Disturbance of circadian rhythms caused by shift work has adverse effects on insulin resistance. Many previous studies have confirmed that shift work and insulin resistance are related using homeostasis model assessment-insulin resistance, one of the insulin resistance indicators. However, the triglycerides and glucose index (TyG index) has recently been studied as an insulin resistance indicator. The aim of this study is to investigate the association of shift work and TyG index, one of the indirect indicators of insulin resistance, using results of health checkups in one workplace.

Based on medical examination data collected in February 2019, a total of 3,794 subjects from one chemical plant in Korea were selected for this study. Cut-off value of TyG index for predicting development of diabetes mellitus (DM) was 4.69. A multiple logistic regression analysis was performed after adjusting for age, employment period, obesity, abdominal obesity, smoking, drinking, physical activity, hypertension, stroke, heart disease.

As a result of logistic regression analysis, compared to day workers, odds ratio (OR) with a TyG index above cut-off value for predicting development of DM in shift workers was 1.220 after adjusting for age, employment period, obesity, abdominal obesity, smoking, drinking, physical activity, hypertension, stroke, heart disease (Model 1, OR: 1.276; 95% confidence interval [CI]: 1.099–1.482; Model 2, OR: 1.232; 95% CI: 1.055–1.438; Model 3, OR: 1.220, 95% CI: 1.030–1.444).

There was a significant association between shift work and TyG index among male workers in a chemical plant. More research studies on the association between shift work and TyG index are needed in the future.

The increasing prevalence of high body mass index (BMI) emphasizes the need for action. Understanding of BMI factors among military hospital healthcare workers remains limited. This study aims to address this gap by analyzing BMI risk factors and changes pre- and post-coronavirus 2019 pandemic among military hospital healthcare workers in central Taiwan from 2019 to 2021.

Conducted at a military hospital in central Taiwan, this study analyzed anonymized health examination data from 2019 to 2021 for 483 healthcare workers. We performed generalized estimating equations to investigate trends in BMI and its association with various factors, including age, sex, job titles, military status, job tenure, work shifts, and lifestyle habits.

The risk of increased BMI was higher in 2021 compared to 2019 (risk ratio [RR]: 1.008, 95% confidence interval [CI]: 1.001–1.014). Individuals on rotating shifts had a higher risk of increased BMI compared to day shift workers (RR: 1.021; 95% CI: 1.008–1.035) and higher odds of obesity (odds ratio: 1.546; 95% CI: 1.099–2.175). Among obese individuals, BMI in soldiers was approximately 4.9% lower than in non-soldiers (RR: 0.951; 95% CI: 0.915–0.988).

This study identified a significant post-pandemic increase in BMI among healthcare workers in a Taiwanese military hospital, with rotating shifts being a key risk factor for both increased BMI and obesity. Work-related factors influenced BMI changes among obese individuals, while non-work-related factors were significant for non-obese individuals. These findings highlight the broader effects of the pandemic and the specific impact of work-related factors on obese healthcare workers.

After the coronavirus disease 2019 pandemic, the widespread adoption of working from home, or teleworking, has prompted extensive research regarding its effects on work productivity and the physical and mental health of employees. In this context, our study aimed to investigate the association between working from home and health-related productivity loss (HRPL).

An online survey was conducted with a sample of 1,078 workers. HRPL was estimated by the Work Productivity and Activity Impairment Questionnaire: General Health version. Workers that have been working from home in the last 6 months were categorized into the “work from home” group. Generalized linear models were used to compare the mean difference of HRPL between “work from home” and “commuters” group. Stratified analyses were conducted based on various factors including gender, age, income level, occupation, education level, previous diagnosis of chronic disease, presence of preschool children, living in studio apartment, living alone, commuting time, working hours and regular exercise.

The overall HRPL was higher in the “work from home” group than in the “commuters” group with a mean difference of 4.05 (95% confidence interval [CI]: 0.09–8.01). In the stratified analyses, significant differences were observed in workers with chronic diseases (mean difference: 8.23, 95% CI: 0.38–16.09), who do not live alone (mean difference: 4.84, 95% CI: 0.35–9.33), and workers that do not exercise regularly (mean difference: 4.96, 95% CI: 0.12–9.80).

Working from home is associated with an increased HRPL in the Korean working population, especially among those with chronic diseases, those who do not live alone, and those who do not exercise regularly.

Occupational neck disability is a prevalent issue, especially among line workers, who are often exposed to elevated levels of cervical ergonomic stress. The aim of this study was to investigate the impact of neck posture and insulating stick use on neck disability in a specific occupational group in Korea.

