Published papers

Siegrist's [1996. Adverse health effects of high-effort/low-reward conditions. Journal of Occupational Health Psychology, 1, 27-41.] Effort-Reward Imbalance (ERI) Model assumes that ERI at one point in time influences health at a later point in time. Empirical cross-sectional and longitudinal findings have supported the influence of ERI on adverse health. However, the ERI model does not explicitly take into account that the relation between ERI and adverse health may be also explained by reversed causal relations, or even reciprocal (bi-directional) relations in which ERI and health mutually influence each other. The present 3-wave panel study among 211 Japanese male blue-collar workers in one construction machinery company examined reciprocal relations between ERI and adverse health (i.e., psychological distress and physical complaints) with a 1-year time-lag per wave. Hypotheses were tested using structural equation modeling (Amos 7.0J). Results showed cross-lagged and causally dominant effects of ERI on both psychological distress and physical complaints after 1 year for both Time 1-Time 2 and Time 2-Time 3. In addition, cross-lagged effects of psychological distress on ERI were found after 1 year for both Time 1-Time 2 and Time 2-Time 3. These findings suggest that (perceived) ERI and employee health influence each other reciprocally rather than uni-directionally, and underline the importance of studying reversed causal effects in the relation between ERI and employee health. © 2008 Elsevier Ltd. All rights reserved.

© 2015 Published by Elsevier B.V. Background Absence due to mental disease in the workplace has become a global public health problem. We aimed to evaluate the influence of presenteeism on depression and absence due to mental disease. Methods A prospective study of 1831 Japanese employees from all areas of Japan was conducted. Presenteeism and depression were measured by the validated Japanese version of the World Health Organization Health and Work Performance Questionnaire (WHO-HPQ) and the K6 scale, respectively. Absence due to mental disease across a 2-year follow up was surveyed through medical certificates obtained for work absence. Results After adjusting for age and gender, participants with higher rates of sickness absolute and relative presenteeism (the lowest tertile of the scores) were significantly more likely to be absent due to mental disease (OR=4.40, 95% CI: 1.65-11.73, and OR=3.31, 95% CI: 1.50-7.27). Subsequently, higher rates of sickness absolute or relative presenteeism were significantly associated with higher rates of depression (K6=13) one year later (OR=3.79, 95% CI: 2.48-5.81, and OR=2.89, 95% CI: 1.98-4.22). Limitations The number of females in the sample was relatively small. However, the rates of absence for females with and without mental illness did not significantly differ from those of men. Conclusions More sickness presenteeism scores were found to be related to higher rates of depression and absence due to mental disease in this large-scale cohort of Japanese workers. Measurement of presenteeism could be used to evaluate the risk for depression and absenteeism. Furthermore, our findings suggest that intervention to improve presenteeism would be effective in preventing depression and absence due to mental illness.

Objectives: Previous European studies reporting low procedural justice and low interactional justice were associated with increased health problems have used a modified version of the Moorman's Organizational Justice Questionnaire (OJQ, Elovainio et al., 2002) to assess organizational justice. We translated the modified OJQ into the Japanese language and examined the internal consistency reliability, and factor-based and construct validity of this measure. A back-translation procedure confirmed that the translation was appropriate, pending a minor revision. Methods: A total of 185 men and 58 women at a manufacturing factory in Japan were surveyed using a mailed questionnaire including the OJQ and other job stressors. Results: Cronbach alpha coefficients of the two OJQ subscales were high (0.85- 0.94) for both sexes. The hypothesized two factors (i.e., procedural justice and interactional justice) were extracted by the factor analysis for men; for women, procedural justice was further split into two separate dimensions supporting a three- rather than two-factor structure. Convergent validity was supported by expected correlations of the OJQ with job control, supervisor support, effort-reward imbalance, and job future ambiguity in particular among the men. Conclusion: The present study shows that the Japanese version of the OJQ has acceptable levels of reliability and validity at least for male employees.

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This study examined whether particular recovery activities after work have a positive or negative effect on employee recovery from work (i.e., cognitive, emotional, and physical detachment) and sleep quality. We used a two-wave panel study of 230 health care employees which enabled looking at both short-term and long-term effects (i.e., two-year time interval). Gender, age, marital status, children at home, education level, management position, and working hours were used as control variables. Hierarchical multiple regression analyses showed that work-related off-job activities were negatively associated with cognitive and emotional detachment in both the short and long run, whereas low-effort off-job activities were positively related to cognitive detachment in the short run. Moreover, household/care off-job activities were positively related to sleep quality in the long run, whereas physical off-job activities were negatively associated with sleep quality in the long run. The long-term findings existed beyond the strong effects of baseline detachment and sleep quality. This study highlights the importance of off-job recovery activities for health care employees’ detachment from work and sleep quality. Practical implications and avenues for further research are discussed.

