Background: As social distancing persists and interest in work-life balance grows, more companies are adopting flexible work policies. While there have been studies on sleep disorders associated with different types of work, such as shift work, research exploring the relationship between flexible work schedules and sleep disorders is still limited, particularly among Korean workers. Methods: We performed a secondary analysis of the 6th Korean Working Conditions Survey, focusing on 31,243 paid workers out of a total of 50,538 participants. We defined flexible workers as those who set their own working hours. Sleep disorders were divided into three categories: ‘difficulty falling asleep,’ ‘frequent waking during sleep,’ and ‘waking up feeling exhausted and fatigued.’ Using scores derived from three specific symptoms, the Minimal Insomnia Symptoms Scale (MISS) was calculated to assess the prevalence of insomnia. We used chi-square tests to analyze demographic and job-related differences. A multivariate logistic regression analysis was employed to identify any relationship between flexible work schedules and sleep disorders. Results: Significant differences were found between flexible and non-flexible workers regarding age, income level, education level, and job type. Flexible workers reported sleep-related symptoms significantly more often. The odds ratio for insomnia was 1.40 (95% CI 1.21–1.61). For males, the odds ratio was 1.68 (1.36–2.08). Conclusion This study establishes a correlation between flexible work schedules and sleep disorders among Korean salaried workers. Potential causes could include changes in circadian rhythm, increased work demands, and extended working hours. To precisely determine causality and associated diseases, further research is required.

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.

OBJECTIVES: Construction workers face an elevated risk for several types of cancer. Nevertheless, there is a lack of large-scale epidemiological studies examining the risk of all cancers in construction workers. This study aimed to investigate the risk of various cancers in male construction workers using the Korean National Health Insurance Service (NHIS) database. METHODS: We used data from the NHIS database from 2009 to 2015. Construction workers were identified using the Korean Standard Industrial Classification code. We calculated the age-standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for cancer occurrence in male construction workers compared to all male workers. RESULTS: Compared to all male workers, the SIRs for esophageal cancer (SIR, 1.24; 95% CI, 1.07 to 1.42) and malignant neoplasms of the liver and intrahepatic bile ducts (SIR, 1.18; 95% CI, 1.13 to 1.24) were significantly higher in male construction workers. The SIRs for malignant neoplasms of the urinary tract (SIR, 1.19; 95% CI, 1.05 to 1.35) and non-Hodgkin lymphoma (SIR, 1.21; 95% CI, 1.02 to 1.43) were significantly elevated in building construction workers. The SIR for malignant neoplasms of the trachea, bronchus, and lung (SIR, 1.16; 95% CI, 1.03 to 1.29) was significantly higher in heavy and civil engineering workers. CONCLUSIONS Male construction workers have an increased risk for esophageal cancer, liver cancer, lung cancer, and non-Hodgkin’s cancer. Our results indicate that tailored strategies for cancer prevention should be developed for construction workers.

Background: This study aimed to estimate the annual prevalence and incidence of urolithiasis stratified by work status based on a large nationwide sample. Methods: This study used data from the National Health Insurance Service-National Sample Cohort from 2002 to 2015. The prevalence and incidence of urolithiasis were estimated based on work status and gender stratification. The risk of urolithiasis among workers was calculated using age-standardized incidence ratio with stratification of work type. Results: The prevalence of urolithiasis was significantly higher in workers than in non-workers, especially men, during the follow-up period. The total estimated number of urolithiasis cases was 41,086 and the overall incidence of urolithiasis was 0.3%. The age-standardized incidence ratio of urolithiasis was significantly higher among the total workers (1.14; 95% confidence interval, 1.13–1.16), self-employed workers (1.08; 95% confidence interval, 1.06–1.11), and paid workers (1.19; 95% confidence interval, 1.17–1.21) than among the non-working population. Conclusions Workers, especially paid workers and men, were vulnerable to urolithiasis. Further studies are required to investigate the effects of working conditions on urolithiasis.

Background: This study aimed to investigate whether working long hours was related to infertility among female Korean workers, while taking age into consideration. Methods: We used data from the 2018 National Survey on Fertility and Family Health and Welfare in Korea that is a cross-sectional, nationally representative, and population-based survey. Infertility was defined as women who were not pregnant after regular unprotected intercourse for a year. Working long hours was classified as ≥52 hours, and subgroups as per age were classified on the basis of being younger or older than 40 years of age. Differences in infertility risk between the long working hour group and none were estimated in crude and fully adjusted logistic regression models with age-group stratification. Results: Of 5,909 Korean female workers, the crude and adjusted odds ratios (95% confidence intervals) of infertility for working long hours were 1.295 (0.948–1.737) and 1.303 (0.921–1.809), respectively. In the subgroup of patients below 40 years of age, the crude and adjusted odds ratios (95% confidence interval) were 1.957 (1.216–3.039) and 1.921 (1.144–3.120), whereas those aged 40 years or older had 0.994 (0.647–1.471) and 0.939 (0.560–1.501), respectively. The weighted prevalence of infertility increased as weekly working hours increased only for the younger than 40-year subgroup. Conclusions Infertility is associated with working long hours, especially in young-aged workers. Thus, the working schedule must be structured to better suit young female workers.

