Sociomedical problems of overwork-related deaths and disorders in Japan

Impacts of Working Hours, Wages, and Regular Employment Opportunity on Suicide Mortalities of Employed and Unemployed Individuals before and during the COVID-19 Pandemic in Japan

Standardized suicide mortality rates per 100,000 population (SMRs) in Japan consistently decreased from 2009-2019, but these decreasing trends were reversed to increase in 2020. To clarify the mechanisms of recent increasing suicide in Japan, temporal fluctuations of SMRs disaggregated by sex and employment status (employed and unemployed individuals) and labor indices such as working hours, wages, and regular employment opportunity index (REO) from January 2012 to June 2023 were analyzed using interrupted time-series analysis. Additionally, temporal causalities from labor indices to SMRs were analyzed using vector autoregressive and non-linear auto-regressive distributed lag analyses. Decreasing trends among employed SMRs of both sexes were attenuated after the enactment of the "Work Style Reform Program" in 2018, but male SMRs were unaffected by the COVID-19 pandemic. However, female employed SMRs sharply increased, synchronized with the "Work Style Reform Act" and the COVID-19 pandemic outbreak (the COVID-19 impact was greater than the "Work Style Reform Act"). Additionally, unemployed SMRs of both sexes sharply increased with the revision and scale-down of countermeasures against economic deterioration caused by COVID-19 ("revision of economic supportive countermeasures against economic deterioration caused by COVID-19"). Unexpectedly, after enacting the "Work Style Reform Act", wages decreased due to possibly decreasing working hours. Increasing REO, which consistently increased, was a protective factor for male suicides, but unemployed SMRs were not affected by any labor indices. It has been established that controlling a heavy workload plays an important role in suppressing the deterioration of physical and mental conditions, including suicide; however, this study suggested that, at least within appropriate ranges of working hours, decreasing working hours due to excessive management probably contributes to increasing suicides of some vulnerable individuals via de-creasing their wages. Although governmental welfare and economic support measures had to be revised according to rapidly changing situations during the COVID-19 pandemic, this study also suggested that temporal gaps among a part of revisions of several welfare and economic support measures were unexpectedly involved in drastically/sharply increasing suicides of unemployed individuals in 2022.

Association between long working hours and the development of suicidal ideation among female workers: An 8-year population-based study using the Korean Longitudinal Survey of Women & Family (2012-2020)

Long working hours and overwork have recently emerged as pressing public health concerns. We explored the association between long working hours and suicidal ideation in female workers. A total of 8017 women (24,331 observations) from the fourth to eighth waves of the Korean Longitudinal Survey of Women and Families (2012-2020) were analyzed. To address the repeated measurements within each participant, we employed a generalized estimating equation to estimate the odds ratio (OR) and 95% confidence intervals (CIs). The prevalence of suicidal ideation was 1.9% for those working 35-40 h/week and 4.4% for those working ≥55 h/week. Compared to individuals working 35-40 h/week, those working ≥55 h/week were more likely to experience concurrent suicidal ideation (OR [95% CI]:1.85 [1.43-2.39]). The OR (95% CI) of the association between long working hours and onset of suicidal ideation in the subsequent wave was 1.69 (1.20-2.38) for ≥55 h/week. In subgroup analysis, this association was pronounced among workers with low-income levels (OR [95% CI]: 1.97 [1.29-3.02]) and blue-collar occupations (OR [95% CI]: 2.27 [1.41-3.66]). Policy efforts are required to protect the mental health of female workers exposed to long working hours.

Multidimensional analysis of schoolteachers' occupational stress by the New Brief Job Stress Questionnaire: focusing on gender differences

This study investigated teachers' occupational stress using a comprehensive job stress questionnaire, or the New Brief Job Stress Questionnaire, while considering gender differences. A total of 1,825 elementary and junior high school teachers participated in the study. The results revealed that female teachers significantly exhibited more psychological and physical stress reactions and perceived less job resource availability than did male teachers. Moreover, multiple regression analyses demonstrated that support from family and friends was a larger factor associated with mental health outcomes among female teachers than among male teachers. The impacts of marital status also differed between male and female teachers. Job demands were strongly associated with psychological and physical stress reactions among teachers. Meanwhile, job resources were more strongly associated with positive workplace outcomes, such as workplace engagement and social capital, than were job demands. Administrators should consider the distinctive nature of teachers' occupational stress in addition to its gender specific influence. Organizational support, such as securing teachers' autonomy, encouraging their career development, and acknowledging diversity, should be considered to foster teachers' work engagement and create a cohesive environment in the school workplace.

