Visual abstract

Introduction

Health and work are fundamentally related. The recent pandemic (March 2020–May 2023) and rapid technological changes that were ushered in, introduced a new era of working conditions, and prompted major policy responses globally [1,2]. Manufacturing countries, such as the Republic of Korea (ROK), continued to prioritize worker safety, as evidenced by the 2021 enactment of the Serious Disaster Punishment Act which penalizes the parties responsible for major accidents [3]. The European Union is focusing on workers’ mental health and the impact of digital technology, with a “Safe and Healthy Work in the Digital Age” campaign (2023 to 2025) [4].

The health effects of work vary according to the type of work. A Korean Health Panel study (2008–2013) reported that older individuals engaged in paid labor (during regular hours) incurred lower healthcare expenses than their nonworking counterparts [5]. A survey of 600 full-time Japanese employees linked flexible working hours to adverse outcomes such as increased burnout, and self-endangering work behavior [6]. In 1996, a European Union study showed that workers’ health indicators, such as stress and pain, varied significantly by employment type (small employers, full and part time permanent employees, full and part time fixed term employees, full and part time sole traders and full and part time temporary contracts) [7].

Across the scope of occupational medicine, Korean medicine (KM) and integrative medicine (IM) have not yet been given a major role, which is surprising especially considering the overall importance of the field. In addition, there has not been enough attention paid to the impact of subjective health components on worker health, such as behaviors for maintaining a healthy body, self-management strategies for mental well-being, and health-related quality of life (HRQOL) [8–10]. Although, this gap likely exists because measuring subjective health is difficult, and bringing about changes in individual behavior and mindset requires intensive, long-term management. This makes management of health in workers less cost-effective and a lower priority compared with not addressing subjective health.

KM and IM are uniquely positioned to address this deficit in measuring subjective health components and assessing the impact on worker health. KM and IM emphasize a holistic approach, considering not only physical symptoms but also the psychological, social, and subjective dimensions of health. By incorporating subjective health components into practice, KM and IM can provide a comprehensive understanding of the overall well-being of workers. Therefore, expanding research in this area, within KM and IM, is essential for advancing occupational health and improving HRQOL. In this study, subjective health components were defined as health maintenance behaviors, HRQOL, and self-management strategies for maintaining health and the associations between types of work, and these subjective health components were assessed using a nationwide cross-sectional survey.

Materials and Methods

1. Study design and data collection

The research questions were as follows: (1) How do subjective health components differ across types of work; and (2) Are there differences in subjective health components due to shift work and working hours among paid workers?

This study used data collected from a national cross-sectional survey of the general population aged 20–64 living in 17 regions of the ROK. Due to restrictions on face-to-face interactions during the COVID-19 pandemic, the survey was conducted online by a specialized research agency. Probability-proportional-to-size (PPS) sampling technique was used with 3 strata (age, gender, and region), based on the resident registration demographics collected by the Korean Ministry of the Interior and Safety in October 2021, to represent the survey samples nationwide. From November 10 to November 26, 2021, an online panel survey of participants who voluntarily agreed to participate was conducted in line with the consent questions included in the survey, with a response rate of 42.3%. Participants’ anonymity was guaranteed during data collection and processing.

2. Variables

2.1. Classification of workers

Worker participation in economic activities was categorized into 4 types of work: unpaid family workers, irregular workers, self-employed workers, and permanent employees. Paid workers (excluding unpaid family workers) were classified based on whether they worked shifts or > 40 hours per week. The legal standard for full-time working hours stipulated by the Korean Labor Standards Act is 40 hours.

2.2. Subjective health components

This study defined the subjective health components as health maintenance behaviors, HRQOL, and self-management strategies for maintaining health.

Health maintenance behaviors such as physical activity, diet control, smoking cessation, abstaining from alcohol, taking supplements, bathing/sauna/steam, sufficient rest, and attendance at regular health checkups were also investigated.

HRQOL was assessed using the HRQOL Instrument with 8 Items (HINT-8) [12]. This tool measured the general population’s HRQOL in the ROK using 8 items on a 4-point scale: climbing stairs, pain, vitality, working, depression, memory, sleep, and happiness [12]. The lower the HINT-8 index, the lower the HRQOL, which was reported as 0.132 for the worst health condition and 1.000 for the best health condition [13].