Background: The present study investigated the association between two domains of physical activity (occupational physical activity [OPA] and leisure-time physical activity [LTPA]) and sleep duration. Methods: We investigated 3,421 paid workers from the Korea National Health and Nutrition Examination Survey, 2014–2015. Sleep duration was categorized into three categories (short for less than 5 h, optimal for 5–9 h, and long for more than 9 h). OPA and LTPA were defined in terms of answers to relevant questions. Odds ratios were calculated for sleep duration according to each physical activity domain using multinomial logistic regression models. Results: There were 464 subjects (13.6%) who showed short sleep duration, and 169 subjects (4.9%) who showed long sleep duration. Prevalence of OPA and LTPA was higher in male workers than in female workers (for OPA: 3.67% and 1.76%, respectively, p = 0.0108; for LTPA: 16.14% and 6.07%, respectively, p < 0.0001). The odds ratio of OPA for long sleep duration in female workers was 3.35 (95% confidence interval, 1.37–8.21). Otherwise, LTPA was not associated with sleep duration in female paid workers, nor both physical activity domains in male paid workers. Conclusion Female paid workers with work-related physical activity were at risk of oversleeping. These findings also suggested that physical activity has distinct associations with sleep duration according to the physical activity domains and sex.

Background: This study investigates the safety and health status of geographically isolated and confined workers. Methods: This study was conducted in Baekryeong Island in Korea in 2020. The agestandardized prevalence ratios (aSPR) for occupational injury, unmet medical needs, psychological status, and lifestyle were estimated from the available data. Also, we compared the aSPRs of workers in Baekryeong Island with a reference study population who participated in a nationally representative survey in Korea. Results: The study revealed that Baekryeong Island workers had an increased risk of acquiring health and safety problems compared to the general worker population. The island workers showed a significant increase in unmet medical care (aSPR, 5.319; 95% confidence interval [CI], 3.984–6.958) and occupational injury (aSPR, 8.371; 95% CI, 3.820–15.892). Conclusion This study identified the safety and health problems of geographically isolated workers in Baekryeong Island. The risk of occupational injury and unmet medical care are simultaneously highlighted in the region's population, thereby underscoring the importance of prevention.

Background: The present study investigated the association between two domains of physical activity (occupational physical activity [OPA] and leisure-time physical activity [LTPA]) and sleep duration. Methods: We investigated 3,421 paid workers from the Korea National Health and Nutrition Examination Survey, 2014–2015. Sleep duration was categorized into three categories (short for less than 5 h, optimal for 5–9 h, and long for more than 9 h). OPA and LTPA were defined in terms of answers to relevant questions. Odds ratios were calculated for sleep duration according to each physical activity domain using multinomial logistic regression models. Results: There were 464 subjects (13.6%) who showed short sleep duration, and 169 subjects (4.9%) who showed long sleep duration. Prevalence of OPA and LTPA was higher in male workers than in female workers (for OPA: 3.67% and 1.76%, respectively, p = 0.0108; for LTPA: 16.14% and 6.07%, respectively, p < 0.0001). The odds ratio of OPA for long sleep duration in female workers was 3.35 (95% confidence interval, 1.37–8.21). Otherwise, LTPA was not associated with sleep duration in female paid workers, nor both physical activity domains in male paid workers. Conclusion Female paid workers with work-related physical activity were at risk of oversleeping. These findings also suggested that physical activity has distinct associations with sleep duration according to the physical activity domains and sex.

Background: This study investigates the safety and health status of geographically isolated and confined workers. Methods: This study was conducted in Baekryeong Island in Korea in 2020. The agestandardized prevalence ratios (aSPR) for occupational injury, unmet medical needs, psychological status, and lifestyle were estimated from the available data. Also, we compared the aSPRs of workers in Baekryeong Island with a reference study population who participated in a nationally representative survey in Korea. Results: The study revealed that Baekryeong Island workers had an increased risk of acquiring health and safety problems compared to the general worker population. The island workers showed a significant increase in unmet medical care (aSPR, 5.319; 95% confidence interval [CI], 3.984–6.958) and occupational injury (aSPR, 8.371; 95% CI, 3.820–15.892). Conclusion This study identified the safety and health problems of geographically isolated workers in Baekryeong Island. The risk of occupational injury and unmet medical care are simultaneously highlighted in the region's population, thereby underscoring the importance of prevention.

BACKGROUND: The number of workers in non-standard employment (NSE) is increasing due to industrial change and technological development. Dependent self-employment (DSE), a type of NSE, was created decades ago. Despite the problems associated with this new type of employment, few studies have been conducted on the effects by DSE on health, especially sleep quality. This study aims to determine the relationship between DSE and sleep quality. METHODS: This study analyzed data of 50,250 wage workers from the fifth Korean Working Conditions Survey. Workers that did not respond or refused to answer any questions related to variables were excluded, and finally 36,709 participants were included in this study. A total of 2,287 workers (6.2%) were compared with non-DSE (34,422; 93.8%) workers, and multiple logistic regression analyses were applied. RESULTS: DSE status had a significant association with difficulty falling asleep (odds ratio [OR]: 1.331, 95% confidence interval [CI]: 1.178–1.504), difficulty maintaining sleep (OR: 1.279; 95% CI: 1.125–1.455), and extreme fatigue after waking up (OR: 1.331; 95% CI: 1.184–1.496). A multiple logistic regression of the variables for sleep quality in DSE showed a significant association with exposure to physical factors for all types of poor sleep quality as well as shift work for difficulty maintaining sleep with extreme fatigue after waking up. Long working hours and emotional labor were also associated with extreme fatigue after waking up. CONCLUSIONS This study shows a significant association between DSE and poor sleep quality, especially when workers were exposed to physical risk factors (noise, vibration, abnormal temperature, etc.) and shift work.