Nonlinear associations between working hours and overwork-related cerebrovascular and cardiovascular diseases (CCVD)

Survival costs and benefits of reproduction: A register-based study in 20th century Estonia

Patterns of individual variation in lifespan and senescence depend on the associations between parental survival and reproductive rates. We studied the associations between parity and survival among 579,271 Estonians born between 1905 and 1945 and in a cohort with a completed lifespan born in 1905-1927. For this cohort, selection for increased lifespan operated on both sexes, but it was stronger in men than in women. However, the median lifespan increased between the subsequent cohorts in women but stagnated in men. Selection for longer lifespan was caused by the below-average lifespan of individuals with no or single offspring. Despite a general positive selection for lifespan, survival costs of reproduction were also detected among a relatively small proportion of individuals with high parities, as mothers of two and fathers of two and three children had the highest median lifespans. Fathers of more than six children had better survival than fathers of few children in their reproductive age, but this association reversed after age 70. The reversal of this association between survival and parity at old age indicates that relative mortality risks between those with lower versus higher parities change across ages, as predicted by the antagonistic pleiotropy theory of aging.

Characteristics of long working hours and subsequent psychological and physical responses: JNIOSH cohort study

OBJECTIVES

This study aimed to examine the prospective association among objectively measured average working hours (AWHs), frequency of long working hours (FLWHs; defined as ≥205 working hours/month (≥45 hours/week)) for 6 months, and workers' self-reported psychological and physical health.

METHODS

The study included 15 143 workers from 5 Japanese companies. We collected monthly attendance records over 6 months before distributing a questionnaire survey on psychological/physical stress responses and work-related demographics. We then evaluated the associations of those attendance records with psychological/physical measures using analysis of covariance adjusted for sex, age, employment, job type, working conditions, work site and experience of emergency state due to COVID-19.

RESULTS

Irritability, anxiety and depression were significantly greater at ≥180 hours (≥45 hours/week), and fatigue and lack of vigour were greater at ≥205 hours than those of the normal working-hour group (140-180 hours/month [35-45 hours/week]). Psychological indices increased significantly with FLWH, with ≥3 times for irritability, depression and fatigue; ≥2 times for lack of vigour; and ≥1 time for anxiety when compared with no long working hours. No significant associations were observed between AWH or FLWH and physical stress responses.

CONCLUSIONS

Longer AWH was associated with higher levels of psychological stress responses. The effects of FLWH in the past 6 months varied among the psychological stress responses and did not occur for physical complaints. Under circumstances requiring long hours, workers' mental health should be protected through minimising the frequency of long work hours.

Physiological State Evaluation in Working Environment Using Expert System and Random Forest Machine Learning Algorithm

Healthy lifestyle is one of the most important factors in the prevention of premature deaths, chronic diseases, productivity loss, obesity, and other economic and social aspects. The workplace plays an important role in promoting the physical activity and wellbeing of employees. Previous studies are mostly focused on individual interviews, various questionnaires that are a conceptual information about individual health state and might change according to question formulation, specialist competence, and other aspects. In this paper the work ability was mostly related to the employee's physiological state, which consists of three separate systems: cardiovascular, muscular, and neural. Each state consists of several exercises or tests that need to be performed one after another. The proposed data transformation uses fuzzy logic and different membership functions with three or five thresholds, according to the analyzed physiological feature. The transformed datasets are then classified into three stages that correspond to good, moderate, and poor health condition using machine learning techniques. A three-part Random Forest method was applied, where each part corresponds to a separate system. The obtained testing accuracies were 93%, 87%, and 73% for cardiovascular, muscular, and neural human body systems, respectively. The results indicate that the proposed work ability evaluation process may become a good tool for the prevention of possible accidents at work, chronic fatigue, or other health problems.

An Index to Assess Overwork-Related Adverse Effects on Employees Under the Occupational Safety and Health Act in Taiwan

Background

The present study aimed to digitally evaluate the risk of overwork-related adverse effects (OrAEs) among employees from various occupational categories in Taiwan.

Methods

Anonymous data of employees from seven companies/factories providing occupational health services were analyzed. The studied population comprised 5505 employees, and the data analyzed included employment duration, working hours, shift work schedules, and health checkup results. The risk for OrAEs was assessed by an index, Karo index (0-4, the larger the value, the higher the risk for OrAEs) obtained using a risk matrix made up of cardiocerebral and occupational risk factors. Karo index values of 3 and 4 were categorized as at high risk for OrAEs (h-OrAEs).

Results

The 5505 employees had an average employment duration of 8.5 years and a mean age of 39.4 years. The prevalence rates for h-OrAEs of the seven companies/factories ranged from 3.9% to 34.2%. There were significant differences in prevalence rates for h-OrAEs between employees of retail stores and high-tech manufacturing factories. Multivariate analysis results indicated that workers of high-tech manufacturing factories had significantly higher risk for h-OrAEs compared with retail store workers.

Conclusion

In terms of satisfying health risk management and legal requirements in Taiwan, the newly issued Karo index, which covers a wide range of occupational risk factors, can serve as an assessment and a warning tool for managing the risk of OrAEs in workplaces. To reduce risks for h-OrAEs, active and prudent control of cerebrocardiovascular risks and working hours is recommended.

The Influence of Long Working Hours, Occupational Stress, and Well-Being on Depression Among Couriers in Zhejiang, China

Objective:

This study aimed to examine the association between long working hours, occupational stress, depression, and well-being, and to explore the intermediary effect of occupational stress and well-being between working hours and depression among couriers in Zhejiang, China.

