Precarious employment and the onset of depressive symptoms and problematic alcohol use in middle-aged or older workers: A Korean longitudinal study (2006-2022).

Although precarious employment (PE) has emerged as a growing public health concern, research on older adults is scarce. This study explored the associations between PE and the onset of depressive symptoms and problematic alcohol use among middle-aged and older workers. A total of 2536 Korean waged workers aged ≥45 years contributed 8486 observations from 2006 to 2022. PE was defined as a multidimensional construct that includes employment insecurity, income inadequacy, and a lack of worker rights and protection. Depressive symptoms and problematic alcohol use were assessed using the Center for Epidemiological Studies Depression Scale and the CAGE questionnaire. Generalized estimating equations were employed to determine the association of PE with depressive symptoms and problematic alcohol use after the two-year follow-up. Risk ratios (RR) and 95% confidence intervals (CI) were estimated. Women, individuals with older age and low educational background, and blue-collar workers were more likely to belong to the high PE group. For individual indicators of PE, daily employment (RR: 1.26, 95% CI: 1.05-1.53), the lowest wage quartile (RR: 1.32, 95% CI: 1.01-1.72), and lack of trade union (RR: 1.55, 95% CI: 1.10-2.17) were positively associated with depressive symptom onset in the follow-up. Compared with the group with the lowest overall PE, the group with the highest PE exhibited increased risks of experiencing the onset of depressive symptoms (RR: 1.62, 95% CI: 1.27-2.08) and problematic alcohol use (RR: 2.45, 95% CI: 1.16-5.17) in the follow-up. This study suggests that PE is a major social determinant of older workers' mental health.

Interaction between old age and precarious employment on poor mental well-being in workers: Evidence from a nationally representative sample in Korea.

OBJECTIVE: This study examined the relationship between precarious employment (PE) and mental well-being, focusing on age-specific interactions. METHODS: Nationally representative Korean workers (N = 29,961) were surveyed between 2020 and 2021 to collect data on multidimensional PE (categorized as low, moderate, or high) and the WHO-5 well-being index. Workers' ages were classified as young (<35 years), middle-aged (35-54 years), and older (≥55 years). Logistic regression was performed to estimate the odds ratios (ORs) and 95% confidence intervals (CIs). The interaction between PE and age on well-being was examined by including interaction terms in the regression models. RESULTS: The prevalence of poor well-being was 25%, 29%, and 39% for low, moderate, and high precariousness, respectively, whereas it was 26%, 30%, and 39% for young, middle-aged, and older workers, respectively. In the overall sample, the OR (95% CI) of the association between PE and poor well-being was 1.24 (1.17-1.32) for moderate and 1.54 (1.43-1.65) for high precariousness, compared with low precariousness. There was a significant interaction between old age and PE on the odds of poor well-being. Compared with young workers with low PE, middle-aged workers with high PE (OR: 1.85, 95% CI: 1.62-2.10) and older workers with high PE (OR: 2.10, 95% CI: 1.83-2.40) exhibited increased odds of having poor mental well-being. CONCLUSION: PE serves as a social determinant of older workers' psychological well-being. Policy interventions are required to protect older workers' psychological well-being.

Longitudinal Trajectories of Depressive Symptoms and Their Associations With Risks of Underweight and Obesity in Women: A Population-Based Longitudinal Study in Korea.

Objective: We explored depressive symptom trajectories and their associations with underweight and obesity in Korean women.Methods: This prospective cohort study involved 7,691 women enrolled in the Korean Longitudinal Survey of Women and Families, with a follow-up period spanning from 2014 to 2020. Depressive symptoms were evaluated through the 10-item version of the Center of Epidemiologic Studies Depression Scale. Growth mixture modeling was employed to identify trajectories of depressive symptoms. Multinomial logistic regressions were conducted to investigate the correlation between depression trajectories and the evolving risks of underweight and obesity over the study period.Results: Five distinct trajectory classes were observed ("persistent low symptoms": N = 5,236, 68.1%; "decreasing symptoms": N = 930, 12.1%; "transient high symptoms": N = 421, 5.5%; "increasing symptoms" N = 825, 10.7%; and "persistent high symptoms": N = 279, 3.6%). Those with a low socioeconomic status, comorbidity, and who were divorced or widowed were more likely to follow the persistent high symptom trajectory. Among the 5 trajectories, the risks of underweight and obesity steadily increased in women following the trajectory with persistent high symptoms. For these women, the odds ratio (OR) of underweight increased from 2.27 (95% CI, 1.32-3.92) in 2014 to 3.39 (1.91-6.05) in 2020. They were not associated with obesity in 2014 (OR [95% CI]: 1.38 [0.61-3.11]) but exhibited an elevated risk of obesity in 2020 (3.76 [1.97-7.17]).Conclusion: We observed considerable heterogeneity in the trajectories of depressive symptoms among women, and individuals with persistent high depressive symptoms face an escalating risk of both underweight and obesity.