Public school teachers' occupational stress across different school types: a nationwide survey during the prolonged COVID-19 pandemic in Japan

Objectives

School teaching is regarded as one of the most stressful professions worldwide. To maintain schoolteachers' mental health, the factors influencing occupational stress among schoolteachers must be clarified. This study aimed to investigate public school teachers' work-related stress considering the differences in school types using data from a large-scale nationwide survey conducted during the prolonged coronavirus disease 2019 (COVID-19) pandemic in Japan.

Methods

Data from a nationwide survey of public school teachers performed between June 2019 and December 2022 were analyzed. The dataset consisted of repeated cross-sectional data. The total number of participants was 270,777 in 2019, 296,599 in 2020, 299,237 in 2021, and 307,866 in 2022. Information on working hours, job demands, workplace support, stress response, and perceived main stressors were assessed for each type of public school.

Results

Regardless of school type, quantitative workload and long working hours were the most significant factors affecting teachers' stress responses. However, stress-related factors among teachers varied significantly between school types. The percentage of junior high school teachers who perceived "extra-curricular club activities" as their main stressor was the highest among all school types. The highest proportion of elementary school teachers perceived "dealing with difficult students" as their main stressor. Meanwhile, interpersonal conflict scores were the highest among special needs school teachers. Teachers' workload and stress levels significantly increased in the third year of the COVID-19 pandemic (2022) compared to the pre-pandemic year (2019) in all school types despite the marginally small score differences.

Conclusions

This study highlighted the importance of reducing teachers' workload for their mental health regardless of school types. Meanwhile, perceived work-related stress among teachers differed significantly between school types. Given the possible prolonged impacts of the pandemic on teachers' occupational stress, teachers' stress levels must be monitored throughout and after the pandemic. The results suggest that increasing the number of schoolteachers and support staff and providing adequate organizational support are necessary to prevent teachers' sick leave due to mental disorders. In addition, taking comprehensive countermeasures against teachers' occupational stress, considering the differences in school types, is crucial for safeguarding schoolteachers' mental health.

Country differences in nocturnal sleep variability: Observations from a large-scale, long-term sleep wearable study

STUDY OBJECTIVES

Country or regional differences in sleep duration are well-known, but few large-scale studies have specifically evaluated sleep variability, either across the work week, or in terms of differences in weekday and weekend sleep.

METHODS

Sleep measures, obtained over 50 million night's sleep from ∼220,000 wearable device users in 35 countries, were analysed. Each person contributed an average of ∼242 nights of data. Multiple regression was used to assess the impact country of residence had on sleep duration, timing, efficiency, weekday sleep variability, weekend sleep extension and social jetlag.

RESULTS

Nocturnal sleep was shorter and had a later onset in Asia than other regions. Despite this, sleep efficiency was lower and weekday sleep variability was higher. Weekend sleep extension was longer in Europe and the USA than in Asia, and was only partially related to weekday sleep duration. There were also cross-country differences in social jetlag although the regional differences were less distinct than for weekend sleep extension.

CONCLUSIONS

In addition to regional differences in sleep duration, cross-country differences in sleep variability and weekend sleep extension suggest that using the latter as an indicator of sleep debt may need to be reconsidered. In countries exhibiting both short sleep and high weekday sleep variability, a culturally different means of coping with inadequate sleep is likely. Country or region differences in culture, particularly those related to work, merit closer examination as factors influencing the variability in normative sleep patterns around the world.

Long working hours and risk of hypertensive intracerebral haemorrhage among Japanese workers claiming compensation for overwork-related intracerebral haemorrhage: an unmatched case-control study

OBJECTIVES

Overwork-related cerebrovascular and cardiovascular diseases (CCVDs) constitute a major occupational and public health issue worldwide. However, to our knowledge, few studies have reported the underlying pathophysiological mechanisms. We aimed to determine whether patients with extreme workload have a greater risk of developing hypertensive intracerebral haemorrhage (ICH) located in the deep brain areas than patients without extreme workload. We also determined the association between the number of hours of overtime work and the risk of developing hypertensive ICH.

DESIGN

Unmatched case-control study.

SETTING

Database of patients claiming compensation for overwork-related CCVDs in Japan.

PARTICIPANTS

A total of 1215 patients who claimed overwork-related ICH in Japan, of whom 621 had their compensation claim approved (patients with extreme workload) and 622 did not.

PRIMARY AND SECONDARY OUTCOME MEASURES

Logistic regression analysis was performed to calculate the risk of developing hypertensive ICH in patients with extreme workload compared with those without extreme workload, adjusted for confounders such as age, occupation, smoking status, alcohol consumption and medical history. We also calculated the risk of developing hypertensive ICH in compensated patients by average monthly overtime working hours.

