Background: This study aims to investigate the associations between work-related activities during free time, including frequency of working during free time and use of communication devices for work during free time, and sleep disturbance. It further explores the underlying mechanisms through mediation analysis. Methods: Data were analyzed from 21,473 participants of the seventh Korean Working Conditions Survey (KWCS, 2023). Multivariable logistic regression was employed to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for sleep disturbance. Three sequential models were constructed to evaluate the effects of weekly working hours and shift work on sleep disturbance risk. Mediation analysis was conducted to identify pathways linking work-related activities during free time and sleep disturbance. Results: Those who worked during their free time daily showed significantly higher risk of sleep disturbance (OR: 4.17; 95% CI: 2.64–6.58). Similarly, daily use of communication devices for work during free time was associated with an increased risk (OR: 1.83; 95% CI: 1.57–2.13). These associations remained robust even after adjusting for weekly working hours and shift work. Mediation analysis revealed that "worry about work while at home" was the primary mediator for device use (13.7%; 95% CI: 0.11–0.18), while "feeling too tired for housework after work" was the strongest mediator for working during free time (26.6%; 95% CI: 0.22–0.32). Conclusions The results indicate that engaging in work-related activities during free time elevates the risk of sleep disturbance, independent of long working hours or shift patterns. Mediation analysis revealed that the strongest effects were driven by the behavioral and psychological dimensions of work–family conflict. These findings suggest that sleep disturbance arises primarily from the erosion of work–life boundaries, fueled by persistent work-related rumination and the spillover of professional burdens into free time.

OBJECTIVES: For employees, work-time control (WTC) may protect against burnout and turnover. However, evidence from Korean workplaces is limited. This study aimed to examine whether WTC is associated with burnout and turnover intention and to test whether burnout mediates this relationship. METHODS: We analyzed data from 4,745 wage workers in the 2024 wave of the Korean Work, Sleep, and Health Study. WTC was assessed across 6 domains, burnout was measured using the Korean Burnout Syndrome Scale, and turnover intention was assessed using a validated 4-item scale. Logistic regression was used to estimate the associations of WTC quartile with burnout and turnover intention, and mediation analysis was used to decompose the association between WTC and turnover intention through burnout. RESULTS: Among 4,745 workers, the prevalence of burnout was 3.9% and turnover intention was 34.5%; both increased stepwise across lower WTC quartiles. In adjusted models, workers in the lowest WTC quartile had higher odds of burnout (odds ratio [OR], 3.95; 95% confidence interval [CI], 2.41 to 6.47) and turnover intention (OR, 2.24; 95% CI, 1.85 to 2.71) than those in the highest quartile. Mediation analysis showed that burnout explained 36.6% (95% CI, 22.3 to 51.0) of the association between WTC and turnover intention. CONCLUSIONS Lower WTC was linked to higher burnout and turnover intention, with burnout explaining more than one-third of this relationship.

Background: As South Korea experiences rapid population aging, preventing early retirement has become a critical concern. Ill health contributes to early retirement, and educational level moderates this relationship. Although well-studied in Europe, it remains less explored in Northeast Asia, where labor markets and educational attainment differ significantly. This study investigated the moderating role of education in the relationship between chronic diseases and labor force non-participation in South Korea, considering disease severity, type, and employment status. Methods: Using data from the Korean Longitudinal Study of Elderly Employment, this study analyzed 5,758 individuals born between 1964 and 1976. Chronic diseases were categorized by severity and type. Labor force participation and retirement from lifetime primary occupation were measured. Education was categorized as low (≤high school) or high (≥college). Logistic regression analyses were conducted, adjusting for sociodemographic and lifestyle covariates, with stratification by education level, employment status, severity, and disease characteristics. Results: Chronic diseases were significantly associated with labor market non-participation and early retirement, with stronger associations among individuals with lower educational levels. Educational disparities were particularly evident for severe and psychiatric disorders. Among wage workers, those with lower education were more likely to exit the labor market due to chronic diseases, whereas those with higher education generally maintained employment, except in cases of musculoskeletal diseases. Low-educated individuals with chronic diseases were also more likely to retire early from their lifetime primary occupations. Conclusions Education moderates the relationship between chronic diseases and labor non-participation, with greater disparities in severe or psychiatric illnesses and among wage workers. Low-educated workers are more vulnerable to early retirement due to ill health, highlighting the need for targeted policy interventions to support this group and prevent early exit from the workforce.

