Published papers

職場環境等の評価と改善の普及・浸透に関する科学的根拠に基づく(EBM)ガイドラインについて検討した。EBMガイドライン案の作成のために、国内外の研究論文をレビューした。職場環境開発を通じたストレス対策EBMガイドライン作成のための対象文献は、レビュー文献から整理し、33文献を基本として抽出した。国内外の文献レビューに基づいて「職場環境等の評価と改善に関する科学的根拠に基づく(EBM)ガイドライン案」を精査し、最終的に4領域合計12項目、八つの推奨項目と四つのヒント項目が含まれる形に整理して、EBMガイドラインを作成した。

The aim of the present study was to examine how job and home demands are related to psychological distress in a sample of Japanese working parents with preschool children (n=196). We expected that job and home demands are partially related to psychological distress through work-to-family conflict (WFC) and family-to-work conflict (FWC), respectively. Structural equation modeling showed that, as expected, home demands were partially related to psychological distress, both directly and indirectly through FWC. In contrast, job demands were only directly related to psychological distress. The differences between the roles of FWC and WFC are discussed using identity theory.

The aim of the present study was to examine how job and home demands are related to psychological distress in a sample of Japanese working parents with preschool children (n=196). We expected that job and home demands are partially related to psychological distress through work-to-family conflict (WFC) and family-to-work conflict (FWC), respectively. Structural equation modeling showed that, as expected, home demands were partially related to psychological distress, both directly and indirectly through FWC. In contrast, job demands were only directly related to psychological distress. The differences between the roles of FWC and WFC are discussed using identity theory.

Objectives: To examine the effects of multiple types of work-family spillover (work-to-family negative spillover, WFNS; family-to-work negative spillover, FWNS; and work-family positive spillover, WFPS) on psychological distress among Japanese dual-earner couples with preschool children. Methods: 2,346 parents completed questionnaires measuring work-family spillover, work- and family-specific variables (i.e., job demands and resources, family demands and resources), and psychological distress. A hierarchical multiple regression analysis was conducted by entering demographic characteristics (gender, age, age of the youngest child, and job contract) in step 1, job demands and resources in step 2, family demands and resources in step 3, work-family spillover in step 4, and three two-way interactions between types of work-family spillover and gender in the final step. Results: Both WFNS and FWNS were positively related to psychological distress after controlling for demographic characteristics and domain specific variables (i.e. job and family demands/resources), and FWNS (β=0.26) had a stronger relation with psychological distress than WFNS (β=0.16). Although WFPS was significantly and negatively related to psychological distress, the relationship was weak (β=-0.05). In addition, two-way interactions of WFNS and FWNS with gender were found; the impact of both WFNS and FWNS on psychological distress is stronger for females than for males. No significant interaction effect was observed between WFPS and gender. Conclusions: In this study of Japanese dual-earner couples with preschool children, work-family negative spillover had a stronger relationship with psychological distress than positive spillover. Gender had a moderating effect on the relationship between negative spillover and psychological distress.

© 2018 World Obesity Federation Background: Work-related psychosocial factors have been associated with metabolic syndrome. However, no systematic reviews or meta-analyses have evaluated this association. Methods: A systematic literature search was conducted, using PubMed, Embase, PsycINFO, PsycARTICLES and the Japan Medical Abstracts Society. Eligible studies included those that examined the previously mentioned association; had a longitudinal or prospective cohort design; were conducted among workers; provided sufficient data for calculating odds ratios, relative risks or hazard ratios with 95% confidence intervals; were original articles in English or Japanese; and were published no later than 2016. Study characteristics, exposure and outcome variables and association measures of studies were extracted by the investigators independently. Results: Among 4,664 identified studies, 8 were eligible for review and meta-analysis. The pooled risk of adverse work-related stress on metabolic syndrome onset was significant and positive (RR = 1.47; 95% CI, 1.22–1.78). Sensitivity analyses limiting only the effects of job strain and shift work also indicated a significant positive relationship (RR = 1.75; 95% CI, 1.09–2.79; and RR = 1.59; 95% CI, 1.00–2.54, P = 0.049 respectively). Conclusion: This study reveals a strong positive association between work-related psychosocial factors and an elevated risk of metabolic syndrome onset. The effects of job strain and shift work on metabolic syndrome appear to be significant.