This cross-sectional study was conducted among 483 line workers in Gwangju and Jeonnam, Korea. Data were collected using the Neck Disability Index, Cervical Degenerative Index, and a structured questionnaire focusing on demographic and occupational factors. Logistic regression analysis was applied to determine the adjusted odds ratio (OR) and 95% confidence interval (CI) for neck posture and factors related to neck disability.

Neck disability prevalence was 17.2% among the participants. Multivariate logistic regression analysis showed that factors related to neck disability included age over 60 years (adjusted OR: 3.08; 95% CI: 1.63–5.83), depression (adjusted OR: 8.33; 95% CI: 3.85–18.00), a history of cervical trauma (adjusted OR: 2.13; 95% CI: 1.04–4.40), and radiological degenerative changes in the cervical spine (adjusted OR: 2.33; 95% CI: 1.26–4.33). In particular, the adjusted OR of neck disability among live-line workers was 2.10 (95% CI: 1.12–3.92) when compared with support workers (model 1). Other analysis models showed that use of insulating sticks for more than 10 hours per week (adjusted OR: 2.46; 95% CI: 1.32–4.61) and higher neck extension (adjusted OR: 2.98; 95% CI: 1.14–3.46) were significant work-related risk factors (model 2,3).

Neck posture, age, depression, cervical trauma history, degenerative changes in the cervical spine, and use of insulating sticks are significant risk factors for neck disability among line workers in Korea. These findings highlight the need to improve the working environment and reduce the burden of cervical ergonomic stress among line workers.

Long working hours are associated with an increased risk of cardiovascular disease, yet the underlying mechanism(s) remain unclear. The study examines how occupational factors like working hours, shift work, and employment status correlate with dietary choices and sodium intake, impacting hypertension risk.

This study used data from the Korea National Health and Nutrition Examination Survey conducted between 2013 and 2020. The dataset included 8,471 respondents, all of whom were wage workers aged 20 or older and reported working at least 36 hours per week. Individuals who have been previously diagnosed with or are currently diagnosed with hypertension, diabetes, or dyslipidemia were excluded. The average daily sodium intake was assessed via a 24-hour dietary recall method. Average weekly working hours were categorized into 3 groups: 36–40 hours, 41–52 hours, and over 52 hours. Multiple logistic regression models were used.

Study findings revealed that 83.7% of participants exceeded the recommended daily sodium intake of 2 g set by the World Health Organization. After adjusting for confounding factors, a positive correlation was observed between average working hours and daily sodium intake. Among males, statistical significance was found in the group with average weekly working hours of 41–52 hours (prevalence ratio [PR]: 1.17; 95% confidence interval [CI]: 1.05–1.30) and the group exceeding 52 hours (PR: 1.22; 95% CI: 1.09–1.38) when comparing the fourth quartile of daily sodium intake to the combined quartiles of Q1, Q2, and Q3. Among females, no significance was noted.

Long working hours were associated with increased sodium intake, primarily among male workers. This connection is likely attributed to having less time for home-cooked meals, resulting in higher fast food consumption and dining out. A workplace intervention promoting healthy eating and reducing stress is essential to lower sodium consumption and mitigate hypertension risk.

Research on job training and job satisfaction has been conducted from various perspectives. Job training is thought to be associated with job satisfaction, which is known as an important factor for depression among workers. We hypothesized that job training duration could influence depression through potential mediators (job satisfaction, motivation to work, and work engagement).

This study encompassed participants from the sixth Korean Working Conditions Survey (KWCS), conducted between 2020 and 2021. To show the relationships between demographic or occupational characteristics and risk of depression, a χ² test was conducted. The association between job training duration, potential mediators, and risk of depression was analyzed by constructing multiple logistic regression models. The mediating effects of potential mediators on job training duration and risk of depression was evaluated with flexible mediation analysis with weighting-based methods.

The final study population consisted of 25,294 participants. Longer job training duration significantly decreased risk of depression after adjusting for confounders. In the group that received the longest job training duration (≥ 10 days), compared with the group without job training, the odds ratio (OR) for high risk of depression was 0.46 (95% confidence interval [CI], 0.39–0.54). Each three potential mediators showed statistically significant indirect effects and direct effect. Although indirect effects were not strong compared to direct effect, motivation to work had the strongest mediating effect in this study, with an OR of 0.94 (95% CI, 0.92–0.95).