The Korean Work, Sleep, and Health Study (KWSHS) was launched in 2022 as a longitudinal panel study to examine the interactions between work conditions, sleep health, and labour market performance among the Korean workforce. Baseline data were collected from 5,517 participants aged 19 to 70, encompassing diverse occupations. Follow-up surveys occur biannually, accommodating seasonal variations in sleep and health dynamics. To ensure stability, refreshment samples were integrated in later waves, maintaining a cohort size of 5,783 participants in wave 5. Key data include socio-demographics, employment characteristics, sleep patterns, health outcomes, and workplace performance. Early findings highlight critical associations, such as the adverse effects of occupational physical activity on productivity, the impact of emotional labour on health-related productivity loss, and the significance of sleep disruptions on mental health. The cohort’s design enables detailed analyses of longitudinal and cross-sectional trends, offering insights into how changing work environments influence health and productivity. The KWSHS could serve as a vital resource for evidence-based interventions aimed at improving occupational health and productivity in Korea's evolving labour landscape. Data access is available through the study’s principal investigator upon request.

Background: The aims of this study are to examine how occupation-related data and information for health (ODH) are collected and managed from census-based surveys and potential occupational illness and injuries (POIS) statistics, and to propose a national strategy for the systematic collection, analysis, and management of ODH by building on the Korean Standard Classification of Occupation (KSCO) and using a job exposure matrix (JEM). Methods: The status of the collection and management of ODH registered as national statistics, drawn not only from the census-based general population and workforce, but also from POIS statistics was reviewed and evaluated. Results: ODH from the Republic of Korea's Census of Population and Labor Force are collected and classified according to the KSCO. In contrast, national statistics on POIS are not systematically collected for KSCO coding, reflecting the lack of an KSCO and related guidelines on how to collect ODH. Key frameworks for the construction of both an KSCO and a reference JEM for public health surveillance are proposed. Conclusions Further research is needed to develop a national system for collecting and managing ODH, which will ultimately contribute to the use of a national KSCO and the construction of JEM for public health surveillance.

OBJECTIVES: Preventing occupational injuries remains a significant challenge in Korea. A positive safety climate can contribute to reducing workplace injuries. However, the impact of safety climate on preventing occupational injuries among the Korean workforce has not been adequately explored. Therefore, this study aimed to investigate the relationship between the perceived safety climate and occupational injuries within the Korean working population. METHODS: This study used baseline data from the Korean Work, Sleep, and Health Study (KWSH). The safety climate was measured using the brief version of the Nordic Safety Climate Questionnaire. Occupational injury was determined by whether injuries or accidents had occurred at workplaces in the past year. Logistic regression analysis was performed to examine the association between the safety climate and occupational injury. RESULTS: Participants who reported an unfavorable workplace safety climate were more likely to experience occupational injuries. Multiple logistic regression analysis revealed that the adjusted odds ratio (OR) for occupational injuries in an unfavorable safety climate was 2.20 (95% confidence interval [CI], 1.38 to 3.51) compared to a favorable safety climate. Specifically, factors such as “not encouraging employees to follow safety rules when on a tight schedule” (OR, 2.02; 95% CI, 1.25 to 3.24) and “not helping each other work safely” (OR, 1.98; 95% CI, 1.17 to 3.25) were significantly associated with occupational injuries. CONCLUSIONS An unfavorable safety climate was associated with increased occupational injuries among Korean workers. Improving the safety climate in the workplace may reduce occupational injuries in Korea.

Public health and clinical medicine should identify and characterize modifiable risk factors for skin cancer in order to facilitate primary prevention. In existing literature, the impact of occupational exposure on skin cancer, including malignant melanoma and nonmelanoma skin cancers, has been extensively studied. This review summarizes the available epidemiological evidence on the significance of occupational risk factors and occupations associated with a higher risk in skin cancer. The results of this review suggest that there is sufficient epidemiological evidence to support the relationship between the increased risk of non-melanoma skin cancers and occupational exposure to solar radiation, ultraviolet radiation, ionizing radiation, arsenic and its compounds, and mineral oils. Occupational exposure to pesticides and polychlorinated biphenyls appears to provide sufficient epidemiological evidence for melanoma, and a higher risk of melanoma has been reported among workers in petroleum refining and firefighters. This comprehensive analysis will establish a foundation for subsequent investigations and developing targeted interventions of focused preventive measures against skin cancer among the working population.

