BACKGROUND: The objectives of the present study are to: (i) evaluate the effect of environmental and metabolic heat on heat-related illnesses in outdoor workers; and (ii) evaluate the effect of personal factors, including heat acclimation, on the risk of heat-related illnesses in outdoor workers. METHODS: We identified 47 cases of illnesses from exposure to environmental heat in outdoor workers in Korea from 2010 to 2014, based on review of workers' compensation data. We also obtained the information on location, time, and work environment of each heat-related illness. RESULTS: Our major results are that 29 cases (61.7%) occurred during a heat wave. Forty five cases (95.7%) occurred when the maximum estimated WBGT (WBGTmax) was equal to or greater than the case specific threshold value which was determined by acclimatization and metabolic rate. Twenty two cases (46.8%) were not acclimated to the heat. Thirty-seven cases (78.7%) occurred after tropical night (temperature above 25 °C), during which many people may find it hard to sleep. CONCLUSION: Personal risk factors such as heat acclimation as well as environmental factors and high metabolic rate during work are the major determinants of heat-related illnesses.
Acclimatization ; Extreme Heat* ; Hot Temperature ; Humans ; Infrared Rays ; Korea ; Risk Factors ; Workers' Compensation

Cerebrovascular and cardiovascular diseases (CVDs) are a major cause of deaths among workers as well as in general population in Korea. The term "Karoshi" in Japan represents work-related cerebrovascular and cardiovascular diseases (WR-CVD) due to excessive overwork. According to the Karasek's Demand-Control Model many prospective studies reported a significant association between working in jobs with high strain and increased likelihood of subsequent development of cardiovascular diseases. However, further understanding of the etiopathology of each different work-relatedness is needed to prevent WR-CVDs effectively. This review was planned to help the readers with knowledge on the etiopathology of the WR-CVDs. Based on the causal or triggering factors, work-relatedness in the literature can be classified into four types: 'accidental type (e.g. sudden cardiac deaths)', 'typical Karoshi type due to extreme overwork', 'maladaptation type due to dramatic change in job characteristics', and 'job stress type due to inherent characteristics'. Even though the outcome of each type is apparently similar, their causes and pathophysiologic mechanisms are quite different. In conclusion, the work-relatedness of CVDs among employees is very limited and usually works as a trigger rather than as the causal factors. A thorough understanding of the etiopathology of WR-CVDs can be very helpful in developing a prevention strategy.
Acute Coronary Syndrome ; Cardiovascular Diseases* ; Cause of Death ; Coronary Artery Disease ; Japan ; Korea

OBJECTIVES: Ischemic heart disease (IHD) is a major cause of death in Korea and known to result from several occupational factors. This study attempted to estimate the current magnitude of IHD mortality due to occupational factors in Korea. METHODS: After selecting occupational risk factors by literature investigation, we calculated attributable fractions (AFs) from relative risks and exposure data for each factor. Relative risks were estimated using meta-analysis based on published research. Exposure data were collected from the 2006 Survey of Korean Working Conditions. Finally, we estimated 2006 occupation-related IHD mortality. RESULTS: For the factors considered, we estimated the following relative risks: noise 1.06, environmental tobacco smoke 1.19 (men) and 1.22 (women), shift work 1.12, and low job control 1.15 (men) and 1.08 (women). Combined AFs of those factors in the IHD were estimated at 9.29% (0.3-18.51%) in men and 5.78% (-7.05-19.15%) in women. Based on these fractions, Korea's 2006 death toll from occupational IHD between the age of 15 and 69 was calculated at 353 in men (total 3,804) and 72 in women (total 1,246). CONCLUSION: We estimated occupational IHD mortality of Korea with updated data and more relevant evidence. Despite the efforts to obtain reliable estimates, there were many assumptions and limitations that must be overcome. Future research based on more precise design and reliable evidence is required for more accurate estimates.
Cardiovascular Diseases ; Cause of Death ; Female ; Humans ; Korea ; Male ; Myocardial Ischemia ; Noise ; Occupations ; Risk Factors ; Smoke ; Tobacco

Obesity is a risk factor for numerous health problems. Behavior therapy is important for obesity treatment. The aim of the present study was to identify the parameters that are associated with successful weight reduction. A database of 123 subjects who underwent weight reduction programs at the Center for Health Promotion, Samsung Medical Center from June 2001 through November 2004 was retrospectively analyzed. The goal of the program was to reduce the body weight by more than 5% during the follow-up period. The study population was divided into 2 categories (the success group and the failure group) based on the outcome of weight reduction. We analyzed the demographic, laboratory and clinical parameters to determine the predictors of successful weight reduction. The prevalence of success group was 36.6% (45/123). Significant correlations for successful weight reduction were found for the follow up period and the frequency of medical visits. Our results suggest that strong motivation was the most important factor for successful weight reduction.

No abstract available.