© 2015 Tsuno et al. Bullying in the workplace is an increasingly recognized threat to employee health.We sought to test three hypotheses related to the determinants of workplace bullying: power distance at work; safety climate; and frustration related to perceived social inequality. A questionnaire survey was administered to a nationally representative community-based sample of 5,000 residents in Japan aged 20-60 years. The questionnaire included questions about employment, occupation, company size, education, household income, and subjective social status (SSS). We inquired about both the witnessing and personal experience of workplace bullying during the past 30 days. Among 2,384 respondents, data were analyzed from 1,546 workers. Multiple logistic regression analyses were used to examine the social determinants of workplace bullying. Six percent and 15 percent of the total sample reported experiencing or witnessing workplace bullying, respectively. After adjusting for gender and age, temporary employees (Odds Ratio [OR]: 2.45 [95%Confidence Interval (CI) = 1.03-5.85]), junior high school graduates (OR: 2.62 [95%CI: 1.01-6.79]), workers with lowest household income (OR: 4.13 [95%CI:1.58-10.8]), and workers in the lowest SSS stratum (OR: 4.21 [95% CI:1.66-10.7]) were at increased risk of experiencing workplace bullying. When all variables were entered simultaneously in the model, a significant inverse association was observed between higher SSS and experiencing bullying (p = 0.002). Similarly in terms of witnessing bullying; SSS was significantly inversely associated (p = 0.017) while temporary employees reported a significantly higher risk of witnessing bullying compared to permanent workers (OR: 2.25 [95%CI:1.04 to 4.87]). The significant association between SSS and experiencing/witnessing workplace bullying supports the frustration hypothesis. The power distance hypothesis was also partly supported by the finding that temporary employees experienced a higher prevalence of workplace bullying.

The association of socioeconomic status (SES) with nutrients intakes attracts public attention worldwide. In the current study, we examined the associations of SES with dietary salt intake and health outcomes in general Japanese workers (2,266) who participated in this Japanese occupational cohort. SES was assessed by a self-administered questionnaire. Dietary intakes were assessed with a validated, brief, self-administered diet history questionnaire (BDHQ). Multiple linear regression and stratified analysis were used to evaluate the associations of salt intake with the confounding factors. Education levels and household incomes were significantly associated with salt intake, as well as blood pressures (P < 0.05). After adjusting for age, sex and total energy intake, both years of education and household income significantly affect the salt intake (for education, β = -0.031, P = 0.040; for household income, β = -0.046, P = 0.003). SES factors also affect the risk of hypertension, those subjects with higher levels of education or income had lower risk to become hypertensive (ORs for education was 0.904, P < 0.001; ORs for income was 0.956, P = 0.032). Our results show that SES is an independent determinant of salt intake and blood pressure, in order to lower the risk of hypertension, the efforts to narrow the social status gaps should be considered by the health policy-makers. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

The association of socioeconomic status (SES) with nutrient intake attracts public attention worldwide. In the current study, we examined the associations of SES with dietary intake of folate and health outcomes in general Japanese workers. This Japanese occupational cohort consisted off 2266 workers. SES was assessed by a self-administered questionnaire. Intakes of all nutrients were assessed with a validated, brief and self-administered diet history questionnaire (BDHQ). The degree of depressive symptoms was measured by the validated Japanese version of the K6 scale. Multiple linear regression and stratified analysis were used to evaluate the associations of intake with the confounding factors. Path analysis was conducted to describe the impacts of intake on health outcomes. Education levels and household incomes were significantly associated with intake of folate and depression scales (p < 0.05). After adjusting for age, sex and total energy intake, years of education significantly affect the folate intake (β = 0.117, p < 0.001). The structural equation model (SEM) shows that the indirect effect of folate intake is statistically significant and strong (p < 0.05, 56% of direct effect) in the pathway of education level to depression scale. Our study shows both education and income are significantly associated with depression scales in Japanese workers, and the effort to increase the folate intake may alleviate the harms of social disparities on mental health. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

© 2016 Wiley Periodicals, Inc. Background: This study investigated the prospective association between source-specific workplace social support and high-sensitivity C-reactive protein (hs-CRP) levels in workers in Japan. Methods: We conducted a 1-year prospective cohort study with 1,487 men and 533 women aged 18–65 years. Participants worked at two manufacturing worksites in Japan and were free of major illness. We used multivariable linear regression analyses to evaluate the prospective association between supervisor and coworker support at baseline, and hs-CRP levels at follow-up. We conducted the analyses separately for men and women. Results: For women, high supervisor support at baseline was significantly associated with lower hs-CRP levels at follow-up (β = −0.109, P < 0.01), whereas coworker support at baseline was not significantly associated with hs-CRP levels at follow-up. Associations between supervisor and coworker support and hs-CRP levels were not significant for men. Conclusions: Supervisor support may have beneficial effects on inflammatory markers in working women. Am. J. Ind. Med. 59:676–684, 2016.