Temporary Employment Is Associated with Poor Dietary Quality in Middle-Aged Workers in Korea: A Nationwide Study Based on the Korean Healthy Eating Index, 2013-2021.

Temporary employment is associated with an elevated risk of cardiovascular diseases and mortality. This study explored the association between temporary employment and dietary quality in middle-aged workers. This cross-sectional study included a nationwide sample of middle-aged Korean workers (n = 6467). Employment type was categorized into regular, fixed-term, and daily employment, based on labor contract duration. Dietary quality was assessed using the Korean Health Eating Index (KHEI), which ranges from 0 to 100, with higher scores indicating superior dietary quality. Linear regression was used to estimate beta coefficients (ß) and 95% confidence intervals (CI). The survey-weighted proportion of regular, fixed-term, and daily employment was 79.0%, 14.2%, and 6.8%, respectively. Fixed-term and daily employment were associated with a reduced KHEI compared with regular employment (ß [95% CI]: -1.07 [-2.11, -0.04] for fixed-term and -2.46 [-3.89, -1.03] for daily employment). In sex-stratified analysis, the association between temporary employment and dietary quality was more pronounced in men (ß [95% CI]: -1.69 [-3.71, 0.33] for fixed-term and -2.60 [-4.63, -0.53] for daily employment than in women. In conclusion, this study suggests that temporary employment is a social determinant of dietary quality in middle-aged workers.

Association between Dietary Quality and Non-Alcoholic Fatty Liver Disease in Korean Adults: A Nationwide, Population-Based Study Using the Korean Healthy Eating Index (2013-2021).

This study explored the relationship between the Korean Healthy Eating Index (KHEI) and non-alcoholic fatty liver disease (NAFLD). This cross-sectional study included 34,174 Korean adults. The KHEI was composed of three subcomponents (adequacy, moderation, and energy balance) and calculated based on a 24 h dietary recall. The total score ranged from 0 to 100, with a higher score indicating a greater adherence to the Korean dietary guidelines. The total KHEI scores were categorized into quartiles (Q1-Q4). NAFLD was classified using the hepatic steatosis index. Logistic regressions were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). The adjusted OR (95% CI) of NAFLD was 0.95 (0.87-1.03) for the Q2 group, 0.90 (0.83-0.98) for the Q3 group, and 0.79 (0.72-0.87) for the Q4 group, compared with the Q1 group. Among the subcomponents of the KHEI, individuals with high scores in the adequacy component, characterized by an abundant consumption of fruits, vegetables, and dairy products, exhibited the most pronounced association with NAFLD. A higher KHEI score was negatively associated with NAFLD in Korean adults. Therefore, the promotion of healthy dietary patterns can play a beneficial role in the prevention or management of NAFLD.

Sex differences in the association between social jetlag and hazardous alcohol consumption in Korean workers: A nationwide cross-sectional study.

BACKGROUND: Social jetlag, the misalignment between biological and social rhythms, can lead to adverse health outcomes. This study explored the association between social jetlag and hazardous alcohol consumption, as well as the sex differences in this association. METHODS: This study included a nationally representative sample of Korean workers consisting of 11,462 individuals (5479 women). Social jetlag was calculated as the difference in the mid-point between sleep onset and offset on free days and workdays. Hazardous alcohol consumption was determined using the Alcohol Use Disorder Identification Test-Consumption (range 0-12), with a cutoff of ≥6 for men, ≥5 for women, and ≥3 for those aged ≥65. Logistic regression analysis was used to estimate the odds ratios (ORs) and 95 % confidence intervals (CIs). RESULTS: Among men, 599 out of 5983 individuals (10.0 %) had ≥120 min of social jetlag. Among women, 550 out of 5479 individuals (10.0 %) had ≥120 min of social jetlag. The prevalence of hazardous alcohol use was 56.2 % for men and 27.3 % for women. In the regression analysis, there was a significant sex interaction, where social jetlag ≥120 min was associated with hazardous alcohol consumption in female workers (OR: 1.52, 95 % CI: 1.18-1.96), but not in male workers (OR: 1.04, 95 % CI: 0.84-1.29). CONCLUSION: High social jetlag was associated with an increased likelihood of hazardous alcohol consumption among women. Our findings underscore the importance of considering sex differences in future research and policy interventions regarding social jetlag and its associated behavior outcomes.