BACKGROUND: To identify work sectors with high risk for work-related musculoskeletal disorders (MSDs) in Korean men and women. METHODS: We analyzed nationwide data to identify ergonomic risk factors in Korean employees. In particular, we analyzed data on exposure to five ergonomic risk factors (painful/tiring postures, lifting/moving heavy materials, standing/walking, repetitive hand/arm movements, and hand/arm vibration) according to employment sector, sex, and age, using the 2014 Fourth Korean Working Conditions Survey. We also used workers' compensation data on work-related MSDs in 2010, which is available by sex. RESULTS: The different work sectors had different gender distributions. “Manufacturing” (27.7%) and “construction” (11.3%) were dominated by males, whereas “human health and social work activities” (12.4%), “hotel and restaurants” (11.7%), and “education” (10.4%) were dominated by females. However, “wholesale and retail trade” and “public administration and defense” employed large numbers of males and females. Furthermore, the work sectors with a greater proportion of work-related MSDs and with multiple ergonomic risk factors were different for men and women. For men, “construction” and “manufacturing” had the highest risk for work-related MSDs; for women, “hotel and restaurants” had the highest risk for work-related MSDs. CONCLUSION: Ergonomic interventions for workers should consider gender and should focus on work sectors with high risk for MSDs, with multiple ergonomic risk factors, and with the largest number of workers.
Employment ; Female ; Humans ; Male ; Posture ; Risk Factors ; Social Work ; Workers' Compensation

No abstract available.
Occupational Health Services ; Occupational Health ; Small Business

Injury to brain transforms resting astrocytes to their reactive form, the hallmark of which is an increase in glial fibrillary acidic protein (GFAP), the major intermediate filament protein of their cell type. The overall glial response after brain injury is referred to as reactive gliosis. Glial-neuronal interaction is important for neuronal migration, neurite outgrowth and axonal guidance during ontogenic development. Although much attention has been given to glial regulation of neuronal development and regeneration, evidences also suggest a neuronal influence on glial cell differentiation, maturation and function. The aim of the present study was to analyze the effects of glial-hippocampal neuronal co-culture on GFAP expression in the co-cultured astrocytes. The following antibodies were used for double immunostaining chemistry; mouse monoclonal antibodies for confirm neuronal cells, rabbit anti GFAP antibodies for confirm astrocytes. Primary cultured astrocytes showed the typical flat polygonal morphology in culture and expressed strong GFAP and vimentin. Co-cultured hippocampal neurons on astrocytes had phase bright cell body and well branched neurites. About half of co-cultured astrocytes expressed negative or weak GFAP and vimentin. After 2 hour glutamate (0.5 mM) exposure of glial-neuronal co-culture, neuronal cells lost their neurites and most of astrocytes expressed strong GFAP and vimentin. In Western blot analysis, total GFAP and vimentin contents in co-cultured astrocytes were lower than those of primary cultured astrocytes. After glutamate exposure of glial-neuronal co-culture, GFAP and vimentin contents in astrocytes were increased to the level of primary cultured astrocytes. These results suggest that neuronal cell decrease GFAP expression in co-cultured astrocytes and hippocampal neuronal-glial co-culture can be used as a reactive gliosis model in vitro for studying GFAP expression of astrocytes.
Animals ; Antibodies ; Antibodies, Monoclonal ; Astrocytes* ; Axons ; Blotting, Western ; Brain ; Brain Injuries ; Chemistry ; Coculture Techniques* ; Glial Fibrillary Acidic Protein ; Gliosis ; Glutamic Acid ; Intermediate Filaments ; Mice ; Neurites ; Neuroglia ; Neurons ; Regeneration ; Vimentin

Background: The present study examined changes in the working hours of Korean workers from 2010 to 2020 according to employment status and industrial sector. Methods: This was a secondary analysis of data from the third (2010), fourth (2014), fifth (2017) and sixth (2020) Korean Working Conditions Surveys, which were conducted by the Korea Occupational Safety and Health Agency. Results: During the past 10 years, workers classified as employees, self-employed, or employers experienced clear declines in average weekly working hours and in the percentages of individuals who worked more than 48 hours per week. During 2020, the largest proportion of employees (52.8%) had 40-hour work weeks, whereas the largest proportions of selfemployed individuals (26.8%) and employers (25.1%) had very long work weeks (≥ 60 h/ week). Also during 2020, individuals who were self-employed or employers in the sectors of ‘Accommodation and food service’ had the longest weekly work hours, whereas employees in the sector of ‘Transportation’ had the longest weekly work hours. All three groups (employees, self-employed, and employers) in all 21 industrial sectors experienced declines in average weekly working hours from 2017 to 2020. Conclusion From 2010 to 2020, employees, self-employed individuals, and employers experienced clear declines in average weekly working hours, and in the percentages of individuals with long weekly working hours. However, there were also differences in the weekly working hours of those who had different employment status and who worked in different industrial sectors. The implementation of the 40-hour work-week and the 52-hour maximum work-week in Korea reduced excessive work hours by individuals who had different employment status and who worked in different industrial sectors, and probably improved worker quality-of-life. We recommend extension of these regulations to workplaces with fewer than 5 employees.

Methods: This was a secondary analysis of data from the fifth Korean Working Conditions Survey conducted in 2017. A structural equation model was used for mediation and moderation analysis. Results: Service and sales workers who had more interactions with angry clients had increased risk for depression and anxiety. Experiencing clients' adverse behaviors (acute episodes) mediated the relationship between interacting with angry clients (a chronic situation) on depression and anxiety. Job satisfaction and managers' support moderated the relationship between interacting with angry clients and mental health problems. Conclusion We suggest that employers of service and sales workers should recruit staff based on their aptitude for such work, thus ensuring job satisfaction, and train them to deal with angry clients in such a way that they experience less emotional burden. Employers should also make bylaws requiring managers to directly take care of adverse social behavior by clients. Furthermore, a sociocultural campaign to prevent adverse social behavior by clients is also needed.