Toxic hepatitis after exposure to humidifier disinfectant: A case series report.

Health damage from humidifier disinfectants is an unprecedented environmental health disaster. Humidifier disinfectants were used broadly in Korea from 1994 to 2011. Most studies have focused on respiratory problems because of the exposure route and primary respiratory symptoms. This overlooks the previous research results that humidifier disinfectants could move to extrapulmonary organs and induce toxic effects. Thus, the objective of this study was to examine toxic hepatitis cases developed after inhaling humidifier disinfectant. We focused on the indications of toxic hepatitis in two pediatric cases and one female adult case. All patients were exposed to humidifier disinfectants in a residential space. These disinfectants all contained polyhexamethylene guanidine (PHMG). Rapid increases in blood hepatic enzyme levels were seen. Two patients were discharged after treatment. Death occurred in one patient who was diagnosed with fulminant hepatitis of unknown cause. This human case series study supports prior knowledge that hepatotoxicity can occur by inhaling humidifier disinfectant.

Development of Korean Version Burnout Syndrome Scale (KBOSS) Using WHO's Definition of Burnout Syndrome.

BACKGROUND: Burnout syndrome (BOS) is defined by the World Health Organization (WHO) as a syndrome conceptualized as resulting from chronic workplace stress that has not been successfully managed. This study aims to create the Korean version burnout syndrome scale (KBOSS) that conforms to WHO's definition of BOS and present the cut-off points for screening. METHODS: We developed the KBOSS based on WHO's definition of BOS. An online survey was conducted through a specialized online research company. We recruited 444 workers for this research. The validity of the KBOSS was assessed using factor analysis and Pearson's correlation. The KBOSS reliability was assessed using Cronbach's alpha coefficient. The cut-off points for each of the three dimensions were derived using the upper quartile score. RESULTS: The validity and reliability of the KBOSS were good. Regarding reliability, the scale's overall Cronbach's alpha was 0.813. Cronbach's alpha of each three-dimension was as follows: exhaustion, 0.916; cynicism, 0.865; and professional inefficacy, 0.819. The cut-off points of BOS three dimensions are exhaustion ≧ 21; cynicism ≧ 18; and inefficacy ≧ 15. CONCLUSION: The developed questionnaire (KBOSS) can be a useful tool for screening of BOS.

Association between nicotine dependency with occupational injury in Korean men.

BACKGROUND: The relationship between smoking status or second-hand smoking and occupational injuries has been the subject of considerable study, but few have studied the relationship between nicotine dependence and occupational injuries. The objective of this study was to investigate the relationship between nicotine dependence and occupational injury among employees at a range of Korean companies. METHODS: Initially, the personal and occupational characteristics and nicotine dependences of workers were measured, and 12 months later a survey was used to determine whether subjects had experienced any occupational injury. This study was conducted in several workplaces on 6,893 male workers in manufacturing and service industries that received health screening at Inha University Hospital in Incheon. RESULTS: The adjusted odds ratios (ORs) of occupational injury in the low, moderate, and high nicotine dependence groups were 1.38 (95% confidence interval [CI]: 1.04-1.84), 1.52 (95% CI: 1.10-2.10), and 1.71 (95% CI: 0.92-3.19), respectively. For smokers only, adjusted ORs tended to increase linearly (p for trend < 0.05). When only smokers were included, analysis of continuous FTND (Fagerstrom Test of Nicotine Dependence) scores showed that adjusted OR increased by 1.10 (95% CI: 1.03-1.19) per FTND point. After stratifying the data by working type and working hours per week, the non-shift work group maintained this relationship (OR: 1.13, 95% CI: 1.04-1.24) and OR was higher in the group that works more than 60 hours per week with FTND score as a continuous variable (OR: 1.24, 95% CI: 1.07-1.44). CONCLUSIONS: The study shows nicotine dependency might affect occupational injury. From a short-term perspective, addressing worker's nicotine dependence by giving an adequate break time or smoking area might reduce work-related injuries.

Employment Status Change and New-Onset Depressive Symptoms in Permanent Waged Workers.

