Objectives: Perfluoroalkyl carboxylic acids (PFCAs) consist of analogs with various carbon chain lengths. Their toxicokinetics have remained unexplored except in the case of perfluorooctanoic acid (8 carbon chemicals). This study aimed to investigate the toxicokinetics of PFCAs with six to fourteen carbon atoms (C6 to C14) in mice and humans. Methods: We applied a two-compartment model to mice administered PFCAs intravenously or by gavage. The time courses of the serum concentration and tissue distribution and elimination were evaluated for 24 hours after treatment. For human samples, urine from healthy volunteers, bile from patients who underwent biliary drainage, and cerebral spinal fluid (CSF) from brain drainage were collected. Results: The mouse experiment showed that short-chained PFCAs (C6 and C7) were rapidly eliminated in the urine, whereas long-chain PFCAs (C8 to C14) accumulated in the liver and were excreted slowly in feces. Urinary clearance of PFCAs in humans also decreased with increasing alkyl chain lengths, while biliary clearances increased. C9 to C10 had the smallest total clearance for both mice and humans. However, disparities existed in the magnitude of the total clearance between mice and humans. A slightly higher partition ratio (brain/serum) was observed for long-chained PFCAs in mice, but this was not observed in the corresponding partition ratio in humans (CSF/serum). Conclusions: The large sequestration volumes of PFCAs in the liver seem to be attributable to the liver's large binding capacity in both species. This will be useful in evaluating PFCA bioaccumulation in other species.(J Occup Health 2015; 57: 1–12)
Objective: Sensor characteristics and performance of three real-time monitors for volatile organic compounds (VOC monitor) equipped with a photo ionization detector (PID), a sensor using the interference enhanced reflection (IER) method and a semiconductor gas sensor were investigated for 52 organic solvent vapors designated as class 1 and class 2 of organic solvents by the Ordinance of Organic Solvent Poisoning Prevention in Japan. Methods: Test vapors were prepared by injecting each liquid solvent into a 50 l Tedlar® bag and perfectly vaporizing it. The vapor concentration was from one-tenth to twice the administrative control level for all solvents. The vapor concentration was measured with the monitors and a gas chromatograph equipped with a flame ionization detector simultaneously, and the values were compared. Results: The monitor with the PID sensor could measure many organic vapors, but it could not detect some vapors with high ionization potential. The IER sensor could also detect many vapors, but a linear response was not obtained for some vapors. A semiconductor sensor could detect methanol that could not be detected by PID and IER sensors. Conclusions: Working environment measurement of organic vapors by real-time monitors may be possible, but sensor characteristics and their limitations should be known.(J Occup Health 2015; 57: 13–19)
Objectives: Long working hours have the possibility to influence human health. In Japan, it is well known that teachers have long working hours, and the number of leaves of absence due to mental disorders among public school teachers increased from 2,687 in 2002 to 4,960 in 2012. The aim of this study was to investigate the association between long working hours and psychological distress among school teachers. Methods: This cross-sectional study was conducted from mid-July to September in 2013 in Hokkaido Prefecture, Japan. Questionnaires were distributed to 1,245 teachers in public junior high schools. Information about basic characteristics, including working hours, and responses to the General Health Questionnaire-28 were collected anonymously. Multiple logistic regression analysis was used to calculate odds ratios (ORs) for the association between long working hours and psychological distress by gender. Results: Of the 1,245 teachers contacted, 558 (44.8%) responded. After excluding responses with missing data, the final sample included 522 teachers (337 males and 185 females). Psychological distress was identified in 47.8% of males and 57.8% of females. Our results showed a significantly increased risk only in males working >60 hours per week (adjusted OR=4.71 [95% CI 2.04–11.56]) compared with those working ≤40 hours per week. There were no significant associations between long working hours and psychological distress for females. Conclusions: There is a significant association between long working hours and psychological distress in male teachers. However, the causal relationship remains unclear. Further studies such as cohort studies with large sample sizes are needed.(J Occup Health 2015; 57: 20–27)
