.

[Effects of carbon disulfide on cardiovascular system of workers occupationally exposed to carbon disulfide].

OBJECTIVE: To study the effects of long-term exposure to carbon disulfide (SC(2)) on cardiovascular system of workers. METHODS: The concentrations of CS(2) were detected in the representative workshops with different exposure levels. The indicators related to cardiovascular system were tested in 633 workers occupationally exposed to CS(2), which included blood pressure, electrocardiogram, blood routine (blood RT), cholesterol (TCHO), triglyceride (TG) and so on. The data were analyzed by chi-square test and multiple logistic regression analysis. RESULTS: The exposure concentration of CS(2) for 389 workers was less than or equal to 5 mg/m(3), which for other 244 workers was higher than 5 mg/m(3). The maximum exposure concentration of CS(2) was 15.73 mg/m(3). There were no significant effects of CS(2) on the electrocardiogram, red blood cells, white blood cells, blood platelet, TCHO and TG of workers. However, the positive effects of CS(2) on blood pressure and negative effects of CS(2) on hemoglobin were found. The rates of high TCHO, TG and hypertension in male workers were significantly higher than those in female workers (P < 0.05). The rates of high TCHO, hypertension and sinus arrhythmia in older workers (≤ 30 years old) were significantly higher than those in young workers (> 30 years old) (P < 0.05). The rate of sinus arrhythmia in workers with 1 - 10 working years was significantly higher than that in workers with more than 10 working years (P < 0.05). The rate of hypertension in workers with 1 - 10 working years was significantly lower than that in workers with more than 10 working years (P < 0.05). CONCLUSION: There were no significant effects of CS(2) exposure on the indexes of cardiovascular system of workers.

[Carbon disulfide exposure level of workers in a chemical fiber industry].

OBJECTIVE: To investigate the exposure levels of carbon disulfide (CS(2)) for a chemical fiber industry. METHODS: The concentration of CS(2) was monitored in representative workshops and types of work, and the datas of that over the years were collected. RESULTS: The short-term exposure concentration of CS(2) about 80% of the type of work was less than or equal to 10 mg/m(3), which of more than 90% was less than or equal to 20 mg/m(3). The time weighted average concentration of CS(2) about 70% of the type of work was less than or equal to 5 mg/m(3), which of more than 90% was less than or equal to 10 mg/m(3). The short-term exposure concentration of CS(2) which was more than 15 mg/m(3) or the time weighted average concentration of CS(2) which was more than 30 mg/m(3) was only for little type of work. CONCLUSION: The concentration of CS(2) for the most type of work was lower, but there were still a number of types of work exposuring the higher concentration, which exceed the national occupational exposure limits.

[The improvement of determination method of carbon disulfide in workplace air with gas chromatography].

OBJECTIVE: Establishment of determination method of carbon disulfide in charcoal tube with low toxicity solvents desorption-gas chromatography. METHODS: Four types of solvent with low toxicity are applied respectively as substitution of benzene to desorb the carbon disulfide in samples of charcoal tube. The signal strength and desorption efficiency of the detector are compared by using different solvents. RESULTS: Chloroform has been considered as the best alternative solvent of benzene. Carbon disulfide has a good linearity (R = 0.9997) over the concentration of 0 ∼ 54.7 µg/ml, detection limit can reach 0.2 µg/ml. When the sampling volume is 3.0 L, the minimum detectable concentration is 0.07 mg/m(3). CONCLUSION: With the use of chloroform, the health hazard to laboratory personnel and environment pollution as well as the costs of experiments are reduced.

[The optimization of 2-thiothiazolidine-4-carboxylic acid back extraction in urine and determination by HPLC].

OBJECTIVE: Establishment of determination method of 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine with HPLC. METHODS: A volume of 0.5 ml hydrochloric acid (2 mol/L) and 0.5 ml pure water was added into 1 ml urine, and then extracted by 4 ml of diethyl ether by shaking for 2 min. Remove the water phase in a tube with plug and extract again, mix the two extraction diethyl ether together, take 4 ml by adding 2 ml borax-monopotassium phosphate buffer and shaking for 2 min to extract, then take the water phase to detect. A C(18) column and UV detector were used for separating and detecting. The wavelength was 273 nm, the flow rate was 1.0 ml/min, and the injection volume was 20 µl. RESULTS: TTCA has a good linearity (r = 0.9995) over the concentration of1 1 ∼ 10 µg and the minimum detectable concentration of TTCA in urine was 0.1 µg/ml. The within-day precision (RSD) were 8.4%, 3.0% and 1.7%, the between-day precision (RSD) were 11%, 3.8%, 1.9%, respectively. The extraction recovery were between 80% ∼ 102%. CONCLUSION: The method was accurate and sensitive to detect TTCA in urine.

[The rervising of biological exposure index for carbon disulfide exposuring].

OBJECTIVE: To study the biological exposure index of carbon disulfide in China. METHODS: High-performance liquid chromatography (HPLC) was used to detect the levels of 2-thiothiazolidine-4-carboxylic acid (TTCA) in the urine of the workers after working shift end, Gas chromatography was used to detect the concentrations of the carbon disulfide in the workplace air. The relationship between the urine TTCA levels and the concentrations of the carbon disulfide was analyzed, the biological exposure index and judgement result from PC-TWA were compared. RESULTS: The levels of TTCA in urine of workers occupationally exposed to carbon disulfide were closely and positively related with the concentrations of the carbon disulfide in the workplace air. The regression equation was Y = 0.265X - 0.165, The biological exposure index of carbon disulfide were calculated by regression equation according to occupational exposure limits of carbon disulfide in China. CONCLUSION: The biological exposure index of CS(2) in China might be revised for 1.2 mg/g Cr.