Abstract
Objectives: This study examined the relationship of potential advisors — human resources or services that advise workers when they experience health issues that affect their work and work-related health — with psychological distress and analyzed which human resources have a greater impact on improving workers’ mental health. Methods: An Internet-based survey using a self-administered questionnaire was conducted. The target population was workers between the ages of 20 and 69 years. Among a total of 5,111 participants, 4,540 were included in the present analysis. Participants were asked questions regarding potential advisors on work-related health issues. The Kessler 6-item Psychological Distress Scale (K6) was used to assess psychological distress. We used a generalized linear model with a binomial response for assessing the relationship between K6 scores and each potential advisor on work-related health issues. Results: Participants without potential advisors on work-related health issues were significantly more likely to score both K6 ≥5 (cutoff for mild psychological distress) and K6 ≥13 (cutoff for severe psychological distress) than the participants with potential advisors (all p<0.001). The participants for whom a supervisor was the potential advisor on work-related health issues were significantly less likely to score K6 ≥13 than their counterparts (p=0.005). Those for whom an occupational physician or family members was the potential advisor on work-related health issues were significantly less likely to score K6 ≥5 than their counterparts (p=0.011 and p=0.001, respectively). Conclusions: Having potential advisors could be important for workers’ mental health improvement. Specifically, having supervisors, occupational physicians, or family members as potential advisors may be effective in reducing workers’ psychological distress.
Introduction
The Occupational Safety and Health Law of Japan indicates that employers must take necessary measures to maintain and promote workers’ health, including providing them with health advice. Furthermore, the law indicates that employers must establish necessary systems and measures to ensure that occupational physicians advise workers on their health and respond appropriately1). Additionally, in the 13th Occupational Safety and Health Program published by the Ministry of Health, Labour and Welfare (MHLW) in 2018, one of the health and safety goals indicated is “Job-related anxiety, distress and stress: Increase the percentage of workers who have access to an advisor, including advisory organizations and resources outside the workplace, to at least 90%”2). Thus, employers are required to provide an advisory system for workers’ health issues in Japan.
Providing appropriate measures for workers’ mental health is one of the most important issues in the occupational health field. The guidelines for supporting the mental health of workers published by the MHLW in Japan are geared toward formulating mental health promotion plans in the worksite, announcing workplace mental health promotion policies to employees, and providing opportunities for education and training on workers’ mental health for employees3). In addition, establishing an advisory system for workers’ health issues is also listed as one of the important items in the guidelines. Indeed, the guidelines indicate that potential advisors — that is, human resources or services that may be able to advise workers if these experience health issues that affect their work — include supervisors, personnel and labor management staff, occupational physicians, health officers, occupational health nurses, and mental health promotion staff. In addition, external organizations, such as medical institutions with expertise in mental health care, The Occupational Health Promotion Center, the Regional Industrial Health Center, and Employee Assistance Program, are also included as potential advisors3).
It is assumed that many workplaces have established advisory systems for workers’ health issues, including mental health issues. It is important to evaluate to what extent the presence of such potential advisors in the workplace systems affects the mental health of workers. A previous study has reported that an advisory system that only provides written feedback based on a descriptive questionnaire on psychological stress for employees does not improve workers’ own psychological distress4). Hence, we assume that for workers, having potential advisors on work-related health issues reduces psychological distress through face-to-face communication.
Potential advisors can be divided into in-workplace and out-of-workplace advisors, and there are further various types and positions among them. It must be assumed that their advisory response to workers may also be different because of each potential advisor’s role. For example, supervisors are considered to be involved in employee health issues, taking into account various business operation perspectives, such as obligations of considering employees’ safety and health (a company has a duty to its employees to ensure their life and their physical safety while at work)5), corporate governance, and securing and distributing the labor force. Family and attending physicians are more likely to be involved in workers’ own life problems, giving priority to medical treatment, lifestyle improvement, and sick leave, rather than work-related problems. Occupational physicians would be involved in workers’ health problems considering balance between private and working life, psychosomatic state, and medical treatment with a comprehensive perspective. We believe it is worthwhile to analyze the potential advisors that have a greater impact on improving workers’ mental health despite their roles’ differences.