Job training duration was found to have a statistically significant negative association on the risk of depression, and three mediators partially mediating this effect. Although the mechanism was unknown, our findings suggest that job training has a positive influence on workers' mental health. Furthermore, by suggesting the possibility of other pathways existing between job training and depression, we provide directions for future research.

As few studies have explored the association between non-regular or precarious employment in parents and adverse birth outcomes, this study aimed to investigate this association using national data in Japan.

This study utilized the census data from 2020 and birth data from the vital statistics in 2021 and 2022 in the analysis. Adverse birth outcomes, including preterm birth, term low birth weight (TLBW), and small-for-gestational-age, were examined. Data linkage was conducted between birth data and census data to link parental employment statuses and educational attainments with birth data. Rates of adverse birth outcomes were calculated for each parental employment status. Additionally, regression analysis was used to determine adjusted risk ratios (RRs) of parental employment statuses for each birth outcome.

After data linkage, 334,110 birth records were included in the statistical analysis. Rates for non-regular workers were consistently higher than those for regular workers across all adverse birth outcomes for maternal employment status. Results of regression analyses indicated that the risks of preterm birth for non-regular workers were statistically significantly higher than those for regular workers, both in mothers and fathers with a RR (95% confidence intervals [CIs]) of 1.053 (1.004–1.104) and 1.142 (1.032–1.264), respectively. Furthermore, the risk of TLBW birth for non-regular workers was statistically significantly higher than that for regular workers in fathers (RR [95% CI]: 1.092 [1.043–1.143]).

Our findings demonstrate that non-regular workers have a higher risk of some adverse birth outcomes compared to regular workers.

In 2019, the International Agency for Research on Cancer re-evaluated the carcinogenicity of night-shift work and reported that there is limited evidence that night-shift work is carcinogenic for the development of prostate cancer. Therefore, in 2020 and 2021, the Korean Epidemiologic Investigation Evaluation Committee concluded that 2 cases of prostate cancer were occupational diseases related to the night-shift work. Here, we report the 2 cases of prostate cancer in night-shift workers which were first concluded as occupational diseases by the Korean Epidemiologic Investigation Evaluation Committee.

Patient A: A 61-year-old man worked as a city bus driver for approximately 17 years, from 2002 to 2019, and was exposed to night-shift work during this period. In March 2017, the patient was diagnosed with high-grade prostate cancer through core-needle biopsy after experiencing stinging pain lasting for 2 months. Patient B: A 56-year-old man worked as an electrician and an automated equipment operator in a cement manufacturing plant for 35 years from 1976 to 2013 and was exposed to night-shift work during this period. In 2013, the patient was diagnosed with high-grade prostate cancer through core needle biopsy at a university hospital because of dysuria that lasted for 6 months.

The 2 workers were diagnosed with high-grade prostate cancer after working night shifts for 17 and 35 years respectively. Additionally, previous studies have reported that high-grade prostate cancer has a stronger relationship with night-shift work than low or medium-grade prostate cancer. Therefore, the Korean Epidemiologic Investigation Evaluation Committee concluded that night-shift work in these 2 patients contributed to the development of their prostate cancer.

This study was conducted to identify the success rate for smoking cessation over time after participation in a therapeutic smoking cessation camp, and to identify how participant characteristics, including a supportive workplace environment for smoking cessation (SWESC), affect the success rate for smoking cessation.

In all, 296 participants at smoking cessation camps in Ulsan between 2015 and 2020 were investigated. The success rates of smoking cessation after weeks 4, 6, 12, and 24 at camp were investigated. The participants were grouped as workers with an SWESC, and workers without an SWESC, and variables (age, education, household income, marital status, drinking, exercise, body mass index, morbidity, job, number of counseling sessions, cigarettes smoked per day and smoking initiation age) were investigated. Multiple logistic regression analysis was conducted at each time point. In addition, Cox regression analysis was performed to evaluate the variables affecting the success rate for smoking cessation over time.

The smoking cessation success rate of workers with an SWESC at week 24 (90.7%) was higher than that for workers without an SWESC (60.5%). Multiple logistic regression was performed to determine the relationship between each variable and the success rates for smoking cessation at week 6, 12, and 24. SWESC was confirmed as significant (p < 0.05) variables for increased success rate for smoking cessation at all 3 time points. After adjusting for all variables, the Cox proportional hazards survival analysis showed a hazard ratio of 6.17 for SWESC (p < 0.001,; 95% confidence interval: 3.08–12.38).