BACKGROUND: This study aimed to investigate the relationship between changes in employment status and new-onset depressive symptoms through a one-year follow-up of permanent waged workers. METHODS: We analyzed the open-source data from the Korea Welfare Panel Study. Using the 2017 data, we selected 2,314 permanent waged workers aged 19 to 59 years without depressive symptoms as a base group. The final analysis targeted 2,073 workers who were followed up in 2018. In 2018, there were five categories of employment status for workers who were followed up: permanent, precarious, unemployed, self-employed, and economically inactive. Multiple logistic regression was used to determine the association between employment status change and new-onset depressive symptoms. RESULTS: Adjusted multiple logistic regression analysis showed that among male workers, workers who went from permanent status to being unemployed (odds ratio: 4.50, 95% confidence interval: 1.19 to 17.06) and from permanent status to being precarious workers (odds ratio: 3.15, 95% confidence interval: 1.30 to 7.65) had significantly high levels of new-onset depressive symptoms compared with those who retained their permanent employment status. There were no significant increases in new-onset depressive symptoms of male workers who went from permanent status to being self-employed or economically inactive. On the other hand, no significant differences were found among female workers. CONCLUSION: Our study suggests that the change of employment status to precarious workers or unemployment can cause new-onset depressive symptoms in male permanent waged workers.

Longitudinal associations between occupational stress and depressive symptoms.

BACKGROUND: Most of the studies that have examined the association between the sub-factors of occupational stress and depressive symptoms have used cross-sectional data. However, our study has longitudinally measured the occupational stress and depressive symptoms of Korean workers of a semiconductor manufacturing company across six years to intending to investigate the associations between the sub-factors of occupational stress and depressive symptoms using longitudinal data. METHODS: Data collected from the workers of a semiconductor manufacturing company. Out of 1,013 recruited workers, 405 (40.0%) completed the survey questionnaires at 3 and 6-year follow-ups. Occupational stress was measured using a shorter version of the Korean Occupational Stress Scale (KOSS), whereas depressive symptoms were assessed using the Korean version of the Center for Epidemiological Studies-Depressive Symptoms Scale (CES-D). The data of male and female participants independently analyzed. Longitudinal associations were analyzed using panel data analysis with fixed effects. RESULTS: In panel data analysis with fixed effects, job insecurity (B = 0.048, p-value = 0.004) was associated with depressive symptoms among male workers. In female workers, inadequate social support (B = 0.080, p-value < 0.001), job insecurity (B = 0.039, p-value = 0.004), lack of reward (B = 0.059, p-value = 0.004) and discomfort in occupational climate (B = 0.074, p-value < 0.001) were associated with depressive symptoms among female workers. CONCLUSIONS: Temporal changes in the sub-factors of occupational stress were associated with changes in depressive symptoms within the same period. There was a gender difference in occupational stress sub-factors related to depressive symptoms.

The relationship between precarious employment and subjective well-being in Korean wage workers through the Cantril ladder Scale.

BACKGROUND: The global labor market is moving towards increasing job instability. Relatively few studies have examined the relationship between precarious employment and subjective well-being using quantitative scales. We evaluated the association between wage workers' employment status and their subjective well-being through the Cantril ladder scale using Korean Welfare Panel Survey data (KOWEPS). METHODS: This study used KOWEPS data. A total of 4,423 wage workers were divided into permanently employed workers, temporarily employed workers and daily employed workers. The relationship between precarious employment and subjective well-being was analyzed by multiple linear regression adjusted for potential confounding factors. RESULTS: The more unstable the employment status, the lower the subjective well-being, which can be expressed by the Cantril ladder scale. The mean score of both temporarily employed and daily employed workers were statistically significantly lower (B = -0.454, p < 0.001; B = -0.994, p < 0.001, respectively) than permanently employed workers. This appeared to be the same when occupational and sociodemographic factors were adjusted (B = -0.153, p = 0.002 for temporarily employed, B = -0.610, p < 0.001 for daily employed). CONCLUSIONS: The more unstable the employment status, the lower the subjective well-being score according to the Cantril ladder scale.

Mismatch in working hours and workaholism in permanent waged workers.