RESULTS

Patients with extreme workloads had a significantly higher odds ratio (OR) for developing hypertensive ICH (1.44, 95% CI: 1.10 to 1.88) than those without extreme workloads. ORs for developing hypertensive ICH according to overtime working hours showed a dose-response relationship; an overtime of 100 hours/month was associated with a significantly higher OR (1.31, 95% CI: 0.89 to 1.91; 1.41, 95% CI: 0.95 to 2.11; and 1.50, 95% CI: 1.01 to 2.22 for 60-79.9, 80-99.9 and≥100 hours/month, respectively) than that for workloads of less than 60 hours/month.

CONCLUSIONS

Regarding Japanese workers, overtime work could be associated with the risk of developing hypertensive ICH, and hypertension may play an important role in overwork-related ICH.

Supervisors' Work Engagement Is Associated With Interactivity and Carefulness in Supporting Subordinates: A Cross-sectional Study Using Text Mining in Japan

OBJECTIVE

This study aimed to structure supervisory support and clarify the relationship between supervisors' work engagement and support for their subordinates.

METHODS

We conducted a cross-sectional study in a manufacturing company using a questionnaire survey. Supervisors provided open-ended responses regarding the provision of support for their subordinates. Using text mining, we structured these descriptions into multiple categories, assigned words to them, and analyzed frequently mentioned categories by the level of work engagement.

RESULTS

We obtained responses from 729 participants that included 13,968 words. We structured supervisory support by three categories (contents, direction, and attitude toward support) and 11 subcategories. As supervisors' work engagement increased, the rates of mentioning information retrieval, information transmission, and carefulness increased.

CONCLUSIONS

Supervisors with work engagement could communicate with each other and be careful in providing support to their subordinates.

Association between shift rotation and 30-year Framingham risk of cardiovascular disease among male workers in a medium-sized manufacturing factory

Rotating shift work is associated with an increased risk of cardiovascular disease (CVD). This study compared the CVD risk score in 129 male line workers aged 22-49 years on different shifts in a medium-sized metal production factory from 2017 to 2020. We classified workers into four groups: permanent day shift, weekly rotation involving five consecutive nights, weekly rotation involving 3-4 consecutive nights, and monthly rotation involving two consecutive nights. We used the Framingham Risk Score to estimate the 30-yr risks of general and hard CVD (CVD risk estimates). We investigated the differences in CVD risk estimates between different groups using linear mixed models. The average 30-yr Framingham CVD risk estimates of each group ranged from 17.5% to 31.2% for general CVD and from 10.5% to 20.5% for hard CVD. Workers on weekly rotations involving 3-5 consecutive nights had 5%-10% significantly higher CVD risk estimates than workers on the permanent day shift. Workers on weekly rotations also had 6%-8% higher BMI-based CVD risk estimates than those on the monthly rotation involving two consecutive nights. While 24-h shift rotations are unavoidable, our findings underscored the potential CVD risk among workers on weekly rotations involving more consecutive nights.

Overtime work, job autonomy, and employees' subjective well-being: Evidence from China

Introduction

Chinese workers suffer more from overtime than in many countries. Excessive working hours can crowd out personal time and cause work-family imbalance, affecting workers' subjective well-being. Meanwhile, self-determination theory suggests that higher job autonomy may improve the subjective well-being of employees.

Methods

Data came from the 2018 China Labor-force Dynamics Survey (CLDS 2018). The analysis sample consisted of 4,007 respondents. Their mean age was 40.71 (SD = 11.68), and 52.8% were males. This study adopted four measures of subjective well-being: happiness, life satisfaction, health status, and depression. Confirmation factor analysis was employed to extract the job autonomy factor. Multiple linear regression methods were applied to examine the relationship between overtime, job autonomy, and subjective well-being.

Results

Overtime hours showed weak association with lower happiness (β = -0.002, p < 0.01), life satisfaction (β = -0.002, p < 0.01), and health status (β = -0.002, p < 0.001). Job autonomy was positively related to happiness (β = 0.093, p < 0.01), life satisfaction (β = 0.083, p < 0.01). There was a significant negative correlation between involuntary overtime and subjective well-being. Involuntary overtime might decrease the level of happiness (β = -0.187, p < 0.001), life satisfaction (β = -0.221, p < 0.001), and health status (β = -0.129, p < 0.05) and increase the depressive symptoms (β = 1.157, p < 0.05).

