Unveiling the Global Surge: Unraveling the Factors Fueling the Spread of Karoshi Syndrome.

Karoshi syndrome, also known as "death by overwork", has been a topic of study and concern in Japan since the 1980s. World Health Organization (WHO) and International Labour Organization (ILO) joint unveiled that in 2021, approximately 750.000 deaths due to Karoshi syndrome globally. The joint defined long working as having > 55 h work/week. Karoshi nowadays is no longer limited to Japan and has become a global issue. Karoshi is primarily attributed to factors such as long working hours, job-related stress, and poor work-life balance. This perspective was sought to provide a short overview of Karoshi syndrome, the underlying mechanisms and the state-of-art preventive measures.

Cerebral gray matter volume correlates with fatigue and varies between desk workers and non-desk workers.

Chronic fatigue syndrome (CFS), a clinical entity of chronic fatigue, has been associated with a decrease in regional gray matter volume (rGMV). In this study targeting a large number of healthy middle-aged individuals without CFS, the relationship between fatigue perception and rGMV was investigated. Considering that the work setting is an environmental factor that influences fatigue perception among healthy individuals, the differences between desk workers and non-desk workers were investigated. Chalder Fatigue Questionnaire (CFQ) scores were used for perceptional evaluation of fatigue, and rGMV of 110 brain regions was adapted with Statistical Parametric Mapping (SPM) 8 on 1.5 T magnetic resonance imaging (MRI) results for the volumetric calculation of gray matter. The CFQ scores were negatively correlated with the right supplementary motor area (SMC) and positively correlated with the right superior parietal lobule (SPL) and left basal forebrain in all participants (n = 1,618). In desk workers and non-desk workers, the CFQ scores correlated with different regions and yielded different mechanisms of fatigue perception in the brain. Identifying the gray matter regions correlated with fatigue perception in healthy individuals may help understand the early stage of fatigue progression and establish future preventive measures.

Overtime working patterns and adverse events in work-related suicide cases: hierarchical cluster analysis of national compensation data in Japan (fiscal year 2015-2016).

BACKGROUND: Although various work-related adverse events affect workers' mental health, the association between long working hours and mental disorders remains unclear. We investigated the characteristics of overtime work and work-related adverse events among all cases of compensated work-related suicide in Japan to empirically reveal the context of the serious consequences. METHODS: We analysed all 167 cases of mental disorders resulting in suicide that were compensated in fiscal year 2015-2016. Hierarchical clustering was applied to the overtime working history. Work-related adverse events were also evaluated as the qualitative aspects of their jobs. RESULTS: More than half of the cases committed suicide within a month of developing a mental disorder. The Administrative and professional or engineering workers had a higher suicide rate. The clustering analysis revealed chronic long working hours (19%), gradual increase (27%), or rapid increase (25%) in working hours before the onset of a mental disorder. A group of cases with less overwork experienced more interpersonal conflicts. CONCLUSION: This is the first study to employ a clustering technique to objectively reveal the actual working patterns behind suicide. The patterns of working overtime before the onset of mental disorders varied considerably among the cases. Taking the transition of working overtime into account may provide clearer insight into the relationship between long working hours and workers' mental health. These results highlight the need for countermeasures especially for causes of chronic overworking, drastic increases in working hours, and interpersonal conflicts to prevent work-related suicide.

Shorter sleep duration is associated with potential risks for overwork-related death among Japanese truck drivers: use of the Karoshi prodromes from worker's compensation cases.

PURPOSE: We aimed to cross-sectionally investigate how work and sleep conditions could be associated with excessive fatigue symptoms as an early sign of Karoshi (overwork-related cerebrovascular and cardiovascular diseases; CCVDs). METHODS: We distributed a questionnaire regarding work, sleep, and excessive fatigue symptoms to 5410 truck drivers, as the riskiest occupation for overwork-related CCVDs, and collected 1992 total samples (response rate: 36.8%). The research team collected 1564 investigation reports required for compensation for Karoshi. Of them, 190 reports listed the prodromes of Karoshi, which were used to develop the new excessive fatigue symptoms inventory. RESULTS: One-way analyses of variance showed that the excessive fatigue symptoms differed significantly by monthly overtime hours (p < 0.001), daily working time (p < 0.001), work schedule (p = 0.025), waiting time on-site (p = 0.049), number of night shifts (p = 0.011), and sleep duration on workdays (p < 0.001). Multivariate mixed-model regression analyses revealed shorter sleep duration as the most effective parameter for predicting excessive fatigue symptoms. Multiple logistic regression analysis confirmed that the occurrences of CCVDs were significantly higher in the middle [adjusted ORs = 3.56 (1.28-9.94)] and high-score groups [3.55 (1.24-10.21)] than in the low-score group. CONCLUSION: The findings suggested that shorter sleep duration was associated more closely with a marked increase in fatigue, as compared with the other work and sleep factors. Hence, ensuring sleep opportunities could be targeted for reducing the potential risks of Karoshi among truck drivers.