We conducted a work systems and health Internet research study (WSHIR study), which was a 2-year prospective cohort study of workers, from October 2021 (baseline survey) to October 2023 (final survey). This study aimed to analyze the relationship between potential advisors on work-related health issues and psychological distress among Japanese workers using the baseline data of the WSHIR study.
Methods
Study design and setting
This study used self-administered questionnaire surveys disseminated through a Japanese Internet survey company (Cross Marketing Inc. Tokyo), for which the baseline survey was conducted from October 1–5, 2021. This study adopted a cross-sectional design using the data from the baseline of the WSHIR study. Details of the protocol of this survey are reported elsewhere6). To improve the validity of this study, we adhered to the Checklist for Reporting Results of Internet E-Surveys or CHERRIES statement7,8). A follow-up survey will be conducted as a prospective cohort study with the same participants.
Participants
The target population was workers between the ages of 20 and 69 years, who were employed at the time of the baseline survey. We planned to collect data from 5,000 people in total. The number of participants in this study was calculated by counting the monitor IDs given to respondents when they accessed the Internet survey system. In the baseline survey, participation invitations were sent via e-mail to approximately 59,000 registered monitors. The initial screening survey for selecting eligible participants was completed by 7,300 respondents. Of these, 5,111 participants met the inclusion criteria for the survey: being a worker between the ages of 20 and 69.
We performed consistency and completeness checks after the questionnaires were submitted. We separated fraudulent respondents from all respondents based on three types of algorithms designed within this survey6). There were 571 participants excluded by consistency and completeness checks; finally, 4,540 eligible participants were included in the study. Informed consent was obtained through the website (Figure 1).
This study was approved by the Ethics Committee of Medical Research of the University of Occupational and Environmental Health, Japan (R3-037), and has followed the principles embodied in the Declaration of Helsinki.
Evaluation of potential advisors on work-related health issues
Participants were asked questions regarding potential advisors on work-related health issues. They were asked “Do you have someone you can talk to about your work-related health issues?” (No/Yes). If yes, the participants were instructed to select all their potential advisors from the following options: supervisors, co-workers, subordinates, family members, attending physicians, friends, occupational physicians, occupational health nurses, and occupational health services outside the workplace. Response data for each item was assigned with a binary variable of none/presence or yes/no.
Assessment of psychological distress
The Kessler 6-item Psychological Distress Scale (K6), which assesses psychological distress9), has been widely used in the occupational health field. The validity of the Japanese version of the K6 has been confirmed10,11). The K6 was developed to screen for mental disorders, such as depression and anxiety, and is also used as an indicator of the degree of such mental health problems, including psychological stress. The K6 scale comprises a six-item scale measuring the extent of psychological distress in the past 30 days with a five-point scale ranging from 0=none of the time to 4=all of the time (response range, 0–24). In the present sample, Cronbach’s α coefficient was 0.939. In the present study, a K6 score of 5 or higher (K6 ≥5) was used as the cutoff for mild psychological distress, and a score of 13 or higher (K6 ≥13) as the cutoff for severe psychological distress.
Outcome and covariates
Participants’ K6 scores in the baseline survey were used as outcome variables. Each item regarding potential advisors on work-related health issues was used as a predictor variable. The sex, age (20–29, 30–39,40–49, 50–59, and 60–69 years), educational background (middle school/high school, junior college/vocational school, or university/graduate school), and marital status of the participant, presence or absence of illnesses under treatment, company size (1–49 employees, 50–299 employees, 300–999 employees, 1,000–9,999 employees, ≥10,000 employees, or unclear), job types (regular employees, managers, or others), income status (≤2.99 million yen, 3.00–4.99 million yen, 5.00–9.99 million yen, ≥10.00 million yen, or decline to answer), average working hours per week (≤29, 30–39, 40–49, 50–59, and ≥60 hours), and standard industrial classification (SIC; primary industry, secondary industry, or tertiary industry) were used as confounders.