Long working hours, work-life imbalance, and poor mental health: a cross-sectional mediation analysis based on the sixth Korean Working Conditions Survey, 2020-2021.

Background There has been growing concern about the negative mental health impact of long working hours and overwork. Our study examined how work-life imbalance (WLI) could be a mediator between working hours and poor mental well-being.Methods We included 34,968 individuals from a nationwide cross-sectional survey in Korea. Self-reported working hours per week was collected, and mental health was assessed by the WHO-5 Well-Being Index. Counterfactual-based mediation models were employed to disentangle the total effects into a direct effect (work hour - poor mental health) and an indirect effect (work hour - WLI - poor mental health).Results Out of 34,968 participants, 52.6% worked 35-40 h/week, 20.0% worked 41-48 h/week, 11.7% worked 49-54 h/week, and 15.6% worked ≥55 h/week. The odds ratios (ORs) of the total impact of working hours on poor mental health were 1.08 (95% CI: 1.01-1.16) for 41-48 h/week, 1.28 (1.17-1.39) for 49-54 h/week, and 1.60 (1.48-1.74) for ≥55 h/week in comparison to 35-40 h/week. The ORs of the indirect effects were 1.04 (1.03-1.05) for 41-48 h/week, 1.08 (1.07-1.09) for 49-54 h/week, and 1.14 (1.12-1.16) for ≥55 h/week, accounting for 51%, 31%, and 28% of the total effects.Conclusion: Our findings suggest that WLI can partially mediate the association of long working hours with mental health deterioration. Policy efforts are required to mitigate the adverse mental health effects of overwork.

Association between sickness presenteeism and depressive symptoms: a cross-sectional study using the 6th Korean working conditions survey.

PURPOSE: This study aimed to reveal the relationship of the days of experiencing sickness presentism and depressive symptoms among Korean workers. Sickness presenteeism which defined as the act of going to work despite being feeling unhealthy triggers various adverse effects on mental health, including increased risks of depression. Furthermore, Sickness presenteeism is a major social issue causing substantial socioeconomic costs. METHODS: The data of 25120 participants from sixth Korean Working Condition Survey was utilized in this cross-sectional study. Sickness presenteeism was defined using a self-reported questionnaire and depressive symptoms were assessed by WHO well-being index. Multivariate logistic regression analysis was conducted to calculate the odd ratios for depressive symptoms regarding the number of days experiencing sickness presenteeism. We calculated odds ratios (ORs) and 95% confidence interval (95% CI) for depressive symptoms after categorizing participants into three groups based on the duration of experiencing sickness presenteeism, using cut-off values of 3 and 5 days. RESULTS: Workers who have experienced sickness presenteeism for more than 5 days were at highest risk for depressive symptoms than referent group (OR 2.87; 95% CI 2.17-3.76 in male, OR 3.86; 95% CI 3.02-4.91 in female). Furthermore, there was a trend of increasing risk for depressive symptom as the duration of experiencing sickness presenteeism extended. CONCLUSION: This study presents the association between experiencing sickness presenteeism in the previous 12 months and depressive symptoms. Based on the results, we provide individual and organizational strategies of reducing sickness presenteeism. Also, screening for workers who have experienced sickness presenteeism are needed to ensure good mental health.

Association between precarious employment and the onset of depressive symptoms in men and women: a 13-year longitudinal analysis in Korea (2009-2022).