Efecto de los factores de riesgo psicosociales relacionados al trabajo en el desarrollo de enfermedades cardiovasculares / The impact of work-related psychosocial risk factors on the development of cardiovascular diseases

Durante los últimos años, las enfermedades cardiovasculares (en adelante ECVs) en Chile se han situado como la primera causa de muerte y discapacidad. Frente a esta situación, el Ministerio de Salud ha generado programas de control de los factores de riesgo comunes para el desarrollo de enfermedades cardiovasculares. Sin embargo, no se ha considerado los factores de riesgo psicosociales relacionados con el trabajo, los que según la tendencia internacional se han validado como parte de los factores causantes de enfermedades cardiovasculares. Este documento tiene por objetivo evidenciar la importancia que tienen los factores de riesgos psicosociales laborales (en adelante FRPSL) para el desarrollo de ECVs, reflexionando sobre la experiencia en otros países y comparando esas realidades con la mirada actual en el control de las enfermedades cardiovasculares en Chile. Las experiencias revisadas validan a los factores de riesgo comunes como los principales para el desarrollo de enfermedades cardiovasculares, pero avalan que los factores de riesgo psicosociales de origen laboral mantienen una relación tanto directa como indirecta con el desarrollo y/o agravamiento de estas patologías, pese a que en Chile esto aún no se reconozca en términos legales. (AU)

In Chile, in recent years, cardiovascular diseases (hereinafter CVD) have been the leading cause of death and disability. Faced with this situation, the Ministry of Health has developed programs to control the common risk factors for the development of cardiovascular diseases, however, the work-related psychosocial risk factors have not been considered, which according to the international trend, have been validated as part of the causative factors of cardiovascular diseases.This study aims to highlight the importance of work-related psychosocial risk factors (hereinaf-ter PWF) for the development of CVD, reflecting on the experience in other countries, com-paring these realities with the current perspective in the control of cardiovascular diseases in Chile.The evidence confirms common risk factors as the key to the development of cardiovascular diseases. However, it guarantees that work-related psychosocial risk factors maintaining a relationship both directly and indirectly with the manifestation of these diseases, in despite of this is not recognized legally in Chile yet. (AU)

Objective and subjective working hours and their roles on workers' health among Japanese employees.

This study investigated the correlation between objective and subjective working hours (OWH and SWH, respectively) and their relation to the workers' health. The study included 6,806 workers of a Japanese company (response rate=86.6%). OWH were collected as the monthly data during fiscal year 2017 from the company record. SWH were self-reported as the weekly data during the past month in November 2017. Both OWH and SWH corresponded to the same period of one month (October 2017). Additionally, the data for the annual health checkup in fiscal year 2017 and self-reported mental health in November 2017 were collected. The results indicated that the longer OWH was related to more underestimation of SWH. The analyses of covariance adjusted for the selected variables showed that irrespective of OWH or SWH, significant relationships were found for stress responses but not for body mass index, aspartate and alanine aminotransferase, fasting blood glucose, hemoglobin A1c, high-density lipoprotein cholesterol, or triglyceride. However, significant relationships with only OWH were noted for systolic and diastolic blood pressure, low-density lipoprotein cholesterol, gamma-glutamyl transpeptidase, and positive work-related state of mind. The present findings show that SWH should be used carefully when assessing the health effects of long working hours.

Expression of Cx43 and Cx45 in Cardiomyocytes of an Overworked Rat Model.

ABSTRACT: Objective To study the effect of overwork stress response on the expression of connexin 43（Cx43） and connexin 45（Cx45） in cardiomyocytes and on cardiac function. Methods The experimental animals were divided into control group, overworked 1-month group and overworked 2-month group. A overworked rat model was established by forcing swimming of overworked group. The expressions of Cx43 and Cx45 in myocardial tissues of experimental animals were detected by Western blotting, while the corresponding myocardial tissues were stained with hematoxylin-eosin （HE） staining and Masson's staining, then histologically observed. Results Western blotting results showed that, compared with the control group, Cx43 expression in myocardial tissues of overworked rats decreased while Cx45 expression increased. HE staining and Masson's staining results showed that hypertrophy, rupture and interstitial fiber tissue hyperplasia were observed in myocardial fibers of overworked rats. Conclusion Overwork stress response may affect cardiac function as an independent factor and may even cause heart failure or arrhythmias and lead to death.

The Concept, Status Quo and Forensic Pathology of Karoshi.