© Springer International Publishing Switzerland 2016. The Asia Pacific is a rapidly growing region with a diverse range of countries, both developing and developed. Across the region there are significant cultural variations and different work practices, creating a range of challenges for those charged with the management of workplace health. This book addresses an important gap, by focusing on research in the Asia-Pacific region that explores psychosocial work environment issues that have a significant influence on worker health and productivity. Most research concerning psychosocial factors at work is from Europe or North America and the generalizability of the research and practical implications is not clear. Consequently, managers, occupational health and safety personnel, human resource professionals, occupational health psychology practitioners, and public health professionals in the Asia Pacific have relied on an evidence basis with largely untested validity. This book extends the work of the first edition, "Psychosocial Factors at Work in the Asia Pacific," applies and tests new and emerging theories, provides insights into different workplace issues pertinent to the Asia Pacific, and practical insights into the management of psychosocial factors in the workplace.

© 2014 Springer Science+Business Media Dordrecht. All rights are reserved. The Asia Pacific is diverse culturally, economically, and socially. Despite being the world's most populous region where many workers experience poor working conditions and insecure employment, little attention has been given to psychosocial factors at work in the region. This chapter argues that in understanding work conditions and worker health it is important to consider influences at the international, national, state, and local levels. Moreover, within nations, power actors such as unions, governments, and corporations, legal requirements, welfare regimes, national culture, corruption, and occupational health and safety policies and guidance, are fundamental influences on work conditions and worker health in the Asia Pacific. The chapter outlines initiatives in the region to foster knowledge development processes, such as the development of the Asia Pacific Academy for Psychosocial Factors at Work. The aim of such initiatives is to address the gap in the global and local stock of knowledge, so that good policies and practices can be developed for the region. A synopsis of each chapter is given to assist navigation through the book.

A causal model of job stressors and stress reactions was examined to clarify the developmental process of employee maladjustment in workplace. Two thousand seven hundred twenty-eight (2728) employees of a research institute in the automobile industry completed Job Stress Scale (JSS), which measured job stressors, stress reactions, coping strategies, and social support. Three hundred ninety-two (392) employees with high stress reaction scores were interviewed to obtain information to construct a theoretical model. Then, the model was evaluated with covariance structure analysis. Results showed that the quantitative job stressors had only an indirect effect, mediated by fatigue and irritability, on mental instability, whereas qualitative ones had both direct and indirect effects. The findings suggest that the developmental processes of employee maladjustment in work place differ depending on the kind of job stressors they experience.

© 2016 National Institute of Occupational Safety and Health. This study explored the efect of workplace psychosocial factors (job demand, job control, and workplace social support) on dual-earner couples in Japan having additional children, using a prospective study design. We conducted a 2-year prospective cohort study with 103 dual-earner couples with preschool children in Japan, as part of the Tokyo Work-Family Interface Study II. We used multivariable logistic regression analyses to evaluate the prospective association of job strain (categorized into low-strain job, active job, passive job, and strain job groups) and workplace social support (high and low) with couples having additional children during the follow-up period, adjusting for age, for men and women separately. Men in the active job group (i.e., with high job demands and high job control) had a signiicantly higher odds ratio (OR) of having additional children during the follow-up period, after controlling for age (OR 9.07, 95% conidence interval: 1.27-64.85). No signiicant association between any workplace psychosocial factor and having additional children was conirmed among women. Having an active job may have a positive inluence on having additional children among men in dual-earner couples.

This study explored the effect of workplace psychosocial factors (job demand, job control, and workplace social support) on dual-earner couples in Japan having additional children, using a prospective study design. We conducted a 2-year prospective cohort study with 103 dual-earner couples with preschool children in Japan, as part of the Tokyo Work–Family Interface Study II. We used multivariable logistic regression analyses to evaluate the prospective association of job strain (categorized into low-strain job, active job, passive job, and strain job groups) and workplace social support (high and low) with couples having additional children during the follow-up period, adjusting for age, for men and women separately. Men in the active job group (i.e., with high job demands and high job control) had a significantly higher odds ratio (OR) of having additional children during the follow-up period, after controlling for age (OR 9.07, 95% confidence interval: 1.27–64.85). No significant association between any workplace psychosocial factor and having additional children was confirmed among women. Having an active job may have a positive influence on having additional children among men in dual-earner couples.

