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.

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.

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.

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.

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.

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.

Does severe subacute noise exposure increase risk of new onset hypertension beyond conventional risk factors? A 30 000 person-years cohort study.

OBJECTIVES: Previous studies mostly focused on the relationship between chronic environmental noise exposure and hypertension but the effects of subacute (under 4 years) exposure with severe (>85 dB) noise exposure on clinical level hypertension have not been explored. This study aimed to reveal the association between severe noise exposure and hypertension. METHODS: The severe noise exposure group was recruited from a Common Data Model conducted for the Korean Participants Health Examination from January 2014 to December 2017. The use of antihypertensive drug and/or blood pressure of at least 140/90 mmHg was defined as new onset clinical hypertension. A multivariate Cox proportional hazard model was implemented to estimate hazard ratios and 95% confidence intervals (CI) by adjusting covariates including demographic, lifestyle, and other chemical exposure factors. Time-dependent Cox analysis and Landmark analysis were further performed as a sensitivity analysis. RESULTS: During the 29 332 person-years follow-up with 12 412 participants of the entire cohort, new onset hypertension occurred in 1222 participants. The findings showed that severe noise exposure was associated with an increased risk of hypertension incidence in the entire cohort [final model hazard ratio 1.28 (95% CI 1.11-1.47)]. Other covariates did not attenuate the association after adjusting age and sex. Time-dependent Cox and Landmark analysis also showed significant results [hazard ratio 1.60 (95% CI 1.38-1.85) and hazard ratio 1.33 (95% CI 1.13-1.57)]. CONCLUSION: Severe noise with subacute exposure is significantly associated with hypertension development. Further studies should be implemented to clarify whether severe exposure to noise could be an important risk factor for hypertension.

Nocardioides palaemonis sp. nov. and Tessaracoccus palaemonis sp. nov., isolated from the gastrointestinal tract of lake prawn.

Two novel Gram-stain-positive, non-motile and non-spore-forming bacterial strains, designated J2M5T and J1M15T, were isolated from the gastrointestinal tract of a lake prawn Palaemon paucidens. Strain J2M5T was an obligately aerobic bacterium that formed milky-coloured colonies and showed a rod-coccus cell cycle, while strain J1M15T was a facultatively aerobic bacterium that formed orangish-yellow-coloured colonies and showed rod-shaped cells. Strains J2M5T and J1M15T showed the highest 16S rRNA gene sequence similarity to Nocardioides ganghwensis JC2055T (98.63 %) and Tessaracoccus flavescens SST-39T (98.08 %), respectively. The whole-genome sequence of strain J2M5T was 4.52 Mbp in size and the genomic G+C content directly calculated from the genome sequence of strain J2M5T was 72.5 mol%. The whole-genome sequence of strain J1M15T was 3.20 Mbp in size and the genomic G+C content directly calculated from the genome sequence of strain J1M15T was 69.6mol %. Strains J2M5T and J1M15T showed high OrthoANI similarity to N. ganghwensis JC2055T (83.6 %) and T. flavescens (77.2 %), respectively. We analysed the genome sequences of strains J2M5T and J1M15T in terms of carbohydrate-active enzymes, antibiotic resistance genes and virulence factor genes. Strains J2M5T and J1M15T contained MK-8 (H4) and MK-9 (H4) as the predominant respiratory quinones, respectively. The major polar lipids of both strains were phosphatidylglycerol and diphosphatidylglycerol. Additionally, strain J2M5T possessed phosphatidylcholine, phosphatidylserine and phosphatidylethanolamine. The cellular sugar components of strain J2M5T were ribose, mannose, glucose and galactose, and its cellular amino acid components were l-alanine and l-lysine. The cellular sugar components of strain J1M15T were rhamnose, ribose, mannose and glucose, and its cellular amino acid component was l-alanine. The major cellular fatty acids of strains J2M5T and J1M15T were iso-C16 : 0 and anteiso-C15 : 0, respectively. The multiple taxonomic analyses indicated that strains J2M5T and J1M15T represent novel species of the genus Nocardioides and Tessaracoccus, respectively. We propose the names Nocardioides palaemonis sp. nov. and Tessaracoccus palaemonis sp. nov. for strain J2M5T (=KCTC 49461T=CCUG 74767T) and strain J1M15T (=KCTC 49462T=CCUG 74766T), respectively.

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.

Relationship between workers' return to work, job retention and income in industrial accidents in Korea: a longitudinal study.