ABSTRACT: "Karoshi" originates from Japan's economic take-off period in the 1960s and 1970s. It is generally believed that overwork lead to the accumulation of fatigue, which triggers the outbreak of potential diseases, and results in sudden death. Karoshi causes great harm to both the community and families because it occurs primarily in 30 to 60 year old young adults. Japan put Karoshi into the category of industrial injury for the first time in 2001 and started to undertake a series of studies in the sociological and pathological fields. However, there is a tremendous gap in the forensic pathological diagnosis domain. In China, research on Karoshi started from the 1990s and is closely related to the reform and opening up policy as well as economic development. According to the incomplete statistics, 600 thousand people die from overwork each year in China, the highest in the world. Karoshi has become one of the most serious social problems in China at the present stage, thus a systematic study in the sociology and forensic pathology fields is urgently required. This paper summarizes the past and present status of Karoshi, and puts forward the problems that need attention during the judicial expertise of Karoshi from forensic pathology perspective.

Sociomedical problems of overwork-related deaths and disorders in Japan.

OBJECTIVES: Cerebrovascular and cardiovascular diseases (CCVDs) and mental disorders, including suicide, are prevalent among overworked individuals in Japan. The 2014 legislation regarding the prevention of overwork-related deaths and disorders has accelerated the research in this field and ultimately the implementation of preventive actions. METHODS: To understand the current problematic situations, the Research Center for Overwork-Related Disorders of the National Institute of Occupational Safety and Health, Japan, conducted analyses of compensated claims for overwork-related CCVDs and mental disorders that were recognized from January 2010 to March 2015. RESULTS: The majority of CCVD cases were the men in their 50s. Transport and postal activities was the highest risk industry. Cerebrovascular cases were higher than cardiovascular ones. Long working hours was the principal factor for CCVDs. The mental disorder cases comprised approximately 70% men and affected younger age groups (peak in the third decade) with various industries at risk. In men, there was an almost equal number of F3 (Mood [affective] disorders) and F4 (Neurotic, stress-related, and somatoform disorders) diagnoses according to the 10th revision of the International Classification of Diseases and Related Health Problems. A larger number of women were diagnosed to have F4. The mental disorder cases were associated not only with long working hours, but also with injuries and disasters as well as interpersonal conflict at work. CONCLUSIONS: Multiple, simultaneous actions need to be made by employees, employers, researchers, and the authorities to achieve the goal of reducing the number of workers suffering from the overwork-related CCVDs and mental disorders.

Policy changes for preventing and recognizing overwork-related cardiovascular diseases in Taiwan: An overview.

OBJECTIVE: Overwork-related cardiovascular and cerebrovascular disease (CVD) has a large impact on workers' rights and labor standards across East Asian countries. This article describes the background and impact of policies regarding overwork-related CVD in the past decades in Taiwan. METHODS: We reviewed government policies, guidelines, literature, and news addressing the problems and impact of policy changes to prevent and recognize overwork-related CVD since the 1990s, and collected data on overwork-related CVD cases in Taiwan from 2006 to 2017. RESULTS: In 2017, overwork-related CVD accounted for 13% of all cases of occupational diseases, but 79% of all deaths due to occupational diseases. Guidelines for recognizing overwork-related CVD cases were established in 1991; however, under-recognition exists in Taiwan due to poor exposure data on working hours and psychological factors and because most medical expenses are covered by the national health insurance system. Amendments on the guidelines, and stricter policies on overwork prevention were enforced following calls from labor unions, nongovernmental organizations, and legislators, but health disparities were introduced when certain industries were exempted from restrictions. CONCLUSIONS: Long working hours and other work characteristics increase the risk of overwork-related CVD. By reviewing the changes in policy for preventing overwork and recognizing overwork-related disease, we identified the need for clearly defined guidance on evaluating overwork-related CVD, with specific criteria for working hours and other risk factors regarding work characteristics. National policies that lead to better working conditions and prevent overwork-related diseases must be developed.

Expression of Cx43 and Cx45 in Cardiomyocytes of an Overworked Rat Model / 法医学杂志

Objective To study the effect of overwork stress response on the expression of connexin 43（Cx43） and connexin 45（Cx45） in cardiomyocytes and on cardiac function. Methods The experimental animals were divided into control group, overworked 1-month group and overworked 2-month group. A overworked rat model was established by forcing swimming of overworked group. The expressions of Cx43 and Cx45 in myocardial tissues of experimental animals were detected by Western blotting, while the corresponding myocardial tissues were stained with hematoxylin-eosin （HE） staining and Masson's staining, then histologically observed. Results Western blotting results showed that, compared with the control group, Cx43 expression in myocardial tissues of overworked rats decreased while Cx45 expression increased. HE staining and Masson's staining results showed that hypertrophy, rupture and interstitial fiber tissue hyperplasia were observed in myocardial fibers of overworked rats. Conclusion Overwork stress response may affect cardiac function as an independent factor and may even cause heart failure or arrhythmias and lead to death.