© 2017 Article author(s). All rights reserved. Introduction: Metabolic syndrome is an important public health target because of its high prevalence worldwide. Work-related psychosocial factors have been identified as determinants of metabolic syndrome components. However, there have been no systematic reviews or meta-analyses conducted to evaluate the relationship between work-related psychosocial factors and metabolic syndrome as an aggregated cluster. The aim of this study is to examine this association from published prospective studies. Methods and analysis: The systematic review and meta-analysis will be conducted using published studies that will be identified from electronic databases (ie, PubMed, EMBASE, PsycINFO, PsycARTICLES and Japan Medical Abstracts Society). Studies that (1) examined the association between work-related psychosocial factors and the onset of metabolic syndrome, (2) had a longitudinal or prospective cohort design, (3) were conducted among workers, (4) provided sufficient data for calculating ORs or relative risk with a 95% CI, (5) were published as original articles written in English or Japanese, and (6) having been published until the end of 2016 will be included. Study selection, data collection, quality assessment and statistical syntheses will be conducted based on discussions among investigators. Ethics and dissemination: Ethics approval was not required for this study because it was based on published studies. The results and findings of this study will be submitted and published in a scientific peer-reviewed journal. The findings from this study could be useful for assessing metabolic syndrome risk factors in the workplace, and determining approaches for prevention of metabolic syndrome in the future.

In work-family research the effects on the individual, or the "self", in terms of personal interests independent of the work and family domains, have been largely neglected. This longitudinal study on 471 Japanese employees with young children investigated how job demands and job resources may have an impact on well-being by facilitating or hindering personal functioning. It was hypothesized that workload would have an unfavourable impact on work-to-self conflict, while supervisor support would have a favourable impact on work-to-self facilitation. In addition, we hypothesized that work-self conflict would diminish well-being (psychological distress and happiness), while work-self facilitation would enhance well-being over time. Structural equation modelling analyses using a full panel design showed that work overload was positively related to work-self conflict over time, whereas supervisor support was positively related to work-self facilitation. Furthermore, work-self conflict predicted psychological distress and happiness at T2, one year later, after controlling for T1 levels. These findings suggest that the demands and resources encountered at work can spill over to the home domain and have an impact on personal functioning and context-free well-being. Further research is needed to determine the importance of work-self constructs in relation to work-family constructs. © 2013 Copyright Taylor and Francis Group, LLC.

Background: This study focused on workaholism as a personal attitude toward work and examined its effects on sleep quality among Japanese employees from various occupations. Purpose: The present study aimed to demonstrate the prospective association of workaholism(i.e., working excessively hard in a compulsive fashion) with sleep quality among Japanese employees. Methods: AWeb-based prospective survey was conducted in October 2010 and May 2011 among registered monitors of a survey company. The questionnaire included workaholism, sleep quality, job characteristics, and demographics. Overall, 13,564 monitors were randomly invited to complete the first wave of the survey. The first 2,520 respondents were included in this study. The respondents who completed the first wave were invited to complete the second wave of the survey; 2,061 answered. A total of 364 respondents who changed their working conditions during the follow-up period were excluded. In addition, due to missing values, data from 14 respondents were excluded. Thus, the responses from 1,683 respondents were included in the analysis (859 males and 824 females). An analysis of covariance (ANCOVA) was conducted to compare adjusted sleep quality at follow-up among workaholism groups (low, middle, and high). To conduct the ANCOVA, we adjusted for demographics, sleep quality at baseline, and job characteristics. Results: The high-workaholic group had significantly longer sleep latency at follow-up compared with the low- and middle-workaholic groups after adjusting for demographics, sleep latency at baseline, and job characteristics. In addition, the high-workaholic group demonstrated significantly higher levels of daytime dysfunction compared with the low-workaholic group. However, no significant differences were found among workaholic groups in terms of overall sleep quality, sleep duration, habitual sleep efficiency, sleep disturbance, and use of sleep medication. Conclusion: Workaholism was associated with poor sleep quality at the 7-month follow-up in terms of sleep latency and daytime dysfunction. © International Society of Behavioral Medicine 2012.

