Cumulative effect of unemployment on suicide mortality in South Korean workers (2018-2019).

BACKGROUND: While unemployment is known to increase the risk of suicide, its cumulative effect remains underexplored. This study investigates how unemployment affects suicide mortality and whether the effect varies based on the number of unemployment spells using two years of nationwide data. METHODS: Using the data from the National Statistical Office and Employment Insurance Database for 2018 and 2019, we identified an average of 2365 cases of suicide over two years among 7.76 million workers aged 25-64 years who had been employed within one year before their suicide. The number of unemployment spells was counted using the employment history of the past five years. We calculated crude suicide mortality rates per 100 000 population, age- and sex- standardized mortality rates (SMRs), and proportionate mortality rates (PMRs) for suicide. RESULTS: Over the two years, the crude suicide rate was 30.0 per 100 000 among the general population and 30.5 among workers. Workers with no unemployment spells in the past five years had a significantly lower SMR (0.44; 0.42-0.46), while those with four or more unemployment spells had a significantly higher SMR (3.13; 2.92-3.35) than the general population. These findings were consistent across all sex and age groups. Additionally, workers with four or more unemployment spells had a significantly higher PMR than the general population. CONCLUSION: The impact of unemployment on suicide mortality intensifies as the number of unemployment spells increases. These results underscore the necessity for additional social and psychological support along with economic assistance for individuals facing recurrent unemployment.

Association Between Commuting Time and Subjective Well-Being in Relation to Regional Differences in Korea.

BACKGROUND: Long commuting times have a negative impact on mental health. However, few studies have explored the relationship between commuting time and well-being based on urbanization by region. Our study examines this relationship as well as the effect of regional differences on Korean workers. METHODS: We used data from the sixth Korean Working Conditions Survey. Commuting time and occupational factors were assessed using a questionnaire, and subjective well-being was assessed using the World Health Organization-5 Well-Being Index. Regions were divided into the cities and the provinces based on Korea's administrative divisions. Logistic regression analysis was performed to investigate the association between commuting time and well-being. Adjusted odds ratios (aORs) with 95% confidence intervals (CIs) for well-being were estimated, using participants commuting time of < 20 minutes as a reference group. RESULTS: The total number of workers was 29,458 (13,855 men, 15,603 women). We found higher aORs for low well-being among workers with long commuting times (aOR, 1.23; 95% CI, 1.11-1.36 and aOR, 1.28; 95% CI, 1.16-1.42 for 60-79 and ≥ 80 minutes, respectively). When stratified by sex and region, higher aORs for low well-being were found only in the workers who lived in cities. CONCLUSION: Long commuting time was negatively associated with well-being in Korean wage workers living in the cities. Policies for reducing commuting time should be discussed to address the mental health of workers, especially those living in metropolitan cities.

Release of hazardous volatile organic compounds from endoscopic submucosal dissection.

BACKGROUND: Although it has been proven that various volatile organic compounds (VOCs) are produced during surgery, there have been no studies focusing specifically on endoscopy. Therefore, we aimed to investigate VOCs produced during endoscopic submucosal dissection (ESD). METHODS: Thirty-one patients scheduled for ESD were enrolled in this study. Sorbent tubes were installed to collect gas at two sites: one in a suction bottle and the other at the level of the endoscopists' upper chest. Gas collections were performed for up to 30 min during submucosal dissection. Quantitative analysis of the VOCs in gas samples was performed using gas chromatography and mass spectrometry. Concentrations of fifteen VOCs were measured. The total concentration of volatile organic compounds (TVOC) was also calculated. RESULTS: Among the five carcinogens-benzene, ethylbenzene, formaldehyde, tetrachloroethylene, and trichloroethylene (TCE)-measured, excess life-time risks of cancer for benzene and TCE were interpreted as unacceptable based on the New Jersey Department of Environmental Protection Division of Air Quality and the Environmental Protection Agency guidelines (5 × 10-4 and 7 × 10-5, respectively). Among the non-carcinogenic VOCs, the mean concentration of toluene was much higher than the reference value (260 µg/m3) in the Japanese guidelines for indoor air quality (IAQ) (1323.7 ± 2884.0 µg/m3 from the air at the upper chest level of endoscopists and 540.9 ± 1345.4 µg/m3 from the suction bottle). Mean TVOCs were at least 10 times higher than the reference value (400 µg/m3) issued by the Japanese guidelines for IAQ. CONCLUSIONS: Various carcinogenic and non-carcinogenic VOCs were detected at levels higher than the reference "safe" values during the submucosal dissection step of ESD. Implementation of counter measures is essential to protect medical personnel who are involved in ESD surgeries.