The Concept, Status Quo and Forensic Pathology of Karoshi / 法医学杂志

"Karoshi" originates from Japan's economic take-off period in the 1960s and 1970s. It is generally believed that overwork lead to the accumulation of fatigue, which triggers the outbreak of potential diseases, and results in sudden death. Karoshi causes great harm to both the community and families because it occurs primarily in 30 to 60 year old young adults. Japan put Karoshi into the category of industrial injury for the first time in 2001 and started to undertake a series of studies in the sociological and pathological fields. However, there is a tremendous gap in the forensic pathological diagnosis domain. In China, research on Karoshi started from the 1990s and is closely related to the reform and opening up policy as well as economic development. According to the incomplete statistics, 600 thousand people die from overwork each year in China, the highest in the world. Karoshi has become one of the most serious social problems in China at the present stage, thus a systematic study in the sociology and forensic pathology fields is urgently required. This paper summarizes the past and present status of Karoshi, and puts forward the problems that need attention during the judicial expertise of Karoshi from forensic pathology perspective.

Overwork accelerates thrombotic reaction: implications for the pathogenesis of Karoshi.

Work-related stressors are potential causes of cardiovascular diseases (CVDs) and stroke; however, the pathophysiological mechanisms by which occupational stress induces and exacerbates CVDs remain unclear. The global thrombosis test (GTT) is a novel in vitro assay for evaluating both thrombotic reactions and subsequent thrombolysis. The time required to form an occlusive thrombus with the GTT, called as the occlusion time (OT), and the time to lyse the thrombus, the lysis time (LT), are markers of thrombotic and thrombolytic reactions, respectively. We investigated the impact of work-related stress on the thrombotic and thrombolytic reactions in 46 healthy medical residents. Off-duty or on-duty blood samples were collected on the mornings of non-work days or after the night duty on the emergent room respectively. The duration of sleep was significantly shorter during night duty than during off-duty nights [2.25 (1.0, 3.0) h vs. 6.0 (5.0, 7.0) h; p < 0.001]. Baseline OT was 310.3 (260.9, 437.7) s. whereas the on-duty OT was significantly shortened [284.2 (230.5, 355.8) s; p < 0.01]. LT was significantly prolonged during overwork conditions compared with off-duty conditions [1547 (1346, 1908) s vs. 1470 (1219, 1692) s; p < 0.05]. Overwork accelerates the thrombotic reactions. These reactions might explain the pathogenesis of overwork-related CVDs. The GTT is a good tool for evaluating of the level of fatigue.

Karoshi Related to Labor Intensity and Risk of Cardiovascular Events：A Case Report / 法医学杂志

Karoshi rem ains one of the m ost troublesom e issues in forensic identification. It is rather a social m edicine than a clinical disease. Japanese scholars pioneered exam ining the relation betw een sud-den cardiac death (SCD ) and chronic fatigue from long tim e and/or high-tension work. In the current case, a 55-year-old m an, w hose job w as loading and carrying heavy cem ent bags, w as found dead after 11 days of continuous hard work. H is fam ily m em bers sued the cem ent factory for his death and claim ed for com pensation.The problemw as the difficulty of identifying the causative relation w ithout the precedent or the relevant regulations. H ow ever, the forensic problems were finally acknow ledged after autopsy and calculation of labor intensity.The law suit w as w on as the first case pertaining to Karoshi in the Chinese court.

Are Cerebrovascular and Cardiovascular Diseases among Employees Work-related? / 대한산업의학회지

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.

Karoshi : Death from Overwork

The first case of karoshi was reported in 1969 with the death from a stroke of a 29-year-old, married male worker in the shipping department of Japan's largest newspaper company. It was initially called occupational sudden death. Shift work and an increased work load, together with excessive overwork in spite of ill health just before the stroke, were finally recognized as the occupational causes of death. It took five years for the family to receive compensation. In 1982, the first book entitled "Karoshi" was published by three physicians. This was the origin of the term karoshi. Karoshi is not a pure medical term but a sociomedical term. Karoshi-deaths were associated with long working hours, shift work, stress, and irregular work schedules. In Korea, karoshi was introduced in 1990. The cases with cerebral hemorrhage, subarachnoid cerebral hemorrhage, cerebral infarction, hypertensive encephalopathy, angina pectoris, myocardial infarction, and dissecting aneurysm would be compensated as occupational diseases if the patients had overworked. Now, the magnitude and kinds of diseases of karoshi is being extended. Medical doctors must understand the karoshi and make efforts to make the victims of karoshi be compensated. The evidence that overwork causes sudden death is still incomplete. More studies are needed to clarify the causal relationship. To prevent karoshi, the working hours should be shortened and health promotion programs for all workers should be encouraged.