AIMS: Increasing social concern surrounds the potential adverse health effects of precarious employment (PE). In this study, we explored the association between PE and the onset of depressive symptoms. METHODS: A total of 11,555 Korean waged workers (5700 females) contributed 62,217 observations from 2009 to 2022. PE was operationalized as a multidimensional construct, including employment insecurity, income inadequacy and lack of rights and protection. Depressive symptoms were evaluated using the Center for Epidemiological Studies-Depression Scale (11-item version). The association between PE and the onset of depressive symptoms in the subsequent year was estimated using generalized estimating equations. Effect sizes were reported as odds ratio (OR) and 95% confidence interval (CI). RESULTS: The overall incidence of depressive symptoms was 8.3% during the study period. In cross-sectional analysis, daily employment, disguised employment, lower monthly wages and lack of social insurance coverage were associated with concurrent depressive symptoms in both men and women. Longitudinally, fixed-term employment (OR: 1.17, 95% CI: 1.07-1.29), daily employment (OR: 1.64, 95% CI: 1.45-1.85) and disguised employment (OR: 1.36, 95% CI: 1.17-1.57) were associated with the onset of depressive symptoms among the overall sample. Among men, the lowest quartiles of wage were associated with the onset of depressive symptoms (OR: 1.34, 95% CI: 1.13-1.60), while the absence of a trade union was associated among women (OR: 1.18, 95% CI: 1.01-1.39). CONCLUSIONS: Employment insecurity, inadequate income and lack of rights and protection may contribute to depressive symptoms. Therefore, PE serves as a significant social determinant of mental health among workers in Korea. Active policy efforts are warranted to improve the overall quality of employment in the workforce.

Relationship between long working hours and smoking behaviors: Evidence from population-based cohort studies in Korea.

OBJECTIVES: Long working hours and overwork are growing public health concerns in the Western-Pacific region. We explored the relationship between working hours and smoking behaviors of Korean workers. METHODS: This study included 284 782 observations (50 508 workers) from four nationwide cohort studies in Korea. Using generalized estimating equations, we estimated the associations of working hours with current smoking status, smoking initiation, and smoking cessation within each cohort. Cohort-specific estimates were combined through random-effect meta-analysis. Effect sizes were presented as odds ratios (OR) and 95 confidence intervals (CI). RESULTS: The overall smoking prevalence was 26.8% within the cohorts. The adjusted OR (95% CI) of the association between working hours and current smoking were 1.01 (0.94-1.08) for <35 hours/week, 1.04 (1.01-1.09) for 41-48 hours/week, 1.06 (1.01-1.10) for 49-54 hours/week, and 1.07 (1.04-1.10) for ≥55 hours/week compared with 35-40 hours/week. The adjusted OR (95% CI) of the association between working hours and smoking cessation in the follow-up were 0.93 (0.85-1.02) for <35 hours/week, 0.89 (0.83-0.96) for 41-48 hours/week, 0.87 (0.81-0.95) for 48-54 hours/week, and 0.91 (0.85-0.98) for ≥55 hours/week compared with 35-40 hours/week. No clear associations were observed between working hours and smoking initiation. CONCLUSION: Long working hours are associated with high current smoking risk and reduced likelihood of smoking cessation among Korean workers. Policy interventions are required to promote smoking cessation and reduce excess overwork for individuals experiencing long working hours.

Association between temporary employment and current smoking and change in smoking behaviors: A prospective cohort study from South Korea (2009-2018).

Background Previous studies have suggested that employment insecurity is associated with adverse health outcomes. We explored the association between temporary employment and smoking behaviors.Methods We analyzed 11,795 workers (51,867 observations) from the Korea Health Panel Study (2009-2018). Employment types were categorized as regular, fixed-term, or daily, based on the duration of labor contract. The outcomes were current smoking status and changes in smoking behavior (initiation or cessation) in the following year. Generalized estimating equations were used to estimate odds ratio (OR) and 95% confidence interval (CI).Results The proportions of fixed-term and daily workers were 41.2% and 16.4% for women and 23.6% and 12.4% for men, respectively. Temporary employment was associated with increased odds of current smoking, while also demonstrating prospective associations with changes in smoking behaviors. For instance, in prospective analyses, male workers with fixed-term and daily employments were associated with a decreased likelihood of smoking cessation (OR:0.77; 95% CI:0.65-0.91 for fixed-term employment and OR:0.66; 95% CI:0.52-0.83 for daily employment) in the following year compared to those with regular employment. Moreover, those experiencing consecutive temporary employment was most inversely associated with smoking cessation in both men (OR:0.56; 95% CI:0.44-0.71) and women (OR:0.37; 95% CI:0.16-0.85) compared to those experiencing consecutive regular employment. However, no clear association between temporary employment and smoking initiation was observed in both men and women.Conclusions Temporary employment is directly associated with current smoking and inversely associated with smoking cessation. Policies are needed to improve job insecurity among temporary employees.