Cancer development in patients with COPD: a retrospective analysis of the National Health Insurance Service-National Sample Cohort in Korea.

BACKGROUND: COPD is a well-known risk factor for lung cancer, independent of smoking behavior. By investigating the retrospective National Health Insurance Service-National Sample Cohort (NHIS-NSC) in Korea, this study attempted to prove the hypothesis that COPD is a risk factor for major cancers developing outside of the lungs. We also aimed to investigate the environmental factors associated with the development of lung cancer in COPD patients. METHODS: This study analyzed data from the NHIS-NSC over a 12-year period. Among the 514,795 subjects in the NHIS-NSC, 16,757 patients who were diagnosed with any cancer from 2002 to 2003 were excluded. This cohort enrolled six arms consisting of never-smokers without COPD (N = 313,553), former smokers without COPD (N = 41,359), smokers without COPD (N = 112,627), never-smokers with COPD (N = 7789), former smokers with COPD (N = 1085), and smokers with COPD (N = 2677). RESULTS: Incident rate of lung cancer per 100,000 person-year was higher according to smoking and COPD (216 in non-COPD and 757 in COPD among never-smokers, 271 in non-COPD and 1266 in COPD among former smokers, 394 in non-COPD and 1560 in COPD among smokers, p <  0.01). Old age, male sex, lower BMI, low exercise level, history of diabetes mellitus, smoking, and COPD were independent factors associated with the development of lung cancer (p <  0.01). Multi-variable analyses showed that COPD, regardless of smoking status, contributed to the development of lung cancer, and colorectal cancer and liver cancer among other major cancers (p <  0.01). CONCLUSION: Our data suggested that COPD was an independent risk factor for the development of lung cancer, and colorectal cancer and liver cancer among other major cancers in the Korean population, regardless of smoking status.

Ethanol production from xylose is highly increased by the Kluyveromyces marxianus mutant 17694-DH1.

Directed evolutionary approach and random mutagenesis were performed on thermotolerant yeast Kluyveromyces marxianus KCTC17694 for isolating a yeast strain producing ethanol from xylose efficiently. The isolated mutant strain, K. marxianus 17694-DH1, showed 290% and 131% improvement in ethanol concentration and ethanol production yield from xylose, respectively, as compared with the parental strain. Sequencing of the KmXYL1 gene of K. marxianus 17694-DH1 revealed substitutions of arginine and tryptophan with lysine and leucine at positions 25 and 202, respectively, as compared to the parental strain. In addition, sequencing of the KmXYL2 gene uncovered a substitution of glutamate with leucine at position 232. When enzymatic assays of xylose reductase (XR) and xylitol dehydrogenase (XDH) from the parental strain and K. marxianus 17694-DH1 were performed, XR activities were not significantly different whereas XDH activities were significantly improved in the mutant strain up to 50 °C of reaction temperatures. RNA-Seq based transcriptome analysis showed that alcohol dehydrogenases and glucose transporters were up-regulated while TCA cycle involved enzymes were down-regulated in K. marxianus 17694-DH1.

Spontaneous lumbar artery rupture and massive retroperitoneal hematoma, successfully treated with arteriographic embolization.

BACKGROUND AND OBJECTIVE: Massive retroperitoneal hematoma caused by lumbar artery rupture is generally associated with trauma or retroperitoneal malignancy. However, despite recent advances in technologies and tools, spontaneous lumbar artery rupture is a very rare disease entity but remains a challenging problem because it is frequently associated with significantly high mortality and morbidity and is very difficult to make a correct diagnosis. METHODS: We evaluated the databases of the PubMed, Embase, Cochrane Central Register of Controlled Trial, Google Scholar, the KoreaMed and the Research Information Sharing Service databases, and a detailed systematic review was performed by searching in PubMed. The initial search was performed on 3 February 2018 and a second search conducted in 29 January 2019. RESULTS: A total of 10 case reports on massive hemoperitoneum caused by spontaneous lumbar artery rupture were identified. Of the 10 case reports involving 14 patients, eight were male and six were female under 62.71 ± 13.93. Of the 14 patients, 9 (64.3%) surviving with transcatheter arterial embolization, three (21.4%) died of multi-organ failure or hypovolemia, and two (14.3%) had no definite records on survival or death. CONCLUSIONS: A massive retroperitoneal hematoma caused by lumbar artery rupture should be considered in patients with late-onset shock accompanied by blunt abdominal/pelvic trauma. Furthermore, early detection and urgent embolization would prevent further complications and eliminate the need for surgical interventions.

