Published papers

Objective This study aimed to identify associations between multimorbidity and subjective health outcomes among the very old persons, after adjusting for coexisting conditions such as frailty and depression. Study setting and participants This was an observational cross-sectional study involving 1012 independent, community-dwelling very old persons (507 men, 505 women; aged 85-89 years) in Kawasaki city, Japan. Outcome measures The primary outcome was the cross-sectional associations between multimorbidity and poor self-rated health (SRH) and life satisfaction using binary logistic regression. The secondary outcome was the association of subjective health with each chronic condition. Results The prevalence of multimorbidity (≥2 conditions) was 94.7%, and the average number of chronic conditions was 4.47±1.9. Multimorbidity was significantly associated with poor SRH in the adjusted model only when six or more chronic conditions were present (OR 4.80; 95% CI 1.34 to 17.11; p=0.016). Cerebrovascular disease, heart disease, respiratory disease, connective tissue disease and arthritis showed significant associations with poor SRH after multivariate adjustment. Sex-specific analysis replicated associations between multimorbidity with six or more conditions and SRH in both men and women, while the diseases with the greatest impact on SRH differed between men and women. Most conditions were not associated with low satisfaction with life scale, with the exception of arthritis (OR 1.92, 95% CI 1.32 to 2.78, p=0.001). Conclusions Multimorbidity is prevalent in the independent, community-dwelling very old persons and is associated with poor SRH when six or more conditions are present; conditions causing mobility limitations, such as cerebrovascular disease, connective tissue disease and arthritis, have a negative impact on SRH. Trial registration number UMIN000026053.

Objectives: This study aimed to evaluate the effectiveness of the Intervention program of Mindfulness and Compassion against COVID-19 (IMACOCO), an online mindfulness-based intervention (MBI), in enhancing mindfulness, mental health, well-being, and productivity among working individuals during the COVID-19 pandemic. Additionally, the study examined the program’s efficacy in individuals directly impacted by the pandemic through a randomized controlled trial and pre-post program comparisons. Method: Three hundred working adults, including office workers, educators, and medical welfare workers, were randomly allocated to the intervention or waiting control group. An 8-week online MBI program, with pre-, interim (4 weeks), and post-program (8 weeks) evaluations, was conducted via the Internet; standardized questionnaires were used to assess mindfulness, psychological distress, life satisfaction, and productivity. After the initial 8-week program, the waiting control group participated in the same program and evaluation surveys for pre-post comparisons. Results: There were 99 participants in the intervention group and 111 in the control group. Significant increases in mindfulness (FFMQ) and life satisfaction (SWLS) as well as decrease in psychological distress (GHQ-12) were observed primarily in the intervention group (Cohen’s d = 0.18–0.52). Furthermore, the pre-post comparisons with 168 participants demonstrated significant improvements in productivity (Cohen’s d = 0.26), and stratified analysis revealed that participants affected by COVID-19 showed more pronounced benefits in mindfulness and life satisfaction than those who were unaffected. Conclusions: Implementing an online MBI program (IMACOCO) can be a potent strategy to reduce mental stress and enhance overall well-being and resilience, in a disaster-prone world. Preregistration: This study is not preregistered.

The importance of workers' well-being has been recognized in recent years. The assessment of well-being has been subjective, and few studies have sought potential biomarkers of well-being to date. This study examined the relationship between well-being and the LF/HF ratio, an index of heart rate variability that reflects sympathetic and parasympathetic nerve activity. Pulse waves were measured using photoplethysmography through a web camera attached to the computer used by each participant. The participants were asked to measure their pulse waves while working for 4 weeks, and well-being was assessed using self-reported measures such as the Satisfaction With Life Scale (SWLS), the Positive and Negative Affect Schedule (PANAS), and the Flourishing Scale (FS). Each of the well-being scores were split into two groups according to the median value, and the LF/HF ratio during work, as well as the number of times an LF/HF ratio threshold was either exceeded or subceeded, were compared between the high and low SWLS, positive emotion, negative emotion, and FS groups. Furthermore, to examine the effects of the LF/HF ratio and demographic characteristics on well-being, a multiple regression analysis was conducted. Data were obtained from 169 participants. The results showed that the low FS group had a higher mean LF/HF ratio during work than the high FS group. No significant differences were seen between the high and low SWLS groups, the high and low positive emotion groups, or the high and low negative emotion groups. The multiple regression analysis showed that the mean LF/HF ratio during work affected the FS and SWLS scores, and the number of times the mean LF/HF ratio exceeded +3 SD had an effect on the positive emotion. No effect of the LF/HF ratio on negative emotions was shown. The LF/HF ratio might be applicable as an objective measure of well-being.