Association between long working hours and diet quality and patterns: A latent profile analysis of a nationally representative sample of Korean workers.

BACKGROUND: Long working hours are associated with cardiovascular and metabolic diseases. This study investigated the relationship between the working hours and dietary qualities and patterns in Korean workers. METHODS: Data from 24,523 workers were extracted from the Korea National Health and Nutrition Examination Survey, 2013-2021. The Korean Healthy Eating Index (KHEI), which ranges from 0 to 100, with a higher score indicating greater adherence to Korean dietary guidelines and superior dietary quality, was used for dietary assessment. We identified dietary patterns and classified workers using latent profile analysis. Logistic regressions were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Five distinct dietary patterns emerged: healthy diet (24.8%), low-vegetable diet (14.0%), average diet (7.8%), low-fruit diet (31.4%), and poor diet (22.0%). The mean KHEI score was 60.8, with the highest score observed in the healthy diet pattern (71.3) and the lowest, in the poor diet pattern (50.0). Compared with working 35-40 h/week, working ≥55 h/week was negatively associated with KHEI scores (ß: -1.08; 95% CI: -1.67, -0.49). Those working ≥55 h/week were less likely to have a healthy diet pattern (OR: 0.81; 95% CI: 0.72, 0.91) and more likely to have a low-fruit diet (OR: 1.36; 95% CI: 1.20, 1.55) or poor diet pattern (OR: 1.23; 95% CI: 1.05, 1.43) compared with those working 35-40 h/week. CONCLUSION: Long working hours are associated with undesirable dietary quality and patterns. Policy interventions aimed at enhancing dietary quality are needed to alleviate the health burdens associated with long working hours.

Job dissatisfaction as a risk factor of depressive symptoms and suicidal ideation among female workers: evidence from a nationwide longitudinal study in South Korea.

This study aimed to investigate the relationship between job dissatisfaction (JD) and depressive symptoms and suicidal ideation among female workers. Additionally, it examined how the cumulative exposure to JD over multiple years can exacerbate the effect. We conducted our analyses on a nationwide sample of 6111 female workers from the Korean Longitudinal Survey of Women and Family (Waves 5-7). Depressive symptoms were measured using the 10-item version of the Centre for Epidemiologic Studies Depression Scale. JD was classified into quartiles (Q1-Q4), and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using generalised estimating equations. The overall prevalence of depressive symptoms and suicidal ideation among study participants was 13.9% and 2.4%, respectively. Our findings revealed that female workers with the highest level of JD (Q4) had a significantly greater risk of depressive symptoms (OR [95% CI]: 1.61 [1.37-1.89]) and suicidal ideation (OR [95% CI]: 2.08 [1.37-3.17]) after 2-year follow-up compared to those with the lowest level of JD (Q1). Consecutive exposure to JD over multiple years was also associated with depressive symptoms and suicidal ideation after a 2-year follow-up. For instance, women exposed to JD for three consecutive waves exhibited a high risk of depressive symptoms (OR [95% CI]: 1.61 [1.33-1.95]) and suicidal ideation (OR [95% CI]: 1.67 [1.04-2.70]). JD was positively associated with depressive symptoms and suicidal ideation. Our study suggests that JD is a risk factor for mental health problems in female workers.

Association between constant connectivity to work during leisure time and insomnia: does work engagement matter?

PURPOSE: The influx of communication media to contemporary workplaces has exposed workers to be always connected to their work. Constant connectivity to work (CCW) refers to the condition in which workers are always connected to work, even during their non-work hours, and are not detached from the work situation. We investigated the association between CCW and insomnia and the moderating effect of work engagement. METHODS: A total of 29,512 nationally representative samples of workers in Korea were used. Insomnia was assessed by the Minimal Insomnia Symptom Scale. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). The additive interaction between CCW and low work engagement was estimated by calculating Relative Excess Risk due to Interaction (RERI). RESULTS: Exposure to CCW was related to insomnia (OR [95% CI] 1.33 [1.22-1.46]). Additionally, a significant negative interaction between CCW and work engagement was observed. The effects of CCW were mitigated in those with high work engagement. The OR of the combined effect of CCW exposure and low work engagement was 2.52 (95% CI 2.22-2.87). RERI between exposure to CCW and low work engagement was 0.69 (95% CI 0.38-0.99), indicating that there is a supra-additive interaction. CONCLUSION: Our study found that CCW is related to an increased risk of insomnia and that high work engagement can mitigate the effect of CCW. Our study suggests that improving work engagement and disconnecting from work outside of work hours can help protect employees' sleep quality.