Impacts of Return-to-Work Type and Period on Job Retention in Workers with Occupational Injuries and Diseases.

BACKGROUND: Despite the necessity of job retention in achieving return-to-work (RTW) goals, many workers leave their jobs after returning to work. The objective of this study was to examine the impacts of RTW type and period on job retention in Korean workers with occupational injuries and diseases. METHODS: Data were derived from the Panel Study of Worker's Compensation Insurance, including data from 2,000 systemically sampled workers who had finished recuperation in 2012; three waves of survey data were included in the analyses. Workers who returned to work (n = 1,610) were included in the analysis of the relationship between RTW type and job retention, and 664 workers who returned to their original workplaces were included in the analysis of the relationship between RTW period and job retention. The participants completed a questionnaire, and administrative data were provided by workers' compensation insurance. RESULTS: A Cox proportional-hazards regression analysis showed an increased hazard ratio (HR) for non-retention of 2.66 (95% confidence interval, 2.11-3.35) in reemployed workers compared to that in workers returning to their original workplaces. Among workers returning to their original workplaces, HRs for non-retention were increased in workers with a RTW period of 13-24 months (3.03 [1.52-6.04]) and > 24 months (5.33 [2.14-13.25]) compared to workers with a RTW period of ≤ 3 months. CONCLUSION: RTW type and period were significantly related to job retention, suggesting that policies for promoting job retention rate should be implemented.

Exposure assessment of particulate matter and blood chromium levels in people living near a cement plant.

This study evaluates the effect of air pollution caused by cement plants on nearby residential areas and performs an exposure assessment of particulate matter (PM) and total Cr, Cr6+, Pb, and Al. Further, the blood Cr levels of residents exposed to PM released by cement plants are also assessed. Nine buildings (eight residential and one elementary school building) close to cement plants were selected for this study, which were located in Pyeongtaek port, in west of Gyeonggi Province, South Korea. A total of 51 suspended particulate samples were collected at a flow rate of 2.0 L/min. Total Cr was more widely detected in residents' houses and elementary schools. PM levels were higher at distances of 4.1 and 4.8 km than those at closer distances of 2.7 km. This was due to the influence of wind direction. The estimated mean blood level of Cr for the study participants was 3.80 µg/L, which is higher than levels estimated by other studies on Cr blood levels. Therefore, cement plants could cause an increase in total Cr and blood Cr levels in residential areas, and more continuous monitoring is necessary to better understand their impacts.

Preoperative risk factor analysis of postoperative stroke after Cox-maze procedure with mitral valve repair.

BACKGROUND: Atrial fibrillation (AF) is a life-threatening arrhythmia that carries the high risk of thromboembolic complication. Stroke often develops in patients who undergo successful Cox Maze procedure, despite the fact that the procedure has shown a high rate of success in sinus conversion from AF. This study examined the preoperative risk factors predictive of stroke following Cox Maze procedure in patients with mitral valve disease. METHODS: 240 patients with the mean age of 57 years underwent Cox-Maze IV procedure with mitral valve repair from November 2007 through December 2010. All patients were available during the follow-up period with the mean duration of 23.6 months. This study excluded those patients who had undergone mitral valve replacement because of maintenance of warfarin medication RESULTS: Sixteen patients had an ischemic stroke. Of these sixteen patients, six had a transitional ischemic accident while the remaining ten had cerebral infarction. Twelve of sixteen showed sustained sinus rhythm, three showed AF and one had pacing rhythm. Univariate analysis showed that only preoperative stroke history was associated with postoperative stroke (p = 0.03). High CHA(2)DS(2)-VASc score, rheumatic etiology, large left atrium (LA), preoperative or postoperative LA thrombus, age, sex, hypertension, and concomitant surgery were not associated with predictive risks for stroke. CONCLUSIONS: In the group of patients who underwent the Cox-Maze procedure with mitral valve repair, having a stroke history was the only preoperative risk factor that could lead to a stroke event after surgery. Accordingly, patients with affliction of ischemic stroke, albeit sustained sinus rhythm, may require prophylactic anticoagulation.