OBJECTIVE: This study aims to compare workers' income before and after an occupational injury, with regard to return to work and job retention, over a period of 5 years. DESIGN: This study was designed as a longitudinal study. SETTING: The Panel Study of Workers' Compensation Insurance (PSWCI) survey targeted workers involved in industrial accidents for which medical care was terminated in the year 2012. PARTICIPANTS: The panel study was conducted on a final sample of 2000 workers who were selected proportionally by region (nine regions) after priority assignment by disability rating (six levels). A total of 1458 workers were finally included in this study. METHODS: This study used data from the first to fifth PSWCI. To identify the effect on income after occupational injury considering return to work and job retention, we used the generalised estimating equation. RESULTS: In regard to workers' return to work, the OR that income after an occupational injury would be higher than that before an occupational injury was 3.17 (2.41-4.17) for those who returned to original work and 2.32 (1.81-2.97) for those re-employed as compared with who did not return to work and 1.27 (1.07-1.15) for those who retained their job as compared with those who did not. The ORs were 2.91 (2.26-3.75) for those who were re-employed and retained jobs and 2.96 (2.15-4.08) for those who returned to original work and did not retain jobs as compared with those who did not return to work and did not retain jobs. CONCLUSIONS: It is important for accident victims to retain their jobs to maintain their economic status.

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.

Combined effect of emotional labor and job insecurity on sleep disturbance among customer service workers.

BACKGROUND: Job insecurity and emotional labor are poor job-related factors that are known to cause sleep disturbances in customer service workers. This study investigates the combined effect of emotional labor and job insecurity on sleep disturbance. METHODS: This study used data from the Fifth Korean Working Condition Survey and included 15,147 paid workers who serve customers below 65 years. We re-classified into 6 groups based on whether the degree of emotional labor increased (Rarely/Sometimes/Always) or whether job insecurity (No/Yes) was present. We performed propensity score matching for several covariates and calculated odds ratio (OR) and 95% confidence intervals (CIs) for sleep disturbance by logistic regression models using only matched subjects. RESULTS: Workers exposed to emotional labor and job insecurity had significantly higher risk for 3 dimensions of sleep disturbance (difficulty falling asleep, waking up repeatedly during the sleep, and waking up with feeling of fatigue) (OR [95% CI]: 1.44 [1.22-1.69], 1.18 [0.99-1.40], 1.52 [1.30-1.79] for emotional labor; and 2.00 [1.75-2.29], 2.20 [1.91-2.53], 1.67 [1.45-1.92] for job insecurity). Compared to those who were exposed to both emotional labor rarely and without job insecurity, when workers had both poor job factors, the OR (95% CI) for sleep disturbance for difficulty falling asleep, waking up repeatedly during the sleep, and waking up with feeling of fatigue were 3.05 (2.42-3.86), 2.89 (2.26-3.69), and 2.60 (2.06-3.29), respectively. The relative excess risk due to Interaction of job insecurity and emotional labor was significant only for difficulty falling asleep, but not the other 2 sleep disturbance dimensions. CONCLUSIONS: Customer service workers suffered from severe sleep disturbances according to the existing degree of emotional labor and job insecurity. The combined effect of both could have an additive influence on serious sleep disturbance among customer service workers.

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.

Mercury Exposure and Associations with Hyperlipidemia and Elevated Liver Enzymes: A Nationwide Cross-Sectional Survey.

Mercury (Hg) has obesogenic properties. However, the associated health outcomes of population-level mercury exposure were unclear. This study investigated the relationships between blood mercury levels and obesity-related outcomes such as hyperlipidemia and elevated liver enzymes. Using the second cycle of the Korean National Environmental Health Survey (n = 6454), we performed logistic regression to examine the effects of Hg on hyperlipidemia and elevated liver enzymes. The blood mercury levels were significantly higher in the hyperlipidemia group (n = 3699, male: 4.03 µg/L, female: 2.83 µg/L) compared to the non-hyperlipidemia group (n = 2755, male: 3.48 µg/L, female: 2.69 µg/L), and high blood mercury levels were associated with an 11% higher risk of hyperlipidemia. The elevated liver enzymes group had higher mean blood mercury levels (n = 1189, male: 4.38 µg/L, female: 3.25 µg/L) than the normal group (n = 5265, male: 3.64 µg/L, female: 2.70 µg/L), and elevated blood mercury was associated with a 35% higher risk of elevated liver enzymes. Moreover, the effect was constant after adjusting for personal medications. These results indicate that mercury exposure is significantly associated with hyperlipidemia and elevated liver enzymes.

