1.Risk of sleep disturbance associated with work-related activities during free time in South Korea: a cross-sectional study with mediation analysis
Ohwi KWON ; Hye-Eun LEE ; Mo-Yeol KANG
Annals of Occupational and Environmental Medicine 2026;38(1):e11-
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.
2.Occupational Risk Factors for Skin Cancer: A Comprehensive Review
Ye-Seo LEE ; Hyejin GU ; Yun-Hee LEE ; Munyoung YANG ; Hyojeong KIM ; Ohwi KWON ; Yeong Ho KIM ; Mo-Yeol KANG
Journal of Korean Medical Science 2024;39(42):e316-
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.
3.Asbestos Exposure and Ovarian Cancer: A Meta-analysis
Seo Young KIM ; Ha Kyun CHANG ; Ohwi KWON ; JaeYoung PARK ; Jun-Pyo MYONG
Safety and Health at Work 2024;15(1):1-8
Background:
The International Agency for Research on Cancer (IARC) Monograph conducted a systematic review of the relationship between asbestos and ovarian cancer. However, there may have been information bias due to the undue weight given to few articles. To address this limitation, the present study performed a meta-analysis integrating studies published both before and after the 2012 IARC Monograph on Asbestos, with the aim of investigating the association between asbestos exposure and ovarian cancer.
Methods:
A comprehensive search of major journal databases was conducted to identify studies examining the relationship between asbestos exposure and ovarian cancer, including those featured in the 2012 IARC Monograph on Asbestos. A meta-analysis on asbestos exposure and cancer risk was performed.
Results:
The meta-analysis of studies published after the 2012 IARC Monograph on Asbestos found a summary Standardized Mortality Ratio (SMR) of 2.04 (95% CI: 1.03—4.05; p = 0.0123; 5 studies), with a significant degree of heterogeneity among the studies (I2 = 72.99%). The combined analysis of 15 studies before and after the 2012 IARC Monograph showed an overall summary SMR of 1.72 (95% CI: 1.43—2.06; p = 0.0349; 15 studies), with a moderate degree of heterogeneity (I2 = 42.99%).
Conclusion
This meta-analysis provides evidence of a significant association between asbestos exposure and ovarian cancer mortality. While the possibility of misdiagnosis in earlier studies cannot be completely ruled out, recent findings suggest a robust correlation between asbestos exposure and ovarian cancer. This highlights the importance of sustained efforts to minimize asbestos exposure and protect public health.
4.Occupational Characteristics and Health Status of Vietnamese Male Migrant Workers in the Republic of Korea
Ohwi KWON ; Ji-Hun SONG ; Jeong-Ok KONG ; Seong-Won MA ; Young Shin LEE ; Joonho AHN
Safety and Health at Work 2023;14(3):267-271
Background:
The objective of this study is to identify the working conditions and health status of Vietnamese male migrant workers in Republic of Korea, in comparison to the Korean general population.
Methods:
We conducted our survey through the Migrant People Center, and we received completed questionnaires from 87 male Vietnamese migrant workers. The questionnaire employed was identical to those used in the Korean Working Conditions Survey and the 2020 Korea National Health and Nutrition Examination Survey. The collected data from the Vietnamese migrant workers was then compared with the Korean reference population using indirect age-standardization.
Results:
Vietnamese male workers demonstrated a higher prevalence of health problems including hearing problems (age-standardized prevalence ratio (aSPR) 13.22, 95% confidence interval [CI]: 8.07–20.4), skin problems (aSPR 13.49, 95% CI: 8.07–20.4), and low back pain (aSPR 8.40, 95% CI: 6.50–10.69). Elevated exposure to workplace hazards such as chemicals (aSPR 2.36, 95% CI: 1.51–3.51), organic solvents (aSPR 2.22, 95% CI: 1.44–3.28), handling of heavy objects (aSPR 1.67, 95% CI: 1.24–2.21), and high temperatures (aSPR 1.96, 95% CI: 1.46–2.57) was observed among them. Additionally, they faced a higher risk of no personal protective equipment (aSPR 2.53, 95% CI: 1.26–4.52) and a greater prevalence of unmet medical needs (aSPR 7.14, 95% CI: 4.74–10.32).
Conclusion
Our findings highlight the elevated workplace hazards, health problems, and unmet medical needs among Vietnamese male workers compared to the Korean reference population. These findings underscores the urgency for enhanced scrutiny over working conditions and protective equipment provision, coupled with efforts to improve healthcare accessibility and worker education.
5.Occupational Risk Factors for Stroke: A Comprehensive Review
Munyoung YANG ; Hyoungseob YOO ; Seo-Young KIM ; Ohwi KWON ; Min-Woo NAM ; Kwang Hyun PAN ; Mo-Yeol KANG
Journal of Stroke 2023;25(3):327-337
For primary prevention, it is important for public health and clinical medicine to identify and characterize modifiable risk factors of stroke. In existing literature, the impact of occupational variables on ischemic and hemorrhagic stroke has been extensively studied. This review summarizes the available data on the significance of occupational variables in stroke. The results of this review suggest that there is sufficient evidence for the relationship between increased risk of stroke and job stress, working in extreme temperatures, long working hours, and/or shift work. The association between long working hours and occupational exposure to noise and chemicals remains inconclusive although several studies have reported this finding. This review will act as a step toward future research and provide information that may serve as a baseline for developing targeted interventions to prevent stroke in the working population.

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