This study indicated the role of conflict and idea acceptance on the relationship between feedback and team creative behaviour. We focused on the team's contextual factors affecting team creative behaviour instead of the behaviour of individuals between the specific hierarchical level in the organizations. We surveyed 535 practitioners in Japanese firms and quantitatively examined the result through hierarchical multiple regression analysis. The results show the positive direct effect of feedback on team creative behaviour and the mediation effects of conflict and idea acceptance on the relationship between feedback and team creative behaviour, which were identified regardless of the creative process. On the other hand, conflict negatively moderated the feedback-team creative behaviour relationship only in the idea-generation phase. This study contributes to team creativity studies by clarifying the effect of conflict, which had contradictory findings in the previous research. In addition, shedding light on idea acceptance within the teams is another contribution since limited studies are focusing on it. The results offer implications to practitioners by giving suggestions to effectively provide and react to feedback within the teams by managing conflicts that have both positive and negative effects on creativity and accepting each other's ideas, which move the idea forward.

Introduction: Mental disorders are a leading cause of disability worldwide. Depression has a significant impact in the field of occupational health because it is particularly prevalent during working age. On the other hand, there are a growing number of studies on the relationship between “well-being” and employee productivity. To promote healthy and productive workplaces, this study aims to develop a technique to quantify stress and well-being in a way that does not disturb the workplace. Methods and analysis: This is a single-arm prospective observational study. The target population is adult (>20 years old) workers at companies that often engage in desk work; specifically, a person who sits in front of a computer for at least half their work hours. The following data will be collected: (a) participants' background characteristics; (b) participants' biological data during the 4-week observation period using sensing devices such as a camera built into the computer (pulse wave data extracted from the facial video images), a microphone built into their work computer (voice data), and a wristband-type wearable device (electrodermal activity data, body motion data, and body temperature); (c) stress, well-being, and depression rating scale assessment data. The analysis workflow is as follows: (1) primary analysis, comprised of using software to digitalize participants' vital information; (2) secondary analysis, comprised of examining the relationship between the quantified vital data from (1), stress, well-being, and depression; (3) tertiary analysis, comprised of generating machine learning algorithms to estimate stress, well-being, and degree of depression in relation to each set of vital data as well as multimodal vital data. Discussion: This study will evaluate digital phenotype regarding stress and well-being of white-collar workers over a 4-week period using persistently obtainable biomarkers such as heart rate, acoustic characteristics, body motion, and electrodermal activity. Eventually, this study will lead to the development of a machine learning algorithm to determine people's optimal levels of stress and well-being. Ethics and dissemination: Collected data and study results will be disseminated widely through conference presentations, journal publications, and/or mass media. The summarized results of our overall analysis will be supplied to participants. Registration: UMIN000036814

In recent years, the effects of forests on the psychological and physiological aspects of human beings have been identified, and effects such as relaxation, stress reduction, and health promotion have been clarified. On the other hand, there are still many unclear points about what elements of the forest environment have a relaxing effect and a stress-reducing effect on humans. Therefore, as one of the elements of them, this study focused on the sounds of the forest environment, extracted characteristics from the measurement data of forest sounds, and investigated the psychological impression of forest sounds. As a result of this study, we found that the sound of the forest is quiet; the sound sources contain high-frequency components, and these sources are fluctuating. Moreover, sounds with this tendency were found to be comforting, open/active, and related to a sense of relaxation. This result suggests that the sound of a forest environment is one of the factors that have a relaxing effect on humans.