Objectives: The aim of this study was to elucidate the effect of illness and unhealthy behavior on early retirement due to health problems (ERdHP) using Korean longitudinal data. Methods: This study used data collected from 3,508 subjects enrolled in the first to fourth phases of the Korean Longitudinal Study of Ageing (KLoSA). This study was conducted from 2006 to 2012 using structured questionnaires on retirement, morbidities, and health-related behaviors. We adopted the Cox proportional hazard model to investigate the effects of diagnosed disease and health-related behaviors on ERdHP. Results: Participants who smoked, were obese, or suffered from hypertension, diabetes, malignancy, heart disease, stroke, or arthritis had a significantly higher risk of health-related early retirement after adjustment for gender, age, and occupation. Further, risk factors such as lack of exercise, stroke, arthritis, obesity, and malignancy differentially affect early retirement by gender. Conclusions: This is the first study, that we are aware of, to examine the effect of illness and unhealthy behavior on ERdHP in Asia, using Korean longitudinal data. We found that hypertension, diabetes, malignancy, arthritis, cardiovascular and cerebrovascular diseases, smoking, and obesity increased the risk of ERdHP. To enhance the sustain ability of labor in an aging society, more studies on ERdHP are needed.(J Occup Health 2015; 57: 28–38)
Objectives: Drivers and conductors working in public transport are frequently exposed to inadequate working conditions and consequently to health problems relating to their work activities. This study investigates the relationship between the working conditions of drivers and conductors in the Metropolitan Region of Belo Horizonte and their perception of health-related quality of life. Method: Health-related quality of life was measured in a sample of 1,607 public transport workers in the city of Belo Horizonte using the SF-12 (Medical Outcomes Study Short-Form General Health Survey). The presence and magnitude of independent associations between the SF-12 domains and the exposure variables were determined by means of odds ratios obtained through logistic regression. Results: After adjustments, the PCS (Physical Component Score) was found to be negatively associated with the existence of breaks during the working day and positively associated with unavailability of technical resources for meeting needs. The MCS (Mental Component Score) was positively associated with being female, having two or more medical diagnoses of illnesses, absenteeism and recent episodes of aggression or threats, and feeling vibration in the whole body. The MCS was negatively associated with the practice of physical exercise. Both components were negatively associated with older age and positively associated with having a poor self-assessment of health. Conclusions: Exposure to a variety of risk factors while performing work worsened health-related quality of life. The results obtained may provide support for rethinking and guiding public policies directed towards metropolitan populations.(J Occup Health 2015; 57: 39–50)
Objectives: Long work hours and overwork may increase the cardiovascular load of workers. But long work hours and overwork are not the same. Cardiovascular overload from working is dependent on the physical demand of the work and the worker's physical fitness, as well as the working hours. This cross-sectional study was designed to identify the association between overwork and cerebrocardiovascular disease, taking into account the physical demand of work, physical fitness, and work hours. Methods: Study data were obtained from surveillance of occupational cerebrocardiovascular disease. Questionnaire surveys including general and work-related characteristics were conducted. Maximum acceptable work time was estimated using the physical work demand and physical fitness of the subjects. The overwork index, which was the ratio of maximum acceptable work time and actual work hours of the subjects, was calculated. Results: In the workers with a moderate or high physical demand of work, the adjusted odds ratios for overwork indexes of 1.01–1.20, 1.21–1.50, and >1.50 were 2.679 (95% confidence interval (CI) 1.025–6.999), 3.124 (95% CI 1.111–8.783), and 4.331 (95% CI 1.719–10.908), respectively. Conclusions: The results indicate that the risk of cerebrocardiovascular disease might be high in the workers with long working hours, high physical demand of work, and poor physical fitness engaged in work with a moderate to high physical work demand. Work hours should be accommodated according to the worker's physical fitness and the physical demand of work, and this could lower the risk of cerebrocardiovascular disease.(J Occup Health 2015; 57: 51–57)
Objectives: This study aimed to examine the potential effects of perceived organizational support (POS) and psychological capital (PsyCap) on combating depressive and anxious symptoms among Chinese underground coal miners. Methods: A cross-sectional survey was conducted in a coal-mining population in northeast China. The Center for Epidemiologic Studies Depression (CES-D) Scale, the Zung Self-Rating Anxiety Scale (SAS), the Survey of Perceived Organizational Support (SPOS) scale and the Psychological Capital Questionnaire (PCQ), which measure depressive and anxious symptoms, POS and PsyCap were distributed to 2,500 underground coal miners (1,925 effective respondents). Hierarchical linear regression was performed to examine the associations of POS and PsyCap (self-efficacy, hope, resilience and optimism) with depressive and anxious symptoms and the moderating roles of PsyCap and its components. The mediating roles of PsyCap and its components were examined using asymptotic and resampling strategies. Results: The mean levels of depressive and anxious symptoms were 19.91 and 49.69, respectively. POS, PsyCap, hope, resilience, optimism and POS × PsyCap were negatively associated with depressive symptoms. POS, PsyCap, resilience, POS × PsyCap and POS × resilience were negatively associated with anxious symptoms. PsyCap, hope, resilience and optimism partially mediated the association between POS and depressive symptoms. PsyCap and resilience partially mediated the association between POS and anxious symptoms. Conclusions: POS, PsyCap, hope, resilience and optimism could be effective resources for reducing depressive and anxious symptoms. PsyCap, hope, resilience and optimism act as moderators and mediators in the associations of POS with depressive and anxious symptoms. Managers should promote supportive settings and investment in PsyCap to improve workers' mental health.(J Occup Health 2015; 57: 58–68)