Multidimensional typologies of precarious employment and their relationships with mental well-being in Korean wageworkers: A latent class analysis based on the Korean Working Conditions Survey (2020-2021).

BACKGROUND: Precarious employment (PE) has been conceptualized as having a multidimensional nature, and research addressing this topic in Asian countries is scarce. This study examined the typologies of PE and their relationships with mental health among Korean workers. METHODS: From October 2020 to April 2021, the Korean Working Conditions Survey was conducted on Korean wageworkers (weighted N = 38,347), representative of the nation. With theory-based operationalization of PE, we identified typologies and classified workers through latent class analysis. Logistic regression was performed to explore the association between PE typologies and mental health among workers, represented as odds ratio (ORs) and confidence intervals (CIs). RESULTS: Four distinct employment typologies emerged: (i) standard employment relationships (SER, 34.5%), (ii) moderate employment precariousness (MEP, 43.5%), (iii) underemployment (17.9%), and (iv) daily laborers (4.1%). Women were overrepresented in the MEP and underemployment types, while the SER type consisted of those with higher educational attainment and white-collar jobs. The OR (95% CI) of depression was 1.38 (1.27-1.50) for the MEP type, 1.48 (1.32-1.66) for the underemployment type, and 2.15 (1.85-2.51) for the daily laborers, compared to the SER type. For individual elements of PE, temporary employment, low wages, low-income predictability, and low involvement in work process were positively associated with depression, whereas part-time employment was negatively associated with depression. CONCLUSION: Employment insecurity, low material rewards, and a lack of rights and protection can contribute to the poor mental health of workers. Policy interventions are warranted to mitigate inequalities in employment quality among Korean workers.

Effects of polycyclic aromatic hydrocarbon exposure on mitochondrial DNA copy number.

Airborne polycyclic aromatic hydrocarbon (PAH) exposure can adversely affect human health by generating reactive oxygen species (ROS) and increasing oxidative stress, which causes changes in mitochondrial DNA copy number (mtDNAcn), a key indicator of mitochondrial damage and dysfunction. This study aimed to determine the effects of atmospheric benzo[a]pyrene (BaP) and 1-nitropyrene (1-NP) exposure on mtDNAcn in humans. One hundred and eight adults living in Cheongju, South Korea, were included in this study. Atmospheric BaP and 1-NP concentrations and urinary 6-hydroxy-1-nitropyrene (6-OHNP), N-acetyl-1-aminopyrene (1-NAAP), and 1-hydroxypyrene concentrations were measured. Blood samples were also collected to assess mtDNAcn. The mean mtDNAcn was 9.74 (SD 4.46). mtDNAcn decreased significantly with age but was not significantly associated with sex, sampling season, or smoking habit. While there was a borderline significant increase in mtDNAcn with increasing ambient total PAH levels, ambient PAH or urinary 1-hydroxypyrene concentrations showed no significant association with mtDNAcn. However, urinary 6-OHNP or 1-NAAP concentrations, 1-NP metabolites, were significantly associated with mtDNAcn. These results suggest that the metabolism of absorbed NPs generates excess ROS, which damages mitochondrial DNA, resulting in increased mtDNAcn.

Changes in total volatile organic compound concentration in Seoul subway stations before (2019) and after (2021) the COVID-19 outbreak.

Volatile organic compounds (VOCs) are major air pollutants often designated as specific hazardous or toxic. This study analyzed the trends in concentration changes and influencing factors of VOCs in underground subway stations in the Seoul Metro before (2019) and after (2021) the COVID-19 pandemic. A total of 506 samples were collected from 253 stations on lines 1-8 between May 2019 and September 2021. Total VOC concentrations in Seoul Metro increased after the COVID-19 pandemic 3.8 times over. The deeper the underground station platform, the greater the difference in the VOC concentrations between 2019 and 2021, which was positively related. Average VOC concentration was the highest (52.8 µg/m3) at a depth of 25-30 m and the lowest (23.9 µg/m3) at a depth of < 10 m in 2019. In conclusion, excessive disinfection during the COVID-19 pandemic resulted in increased VOC concentrations in the Seoul Metro, especially in the deeper underground stations. Less frequent quarantine disinfection is recommended to improve air quality.