Workplace psychosocial factors associated with work-related injury absence: a study from a nationally representative sample of Korean workers.

BACKGROUND: Little is known about the association between psychosocial factors and injury absence in the workplace. PURPOSE: This study aims to assess the association of comprehensive workplace psychosocial factors with work-related injury absence among Korean workers. METHODS: The data (n = 7,856) were derived from the First Korean Working Conditions Survey conducted in 2006 with a representative sample (n = 10,043) of the Korean working population. The survey instrument contained questions about hours of work, physical risk factors, work organization, and the effect of work on health/injury. Work-related injury absence was indicated by a dichotomous variable with at least 1 day absence during the preceding 12 months. Logistic regression models were used to calculate odds ratio and confidence interval (CI). Incremental adjustments for sociodemographic, health behavior, and occupational confounding variables were employed in the models. RESULTS: The overall 1-year prevalence of work-related injury absence in this study was 1.37 % (95 % CI, 1.11-1.63 %). Those who experienced violence at work (adjusted odds ratio (aOR), 7.05 (95 % CI, 2.69-18.5)), threat of violence at work (aOR, 4.25 (95 % CI, 1.32-13.64)), low job autonomy (aOR, 1.79 (95 % CI, 1.17-2.74)), and high job strain (aOR, 2.38 (95 % CI, 1.29-4.42) had an increased risk of injury absence, compared with their respective counterparts (p < 0.05). Among all job types, skilled workers in Korea were at a near fourfold risk of work absence due to occupational injuries, compared with managers in low-risk jobs. CONCLUSION: Workplace violence and increased job strain were two key workplace psychosocial factors associated with work-related injury absence.

Association between commuting time and work-related low back pain with respect to sports and leisure activities in Korean workers.

Long commuting times can induce work-related low back pain (LBP), which can be exacerbated by reduced sports and leisure activities. However, there is a lack of empirical research on commuting time and work-related LBP in Korea. In this study, we aimed to investigate the relationship between commuting time and work-related LBP as well as the effect of sports and leisure activities on Korean workers. We utilized data from the sixth Korean Working Conditions Survey to analyze the relationship between commuting time and work-related LBP using multivariable logistic regression. The total number of included workers was 28,202. Workers without sports and leisure activities, and long commuting times (40-59, 60-79, and ≥80 min) showed significantly higher odds ratios for work-related LBP (1.29 [95% Confidence intervals=1.12-1.49], 1.42 [1.22-1.65], and 1.96 [1.68-2.28], respectively). However, in workers with sports and leisure activities, the results were significant only for commuting times of 60-79 and ≥80 min (1.41 [1.13-1.75], 1.60 [1.28-1.99], respectively). Long commuting times were associated with work-related LBP, and engagement in sports and leisure activities was found to play a role in mitigating the impact among Korean wage workers.

The changing dynamics of work from home and its association with sleep disturbance through work-family conflict during the COVID-19 pandemic.

OBJECTIVES: Work from home (WFH) can increase sleep disturbances. However, only few studies have examined the connection between WFH and sleep disturbance while considering work-family conflict (WFC) and the changes brought about by the COVID-19 pandemic. This study aimed to examine the association between WFH and sleep disturbance, considering WFC, and assess how this association changed during the COVID-19 pandemic. METHODS: We used data from the fifth and sixth Korean Working Conditions Survey. WFH workers and a control group were selected using propensity score matching. Conditional logistic regression analysis was used to estimate the odds ratios (ORs) with 95% CIs for sleep disturbance in the WFH and control groups. RESULTS: The workers working from home showed significantly higher ORs for sleep disturbance before (4.26; 95% CI, 3.59-5.05) and during (1.52; 95% CI, 1.26-1.83) the COVID-19 pandemic. When stratified by WFC, the association was significant only in the workers with WFC before COVID-19. However, the association was not significant during COVID-19 among the workers with WFC. CONCLUSIONS: WFH was significantly associated with sleep disturbance among workers before COVID-19, but this association was not observed during the COVID-19 pandemic. Considering the significant role that WFC plays in this association, companies should provide a family-friendly WFH environment when adopting WFH practices.