Background: The present study aimed to analyze several aspects of the working conditions and health status of platform workers in the Republic of Korea, such as ergonomic and emotional hazards. We also compared the health status of the platform workers with that of the general population. Methods: A total of 1,000 platform workers participated in this survey from August 7 to August 17, 2022. The participants included 400 designated drivers, 400 food-delivery drivers, and 200 housekeeping managers. A face-to-face survey with a structured questionnaire was conducted by researchers who had received specific instructions. The focus of the survey extended to the work environment, encompassing factors such as workplace violence, as well as physical, chemical, and ergonomic hazards. Health-related data for the previous year were also collected, covering a range of issues such as hearing problems, skin problems, musculoskeletal symptoms, headaches, injuries, mental health issues, and digestive problems. Subsequently, we compared the health symptom data of the responders with those of the general population in the Republic of Korea. Results: Platform workers, including designated drivers, food-delivery drivers, and housekeeping managers, existed in the blind spot of social insurance, facing frequent exposure to physical and chemical hazards, ergonomic risk factors, and direct or indirect violence. The prevalence of health problems, including musculoskeletal symptoms, general fatigue, and depressive symptoms, in each occupational group was statistically higher than that in the general population after standardization for age and gender. Conclusion The results revealed unfavorable working environment and inferior occupational health of platform workers compared with those of the general population.

Background/Aims: Chronic obstructive pulmonary disease (COPD) is less prevalent in females than males, but it affects mortality in females. There may be sex differences in the clinical characteristics of COPD. Methods: We analyzed the Korea National Health and Nutrition Examination Survey dataset from 2007 to 2018. We compared the clinical characteristics and comorbidities in subjects with COPD according to sex. We adjusted the multivariate logistic regression of lung cancer prevalence according to COPD and sex by age and smoking amount. Results: Females with COPD tended to be older than males with COPD (64.1 ± 0.4 yr vs. 62.3 ± 0.2 yr, respectively, p < 0.001). Approximately 89% of males with COPD had a smoking history, while 86% of females with COPD were non-smokers (p < 0.001). Household income was lower (p < 0.001) and asthma and overall malignancy were more prevalent in females with COPD than males with COPD (25.5 vs. 11.6%, respectively, p < 0.001; (6.3 vs. 5.4%, respectively, p < 0.001). However, lung cancer was more common in males with COPD than females with COPD (0.9 vs. 0.1%, respectively, p < 0.001). Lung cancer prevalence increased in males with moderate COPD compared to subjects without COPD (OR, 4.409; 95% CI, 1.741–9.419). Conclusions Females with COPD had a lower smoking rate, household income, and lung cancer prevalence than males with COPD. More active COPD screening is needed for women of low socioeconomic status, even if they do not smoke.

Background: Patients with chronic obstructive pulmonary disease (COPD) expressing eosinophilia experience slightly fewer episodes of community-acquired pneumonia (CAP), than those without eosinophilia. However, the severity and burden of hospitalized pneumonia patients with COPD involving eosinophilia have not been assessed. Methods: We evaluated the differences in clinical characteristics between patients with CAP and COPD with or without eosinophilia by a post hoc analysis of a prospective, multi-center, cohort study data. Results: Of 349 CAP patients with COPD, 45 (12.9%) had eosinophilia (blood eosinophil ≥300 cells/μL). Patients with eosinophilia had a lower sputum culture percentile (8.1% vs. 23.4%, p<0.05), a lower percentile of neutrophils (70.3% vs. 80.2%, p<0.05), reduced C-reactive protein levels (30.6 mg/L vs. 86.6 mg/L, p<0.05), and a lower pneumonia severity index score (82.5 vs. 90.0, p<0.05), than those without eosinophilia. The duration of antibiotic treatment (8.0 days vs. 10.0 days, p<0.05) and hospitalization (7.0 days vs. 9.0 days, p<0.05) were shorter in eosinophilic patients. The cost of medical care per day (256.4 US$ vs. 291.0 US$, p<0.05), cost for the medication (276.4 US$ vs. 349.9 US$, p<0.05), and cost for examination (685.5 US$ vs. 958.1 US$, p<0.05) were lower in patients with eosinophilia than those without eosinophilia. Conclusion Eosinophilia serves as a favorable marker for the severity of pneumonia, health-care consumption, and cost of medical care in patients with CAP and COPD.