Statistical analysis
To assess the relationship between the K6 score and each of the potential advisors on work-related health issues, we used a logistic regression model that is a generalized linear model with a binomial response in this study. An age- and sex-adjusted model and multivariate-adjusted model were estimated. These two models included sex, age, educational background, marital status, presence or absence of illnesses under treatment, company size, job types, income status, average working hours per week, and SIC as the potential confounders. In all tests, the threshold for significance was set at p<0.05. All statistical analyses were conducted using IBM SPSS Statistics (version 23.0, IBM Co., Armonk, NY, USA).
Results
Table 1 shows the data for the characteristics of participants in this study. Out of the total eligible participants, the number of males and females was similar, but the proportion of young participants was small because of the exclusion criteria by consistency and completeness checks for detecting fraudulent respondents. The proportion of participants was higher for the following variables: those with a university or graduate school level education (57.3%), regular job type employees (57.5%), and those working in a small company with 1–49 employees (32.2%). The number of participants with mild psychological distress (K6 ≥5) was 1,694 (37.3%) and of participants with severe psychological distress (K6 ≥13) was 367 (8.1%).
Table 1. Participants’ characteristics
| Items | Total
(n=4,540) |
|---|
| n | (%) |
|---|
| Age, years | | |
| 20–29 | 843 | (18.6) |
| 30–39 | 868 | (19.1) |
| 40–49 | 915 | (20.2) |
| 50–59 | 961 | (21.2) |
| 60–69 | 953 | (21.0) |
| Sex, male | 2,273 | (50.1) |
| Education | | |
| Middle school/high school | 976 | (21.5) |
| Junior college/vocational school | 963 | (21.2) |
| University/graduate school | 2,601 | (57.3) |
| Marital status; unmarried | 2,190 | (48.2) |
| Income status | | |
| Declined to answer | 686 | (15.1) |
| ≤2.99 million yen | 994 | (21.9) |
| 3.00–4.99 million yen | 1,455 | (32.0) |
| 5.00–9.99 million yen | 1,141 | (25.1) |
| ≥10.00 million yen | 264 | (5.8) |
| Average working hours per week | | |
| ≤29 | 602 | (13.3) |
| 30–39 | 853 | (18.8) |
| 40–49 | 2,225 | (49.0) |
| 50–59 | 552 | (12.2) |
| ≥60 | 308 | (6.8) |
| Standard industrial classification | | |
| Primary industry | 11 | (0.2) |
| Secondary industry | 1,099 | (24.2) |
| Tertiary industry | 3,430 | (75.6) |
| Company size, employees | | |
| Unknown | 395 | (8.7) |
| 1–49 | 1,461 | (32.2) |
| 50–299 | 902 | (19.9) |
| 300–999 | 561 | (12.4) |
| 1,000–9,999 | 756 | (16.7) |
| ≥10,000 | 465 | (10.2) |
| Job type | | |
| Regular employees | 2,611 | (57.5) |
| Managers | 409 | (9.0) |
| Others | 1,520 | (33.5) |
| Presence of illnesses under treatment | 1,363 | (30.0) |
| Mild psychological distress (K6 ≥5) | 1,694 | (37.3) |
| Severe psychological distress (K6 ≥13) | 367 | (8.1) |
K6, Kessler 6-item Psychological Distress Scale.
Table 2 shows the distribution of the K6 results for each of the potential advisors on work-related health issues. The proportion of participants with potential advisors on work-related health issues was 71.7%. Family members were the most common potential advisor (49.1%), followed by friends (19.7%) and superiors (18.4%). The proportion of participants without potential advisors and mild psychological distress, and those without potential advisors and severe psychological distress was 63.3% and 51.5%, respectively (Table 2).
Table 2. K6 results for each of potential advisors on work-related health issues
| Potential advisors on work-related health issues | Total | K6 ≥5 | K6 ≥13 |
|---|
| (n=4,540) | (n=1,694) | (n=367) |
|---|
| n | (%) | n | (%) | n | (%) |
|---|
| Presence of potential advisors | 3,254 | (71.7) | 1,073 | (63.3) | 189 | (51.5) |
| Type of potential advisors | | | | | | |
| Supervisors | 837 | (18.4) | 285 | (16.8) | 41 | (11.2) |
| Co-workers | 711 | (15.7) | 235 | (13.9) | 39 | (10.6) |
| Subordinates | 93 | (2.0) | 31 | (1.8) | 6 | (1.6) |
| Family member | 2,230 | (49.1) | 692 | (40.9) | 117 | (31.9) |
| Attending physician | 800 | (17.6) | 255 | (15.1) | 55 | (15.0) |
| Friends | 894 | (19.7) | 320 | (18.9) | 56 | (15.3) |
| Occupational physicians | 255 | (5.6) | 62 | (3.7) | 11 | (3.0) |
| Occupational health nurses | 185 | (4.1) | 60 | (3.5) | 14 | (3.8) |
Occupational health services
outside the workplace | 80 | (1.8) | 32 | (1.9) | 13 | (3.5) |
K6, Kessler 6-item Psychological Distress Scale.