Organizational factors associated with work-related sleep problems in a nationally representative sample of Korean workers.

PURPOSE: The purpose of this study was to assess the association of organizational factors with work-related sleep problems (WRSP) among Korean workers. METHODS: The data were derived from the First Korean Working Conditions Survey conducted in 2006 with a representative sample of the Korean working population (n = 10,039). RESULTS: The overall prevalence of WRSP was 5.1% (95% confidence interval (CI) 4.7-5.5). Those who experienced sexual harassment at work (adjusted odds ratio (aOR) 3.47: 95% CI 1.77-6.81), discrimination due to sex (aOR 2.44: 95% CI 1.36-4.36) or age (aOR 2.22: 95% CI 1.52-3.23), violence at work (aOR 1.98: 95% CI 1.06-3.68), threat of violence (aOR 1.96: 95% CI 1.05-3.66), poor work-life balance (aOR 1.78: 95% CI 1.44-2.20), low job satisfaction (aOR 1.69: 95% CI 1.37-2.09), high cognitive (OR 1.64: 95% CI 1.32-2.03) and emotional (aOR 1.53: 95% CI 1.22-1.91) demands, job insecurity (aOR 1.32: 95% CI 1.07-1.63), and high work intensity (aOR 1.55: 95% CI: 95% CI 1.25-1.92) had an increased risk of WRSP compared to their respective counterparts (p < 0.01). Low social support was not significantly associated with WRSP (aOR 0.88: 95% CI 0.67-1.15). CONCLUSION: The results revealed that poor psychosocial working conditions may be related to a high prevalence of WRSP among representative Korean workers.

Combined effect of work from home and work during nonwork time on sleep disturbance.

Background: Owing to the coronavirus disease 2019 pandemic, being exposed to work from home and work during nonwork time simultaneously can lead to sleep disturbance; however, their combined effect is unclear. We aimed to investigate the combined effect of work from home and work during nonwork time on sleep disturbance. Methods: This study used data from the Sixth Korean Working Condition Survey and included 27,473 paid workers. Logistic regression analysis was conducted to investigate the relationship between work from home, work during nonwork time, and sleep disturbance according to sex. We re-classified participants into 4 groups based on their working from home (No/Yes) and working during nonwork time (No/Yes). The relative excess risk due to interaction was calculated to examine the effect of exposure to both telecommuting and non-regular work hours on sleep disturbance. Results: Workers exposed to work from home and work during nonwork time had significantly higher risks of sleep disturbance for all, men, and women workers (OR [95% CI]: 1.71 [1.46-2.02], 1.79 [1.43-2.23], and 1.64 [1.29-2.08] for work from home and 3.04 [2.70-3.42], 3.61 [3.09-4.22], and 2.41 [2.01-2.90] for work during nonwork time, respectively). Compared to those who were not exposed to both factors, when workers had both job factors, the ORs (95% CI) of sleep disturbance for all, men, and women were 3.93 (2.80-5.53), 5.08 (3.21-8.03), and 2.91 (1.74-4.87), respectively. The relative excess risk due to interaction of work from home and work during nonwork time was not significant for sleep disturbance. Conclusions: Work from home and work during nonwork time were each associated with sleep disturbance, but the interaction between the two factors on sleep disturbance was not observed in both men and women.

Resection arthroplasty for septic arthritis of the sternoclavicular joint.