This study among Japanese dual-earner couples examined the impact of workaholism on employees' and their partners' work-family conflicts and psychological distress. The matched responses of 994 couples were analyzed with logistic regression analyses. Results showed that workaholics (i.e., employees scoring high on both working excessively and working compulsively) were more likely to experience work-to-family conflict and psychological distress compared to relaxed workers (i.e., low on both working excessively and working compulsively) for both genders. Results also showed that husbands of workaholic women were more likely to experience family-to-work conflict, whereas wives of workaholic men were not. These findings integrate and expand previous findings on workaholism and the recently formulated spillover-crossover model. © 2011 Elsevier Ltd.

Objectives:Although it is understood that work-related factors, including job demands, job control, and workplace support, are associated with workers' health and well-being, the role played by personal characteristics, especially workaholism, has not been fully investigated. This study examined workaholism's associations with psychological ill health, low back pain with disability, and sickness absence among Japanese workers.Methods:A cross-sectional Internet survey was conducted using self-administered questionnaires. Data from 3,899 Japanese workers were analyzed. Workaholism was measured using the Dutch Workaholism Scale (DUWAS). Scores were divided into tertiles, where respondents were classified into three groups (high, middle, and low). Depressive mood as a measure of psychological ill health was assessed using the SF-36 mental health subscale, and low back pain using a standardized question. Sickness absence, except that due to physical injuries, was categorized either as absence due to mental health problems or to physical/somatic problems including the common cold. Multiple logistic regression analyses were conducted to examine the association between workaholism and depressive mood, low back pain with disability, and sickness absence, adjusting for demographic characteristics, job demand, job control, and workplace support.Results:Compared to the low workaholism group, the middle and high workaholism groups had significantly higher odds for depressive mood (Odds ratio (OR) = 1.93 and 3.62 for the middle and high groups, respectively), disabling back pain (ORs = 1.36 and 1.77 for the middle and high groups, respectively). Workaholism was more strongly associated with sickness absence due to mental health problems than that for other reasons (ORs = 1.76 vs. 1.21 for the middle group and 3.52 vs. 1.37 for the high groups).Conclusions:Workaholism is significantly associated with poor psychological health, disabling back pain, and sickness absence, particularly from mental health problems. Therefore, workaholism must be considered when addressing well-being of workers. © 2013 Matsudaira et al.

© 2014, International Society of Behavioral Medicine. Purpose: This study investigated the distinctiveness of two types of heavy work investment (i.e., workaholism and work engagement) by examining their 2-year longitudinal relationships with employee well-being and job performance. Based on a previous cross-sectional study by Shimazu and Schaufeli (Ind Health 47:495–502, 2009) and a shorter term longitudinal study by Shimazu et al. (Ind Health 50:316–21, 2012; measurement interval = 7 months), we predicted that workaholism predicts long-term future unwell-being (i.e., high ill-health and low life satisfaction) and poor job performance, whereas work engagement predicts future well-being (i.e., low ill-health and high life satisfaction) and superior job performance. Method: A two-wave survey was conducted among employees from one Japanese company, and valid data from 1,196 employees was analyzed using structural equation modeling. T1–T2 changes in ill-health, life satisfaction, and job performance were measured as residual scores, which were included in the structural equation model. Results: Workaholism and work engagement were weakly and positively related to each other. In addition, and as expected, workaholism was related to an increase in ill-health and to a decrease in life satisfaction. In contrast, and also as expected, work engagement was related to increases in both life satisfaction and job performance and to a decrease in ill-health. Conclusion: Although workaholism and work engagement are weakly positively related, they constitute two different concepts. More specifically, workaholism has negative consequences across an extended period of 2 years, whereas work engagement has positive consequences in terms of well-being and performance. Hence, workaholism should be prevented and work engagement should be stimulated.