Participants with potential advisors on work-related health issues were significantly less likely to score both K6 ≥5 and K6 ≥13 than the participants without potential advisors in the age- and sex-adjusted model and in the multivariate model (all p<0.001). Those participants for whom a supervisor was the potential advisor on work-related health issues, were significantly less likely to score K6 ≥13 than their counterparts in the two models (p=0.025 and p=0.005). Those for whom an occupational physician was a potential advisor were significantly less likely to score K6 ≥5 than their counterparts in the two models (p=0.008 and p=0.011). Those for whom the attending physician was a potential advisor were significantly less likely to score K6 ≥5 than their counterparts in a multivariate model (p=0.048). Those for whom a family member was a potential advisor on work-related health issues were significantly less likely to score K6 ≥5 than their counterparts in the sex- and age-adjusted and multivariate models (p<0.001 and p=0.001). Those for whom an occupational health service outside the workplace was the potential advisor were significantly more likely to score K6 ≥13 than their counterparts in the two models (p=0.002 and p=0.012) (Table 3).
Table 3. Association of K6 and potential advisors on work-related health issues
| K6 ≥5 | K6 ≥13 |
|---|
| Age- and sex-adjusted | Multivariate | Age- and sex-adjusted | Multivariate |
|---|
| OR | [95% CI] | p | OR | [95% CI] | p | OR | [95% CI] | p | OR | [95% CI] | p |
|---|
| Presence of potential advisors (ref. No) | 0.67 | [0.55–0.81] | <0.001 | 0.66 | [0.54–0.81] | <0.001 | 0.50 | [0.35–0.70] | <0.001 | 0.49 | [0.34–0.70] | <0.001 |
| Type of potential advisors | | | | | | | | | | | | |
| Supervisors; Yes (ref. No) | 0.94 | [0.78–1.13] | 0.522 | 0.87 | [0.72–1.06] | 0.162 | 0.64 | [0.43–0.94] | 0.025 | 0.57 | [0.38–0.84] | 0.005 |
| Co-workers; Yes (ref. No) | 0.89 | [0.73–1.08] | 0.234 | 0.9 | [0.74–1.11] | 0.327 | 0.9 | [0.60–1.35] | 0.624 | 0.94 | [0.62–1.41] | 0.749 |
| Subordinates; Yes (ref. No) | 1.12 | [0.69–1.80] | 0.644 | 1.21 | [0.75–1.98] | 0.435 | 1.14 | [0.45–2.92] | 0.782 | 1.21 | [0.46–3.18] | 0.701 |
| Family member; Yes (ref. No) | 0.69 | [0.59–0.82] | <0.001 | 0.75 | [0.64–0.89] | 0.001 | 0.66 | [0.48–0.90] | 0.009 | 0.77 | [0.56–1.07] | 0.124 |
| Attending physician; Yes (ref. No) | 1.16 | [0.97–1.39] | 0.111 | 0.82 | [0.67–1.00] | 0.048 | 1.68 | [1.19–2.36] | 0.003 | 0.98 | [0.68–1.40] | 0.892 |
| Friends; Yes (ref. No) | 1.11 | [0.93–1.32] | 0.241 | 1.07 | [0.90–1.28] | 0.45 | 1.03 | [0.73–1.44] | 0.877 | 0.95 | [0.67–1.34] | 0.774 |
| Occupational physicians; Yes (ref. No) | 0.65 | [0.47–0.89] | 0.008 | 0.65 | [0.47–0.91] | 0.011 | 0.66 | [0.34–1.30] | 0.230 | 0.77 | [0.38–1.55] | 0.467 |
| Occupational health nurses; Yes (ref. No) | 1.1 | [0.78–1.54] | 0.602 | 1.09 | [0.77–1.55] | 0.63 | 1.31 | [0.71–2.44] | 0.391 | 1.41 | [0.74–2.69] | 0.298 |
Occupational health services
outside the workplace; Yes (ref. No) | 1.25 | [0.78–2.00] | 0.356 | 1.22 | [0.75–1.99] | 0.422 | 2.74 | [1.44–5.23] | 0.002 | 2.41 | [1.22–4.77] | 0.012 |
CI, confidence interval; OR, odds ratio; ref, reference.