Conclusion

While overtime had a minimal negative effect on individual subjective well-being, involuntary overtime significantly enlarged it. Improving individual's job autonomy is beneficial for individual subjective well-being.

Does voluntary health insurance improve health and longevity? Evidence from European OECD countries

The financing structure of the healthcare system and, particularly, the voluntary health insurance (VHI) constituent, has been a vital pillar in improving the overall quality of life. Consequently, this study aims to shed light on the effect of VHI on the population's health and longevity in a sample of 26 European OECD countries. The methodology employed covers both hierarchical clustering and the novel dynamic panel threshold technique. First, the descriptive cluster analysis unveils a delimitation of the countries into four main groups with respect to a broad set of health status indicators. Second, the estimates show that VHI is a significant determinant of health and longevity. More specifically, we find that the relationship between variables is characterized by a threshold effect, whose estimated value is roughly 6.3% of the total healthcare financing. Also, the heterogeneity analysis unveils consistent differences regarding the impact of VHI on health and longevity for the supplementary and complementary types of VHI. Overall, results are strongly robust, the signs and the significance of the coefficients being preserved in the presence of several additional control factors. From a policy perspective, the study's findings can be used nationwide to stimulate regulatory policies to encourage the achievement of a satisfactory level of private health insurance.

Workplace Mistreatment and Health Conditions Prior and during the COVID-19 in South Korea: A Cross-Sectional Study

BACKGROUND

This study examined the relationship between workplace mistreatment, including discrimination, abuse, and overworking, and health problems among full-time workers prior to and during the coronavirus disease (COVID-19) outbreak in South Korea.

METHODS

We analyzed data from the 2017 and 2020-2021 Korean Working Conditions Surveys, including the final sample of 44,425 participants. Multiple logistic regression was used to examine the relationship between workplace mistreatment and health problems among workers by gender. Interaction analysis was conducted to establish the association between the COVID-19 pandemic and health problems related to mistreatment. The occupational, demographic, and socioeconomic backgrounds were adjusted.

RESULTS

We found a significant association between workplace mistreatment and health problems, including headaches, eyestrain, and anxiety. The association increased after the COVID-19 pandemic: "discrimination" (men (OR 2.26, 95% CI 1.93-2.65), women (OR 2.73, 95% CI 2.36-3.17)); abuse (men (OR 5.42, 95% CI 2.87-10.23), women (OR 4.70, 95% CI 3.12-7.08)); and overworking: men (OR 2.36, 95% CI 2.01-2.77), women (OR 3.52, 95% CI 2.68-4.61). The interaction indicates an increased incidence of people having health problems due to workplace mistreatment (OR 1.03, 95% CI 1.00-1.06) during the COVID-19 pandemic.

CONCLUSION

Statistically, employees who experience workplace mistreatment have worse health conditions. The COVID-19 pandemic has affected the job environment and increased the association between workplace mistreatment and health problems. To eliminate the health problems related to workplace mistreatment, it is necessary to address the impact of the COVID-19 pandemic on work and employee health conditions.

[Characteristics of compensated mental disorders caused by overwork among drivers and non-drivers in the Japanese trucking industry]

OBJECTIVES

This study examined the characteristics of occupational mental disorders among those involved in the transport and postal activities in the trucking industry.

METHOD

We examined 237 out of 3,517 cases of occupational mental disorders, compensated between the fiscal years 2010 and 2017. An assessment was made for sex, "life-or-death" status at compensation, age at the onset and suicide, the diagnosis according to the International Classification of Diseases, Tenth Revision, and other factors regarding occupational compensation. The participants were divided into two groups: truck drivers and non-truck drivers.

RESULTS

Men accounted for approximately 90% of the cases. Depressive episode (F32) was the most common diagnosis in drivers and non-drivers, thus constituting 65 out of 149 and 48 out of 88 cases, respectively. The next most common type of mental disorder was adjustment disorders (F43.2), with 34 out of 149 drivers and 24 out of 88 non-drivers reporting them. Furthermore, the majority of drivers that had posttraumatic stress disorder (24 out of 27 cases) reported that they "suffered a serious illness or injury" and "experienced or witnessed a terrible accident or disaster." Occupational disasters due to long working hours were 52.4% for drivers and 73.9% for non-drivers. A total of 30.8% of the drivers reported working long hours since they joined the company.

CONCLUSION

Drivers' long working hours entail waiting at the origin and cargo destination site, handling cargo, and incidental tasks other than driving. Thus, the reduction in work hours regarding these tasks needs to be a fundamental goal, and measures that include mental health care for accidents and miserable experiences must be implemented. However, long working hours for non-drivers are likely linked to job expansion/increase and reassignment/relocation. These findings highlight that to prevent overwork-related mental disorders, appropriate actions should be taken considering different sources of exposure for drivers or non-drivers.