Short rest between shifts and risk of hypertension in hospital workers.

OBJECTIVES: Shift work is related to hypertension and other cardiovascular diseases, and short shift intervals of less than 11 h (quick returns) are reported to be related to health problems, including sleep disturbance and fatigue. However, its cardiovascular effect has rarely been examined. The purpose of this study was to investigate the relationship between quick returns, consecutive night shifts, and risk of hypertension in hospital workers. METHODS: Data collected from a medical examination of 1372 nonhypertensive shift workers in a hospital were retrospectively followed up. Demographic factors (sex and age), lifestyle habits (smoking, alcohol use, exercise, and obesity), and work-related factors (working hours, shift work experience, consecutive night shifts, and quick returns status) were included in the analyses. Multivariate Cox proportional-hazard models were conducted to estimate hazard ratio and 95% confidence interval (CI). RESULTS: The findings showed that quick returns was related to an increased risk of hypertension (hazard ratio, 95% CI: 1.88, 1.00-3.54), whereas consecutive night shifts were not. However, the risk of hypertension was significantly higher in workers with quick returns and 2-3 days of consecutive night shifts (3.33, 1.18-9.39) and those with quick returns and at least 4 days of consecutive night shifts (3.79, 1.22-11.76), compared with the reference group. CONCLUSION: The findings of this study indicate that short shift intervals and consecutive night shifts are related to an increased risk of hypertension in shift-working hospital workers.

The association between dependent self-employment and self-reported depression/anxiety and sleep disorder in South Korea.

BACKGROUND: Dependent self-employment is precarious employment, which can be vulnerable to mental health problems. This study aimed to investigate the association of dependent self-employment with depression, anxiety, and sleep disorder in South Korea. METHODS: This study used data from the Fourth Korean Working Conditions Survey and included 32,691 paid workers. Dependent self-employment and self-reported depression/anxiety, and sleep disorder were investigated using a questionnaire. Logistic regression analysis was performed to investigate the association between dependent self-employment and mental health problems. RESULTS: Of the 32,691 paid workers, 2,371 (7.3%) were dependent self-employed workers. The odds ratio (OR) of dependent self-employment for self-reported depression/anxiety was 1.78 (95% confidence interval [CI]: 1.29-2.45) and the OR of dependent self-employment for self-reported sleep disorder was 1.26 (95% CI: 1.01-1.59) compared to other paid workers. CONCLUSIONS: Dependent self-employment is related to an increased risk of self-reported depression/anxiety and sleep disorder in South Korea.

Association between the return-to-work hierarchy and self-rated health, self-esteem, and self-efficacy.

PURPOSE: This study aimed to examine whether change of employer and/or job upon return-to-work after work-related injuries and diseases is related to health outcomes; self-rated health, self-esteem, and self-efficacy were used as indicators. METHODS: Data from the Panel Study of Workers' Compensation Insurance in Korea were used. A total of 1,610 workers who had returned to work after work-related injuries and diseases were included. The workers were divided into four groups according to their return-to-work characteristics: same employer, same job (n = 660); same employer, different job (n = 57); different employer, same job (n = 318); and different employer, different job (n = 575). Self-rated health, Rosenberg Self-Esteem Scale, and Self-Efficacy Scale scores were used as outcome variables. Logistic regression analysis was used. RESULTS: Compared to workers who had returned to the same employer and same job, those who had returned to the same employer but a different job were less likely to report good self-rated health (odds ratio [OR] 0.54; confidence interval [CI] 0.30-0.97). Those returning to a different employer but the same job were less likely to report good self-rated health (0.47, 0.35-0.64) and high self-esteem (0.73, 0.55-0.96). Those returning to a different employer and different job were less likely to report good self-rated health (0.49, 0.38-0.63), high self-esteem (0.68, 0.54-0.86), and high self-efficacy (0.66, 0.52-0.83). CONCLUSIONS: Change of employer and/or job related to health outcomes. Returning to the same employer and same job should be set as a goal in the vocational rehabilitation process.

Irregular work schedule and sleep disturbance in occupational drivers-A nationwide cross-sectional study.