Self-management strategies for maintaining health were assessed using the Smart Management Strategy for Health Assessment Tool (SAT) short form [11]. The SAT evaluates patients’ strategies for health support to overcome crises and promote their positive growth [11]. The SAT consists of 3 major domains: 10 items on core strategies, 9 items on preparation strategies, and 10 items on implementation strategies. A higher SAT score indicated better self-care strategies. Individuals can use core strategies to overcome challenges and foster positive growth in a self-directed manner, prepare strategies to set life goals, make specific plans, and implement strategies to achieve those plans.

3. Statistical analysis

The characteristics of the variables included in the analysis were summarized using descriptive statistics including measures of central tendency and dispersion for continuous variables, and frequency distributions for categorical variables. Multivariate logistic regression analysis was conducted among paid workers to identify factors associated with subjective health components using separate models for shift workers and working hours. Odds ratios (ORs) with a 95% confidence interval (CI) were calculated to assess the strength of the associations. Statistical significance was set at p < 0.05. All data manipulation and statistical analyses were conducted using Stata/MP Version 17 (StataCorp LLC, College Station, TX, USA).

Results

1. Subjective health components by types of work

Among the 3,900 survey respondents (excluding students and the unemployed), 3,275 (83.97%) were engaged in economic activities. Participants were classified as permanent employees [n = 2,217 (67.69%)], followed by unpaid family workers [n = 453 (13.83%)], irregular workers [n = 317 (9.68%)], and self-employed workers [n = 288 (8.79%)].

Statistically significant differences were observed in health maintenance behaviors (including controlling diet, quit drinking, taking supplements, getting enough rest, and attending regular health screenings), including HRQOL and the type of work the participant engaged in. No statistically significant differences were observed in the total scores for self-management strategies for maintaining health according to type of work (Table 1). However, the mean scores for the 1 core strategy, 3 preparation strategies, and 3 implementation strategies showed statistically significant differences by type of work (Supplementary Table 1).

2. Subjective health components among paid workers

Of the 3,275 workers, (excluding unpaid family workers) 2,822 were paid workers; among them, 574 (20.34%) were shift workers, and 932 (33.03%) worked more than 41 hours per week. Statistically significant differences were observed between shift and non-shift workers in terms of health maintenance behaviors (bathing/sauna/steaming and getting enough rest), self-management strategies for maintaining health, and HRQOL (Table 2). For the 4 core strategies, 5 preparation strategies, and 5 implementation strategy items, the mean scores differed significantly between non-shift and shift workers (Supplementary Table 2).

Statistically significant differences were observed between the group working ≤ 40 hours per week and the group working ≥ 41 hours per week in terms of health maintenance behaviors (getting enough rest) and HRQOL (Table 2). Additionally, for the 2 core strategies, and 2 implementation strategy items, the mean scores showed statistically significant differences between the 2 groups (Supplementary Table 2).

3. Multivariate logistic regression analysis among paid workers

Shift work and working over 41 hours a week both had a negative association with getting enough rest [shift work: adjusted OR (aOR) = 0.791, 95% CI = 0.647–0.968, working over 41 hours a week: aOR = 0.758, 95% CI = 0.640–0.897] among health-maintenance behaviors, and a positive association with preparation strategies (shift work: aOR = 1.052, 95% CI = 1.015–1.090, working over 41 hours a week: aOR = 1.035, 95% CI = 1.005–1.067). Shift work also had a negative association with HRQOL (aOR = 0.026, 95% CI = 0.009–0.070), and was positively associated with bathing/sauna/steaming (aOR = 1.417, 95% CI = 1.100–1.824) among health-maintenance behaviors.