Multivariate model was adjusted for sex, age, education, marital status, income status, average working hours per week, standard industrial classification, company size, job type, presence of illnesses under treatment.
Discussion
The relationship between psychological distress and the presence or absence of a potential advisor on work-related health issues was supported by the data. We found that those with a potential advisor tend to have less psychological distress, and, stated differently, those without a potential advisor were more likely to display mild or severe psychological distress. In the previous study conducted on Japanese workers with depression, the most common difficulty perceived by them when they fell into depression was that “there were no advisors in the workplace,” at 53.1%. In addition, what these workers expected the most from their workplaces when they fell into depression was “establishing the workplace advisory system for mental health,” at 43.8%12). Although the study protocol and results used in this study differ from those of the abovementioned study, the studies are consistent with each other. We suggest that not having a potential advisor is likely to have a negative influence on the prevention stage of mental health disturbance, as well as on the progression of mental disorders.
Adverse effects on health have been reported to occur as a result of reduced communication and feelings of isolation among workers13,14). Additionally, there have been reports that the recent novel coronavirus 2019 (COVID-19) pandemic has increased the number of workers who feel lonely, thus increasing their psychological distress15). The findings of this study are consistent with those of similar studies, since not having a potential advisor could be related to a state of loneliness and isolation. However, this study differs from previous studies in that it evaluated the relationship between loneliness and anxiety from an occupational health perspective. We believe that providing workers with appropriate advisory support regarding work-related health issues is important for addressing their general mental health.
Not having a supervisor as their potential advisor was associated with severe psychological distress for workers. Many previous studies have reported that having a supervisor’s social support is one of the important factors affecting workers’ physical and mental health concerning perceived organizational support16,17,18) and demand-control-(support) models19,20). A unique finding of this study was that the supervisor not being a potential advisor was not merely indicated as being related to mild psychological distress, but significantly related to severe psychological distress. In other words, the role of the supervisor in detecting and intervening in the early stages of mental health disorders should be emphasized rather than only decreasing psychological distress. It has been reported that workers with disturbed mental health have shorter periods of disability when they communicate more frequently with their supervisors21,22). It would be important for workers to share their health problems with their supervisors and discuss measures and solutions to maintain their work productivity.
Those not having an occupational physician as a potential advisor were more likely to display mild psychological distress. In Japan, occupational physicians are appointed in accordance with the Occupational Safety and Health Laws1). They can be familiar medical professionals from whom workers can easily obtain advice. In addition, occupational physicians are expected to play an important role as experts in mental health promotion measures in the workplace. This is mandated under the Occupational Health and Safety Law and various mental health guidelines issued by the MHLW3,23). Workers’ perception of occupational physicians as potential advisors can impact their stress reduction.
In contrast, we found that having an occupational physician as a potential advisor may not be associated with a reduction in severe psychological distress because there was no significant difference between those for whom an occupational physician was a potential advisor and those for whom it was not. It is inferred that the participants with severe psychological distress may be in a phase that requires medical intervention, or in a phase in which medical intervention is already underway. There could be a potential effect modifier between the occupational physician and the attending physician, which may have made the ORs statistically unstable. Indeed, the ORs of severe psychological distress for having an attending physician were also not significant. In addition, it is also possible that there reverse causality, in which workers with severe psychological distress often have an interest in and seek advisory services from occupational physicians.