Methods:

The study used a cluster random sampling method to select 1,200 couriers from mainstream express companies in Zhejiang, China. The data were collected and analyzed using the Core Occupational Stress Scale (COSS) to measure occupational stress, the Patient Health Questionnaire-9 (PHQ-9) scale to evaluate depression, and the World Health Organization five-item Well-Being Index (WHO-5) scale to assess well-being. Structural equation modeling (SEM) was used to test the hypothesized relationship among the variables.

Results:

The phenomenon of long working hours (75.1%) was quite common among couriers in Zhejiang, China. Working hours had a direct positive effect on depression (β = 0.008, p < 0.001) and on occupational stress (β = 0.009, p < 0.001), and working hours had a negative effect on well-being (β = −0.013, p < 0.001). Occupational stress had a direct positive effect on depression (β = 0.272, p < 0.001), but well-being had no significant direct effect on depression. Working hours had an indirect effect on depression through the mediating effect of occupational stress while the mediating effect of well-being was not found.

Conclusion:

Long working hours is associated with occupational stress, well-being, and depression. Our results confirmed that working hours, occupational stress, and well-being were strong predicators of depression. Working hours had a significant indirect effect on depression via occupational stress. The result of this study showed that decreasing working hours and reducing occupational stress would be effective for couriers to prevent depression. However, more studies are needed to verify the relationship between working hours and depression.

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.

Protective effect of teprenone on gastric mucosal injury induced by dual antiplatelet therapy in rats

OBJECTIVE

To investigate the protective effect of teprenone on gastric mucosal injury induced by dual antiplatelet therapy in rats.

METHODS

Healthy, specifically pathogen free SD, rats were selected and divided into 4 groups: Normal group (normal rats, without any treatment), Model group (rats received dual antiplatelet therapy: aspirin and clopidogrel), Teprenone group (rats received dual antiplatelet therapy and teprenone) and Pantoprazole group (rats received dual antiplatelet therapy and pantoprazole). The gastric mucosal blood flow, ulcer index, gastric gel mucus thickness, the levels of gastrin (Gas), prostaglandin (PG), prostaglandin E2 (PGE2), endothelin-1 (ET-1) tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and IL-10 in serum, the levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD) and myeloperoxidase (MPO) in the gastric mucosa, as well as the expression of vascular endothelial growth factor (VEGF) in the rat's stomach were measured.

RESULTS

Compared with the Normal group, the other groups showed more severe gastric injury, elevated levels of inflammatory factors (TNF-α, IL-1β, IL-6 and IL-10), elevated levels of MDA and MPO, as well as reduced levels of GSH, SOD and VEGF (all P<0.05). Compared with the Model group, the gastric mucosal lesions in the Teprenone group and the Pantoprazole group were improved significantly (both P<0.05). Compared with the Pantoprazole group, the Teprenone group had reduced levels of ET-1 and elevated levels of PG and PGE2 (all P<0.05).

CONCLUSION

Teprenone protects against gastric mucosal injury induced by dual antiplatelet therapy through inhibiting gastric mucosal inflammation inhibiting oxidative stress and improving gastric mucosa indices.

Associations among working hours, sleep duration, self-rated health, and health-related quality of life in Korean men

BACKGROUND

This study aimed to examine the relationship between working hours and health-related quality of life (HRQOL) in men and to determine whether this relationship was mediated by sleep duration and self-rated health (SRH).

MATERIALS AND METHODS

Our study population included 2141 working men aged 20 to 49 years old from the Korea National Health and Nutrition Examination Survey 2016-2017. Working hours, SRH, and HRQOL were measured by a structured questionnaire survey. Sleep duration was calculated based on self-reported data. We investigated the association between working hours and HRQOL and performed a mediation analysis to evaluate the contributions of sleep duration and poor SRH to this relationship.

RESULTS

This study identified a significant association between working hours and HRQOL. Long working hours directly and indirectly affected HRQOL through poor SRH. Men who overworked were more likely to report poor HRQOL due to worsened SRH. Poor SRH was responsible for 26.3% of this relationship. But sleep duration did not explain the relationship between working hours and HRQOL.

CONCLUSIONS

Working hours were directly associated with HRQOL in men. Furthermore, there was an indirect effect of working hours on HRQOL mediated by poorer SRH. An improved work-life balance is necessary to promote men's health and quality of life.

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.

Mediation analysis for new recognition criteria, working hours and overwork-related disease: a nationwide ecological study using 11-year follow-up data in Taiwan

OBJECTIVES

Taiwan revised its criteria for overwork-related cerebrovascular and cardiovascular disease (CCVD) in 2010. A new definition of overwork increased the number of recognised cases. Meanwhile, actual average working hours decreased. We estimated the effects of the revised criteria on the number of overwork-related CCVD cases and the mediation effect through reduced working hours.

METHODS

From the Labor Insurance of Taiwan, we collected data on the total number of overwork-related CCVD cases from 2006 to 2016 and average monthly working hours for 13 industry groups. We conducted causal mediation analysis to investigate the mechanism of the effect of new criteria on CCVD mediated by working hours.

RESULTS

From 2006 to 2016, 594 overwork-related cases of CCVD were recognised across 13 industry groups. After introducing the new criteria, overwork-related CCVD increased by 8.40 cases (per one million person-years) (95% CI 4.53 to 15.05), which resulted from a decrease of 1.54 (95% CI 0.22 to 3.82) cases due to reduced working hours (mediation effect) and an increase of 9.93 (95% CI 5.24 to 18.17) cases related to the effect of the criteria change and other covariates excluding working hours (alternative effect).

CONCLUSIONS

Working hours are an important mediator of the effect of policy on the rate of overwork-related CCVD. Introducing new criteria for recognising overwork-related disease might raise awareness and prompt reductions in working hours, which also help to reduce CCVD. Our findings suggest that understanding mediation effects is important to evaluating national health policies.

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.

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.