Discussion

This study investigated the associations between type of work, shift work, working hours, and subjective health components. Among health maintenance behaviors, getting enough rest showed statistically significant associations with type of work, shift work, and working over 41 hours a week, confirming the need to prioritize adequate rest for workers. The challenges workers face in achieving sufficient rest may be linked to systemic issues in Korea’s vacation policies. Workplace vacations serve as a critical period for physical and psychological recovery. However, Korean workers are rarely allowed more than 4 consecutive days of vacation leave. These findings underscore the urgency of systemic reforms to ensure adequate rest periods, including stronger enforcement of existing labor laws and expanded legal protections for workers’ rights to rest [14,15]. Furthermore, shift work showed statistically significant associations with HRQOL in both univariable and multivariate analyses, whereas extended working hours (≥ 41 hours/week) demonstrated no significant associations with HRQOL. The negative association observed between shift work and health-related indicators has been observed previously [16]. Conversely, the reason why working hours and HRQOL were not significantly associated is that while the ROK has one of the longest working hours among the Organization for Economic Cooperation and Development countries, this figure is a national average rather than a median, which overlooks significant differences across various workplaces [17]. Specifically, the issue of working hours may be particularly critical in small- and medium-sized enterprises and service sectors, where exceeding statutory working hour limits is more common [17]. Moreover, factors such as remote work and commute time between home and work may also play a role, as longer commute times have been shown to negatively affect health-related behaviors [18–20]. Therefore, it is necessary to conduct a detailed investigation of the impact on subjective health components among participants selected from a diverse range of working conditions, considering factors such as working hours and commuting time. Furthermore, interventions tailored to specific types of work are required when implementing health programs that use KM and IM approaches.

Among self-care strategies for maintaining health, the finding that preparation strategies are related to working shifts or working > 41 hours a week, suggests a willingness to overcome work environments that can negatively affect health by focusing on preparation strategies to set life goals and make specific plans [21].

This study has several limitations. Firstly, a primary challenge in the fields of KM and IM is the lack of formally developed and validated tools for assessing crucial diagnostic factors, such as subjective health, patient attitude, and will. To address this issue, the HINT-8 and SAT tools, that were developed and validated in the ROK, were used. There is a need to develop tools that are more suitable for specific academic areas within KM and IM, such as Suboptimal health status and Yangsaeng. Secondly, the reliance on the HINT-8 and SAT tools, which were tailored for the Korean population, limited the cross-cultural comparability of these findings with results from other countries. Thirdly, the survey results may also lack generalizability because of the use of an allocation sampling method, even though the survey was designed to mirror the population structure.

Despite these limitations, this study lays an important foundation for understanding the link between working conditions and subjective health, and highlights the need for a more nuanced approach to comprehensive health assessment. These findings suggest that traditional objective measurement tools may be insufficient to fully capture the complexity of workers’ subjective health experiences. By emphasizing the value of incorporating subjective and psychological dimensions, this study provides a strong incentive to explore and develop innovative assessment methods for diagnostic areas that are highly valued in KM and IM research. These results may lead to more effective strategies for promoting occupational health and enhancing subjective health components. Finally, in parallel with tool development, future large-scale national surveys are required to establish robust evidence regarding the relationship between occupational patterns and subjective health outcomes.

Conclusion

Subjective health components (including health maintenance behaviors, HRQOL, and self-management strategies for maintaining health) are influenced by differences in type of work, working conditions, and, especially, the presence of shift work or long weekly hours. Specifically, shift work and working over 41 hours were negatively associated with “getting enough rest” but positively associated with utilizing “preparation strategies.” Future efforts to develop worker health management indicators for KM and IM must leverage this knowledge to prioritize interventions tailored to these high-risk working conditions and types of work, thereby ensuring efficient health management and significantly expanding the application scope to KM and IM.

Supplementary Materials

Article information

Conflicts of Interest

The author has no conflicts of interest to declare.

Author Use of AI Tools Statement

The author used Gemini solely for grammar and language improvement.

Funding

This research was supported by a grant from the Korea Health Technology R&D Project through the Korea Health Industry Development Institute, funded by the Ministry of Health and Welfare (no.: HF20C0104).

Ethical Statement

This study was conducted in accordance with the principles of the Declaration of Helsinki. The first page of the questionnaire introduced the purpose and contents of the study. Respondents were asked if they had consented to participate. Participants in the online panel survey voluntarily agreed to participate by answering consent questions included in the survey. The survey data were anonymized to ensure the removal of any identifiable information associated with the individuals. This study was approved by the Institutional Review Board of Dongguk University, Gyeongju (DRG IRB no.: 20210039).

Data Availability

Upon reasonable request.

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