© 2018 Iwanaga et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Objective The aim of this study was to investigate the long-term impact of being bullied at school on current psychological distress and work engagement in adulthood among Japanese workers. We hypothesized that workers who had been bullied at school could have higher psychological distress and lower work engagement compared to those who had not been bullied. Methods We used data from the Japanese Study on Stratification, Health, Income, and Neighborhood (J-SHINE) project, conducted from July 2010 to February 2011 in Japan. This survey randomly selected the local residents around a metropolitan area in Japan. Of 13,920 adults originally selected, 4,317 people participated this survey, and the total response rate was 31%. The self-administered questionnaires assessed current psychological distress (K6), work engagement (UWES), the experiences of being bullied in elementary or junior high school and other covariates. Statistical analyses were conducted only for workers. Hierarchical multiple regression analyses were conducted to determine associations between experiences of being bullied at school and psychological distress/work engagement, with six steps. Result Statistical analysis was conducted for 3,111 workers. The number of respondents who reported being bullied in elementary or junior high school was 1,318 (42%). We found that the experience of being bullied at school was significantly associated with high psychological distress in adulthood (β = .079, p = < .0001); however, the work engagement scores of respondents who were bullied were significantly higher than for people who were not bullied at school (β = .068, p = < .0001), after adjusting all covariates. Conclusion Being bullied at school was positively associated with both psychological distress and work engagement in a sample of workers. Being bullied at school may be a predisposing factor for psychological distress, as previously reported. The higher levels of work engagement among people who experienced being bullied at school may be because some of them might have overcome the experience to gain more psychological resilience.

© 2017 Watanabe et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Objectives This study of Japanese dual-earner couples examined the impact of family and job demands on one's own and one's partner's fatigue as well as gender differences in these effects. Methods A total of 2,502 parents (1,251 couples) were surveyed using a self-administered questionnaire. A crossover model was tested using structural equation modeling. Results The results of structural equation modeling analyses showed that both job and family demands independently exacerbated fatigue. There was an indirect effect of job and family demands on partner fatigue through one's own fatigue only from husbands to wives. An indirect effect of job demands on partner fatigue through partner's family demands was identified only from wives to husbands. Furthermore, there were gender differences in the crossover of fatigue. Conclusions This study shows that job and family demands influence family circumstances. When considering means to reduce employees' fatigue, gender differences in the mechanism of fatigue need to be taken into account.

© Article author(s). Objectives: Although well-being at work is important for occupational health, multi-dimensional workplace well-being measures do not exist for Japanese workers. The purpose of this study was to investigate the validity of the Japanese version of the Workplace PERMA-Profiler. Methods: Japanese workers completed online surveys at baseline (N = 310) and 1 month later (N = 100) . The Workplace PERMA-Profiler was translated according to international guidelines. Job and life satisfaction, work engagement, psychological distress, work-related psychosocial factors, and work performance were measured as comparisons for convergent validity. Cronbach's alphas, Intra-class Correlation Coefficients (ICCs), and measurement errors were calculated for the reliability, and the validity of the measure was tested by correlational analyses and confirmatory factor analysis. Results: A total of 310 (baseline) and 86 (follow-up) workers responded and were included in the analyses. Cronbach's alphas and ICCs of the Japanese Workplace PERMA-Profiler ranged from 0.75 to 0.96. Confirmatory factor analysis indicated that the 5-factor model demonstrated a marginally acceptable fit (χ2 (80) = 351.30, CFI = 0.892, TLI = 0.858, RMSEA = 0.105, SRMR = 0.051). Overall well-being and the five PERMA domains had moderate-to-strong correlations with job satisfaction, psychological distress (inversely), and workrelated factors. Conclusions: The Japanese version of the Workplace PERMA-Profiler demonstrated adequate reliability and validity. This measure could be useful to assess well-being at work, promote well-being research among Japanese workers, and address the problem of definition for well-being in further studies.

Copyright © 2016 American College of Occupational and Environmental Medicine. Objective: This longitudinal study aimed to investigate the moderating effect of health-improving workplace environment on relationships between physical activity, self-efficacy, and psychological distress. Methods: Data were collected from 16 worksites and 129 employees at two time-points. Health-improving workplace environment was measured using the Japanese version of the Environmental Assessment Tool. Physical activity, self-efficacy, and psychological distress were also measured. Multi-level structural equation modeling was used to investigate the moderating effect of health-improving workplace environment on relationships between psychological distress, self-efficacy, and physical activity. Results: Psychological distress was negatively associated with physical activity via low self-efficacy. Physical activity was negatively related to psychological distress. Physical activity/fitness facilities in the work environment exaggerated the positive relationship between self-efficacy and physical activity. Conclusions: Physical activity/fitness facilities in the workplace may promote employees' physical activity.