BACKGROUND: Treatment for septic arthritis of the sternoclavicular (SC) joint with concomitant osteomyelitis of the clavicle often requires joint resection rather than simple incision and drainage. We evaluated the effectiveness of resection arthroplasty for patients with septic arthritis of the SC joint. METHODS: We retrospectively reviewed 10 patients who underwent resection arthroplasty for SC joint septic arthritis between 1996 and 2008. The mean patient age was 52.8 ± 10.5 years (range, 40-72 years), the mean symptom duration before surgery was 16.9 days (range, 2-60 days), and the mean follow-up period was 35.4 ± 42.2 months (range, 10-108 months). Diagnoses were based on physical examination, laboratory tests, and radiologic studies including magnetic resonance imaging. Each patient had concomitant osteomyelitis of the clavicle. In addition, 4 patients had mediastinitis and 1 had osteomyelitis of the adjacent ribs. All patients underwent SC joint resection and intramedullary ligament reconstruction, followed by intravenous antibiotics for 4 to 8 weeks. Intraoperative cultures were positive in 6 patients. RESULTS: All infections resolved, with only 1 patient having complications-systemic sepsis and pneumonia. The mean ranges of motion were 146° of forward flexion (range, 135°-155°) and 48° of external rotation (range, 40°-55°), with the internal rotation level ranging from T5 to L3. The mean superior migration of the clavicle was 1.5 mm (range, 0-4 mm), and the mean visual analog pain score was 1.4 ± 0.7 (range, 0-2). CONCLUSION: Resection arthroplasty in patients with septic SC joints results in relatively good shoulder function.

Inequalities in External-Cause Mortality in 2018 across Industries in Republic of Korea.

Background: External-cause mortality is an important public health issue worldwide. Considering its significance to workers' health and inequalities across industries, we aimed to describe the state of external-cause mortality and investigate its difference by industry in Republic of Korea based on data for 2018. Methods: Data obtained from the Statistics Korea and Korean Employment Information System were used. External causes of death were divided into three categories (suicide, transport accident, and others), and death occurred during employment period or within 90 days after unemployment was regarded as workers' death. We calculated age- and sex-standardized mortalities per 100,000, standardized mortality ratios (SMRs) compared to the general population and total workers, and mortality rate ratios (RRs) across industries using information and communication as a reference. Correlation analyses between income, education, and mortality were conducted. Results: Age- and sex-standardized external-cause mortality per 100,000 in all workers was 29.4 (suicide: 16.2, transport accident: 6.6, others: 6.6). Compared to the general population, all external-cause and suicide SMRs were significantly lower; however, there was no significant difference in transport accidents. When compared to total workers, wholesale, transportation, and business facilities management showed higher SMR for suicide, and agriculture, forestry, and fishing, mining and quarrying, construction, transportation and storage, and public administration and defense showed higher SMR for transport accidents. A moderate to strong negative correlation was observed between education level and mortality (both age- and sex-standardized mortality rates and SMR compared to the general population). Conclusion: Inequalities in external-cause mortalities from suicide, transport accidents, and other causes were found. For reducing the differences, improved policies are needed for industries with higher mortalities.

Association between split shift work and work-related injury and disease absence.

BACKGROUND: Shift work (particularly split shifts) has been noted among the working conditions that hinder sustainable work. However, little is known regarding the effects of split shifts on health. This study aimed to investigate the association between split shift work and work-related injury and disease absence. METHODS: This study used data from the fifth Korean Working Conditions Survey and included 4,042 paid shift workers. Shift work type and self-reported work-related injury and disease absence were investigated using a questionnaire. Logistic regression analysis was performed to investigate the association between split shift work and work-related absence with rotating shift worker as the reference group. RESULTS: Of the 4,042 shift workers, 980 (24.3%) were split shift workers. The adjusted odds ratio (aOR) of split shift for absence due to work-related injury was high at 2.94 (95% confidence interval [CI]: 1.85-4.68) and the aOR of split shift for absence due to work-related disease was also high at 1.58 (95% CI: 1.09-2.29) compared to rotating shift. CONCLUSIONS: Split shift work leads to an increased risk of absences due to work-related injury and disease.

Effects of work organization on the occurrence and resolution of sleep disturbances among night shift workers: a longitudinal observational study.

This study aimed to investigate the association between work organization and the trajectories of insomnia patterns among night shift workers in a hospital. The health examination data of hospital workers, recorded from January 2014 to December 2018, were collected; 6765 records of 2615 night shift workers were included. Insomnia was defined as a score of ≥ 15 on the Insomnia Severity Index (ISI). Participants were categorized into five groups according to insomnia patterns derived from the analysis of their ISI scores. Work organization and socio-demographic characteristics were also investigated. Generalized estimating equation models and linear mixed models were constructed to analyze the longitudinal data. Of the total participants, 53.0% reported insomnia at least once during the follow-up period. The lack of nap opportunities and work-time control was associated with the occurrence of insomnia, whereas more than 5 years of shift work experience was related to the resolution of insomnia. All work-related factors were significantly related to insomnia risk; however, the effects were not significant in the sustained insomnia group. Although sleep problems are inevitable in night shift workers, well-designed work schedules and better work organization can help reduce the occurrence of insomnia among them.