In the survey conducted by the MHLW, it was reported that more than 70% of workers consult their supervisors, coworkers, or family members on job stress, while only approximately 10% consult an occupational physician24). Similarly, in the present study, the proportion of those that had occupational physicians as potential advisors was lower than that of those that had supervisors, colleagues, and family members. In Japan, occupational physicians must be appointed in workplaces with 50 or more employees, but this is voluntary for workplaces with less than 50 employees25). These smaller workplaces are expected to use the services of industrial health specialists, including industrial physicians from outside industrial hygiene organizations; however, this may not be convenient due to restrictions on use and provision (e.g., use up to twice a year). It is a future challenge to effectively distribute the services of occupational physicians to a large number of workers.
Those not having a family member as a potential advisor were found to be more likely to display mild psychological distress. Family members are highly likely to contribute to mental health maintenance, stress reduction, and early detection of mental health disturbance for workers in their private lives. Family-related research in the work setting focused on social support has been conducted in the past, and it has been reported that low general family support is associated with higher psychological distress26). In addition, it has been reported that family support not only reduces negative mental health but also promotes positive mental health27,28). We suggest that this type of family support may be an important factor in reducing psychological distress for workers.
Having an occupational health service outside the workplace as a potential advisor was associated with severe psychological stress. We believe that this result has a different interpretation as compared to the other types of advisors. Unlike the other potential advisors that we evaluated in this study, external occupational health services are typically paid services of health guidance, psychological counseling, and psychological stress check, contracted by companies to strengthen the mental health support for their employees29). In other cases, they are contacted by workers with mental health disturbances who approach an available public counseling service. In other words, it is possible that those who already need mental health support recognize these types of services as potential advisors. Meanwhile, those with good mental health may not recognize these services as potential advisors. We believe that further study is needed to clarify this aspect of workers’ mental health service utilization.
Limitations
This study has several limitations. The generalizability of the results is limited because the WSHIR study is an Internet-based survey including only workers in Japan. We have attempted to reduce the bias of the participants as much as possible by sampling across the categories of sex and age. Furthermore, we intend to increase the validity of the findings of this study through follow-up surveys over the next year (the final survey in October 2023). Another limitation of this study is the cross-sectional design, due to which the causal relationship between potential advisors on work-related health issues and psychological distress is unknown. The K6 measures psychological distress over the past 30 days. However, the response option under potential advisors does not mention how long the participant has received support from their advisor. It also does not clarify whether the advisor is present or absent at the time of assessment. We believe that the influence of the presence or absence of a potential advisor on psychological conditions is pertinent to this study. Additionally, there is a possibility that the results of this study may differ slightly from those obtained under normal circumstances because this study was conducted during the COVID-19 pandemic. The only way to resolve this limitation is to conduct this study again when the COVID-19 pandemic is under control. However, we believe that we were able to ensure a certain degree of robustness by adjusting for potential confounding variables in this study.
Conclusion
In this study, we analyzed the relationship between potential advisors on work-related health issues and psychological distress. Having potential advisors would be important for workers’ mental health improvement. In particular, having supervisors, occupational physicians, or family members as potential advisors may be effective in reducing workers’ psychological distress.
Acknowledgements
We would like to thank Cross Marketing Inc. (Tokyo, Japan) for conducting this Internet survey and Editage (www.editage.com) for English language editing.
Funding
This study was funded by a research grant from the University of Occupational and Environmental Health, Japan; Health, Labour and Welfare Sciences Research Grants (Grants No. 210801-01, 210301-01, 21LA1002), a grant in aid for the operation of the University of Occupational and Environmental Health, Japan from the Ministry of Health, Labour, and Welfare (related to the survey on demand and supply of occupational physicians), and scholarship donations.
Ethical approval
This study was approved by the Ethics Committee of Medical Research, University of Occupational and Environmental Health, Japan (R3-037).
Data availability statement
All data produced in the present study are available upon reasonable request to the authors.
Informed consent
Informed consent was obtained in the form on the website.
Conflicts of interest
The authors declare no conflicts of interest associated with this manuscript.
Author contributions
KI was the chairperson of the study group, wrote the manuscript, and analyzed the data. HA analyzed the data. All authors designed the research protocol and developed the questionnaire. All authors reviewed and approved the final manuscript.
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