Association between high emotional demand at work, burnout symptoms, and sleep disturbance among Korean workers: a cross-sectional mediation analysis.

We explored the mediating role of burnout on the association between EDW and sleep disturbances. Our study included 18,744 Korean workers. Respondents were grouped into four levels (none, low, moderate, and high) based on their exposure to two EDW factors: handling angry clients (HAC) and hiding emotion (HE). Mediation models were used to estimate odds ratios (OR) at a 95% confidence interval (CI). Compared to those not exposed, low, moderate, and high HAC increased odds of sleep disturbance by 1.52 (95% CI 1.30-1.78), 3.20 (95% CI 2.57-3.98), and 3.28 (95% CI 2.77-3.88) times, respectively. The indirect effect via burnout accounted for 29.9%, 24.1%, and 23.6% of the total effect, respectively, with estimates of 1.13 (95% CI 1.11-1.16), 1.32 (95% CI 1.26-1.39), and 1.32 (95% CI 1.27-1.37). Low, moderate, and high HE increased the odds of sleep disturbance by 1.45 (95% CI 0.93-2.28), 2.38 (95% CI 1.57-3.61), and 3.14 (95% CI 2.08-4.71) times, respectively. The indirect effect via burnout accounted for 10.5%, 29.7%, and 33.1% of the total effect, with estimates of 1.04 (95% CI 0.98-1.10), 1.29 (95% CI 1.22-1.37), and 1.46 (95% CI 1.38-1.55), respectively. Effective policies are required to protect the psychological wellbeing of workers who frequently engage in interpersonal tasks.

Impact of multi-heavy metal exposure on renal damage indicators in Korea: An analysis using Bayesian Kernel Machine Regression.

Exposure to cadmium (Cd), arsenic (As), and mercury (Hg) is associated with renal tubular damage. People living near refineries are often exposed to multiple heavy metals at high concentrations. This cross-sectional study investigated the association between combined urinary Cd, As, and Hg levels and renal damage markers in 871 residents living near the Janghang refinery plant and in a control area. Urinary Cd, As, Hg, N-acetyl-ß-D-glucosaminidase (NAG), and ß2-microglobulin (ß2-MG) levels were measured. The combined effects of Cd, As, and Hg on renal tubular damage markers were assessed using linear regression and a Bayesian Kernel Machine Regression (BKMR) model. The results of the BKMR model were compared using a stratified analysis of the exposure and control groups. While the linear regression showed that only Cd concentration was significantly associated with urinary NAG levels (ß = 0.447, P value < .05), the BKMR model showed that Cd and Hg levels were also significantly associated with urinary NAG levels. The combined effect of the 3 heavy metals on urinary NAG levels was significant and stronger in the exposure group than in the control group. However, no relationship was observed between the exposure concentrations of the 3 heavy metals and urinary ß2-MG levels. The results suggest that the BKMR model can be used to assess the health effects of heavy-metal exposure on vulnerable residents.

Exposure to Benzo[a]pyrene and 1-Nitropyrene in Particulate Matter Increases Oxidative Stress in the Human Body.

Polycyclic aromatic hydrocarbons (PAHs) have been reported to cause oxidative stress in metabolic processes. This study aimed to evaluate the relationship between exposure to PAHs, including benzo[a]pyrene (BaP) and 1-nitropyrene (1-NP), in the atmosphere and oxidative stress levels in the human body. This study included 44 Korean adults who lived in Cheongju, Republic of Korea. Atmospheric BaP and 1-NP concentrations and urinary 6-hydroxy-1-nitropyrene (6-OHNP), N-acetyl-1-aminopyrene (1-NAAP), and 1-hydroxypyrene (1-OHP) concentrations were measured. The oxidative stress level was assessed by measuring urinary thiobarbituric acid-reactive substances (TBARS) and 8-hydroxydeoxyguanosine (8-OHdG) concentrations. Urinary TBARS and 6-OHNP concentrations significantly differed between winter and summer. BaP exposure was significantly associated with urinary 8-OHdG concentrations in summer. However, atmospheric 1-NP did not show a significant correlation with oxidative stress marker concentrations. Urinary 1-NAAP concentration was a significant determinant for urinary 8-OHdG concentration in summer. Oxidative stress in the body increases in proportion to inhalation exposure to BaP, and more 8-OHdG is produced in the body as the amount of 1-NP, which is metabolized to 1-AP or 1-NAAP, increases.