Taking the upcoming “Society 5.0" and "100 years of lifetime” into account, what should each and every one of us, as a worker, do to confront our work positively and realize a fulfilling career? Moreover, in economic circumstances that are insecure and uncertain for businesses, what should we do to develop human resources capable of creating new values and enhancing labor productivity? In this study, in order to meet personal and organizational demands, the author defines the fundamental problem as “What should we do to get each employee to work with more initiative?" If you are in a comfortable, active state in which you find your work rewarding, and you work with initiative, then you have high work engagement. This study focuses on the mediation effect of work engagement and positive emotion. We also give heed to “Waku-Waku,” an onomatopoeia expressing positive emotion that is unique to the Japanese language. Originally, onomatopoeia has rarely been used in academic papers as it does not have a solid conceptual definition. It, however, is a linguistic expression that is excellent in conveying our intention with complexity and precision. Although “Waku-Waku” is often translated into “excitement” in English, it has been confirmed in a prior study that its nuance is much closer to concepts such as “well-being” and “flow”. These concepts are considered from the standpoint of new intervention to make work more satisfying and fulfilling in light of human resource management. This study focuses on the positive emotion of “Waku-Waku,” and builds up a statistic structure of the main factor that can evoke this motion in working scenes, through qualitative and quantitative analysis. Among others, reported here is a study of analysis on factors of feeling “Waku-Waku” at work that many working individuals in Japan are aware of. As a result, four factors were confirmed: 1. Challenge to creativity and the unknown; 2. Fortune and pleasure; 3. Interest in others at work and; 4. Passion in terms of sensitivity. Since it was shown that working individuals feel “Waku-Waku” when they face these things, the concept of “Waku-Waku” was tentatively defined in conclusion.

To encourage creativity through ideation mode in design thinking, we conducted three workshops dealing with regional challenges with 44 participants. The systematic feedback method applied to the workshops supports the multi-disciplinary participants to feedback during the ideation mode to diverge ideas from diverse perspectives. The method is composed of feedback cards and the process of using them. Two kinds of cards encourage communication within the team. The next three cards aim to diverge the viewpoints of the feedback systematically to support the team to imagine the possibility of the idea evolving from a bird's eye view. Through quantitative analysis of the survey, we identified the significant and positive correlations between acceptance of the team's idea and team creativity, the effectiveness of the method on team creativity, and the team's characteristics that firmly realized the effect of the method. By categorizing the free comments, we indicated the valid functions and improvements that need further research in the future. Identified valid functions were not only diverging minds and perspectives but encouraging communication and understanding of the team members leading to acceptance and creativity.

To indicate the effective team-building activities implemented independently by the students in a project-based learning class in higher education in Japan, we conducted semi-structured interviews with the students of the Design Project class held at a Japanese graduate school in 2020 and 2021. The interviewees are 12 students belonging to the top three teams regarding the evaluation of the final presentation. Based on the classifications of the comments, we indicate the best practices of team-building activities corresponding to the timing and team characteristics.

To encourage creativity through ideation mode in design thinking, we conducted three workshops dealing with regional challenges with 44 participants. The systematic feedback method applied to the workshops supports the multi-disciplinary participants to feedback during the ideation mode to diverge ideas from diverse perspectives. The method is composed of feedback cards and the process of using them. Two kinds of cards encourage communication within the team. The next three cards aim to diverge the viewpoints of the feedback systematically to support the team to imagine the possibility of the idea evolving from a bird's eye view. Through quantitative analysis of the survey, we identified the significant and positive correlations between acceptance of the team's idea and team creativity, the effectiveness of the method on team creativity, and the team's characteristics that firmly realized the effect of the method. By categorizing the free comments, we indicated the valid functions and improvements that need further research in the future. Identified valid functions were not only diverging minds and perspectives but encouraging communication and understanding of the team members leading to acceptance and creativity.