OBJECTIVES: A cross-sectional study was conducted to investigate whether working hours mismatch is associated with workaholism. MATERIAL AND METHODS: This study used the data from the 17th wave (2014) of the nationwide Korean Labor and Income Panel Study. Workaholism was evaluated using the Workaholism Analysis Questionnaire. The final study involved 3157 subjects who answered questions regarding both workaholism and working hours mismatch. To identify the association between working hours mismatch and workaholism according to weekly working hours, a stratification analysis was conducted by dividing the number of working hours/week into 3 groups (≤40 h, 41-59 h, and ≥60 h). The odds ratios were calculated using a multiple logistic regression model, which was adjusted for potential confounders. RESULTS: The workers working more hours than desired showed the greatest frequency of workaholism. As regards workaholism, in all weekly working hours groups, the odds ratios of the group working more hours than desired were 4.28, 95% CI: 2.29-7.99 (≥40 h), 2.14, 95% CI: 1.34-3.43 (41-59 h), 3.40, 95% CI: 1.60-7.21 (≤60 h), which were statistically significant compared to the reference (matched) group. There was no statistically significant relationship between working hours and workaholism when stratified according to the mismatch in working hours. CONCLUSIONS: The workers' working hours mismatch can be significantly related to workaholism. Int J Occup Med Environ Health. 2020;33(2):187-94.

Relationship between occupational sunlight exposure and the incidence of renal cancer.

BACKGROUND: The risk factors for renal cancer include smoking, obesity, hypertension, and exposure to trichloroethylene. Recent studies have shown that low sunlight exposure increases the risk of developing a range of cancers, including renal cancer. Given that most of the daytime is spent at work, a lack of occupational sunlight exposure can be a risk factor for renal cancer. Therefore, this study examined the relationship between occupational sunlight exposure and the incidence of renal cancer. METHODS: This was a university hospital-based case-control study on renal cancer. Of the 706 newly diagnosed patients with renal cell carcinoma (RCC), 633 cases were selected; 73 who had no occupational history were excluded. In addition, 633 controls were selected from the general population after 1:1 matching with respect to sex, age (within 5 years), and residential area (constituency-level). Information on sunlight exposure by the occupational group was referred to data from France. To estimate the association between occupational sunlight exposure and the RCC risk, the odds ratios (ORs) were calculated using conditional logistic regression analysis. RESULTS: Sunlight exposure was divided into quartiles and the risk of RCC was analyzed. The adjusted OR of RCC (OR: 0.664, 95% confidence interval: 0.449-0.983) was significantly lower for the Q4 group than Q1 group but the Q2 and Q3 groups did not show significant results. The risk of RCC tended to decrease with increasing exposure to sunlight (p for trend < 0.028). CONCLUSIONS: Higher occupational sunlight exposure reduces the risk of RCC.

Sleep Assessment During Shift Work in Korean Firefighters: A Cross-Sectional Study.

BACKGROUND: This cross-sectional study assessed the sleep quality using the ActiGraph and investigated the relationship between the parameters of sleep assessment and the type of shift work in Korean firefighters. METHODS: The participants were 359 firefighters: 65 day workers (control group) and 294 shift workers (shift work group: 77 firefighters with 3-day shift, 72 firefighters with 6-day shift, 65 firefighters with 9-day shift, and 80 firefighters with 21-day shift). Sleep assessments were performed using the ActiGraph (wGT3X-BT) for 24 hours during day shift (control and shift work group) and night shift and rest day (shift work group). The participants recorded bed time and sleep hours during the measurement period. RESULTS: Sleep efficiency, total sleep time, and percentage of wake after sleep onset during night work were lower in the shift work group than control group (p < 0.05). Sleep efficiency decreased in night shift and increased in rest day, whereas wake after sleep onset increased in night shift and decreased in rest day (p < 0.05). Among shift work groups, sleep efficiency of 6-day shift was higher in day shift, and sleep efficiency of 21-day shift was lower in night shift than other shift groups (p < 0.05). CONCLUSION: We found that the sleep quality in night shift of the shift work group was poorer than the control group. As to the type of shift work, sleep quality was good in 6-day shift and poor in 21-day shift. Thus, fast rotating shift such as 6-day shift may be recommended to improve the sleep quality of the firefighters.

An overview of compensated work-related injuries among Korean firefighters from 2010 to 2015.