© 2017 Andreassen, Bakker, Bjorvatn, Moen, Magerøy, Shimazu, Hetland and Pallesen. This study focuses on individual differences and the demand-support-control model in relation to workaholism. We hypothesized that unfavorable working conditions (high job demands, low job control/decision latitude, and low social support at work) and individual differences concerning sleep/wake-related variables (high flexibility, high morningness, and low languidity) would be related to workaholism measured 2-3 years later. Survey data stemmed from a prospective cohort of shift-working nurses (N = 1,308). The results showed that social support at work was negatively related to workaholism, whereas job demands were positively related to workaholism. Flexibility in terms of time for working/sleeping was also positively related to workaholism. The analyses further revealed that workaholism was inversely associated with age as well as having a child or having a child move in. Conjointly, the independent variables explained 6.4% of the variance in workaholism, while their relative importance was small overall. After controlling for all other independent variables, high job demands had the strongest relationship (small-to-medium) with workaholism. This implies that less pressure from the external environment to work excessively hard may prevent an increase in workaholic behaviors. Overall, the study adds to our understanding of the relationships between working conditions, individual differences, and workaholism.

Objectives: Although incivility is a common interpersonal mistreatment and associated with poor mental health, there are few studies about it in Asian countries. The aim of this study was to develop the Japanese version of the modified Work Incivility Scale ( JMWIS), investigate its reliability and validity, and reveal the prevalence of incivility among Japanese employees in comparison with data on Canadian employees. Methods: A total of 2,191 Japanese and 1,071 Canadian employees were surveyed, using either the J-MWIS or MWIS. Japanese employees additionally answered questions on civility, worksite social support, workplace bullying, psychological distress, intention to leave, and work engagement to investigate construct validity. Results: At least one form of workplace incivility was experienced by both Japanese ( 52.3% ) and Canadian (86.0%) employees in the previous month. Internal consistency reliability of the J-MWIS was acceptable (a= 0.71-0.81), and correlation analyses also confirmed its construct validity as expected. Workplace incivility was associated with lower workgroup civility, lower supervisor and coworker support, higher workplace bullying, higher psychological distress, higher intention to leave, and lower work engagement. Confirmatory factor analyses showed that the original three-factor model (supervisor incivility, coworker incivility, and instigated incivility) fitted moderately in both Japan and Canada data, though the privacy/overfamiliarity factor was additionally extracted from exploratory factor analysis for the J-MWIS. Conclusions: The results of this study suggested that the JMWIS has moderate internal consistency reliability and good construct validity.

Background This study examined the prospective association of workplace social capital (WSC) with major depressive episode (MDE) among Japanese employees. Methods A 3-year prospective cohort study was conducted among 1058 employees from a private thinktank company who participated in a baseline survey; after excluding those with MDE in the past 12 months, 929 were followed up. WSC at baseline was measured using a 3-item scale. MDE was assessed at baseline and at follow-up every year, by using a web-based, selfadministered version of the WHO Composite International Diagnostic Interview (WHO-CIDI) 3.0 depression section, based on the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition: Text Revision (DSM-IV-TR)/DSM-5 criteria. Cox discretetime hazards analyses were used to estimate HRs and 95% CIs, adjusting for covariates. Results A group with middle-level WSC scores had the lowest risk of MDE after being fully adjusted (HR 0.34, 95% CI 0.14 to 0.84, p=0.02). The relationship between WSC and MDE was U-shaped, although a nonlinear model fit better than a linear model, with only marginally statistical significance (p=0.06). Dichotomised and continuous variables of WSC scores were significantly and negatively associated with MDE (p=0.03 and p<0.01, respectively). Conclusions The current study replicated a previous finding from Finland that WSC was a protective factor of the onset of MDE in Japan. The slightly U-shaped relationship, that is, the group with high WSC having a small elevated risk of MDE, may reflect a dark side of WSC in a country with collectivity-oriented and hierarchy-oriented culture, such as Japan.