A Meta-Analysis of Sleep Disorders and Nonalcoholic Fatty Liver Disease: Potential Causality and Symptom Management

Nonalcoholic fatty liver disease is a type of metabolic disease, and recent research indicates that it may be associated with sleep disorders. We conducted a meta-analysis of current studies to estimate the associations between nonalcoholic fatty liver disease and sleep situation, including sleep duration, daytime sleepiness, and sleep disorder. This study follows the checklist of the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). Articles in the recent 10 years were searched from five databases. Eighteen articles, which met the eligibility criteria, were included in this meta-analysis. The results show that patients with nonalcoholic fatty liver disease have a shorter sleep duration and higher Epworth Sleepiness Scale score. Patients with short sleep duration (≤6 hours per night) or with obstructive sleep apnea have a higher risk of nonalcoholic fatty liver disease. In conclusion, there is a significant association between nonalcoholic fatty liver disease and sleep disorders in the included studies. In addition, patients with nonalcoholic fatty liver disease may have more severe daytime sleepiness and shorter sleep duration. More attention should be paid to the sleep situation of nonalcoholic fatty liver disease patients to potentially slow the disease progression.

Mortality of Suicide and Cerebro-Cardiovascular Diseases by Occupation in Korea, 1997-2020

Although studies on occupational mortality have been conducted in Korea, the results for occupations with high mortality around 2010 are inconsistent. This study aimed to examine occupational mortality from overwork-related suicide and cerebro-cardiovascular diseases (CCVD) from 1997 to 2020. We used microdata of the Causes of Death Statistics (CDS) and Economically Active Population Survey (EAPS) to obtain indirect standardized mortality ratio (SMR) and standardized proportional mortality ratio (PMR) of suicide (X60-X84) and CCVD deaths (I20-I25 and I60-I69) by gender and eight occupational categories. The trend of SMR of suicide and CCVD by occupation was similar within individual genders. The SMR of managers (MNG) was the highest for men and women in 2012-2017 and 2008-2020, respectively, whereas the SMR of professionals and related workers (PRF) was consistently low. Despite the similar socioeconomic status of MNG and PRF, we suggest that their mortality should be analyzed separately in Korea. SMR of suicide and CCVD in female MNG were consistently highest, although the PMR was low. Female MNG may have been more directly affected by the economic crisis. There is a need for work-related stress management, early intervention, and prevention policies in occupations vulnerable to mortality.

Study profile: protocol outline and study perspectives of the cohort by the National Institute of Occupational Safety and Health, Japan (JNIOSH cohort)

How work burden affects physical and mental health has already been studied extensively; however, many issues have remained unexamined. In 2017, we commenced a prospective cohort study of workers at companies in Japan, with a follow-up period of 5-10 years, in order to investigate the current situation of overwork-related health outcomes. From 2017 to 2020, a target population of 150,000 workers across 8 companies was identified. Of these, almost 40,000 workers agreed to participate in the baseline survey. Data on working hours, medical check-up measurements, occupational stress levels, and lifestyle habits were collected. The average age of the participants at baseline was 39.2 ± 11.7 years; 73.1% were men, and 87.7% were regular employees. The most common working hours by self-reported was 41-50 hours per week during normal season, and it increased to more than 50 hours during busy season. Furthermore, more than half of the participants reportedly experienced a form of sleep problem, and the percentage of those who experienced nonrestorative sleep was particularly high.

Psychometric properties of the Japanese version of the Occupational Fatigue Exhaustion Recovery Scale among shift-work nurses

Objectives

Shift‐work nurses are at a higher risk of inadequate recovery from fatigue and developing maladaptive fatigue with significant health consequences. Therefore, it is necessary to monitor fatigue and recovery levels with a reliable scale. We investigated psychometric properties of the Japanese version of the Occupational Fatigue Exhaustion Recovery scale (OFER‐J) for shift‐work nurses.

Methods

Japanese shift‐work nurses responded to self‐administered questionnaires at baseline (n = 942) and one month later (n = 334). The confirmatory factor analysis (CFA) and exploratory factor analysis (EFA) were conducted to verify the structural validity and the correlation analysis and one‐way analysis of variance were conducted to test the construct and discriminative validity. Cronbach's alpha coefficient, intra‐class correlation coefficient (ICC), and smallest detectable change (SDC) were calculated to assess reliability.