BACKGROUND: Although one in two firefighters in South Korea have experienced work-related injuries, there are few studies which show the overview description on work-related injuries and its analysis regarding such causes. Therefore, we aimed to show the overview of compensated work-related injuries in order to serve fundamental data for establishing prevention policies on work-related injuries for Korean firefighters. METHODS: We requested the all claimed work-related injury data of Korean firefighters from 2010 to 2015 to the Korean National Fire Agency (NFA). The data from NFA including 2457 claimed cases was analyzed and we confirmed, 2154 approved work-related injuries for the kinds of job activities, cause of accident and type of injuries. Among 2154 approved cases, we analyzed more variables for the sex, age, and job duration of 1344 compensated cases through served text file on summary of accident. RESULTS: The Government Employees Pension Service (GEPS) recognized 2154 (87.7%) approved work-related injuries among 2457 claimed cases. The incidence of work-related injuries per 1000 firefighters was 9.8 persons. By region, the incidence of work-related injuries per 1000 firefighters ranged from a maximum of 14.5 to a minimum of 4.0. The most common job activity caused the accident was fire suppression (18.0%), followed by Emergency medical services (EMS) (17.5%) and training (10.7%). The most common cause of these accident was movement imbalance (30.3%), followed by falls (18.9%) and traffic accident (13.4%). In these work-related injuries, sprains and bruises were the most common type of injury (27.2%), and the most commonly injured body site was the upper and lower back (25.3%). Data from identified 1344 firefighters showed that 1264 (94.0%) were male and 80 (6.0%) were female. Age group was the highest in the 40s with 623 cases (46.4%), and job duration was the highest with 650 cases in 5-10 years (48.4%). CONCLUSION: In this study, we could obtain the preliminary data necessary to establish preventive measures, including the cause of accident and region with high accident rates. However, the number of applications for compensated injuries was very small compared to the frequency of injuries found in previous studies. The lack of appropriate treatment suggested that many firefighter injuries can become chronic. In this study, we suggest that it is necessary to introduce an injury monitoring system and improve the accessibility of compensated injuries. TRIAL REGISTRATION: CR318031. Registered 20 June 2018.

The characteristics of asbestos-related disease claims made to the Korea Workers' Compensation and Welfare Service (KCOMWEL) from 2011 to 2015.

BACKGROUND: This study aimed to enhance understanding of the epidemiologic characteristics of asbestos-related diseases, and to provide information that could inform policy-making aimed at prevention and compensation for occupational asbestos exposure, through analyzing asbestos-related occupational disease claims to Korea Workers' Compensation and Welfare Service from 2011 to 2015. METHODS: We analyzed 113 workers who filed medical care claims or survivor benefits for asbestos exposure and occupational-related disease from 2011 to 2015. Among these claims, we selected approved workers' compensation claims relating to malignant mesothelioma and lung cancer, and analyzed the general characteristics, exposure characteristics, pathological characteristics, and occupation and industry distribution. RESULTS: Malignant mesothelioma and lung cancer occurred predominantly in males at 89.7 and 94%, respectively. The mean age at the time of diagnosis for malignant mesothelioma and lung cancer was 59.5 and 59.7 years, respectively, while the latency period for malignant mesothelioma and lung cancer was 34.1 and 33.1 years, respectively. The companies involving exposed workers were most commonly situated within the Busan-Ulsan-Gyeongnam region. Histology results for lung cancer indicated adenocarcinoma as the most common form, accounting for approximately one half of all claims, followed by squamous cell carcinoma, and small cell lung cancer. The most common occupation type was construction in respect of malignant mesothelioma, and shipbuilding in respect of lung cancer. CONCLUSIONS: Considering the long latency period of asbestos and that the peak period of asbestos use in Korea was throughout the mid-1990s, damage due to asbestos-related diseases is expected to show a continued long-term increase. Few studies providing an epidemiologic analysis of asbestos-related diseases are available; therefore, this study may provide baseline data to assist in predicting and preparing for future harm due to asbestos exposure. TRIAL REGISTRATION: DUIH 2018-02-004-001. Registered 28 Februrary 2018.

Comparison of facet joint degeneration in firefighters and hospital office workers.

BACKGROUND: There are few published studies on the relationship between occupational lumbar load and facet joint degeneration (FJD). This cross-sectional study was conducted to evaluate the effect of physical lumbar load on FJD by comparing magnetic resonance imaging (MRI) findings of firefighters (FFs) and hospital office workers (HOWs). METHODS: We randomly sampled 341 male FFs and 80 male HOWs by age stratification. A questionnaire and clinical examination, including MRI of the lumbar spine (T12-S1), were conducted. FJD was diagnosed and graded by using the classification of Pathria et al., and reclassified into two groups as follows: no FJD (grade 0) and FJD (grades 1, 2, and 3). The prevalence of FJD was analyzed according to occupational group. RESULTS: The prevalence of FJD ranged from 31% (L1-L2) to 75% (L4-L5) in the FFs, and from 18% (L1-L2) to 69% (L4-L5) in the HOWs. After adjustment for age, body mass index, and frequency of physical exercise, the adjusted odds ratios (OR) for FJD in the FFs were significantly higher than those in the HOWs at all lumbar spinal levels, except for L3-L4 (L1-L2: OR, 2.644; 95% confidence interval [CI], 1.317-5.310; L2-L3: OR, 2.285; 95% CI, 1.304-4.006; L4-L5: OR, 1.918; 95% CI, 1.037-3.544; L5-S1: OR, 1.811; 95% CI, 1.031-3.181). CONCLUSION: This study shows that FFs exhibit a greater likelihood of having FJD than HOWs after controlling for other risk factors of FJD. This suggests that the physical occupational demands of FFs affect their risk of developing FJD.