Personal relative deprivation (PRD) refers to emotions of resentment and dissatisfaction caused by feeling deprived of a deserved outcome compared to some reference. While evidence suggests that relative deprivation based on objective data such as income affects well-being, subjective PRD has been less explored, especially in the East. This study evaluated the relationship between PRD and subjective well-being based on various aspects in the context of Japan. An online questionnaire survey, including the Japanese version of the Personal Relative Deprivation Scale (J-PRDS5) and various well-being indices, was administered to 500 adult participants, balanced for sex and age. Quantitative data analysis methods were used. PRD significantly correlated with subjective well-being as assessed by various aspects. Through mediation analysis, we found that a strong tendency to compare one’s abilities with others may undermine subjective well-being through PRD. The results also indicated that well-developed human environments may be associated with the maintenance of subjective well-being levels, even when PRD is high. Toward developing future interventions to improve well-being and health, efforts must be undertaken in Japan to monitor PRD and further clarify the mechanism of the association between PRD and the factors that showed a strong relationship in this study.

This study developed and validated a 5-item Japanese translation of the Personal Relative Deprivation Scale (J-PRDS5), originally developed in English by Callan et al. Personality and Social Psychology Bulletin, 34, 1514–1529, (2008), Callan et al. Journal of Personality and Social Psychology, 101, 955–973, (2011) to measure feelings of resentment and dissatisfaction stemming from the belief that one has been deprived of a desired or deserved outcome as compared to others similar to them. Most studies on feelings of personal relative deprivation (PRD) have included Western participants and no such studies have been conducted in Japan. To bridge this gap, we conducted a factor analysis of the J-PRDS5’s items, which demonstrated a single-factor structure consistent with Western studies. Through validation of the scale for Japan, our version (J-PRDS5) exhibited high internal consistency. In contrast to feelings of PRD, subjective socioeconomic status (SSS) focuses on cognitive appraisals by comparing oneself to all people in the same society. Higher J-PRDS5 scores were significantly and negatively correlated with SSS, and lower J-PRDS5 scores and higher SSS scores were significantly correlated with higher self-esteem, general health, and subjective well-being (SWB). Based on a mediation analysis, we found that PRD mediated the relationship between SSS and self-esteem, general health, and SWB. Our study is the first to assess individuals’ feelings of PRD in Japan, and our findings suggest that reducing feelings of PRD may improve individuals’ health and happiness.

Background: Materialism indicates the extent to which an individual’s life is focused on consumerism, or the acquisition of money and possessions. The Material Values Scale (MVS), comprising the factors “success,” “centrality,” and “happiness,” is a well-known rating scale for materialism. However, a Japanese version of the materialism scale has not yet been established, and the details of the factors and effects related to materialism have not yet been clarified in Japan. The purpose of this study is to develop and evaluate the Japanese version of the MVS (J-MVS). Methods: We developed the translated J-MVS using a back-translation process. To validate and evaluate the scale based on an online survey, we recruited 500 people, with 100 participants (50 men, 50 women) in five age groups, from 20 to 69 years. We compared and evaluated several factor structure models based on exploratory and confirmatory factor analysis. To evaluate the external criterion-referenced validity of the developed J-MVS scale, we examined the relationship between age, personality, and well-being, which have shown stable relationships with materialism in previous studies. Results: We developed two six-item dual-factor models. Both models showed significant positive correlations with social comparison orientation and neuroticism, and had significant negative correlations with various subjective well-being indices, suggesting sufficient external criterion-referenced validity. The J-MVS comprising six positive-worded items (J-MVS-P6; without any reverse-worded items) showed a higher correlation with other indicators than the version comprising six items representing all item types and was considered to have higher external criterion-referenced validity. Conclusions: We propose the J-MVS-P6 for use as a materialism scale in Japan. Compared with the findings from other countries, materialism in Japan may be more closely related to subjective well-being. This scale may be used to examine the effectiveness of various intervention methods for improving individuals’ happiness, based on changes in factors closely related to materialism in Japan.