BACKGROUND: The objective of this study was to investigate the relationship between irregular work schedules and sleep disturbance and compare the impacts of work schedule on sleep disturbance between occupational drivers and office workers. METHODS: Using data from the 3rd and 4th Korean Working Conditions Survey, 3,070 occupational drivers and 9,898 office workers were included in this study. The subjects' days of night work, evening work, and subjective complaints of sleep disturbance were investigated along with other covariates. RESULTS: In the multivariate logistic regression analyses, occupational drivers (odds ratio [OR], 95% confidence interval [CI]: 1.51, 1.11-2.05), workers who were engaged in more night work (2.49, 1.84-3.38 for 1-15 days, and 3.80, 2.67-5.41 for 16-30 days) and evening work (2.22, 1.66-2.97 for 1-15 days, and 1.76, 1.26-2.45) were more likely to report sleep disturbance. Moreover, occupational driving showed significant interaction effects with both night and evening work on sleep disturbance, and therefore, showed higher ORs for sleep disturbance in the 16-30 days night (5.38, 3.40-8.52) and evening (3.13, 1.97-4.98) compared to no night and evening working office workers. CONCLUSIONS: Occupational drivers who are exposed to night work and evening work are at higher risks for sleep disturbance. Therefore, for the public and drivers' safety, optimal work schedules for minimising sleep disturbance should be developed.

Impact of near work on perceived stress according to working hours: The Korea National Health and Nutrition Examination Survey VI (2013-2015).

The purpose of this study was to investigate the relationships among working hours, near work time, and perceived stress. In total, data of 3,776 workers from the Korea National Health and Nutrition Examination Survey VI were examined. The workers' working hours per week, daily near work time, and complaints of perceived stress were analyzed in conjunction with other sociodemographic and occupation-related variables. Multivariate logistic analysis found that workers with 3 and ≥4 hours of near work were more likely to report high perceived stress than were the reference group who had <1 hour per day of near work, with odds ratios (ORs) (95% confidence intervals [CIs]) of 1.34 (1.01-1.78) and 1.94 (1.53-2.46), respectively. Additionally, those working 50 and more hours a week were more likely to report high perceived stress with ORs of 1.51 (1.19-1.90) and 1.88 (1.42-2.48), respectively. When stratified by working hours, workers with daily near work time of ≥4 hours were more likely to report high perceived stress with ORs of 2.21 (1.45-3.37), 2.27 (1.30-3.97), and 3.47 (1.80-6.69), among the workers with 40-49, 50-59, and ≥60 weekly working hours, respectively. Workers with greater near work time are at risk for high perceived stress. Moreover, this risk was found to be higher among workers with longer working hours. Therefore, work cycle modification and reductions in near work time are necessary to prevent stress-related health outcomes.

Effects of changes in occupational stress on the depressive symptoms of Korean workers in a large company: a longitudinal survey.

BACKGROUND: Prospective studies on occupational stress and depression among Korean workers are scarce. This study aimed to investigate the causal relationship between changes in occupational stress and the presence of depression. METHODS: This study analyzed data from a survey conducted with workers in a large Korean company (2015-2016). Occupational stress was measured using the Korean Occupational Stress Scale, and depression was screened using the WHO-5 Well-being Index. The levels of occupational stress were grouped in quartiles based on subjects' occupational stress scores in 2015, and changes in occupational stress were measured using the score changes between the 2015 and 2016 surveys. Subjects were divided into four groups according to the presence or absence of depression in 2015 and 2016: a non-depressed group whose mental health did not change, a non-depressed group whose mental health deteriorated, a depressed group that continued to be depressed, and a depressed group whose symptoms of depression were alleviated. Logistic regression analysis was used to calculate the odds ratios (ORs) and confidence intervals (CIs) of the subjects' deterioration in mood or alleviation of depression by occupational stress levels and changes. RESULTS: The OR for developing depressive symptoms was 2.51 (95% CI 1.46-4.33) and 2.73 (95% CI 1.39-5.36) in the third and the fourth quartiles of occupational stress, respectively, compared to the first quartile. When the occupational stress score increased by 1 point, the OR for increasing depressive symptoms was 1.07 (95% CI 1.04-1.10). There was no significant difference in the alleviation of depressive symptoms between the groups by level of occupational stress. However, when the occupational stress score decreased by 1 point, the OR for alleviating depressive symptoms was 1.08 (95% CI 1.05-1.11). CONCLUSION: The results showed that increased occupational stress increased the presence of depressive symptoms, and that reduced occupational stress suppressed the development of depressive symptoms. More attention should be paid to stress management among workers.