Protective action of the immunomodulator ginsan against carbon tetrachloride-induced liver injury via control of oxidative stress and the inflammatory response.

The aim of the present study was to evaluate immunomodulator ginsan, a polysaccharide extracted from Panax ginseng, on carbon tetrachloride (CCl(4))-induced liver injury. BALB/c mice were injected i.p. with ginsan 24 h prior to CCl(4) administration. Serum liver enzyme levels, histology, expression of antioxidant enzymes, and several cytokines/chemokines were subsequently evaluated. Ginsan treatment markedly suppressed the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and hepatic histological necrosis increased by CCl(4) treatment. Ginsan inhibited CCl(4) induced lipid peroxidation through the cytochrome P450 2E1 (CYP2E1) downregulation. The hepatoprotective effect of ginsan was attributed to induction of anti-oxidant protein contents, such as superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPX) as well as restoration of the hepatic glutathione (GSH) concentration. The marked increase of proinflammatory cytokines (IL-1beta, IFN-gamma) and chemokines (MCP-1, MIP-2beta, KC) in CCl(4) treated mice was additionally attenuated by ginsan, thereby preventing leukocyte infiltration and local inflammation. Our results suggest that ginsan effectively prevent liver injury, mainly through downregulation of oxidative stress and inflammatory response.

Overexpression of alpha1-protease inhibitor and galectin-1 in radiation-induced early phase of pulmonary fibrosis.

PURPOSE: Radiation-induced pulmonary fibrosis (RIF) is a significant complication of radiotherapy for lung cancer. Despite the large number of studies, the molecular mechanisms of RIF are poorly understood. Therefore, the complex protein expression pattern in RIF was characterized by identifying the proteins with an altered expression level after thorax irradiation using two-dimensional electrophoresis (2-DE) and mass spectrometry. MATERIALS AND METHODS: A mouse model of RIF was used to examine the alteration of the lung proteome because of availability of murine data related to human cases and the abundance of murine fibrotic lung samples. A mouse model of RIF was induced in radiosensitive C57BL/6 mice. Twenty-one weeks after 25 Gy irradiation, hematoxylin-eosin staining and hydroxyproline assay confirmed the early-phase pulmonary fibrosis. RESULTS: Lung samples from the irradiated and age-matched control mice were used to generate 16 high quality 2-DE gels containing approximately 1,000 spots. Of the 31 significantly up- or down-regulated protein spots, 17 were identified by MALDI-TOF/MS. CONCLUSIONS: Two important upregulated proteins were found, the alpha1-protease inhibitor and galectin-1, which might be used as potential markers for the early phase of RIF.

Effects of polysaccharide ginsan from Panax ginseng on liver function.

Ginsan, a polysaccharide isolated from Panax ginseng, has been shown to be a potent immunomodulator, producing a variety of cytokines such as TNF-alpha, IL-1, IL-2, IL-6, IL-12, IFN-gamma and GM-CSF, and stimulating lymphoid cells to proliferate. In the present study, we analyzed some immune functions 1st-5th days after ginsan i.p. injection, including the level of non-protein thiols (NPSH) as antioxidants, heme oxygenase (HO) activity as a marker of oxidative stress, zoxazolamine-induced paralysis time and level of hepatic cytochrome P-450 (CYP450) as indices of drug metabolism system, and activities of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin, and albumin level as indicators of hepatotoxicity. Ginsan in the dose of 100 mg/kg caused marked elevation (1.7 to approximately 2 fold) of HO activity, decrease of total CYP450 level (by 20-34%), and prolongation of zoxazolamine-induced paralysis time (by 65-70%), and showed some differences between male and female mice. Ginsan treatment did not seem to cause hepatic injury, since serum AST, ALT, and ALP activities and levels of total bilirubin and albumin were not changed.