Results

The CFA showed high correlations between the factors and whilst the goodness‐of‐fit of the three‐factor model was suboptimal, it was in an acceptable range. Most modifications included the error covariance of the Acute Fatigue (AF) and Intershift Recovery (IR) items. The EFA showed that Chronic Fatigue (CF) and AF were not clearly separated, indicating that the two AF items dropped out. Construct and discriminative validity were also well indicated. Cronbach's alpha coefficients were 0.75–0.85. Only CF showed sufficient reproductivity (ICC = 0.74). The SDC for CF, AF, and IR was 14.0, 17.1, and 18.7, respectively.

Conclusions

The validity and reliability of the OFER‐J were verified as acceptable for shift‐work nurses. The OFER‐J could contribute to a data‐based approach to fatigue management in nursing management practice.

A Preliminary Study on the Abnormal Deaths and Work Burden of Chinese Physicians: A Mixed Method Analysis and Implications for Smart Hospital Management

Background: The population of Chinese physicians is frequently threatened by abnormal death, including death by overwork or homicide. This is not only a health problem, but also a social problem that has attracted the attention of both hospitals and the government. Objective: This study aims to analyze the characteristics of abnormal death in physicians in Chinese hospitals from 2007 to 2020 and to investigate the relationship between abnormal death and physician workload, in order to provide information for policy makers and request improvement technologies. Methods: A mixed research method was used. In order to ensure accuracy and completeness, a relatively comprehensive search was conducted using multiple heterogeneous data sources on the abnormal death of physicians in Chinese hospitals from 2007 to 2020. The collected cases were then descriptively analyzed using the work-related overwork death risk concept framework and the deductive grounded theory approach. In addition, the workload of physicians was calculated between 2007 and 2019 based on three important workload indicators. Results: Between 2007 and 2020, 207 abnormal death events of physicians on the Chinese mainland were publicly reported. Among the 207 victims, the majority (~79%) died from overwork or sudden death. The number of victims who were men was 5.5 times higher than that of women, and victims were between the ages of 31-50 years. These physicians mainly belonged to the departments of surgery, anesthesiology, internal medicine, and orthopedics. Further analysis of the direct causes of death in cases of overwork death showed that 51 physicians (31.1%) died from cardiogenic diseases. Additionally, the per capita workload of physicians in China increased drastically by about 42% from 2007 to 2019, far exceeding physician workloads in Europe, Asia, and Australia (number of inpatients per physician in 2017: 72 vs. 55, 50, 45). The analysis revealed that there was a strong correlation between the number of abnormal deaths of physicians in China and the number of inpatients per physician (r = 0.683, P = 0.01). Conclusion: High-intensity working conditions may be positively correlated with the number of abnormal deaths among physicians. Smart hospital technologies have the potential to alleviate this situation.

Comparison of Work-Related Stress in Cluster of Workers' Suicides in Korea: Analysis of Industrial Accident Compensation Insurance, 2010-2017

Background: There is limited research on the heterogeneity of worker suicides. We compared differences in workers’ suicides by clustering suicide deaths. Methods: From 2010 to 2017, 353 suicide deaths were claimed in the Industrial Accident Compensation Insurance; variables were coded using a standardized methodology. A two-step cluster analysis classified the clusters based on demographic and employment conditions. Details of the suicide, clinical variables, personal stresses, and work-related stresses were compared using the chi-square test and one-way analysis of variance. Results: We identified five clusters and they differed particularly in work-related stress. “Responsibility-burdened type” experienced excessive responsibility as managers; “role-changed type” experienced a sudden and unpredictable role change as clerks or sales workers; “risk-exposed type” experienced physical risk factors at work (working alone, outdoors, and in shifts) as machine operating and assembling workers, or craft and related trades workers; “job-insecurity type” experienced unstable employment (irregular, nonpermanent) as elementary or service workers; “workplace-violence type” was mainly unmarried women who lived alone, and experienced interpersonal conflict and violence as professionals and related workers. There were no differences between clusters in clinical variables (except problem drinking) and personal stresses. Conclusion: Interventions to alleviate work-related stress in worker clusters are needed to prevent suicide in workers.

The Relationship Between Long Working Hours and Stress Responses in Junior High School Teachers: A Nationwide Survey in Japan

Background: Long working hours and mental health problems among teachers are a concern in Japan. More specifically, it has been reported that junior high school teachers tend to work overtime. In this study, examined the working hours of junior high school teachers in public schools and investigated the association between overtime work and stress responses across job titles.

Methods: From June to December 2018, 54,772 teachers in public junior high schools completed a web-based nationwide survey regarding occupational stress and submitted self-evaluated working hours per day of the previous month. Psychological and physical stress responses were assessed using the Brief Job Stress Questionnaire.