Association of Intensive Endoscopic Screening Burden With Gastric Cancer Detection.

Importance: The rapidly increasing number of gastric cancer examinations performed over a short period might influence screening performance. Accessing the association between calendar month and gastric cancer detection rates might improve policy and guide institutional support. Objective: To evaluate the association between the increased number of examinations over a certain period and gastric cancer detection rates among a large population included in the Korean National Cancer Screening Program (KNCSP). Design, Setting, and Participants: This retrospective, population-based cohort study used data from the KNCSP comprising 26 765 665 men and women aged 40 years or older who participated in the screening program between January 1, 2013, and December 31, 2016. Data were analyzed from November 1, 2019, to March 31, 2020. Exposures: Gastric cancer screening with endoscopy. Main Outcomes and Measures: The primary outcome was monthly gastric cancer detection rates in the KNCSP. A negative binomial regression model was used to evaluate the association between the screening month and detection rates. Results: In total, 21 535 222 individuals underwent endoscopy (mean [SD] age, 55.61 [10.61] years; 11 761 709 women [54.62%]). The quarterly number of participants was the highest in the last quarter of the study period (2013-2014: 4 094 951 [41.39%], 2015-2016: 4 911 629 [42.19%]); this proportion was 2.48 to 2.84 times greater than that of the first quarter. Cancer detection rates were the lowest in December (2013-2014: 0.22; 95% CI, 0.22-0.23; 2015-2016: 0.21; 95% CI, 0.21-0.22); this was approximately a 40.0% to 45.0% reduction compared with the rates in January. The age group was the significant factor for monthly detection rates. After adjustment for the age group and taking account of the number of screenings, the estimated coefficient range for the screening month was negative and the detection rate in December was significantly different than in January for both the consequent cycles (2013-2014: -0.05 to -0.18; P < .001; and 2015-2016: -0.06 to -0.19; P < .001). In the multivariable logistic model, the association of calendar month with detected cancer remained after adjusting for other confounding factors (December, 2013-2014: odds ratio, 0.82; 95% CI, 0.76-0.87; P < .001; 2015-2016: odds ratio, 0.83; 95% CI, 0.79-0.89; P < .001). Conclusions and Relevance: The findings of this cohort study suggest that the workload of endoscopists increased with the increasing number of examinations toward the end of the year, as demonstrated by the decreased cancer detection rates. These findings may help to improve gastric cancer detection rates of screening programs by controlling the monthly screening number and policy modifications.

Association between change in working time arrangements and sleep disturbance.

BACKGROUND: Change in working time arrangement (WTA) can be harmful to workers' sleep and health. This study aimed to investigate the association between change in working time arrangement and sleep disturbance. METHODS: This study used data from the Fifth Korean Working Condition Survey and included 33,203 paid workers. We performed a stratified analysis by sex. After dividing the participants into 6 groups based on whether or not they experienced WTA changes, and their weekly working hours (≤40, 41-52, ≥53 hours), we calculated odds ratio (OR) using the weekly working hours ≤40 hours and with no WTA change as the reference group. RESULTS: Of the 33,203 paid workers, participants who experienced change in working time arrangement had higher prevalence of all three types of sleep disturbance symptoms (difficulty in falling asleep, waking up repeatedly during sleep, and waking up with a feeling of exhaustion and fatigue) in both sexes. Compared to the reference group at 95% confidence interval (CI), the group with change in WTA showed elevated OR values of 1.91 (95% CI: 1.73-2.11), 1.93 (95% CI: 1.74-2.14), 2.47 (95% CI: 2.26-2.71) for male workers; and 1.93 (95% CI: 1.73-2.16), 2.02 (95% CI: 1.80-2.27), 2.24 (95% CI: 2.01-2.50) for female workers, for difficulty in falling asleep, waking up repeatedly during the sleep, waking up with a feeling of exhaustion, and fatigue, respectively. CONCLUSIONS: Workers who experience change in work time arrangement show a high risk of sleep disturbance in both sexes.