Objectives: The aim of this study was to investigate workplace violence by patients or their relatives towards health-care workers in Congolese hospitals. Methods: Through the autumn of 2012, a cross-sectional survey on workplace violence was conducted in a sample of 2,210 registered health-care workers (989 males and 1,221 females, aged 33 ± 8 years) from 436 hospitals located in the province of Katanga, Democratic Republic of the Congo. Verbal aggression, harassment and physical violence perpetrated by patients or their relatives within the previous year along with factors contributing to violence, were recorded, and the response rate was 99%. Results: About 80.1% of the health-care workers had experienced one or more types of workplace violence. Overall, the severity of workplace violence varied from verbal aggression (57.4%) and harassment (15.2%) to physical violence (7.5%). Patients were the major perpetrators of verbal aggression and harassment, whereas patients' relatives were mainly involved in physical violence. The frequency of workplace violence was similar across hospitals. Male health-care workers were more likely to be victims of physical violence, whereas female health-care workers were the prime target for harassment. Only 34.3% of the violent episodes were reported to a supervisor. Furthermore, disrespect for medical deontology was the main cause of workplace violence perceived by 68.8% of the health-care workers. Conclusions: Although it has not been officially recognized, there has been workplace violence towards health-care workers perpetrated by patients or their relatives despite the fact that health-care workers have traditionally been highly respected in Congolese society. Further studies on this issue may suggest opportunities for combating violence in Congolese hospitals.(J Occup Health 2015; 57: 69–80)
Objectives: The health benefits of breastfeeding are widely recognized. The World Health Organization recommends exclusive breastfeeding for six months after birth and for two years or longer together with nutritionally adequate complementary foods. To respond to the needs of industry, employed breastfeeding mothers must adapt to the rotating night shift (RNS). However, the RNS is associated with a higher risk of health problems in career women. We investigated the relationship between the RNS and breast milk volume. Methods: Mothers who used a breastfeeding room while working at a technology company in Taiwan voluntarily participated in this study from March 1 through April 30, 2013. We compared two groups: breastfeeding mothers on (RNS+) and not on a RNS (RNS−) to determine independent predictors for breast milk volume. We analyzed data from 109 participants: RNS+ group n=56; RNS− group n=53. Results: There was no significant difference in daily milk collection volume between the groups. Daily milk collection frequency and exclusive breastfeeding were independent predictors for a daily breast milk collection volume >350 ml. Conclusions: The RNS may not affect the breast milk volume. This result may help the government and employers make policies more appropriate for supporting employed breastfeeding mothers.(J Occup Health 2015; 57: 81–86)
Objectives: It has been reported that chlorinated organic solvent is a cause of hepatitis. Methods: we investigate clinical and pathological findings of a patient with severe acute hepatitis who was exposed to chlorinated organic solvents. Results: A 34-year-old man who was exposed to chlorinated organic solvents including dichloromethane, 1,2-dichloropropane, and trichloroethylene, presented with general fatigue, vomiting, and diarrhea. At admission, his laboratory test results showed extremely elevated aspartate aminotransferase (4,872 IU/l), alanine aminotransferase (3,000 IU/l), and lactate dehydrogenase (11,600 IU/l) levels and a prothrombin level below normal (41%). No encephalopathy was noted. These findings were indicative of severe acute hepatitis. Viral hepatitis, autoimmune hepatitis, alcoholic disease, bile duct disease, and viral infection were excluded as causes of hepatitis by clinical, laboratory, and imaging findings. After diagnosis, the patient was administered fresh frozen plasma and glucagon-insulin therapy. Liver function recovered within a few weeks, and a liver biopsy performed 25 days after admission showed the recovery phase after acute liver damage. Conclusions: These clinical and pathological findings indicate that exposure to chlorinated organic solvents may have induced severe acute hepatitis in this patient.(J Occup Health 2015; 57: 87–90)
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