Results: Results showed that 59.6% of the participants worked 11 h or more per day. Additionally, the length of working hours significantly differed across job titles (χ² (30) = 5295.8, p < 0.001, Cramér’s V = 0.14). With respect to tenured teachers, sex (female), age, taking charge of the class, number of working years in the same school, working hours of 10 to 11 h, 11 to 12 h, 12 to 13 h, and 13 h or more were significantly associated with high stress, compared to those who worked less than 9 h per day. Moreover, for fixed-term teachers, sex (female), age, working hours of 9 to 10 h, 10 to 11 h, 11 to 12 h, 12 to 13 h, and 13 h or more were related with more stress as compared to those who worked less than 9 h per day. On the other hand, there was no significant relationship between long working hours and stress response among vice-principals, even though they tended to work the longest hours.

Conclusion: We verified that Japanese junior high school teachers work long hours. Long working hours were associated with stress responses in both tenured and fixed-term teachers, but not in vice-principals. However, vice-principals work the longest hours among teachers, and we suggest that these long working hours may be a hidden problem that is often overlooked.

Health problems associated with single, multiple, and the frequency of months of objectively measured long working hours: a cohort study by the National Institute of Occupational Safety and Health, Japan

Purpose

We aimed to examine the prospective associations of monthly working hours measured in a month, the 6-month averaged hours, and the frequency of long working hours (≥ 205 h/month) during the past 6 months with health indicators.

Methods

This study included 6,806 Japanese company workers (response rate = 86.6%). Data on the workers’ monthly attendance during the second half of fiscal year 2016 and annual health checkups in fiscal years 2016 and 2017 were collected. We evaluated the association of the above three types of monthly working hours with subsequent health checkup data in fiscal year 2017. We adjusted for the corresponding data in fiscal year 2016.

Results

Multivariate logistic regression analyses revealed significant associations between monthly working hours and workers’ systolic and diastolic blood pressure as well as aspartate aminotransferase, alanine aminotransferase, low-density lipoprotein cholesterol (LDL), and triglyceride levels. However, the associations were not consistent between months. The average monthly working hours were significantly associated with higher LDL levels for the 220–240 h/mo group (OR: 1.49, 95%CI: 1.07–2.08) and lower triglyceride levels for the < 140 h/mo group (OR: 0.15, 95%CI: 0.03–0.77), compared to the 140–180 h/mo group. The frequency of long working hours was significantly associated with higher LDL levels.

Conclusions

Working hours over several months produced various associations with health indicators compared to those measured in a single month. Our present data suggest that the effects of average or frequency of long working hours during the past 6 months are likely to appear in LDL levels.

Effect of internet-based attention bias modification on the anxiety of Japanese workers: A randomized controlled trial

Objectives

This study comprised a randomized controlled trial to examine the effect of internet‐based attention bias modification (iABM) on reducing workers' anxiety.

Methods

In total, 300 eligible participants were randomized according to sex and age; 180 were assigned to the intervention group and 120 to the control group. The word stimuli used in the iABM included eight positive words and eight neutral words. Participants were instructed to indicate the positive word's position as quickly and accurately as possible by tapping one of the two directions on display. The intervention included five sessions per participant over 1 month, resulting in a total of 600 trials. The main outcome measure was the total state anxiety score of the State‐Trait Anxiety Inventory (STAI).

Results

There was no significant difference in the net change in STAI scores between the intervention and control groups. The mean reaction time of the fifth session was significantly shorter than the mean reaction time of the first session. Furthermore, although there was no effect on the index of effect size Δ, the paired t‐test showed a significant decrease in the anxiety score.

Conclusions

The iABM intervention in this study did not enhance the amelioration of workers' anxiety when compared with the control condition.

Attitudes toward overtime work and self-training: A survey on obstetricians and gynecologists in Japan

AIM

The Ministry of Health, Labour, and Welfare of Japan proposed a regulation of overtime work as a reform in work style. However, the regulation may deteriorate the quality of medical services due to the reduction in training time. Thus, the study aimed to reveal perceptions in terms of generation gaps in views on self-training and overtime work, among members of the Japan Society of Obstetrics and Gynecology (JSOG).

METHODS

A web-based, self-administered questionnaire survey was conducted among members of the JSOG. In total, 1256 respondents were included in the analysis. Data were collected on age, sex, experience as a medical doctor, location of workplace, work style, the type of main workplace, and number of full-time doctors in the main workplace. The study examined the attitudes of the respondents toward overtime work and self-training. The respondents were categorized based on experience as a medical doctor.

RESULTS

According to years of experience, 112 (8.9%), 226 (18.0%), 383 (30.5%), 535 (42.6%) doctors have been working for ≤5, 6-10, 11-19, and ≥ 20 years, respectively. Although 54.5% of doctors with ≤5 years of experience expected the regulation on working hours to improve the quality of medical services, those with ≥20 years of experience expressed potential deterioration. After adjusting for covariates, more years of experience were significantly related with the expectation of deterioration in the quality of medical services.

CONCLUSIONS

The study revealed a generation gap in the views about self-training and overtime work among obstetricians and gynecologists in Japan.

Measurement Invariance of the Burnout Assessment Tool (BAT) Across Seven Cross-National Representative Samples

The aim of this study was to investigate the measurement invariance of the Burnout Assessment Tool (BAT) across seven cross-national representative samples. In this study, burnout was modeled as a second-order factor in line with the conceptual definition as a syndrome. The combined sample consisted of 10,138 participants from countries in Europe and Japan. The data were treated as ordered categorical in nature and a series of models were tested to find evidence for invariance. Specifically, theta parameterization was used in conjunction with the weighted least squares (mean- and variance adjusted) estimation method. The results showed supportive evidence that BAT-assessed burnout was invariant across the samples, so that cross-country comparison would be justifiable. Comparison of effect sizes of the latent means between countries showed that Japan had a significantly higher score on overall burnout and all the first-order factors compared to the European countries. The European countries all scored similarly on overall burnout with no significant difference but for some minor differences in first-order factors between some of the European countries. All in all, the analyses of the data provided evidence that the BAT is invariant across the countries for meaningful comparisons of burnout scores.

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.

Association of long working hours with accidents and suicide mortality in Korea

Objectives:

The deleterious health effects of long working hours have been previously investigated, but there is a dearth of studies on mortality resulting from accidents or suicide. This prospective study aims to examine the association between working hours and external-cause mortality (accidents and suicide) in Korea, a country with some of the longest working hours in the world.

Methods:

Employed workers (N=14 484) participating in the Korean National Health and Nutrition Examination Survey (KNHANES) were matched with the Korea National Statistical Office’s death registry from 2007–2016 (person-years = 81 927.5 years, mean weighted follow-up duration = 5.7 years). Hazard ratios (HR) for accident (N=25) and suicide (N=27) mortality were estimated according to weekly working hours, with 35–44 hours per week as the reference.

Results:

Individuals working 45–52 hours per week had higher risk of total external cause mortality compared to those working 35–44 hours per week [HR 2.79, 95% confidence interval (CI) 1.22–6.40], adjusting for sex, age, household income, education, occupation, and depressive symptoms. Among the external causes of death, suicide risk was higher (HR 3.89, 95% CI 1.06–14.29) for working 45–52 hours per week compared to working 35–44 hours per week. Working >52 hours per week also showed increased risk for suicide (HR 3.74, 95% CI 1.03–13.64). No statistically significant associations were found for accident mortality.

Conclusions:

Long working hours are associated with higher suicide mortality rates in Korea.

Effect of implementing an overwork-prevention act on working hours and overwork-related disease: A mediation analysis

OBJECTIVES

Overwork has been recognized as a risk factor for cerebrovascular and cardiovascular disease (CCVD). To our best knowledge, Japan is the first country in the world to implement an independent act (the 2014 Act) for the prevention of overwork-related disease, which was promoted through application of preventive measures, such as reductions in working hours. We assessed changes in working hours and overwork-related CCVD before and after introduction of the 2014 Act.

METHODS

We calculated the overwork-related CCVD incidence rate and average monthly working hours for 10 industry groups in Japan with data from 2012 to 2018. We applied a causal mediation analysis to estimate the total effect of implementing the 2014 Act on the overwork-related CCVD and the effect mediated by working hours.

RESULTS

An average of 271 for every 48 million employees developed overwork-related CCVD per year. After introducing the 2014 Act, the incidence rate ratio of overwork-related CCVD was 0.881-fold lower (95% CI 0.780-0.995) compared with before the policy change. The 2014 Act contributed to a decrease of 26% (78 cases per year; 95% CI 29-173) of the overwork-related CCVD incidence per year. Approximately 41% (32 cases per year) of this effect could be explained by reduced working hours.

CONCLUSIONS

Our study highlights the impact of the 2014 Act in Japan on the reduction in working hours, which further contributes to the reduction in overwork-related CCVD. Policymakers should consider adopting our innovative approach to assess the mediation effect underlying the implementation of new policies.

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.