At a professional treatment smoking cessation camp, participants with an SWESC showed a significantly higher success rate for smoking cessation. Supportive workplace environment for workers’ health is expected to be an important factor for smoking cessation projects as well as other health promotion projects at workplace.

As unpredictable work schedule (UWS) has increased worldwide, various studies have been conducted on the resulting health effects on workers. However, research on the effect of UWS on workers' well-being in Korea is still insufficient. This study aimed to investigate the relationship between UWS and work-family conflict (WFC) using 6th Korean Working Conditions Survey (KWCS).

Both UWS and WFC were measured using self-reported questionnaires, using data from the 6th KWCS conducted between 2020 and 2021, including 31,859 participants. UWS was measured by questions regarding the frequency of changes in work schedules and limited advanced notice. WFC was measured by questions regarding work to family and family to work conflicts. Logistic regression analysis was conducted to investigate the association between UWS and WFC.

The prevalence of UWS was higher among men, those under 40 years old, service and sales workers and blue-collar workers, and those with higher salaries. Workplace size also influenced UWS prevalence, with smaller workplaces (less than 50 employees) showing a higher prevalence. The odds ratio (OR) for WFC was significantly higher in workers with UWS compared to workers without UWS after adjusting for gender, age, marital status, occupation, salary, education, weekly working hours, shift work, company size, and having a child under the age of 18 years, employment status (OR: 3.71; 95% confidence interval: 3.23–4.25).

The analysis of nationwide data revealed that UWS interferes with workers’ performance of family roles, which can lead to WFC. Our findings suggest that it is crucial to implement policies to address unfair work schedule management, promoting a healthier work-life balance and fostering a conducive environment for family responsibilities.

Gig workers, also known as platform workers, are independent workers who are not employed by any particular company. The number of gig economy workers has rapidly increased worldwide in the past decade. There is a dearth of occupational health studies among gig economy workers. We aimed to investigate the association between exposure to violence and job stress in gig economy workers and depressive symptoms.

A total of 955 individuals (521 gig workers and 434 general workers) participated in this study and variables were measured through self-report questionnaires. Depressive symptoms were evaluated by the Patient Health Questionnaire-9 when the score was greater than or equal to 10 points. The odds ratio with 95% confidence interval was calculated using multivariable logistic regression adjusted for age, sex, working hours, education level, exposure to violence and job stress.

19% of gig economy workers reported depressive symptoms, while only 11% of general workers reported the depressive symptoms. In association to depressive symptoms among gig economy workers, the mainly result of odds ratios for depressive symptoms were as follows: 1.81 for workers type, 3.53 for humiliating treatment, 2.65 for sexual harassment, 3.55 for less than three meals per day, 3.69 for feeling too tired to do housework after leaving work.

Gig economic workers are exposed to violence and job stress in the workplace more than general workers, and the proportion of workers reporting depressive symptoms is also high. These factors are associated to depressive symptoms. Furthermore, the gig workers associated between depressive symptoms and exposure to violence, job stress.

Shift work has been reported to have several harmful effects on the human body. However, a small number of studies have evaluated the association between shift work and adverse effects on the thyroid. In our longitudinal study, we examined the causal association between shift work and the risk of hypothyroidism.

A Kangbuk Samsung Cohort Study was conducted on 112,648 men without thyroid disease at baseline who were followed up at least once between 2012 and 2019. Shift work status and shift schedule types were categorized using standardized questionnaires. Hypothyroidism was defined using the reference ranges of serum thyroid-stimulating hormones and free thyroxine levels. Hazard ratios (HRs) and 95% confidence intervals (CIs) for incident hypothyroidism were estimated using Cox proportional hazards regression analyses with the daytime work group as the reference.

During the 501,237 person-years of follow-up, there were 6,306 incident cases of hypothyroidism (incidence density, 1.26 per 100 person-years). The multivariable-adjusted HR of incident hypothyroidism for the shift work total group that included all shifts compared with the daytime work group was 1.27 (95% CI: 1.15–1.40). For the fixed evening, fixed night, rotating shift, and other shift workers, the multivariable-adjusted HRs (95% CI) were 1.11 (0.76–1.61), 2.18 (1.20–3.93), 1.39 (1.23–1.56), and 1.00 (0.82–1.22), respectively. In subgroup analyses by age, the association between shift work and hypothyroidism was more pronounced in younger participants (< 40 years; HR: 1.31; 95% CI: 1.16–1.47).

Our large-scale cohort study showed an association between shift work and the incidence of hypothyroidism, especially in younger workers with night shifts.

Diseases affecting the lungs and airways contribute significantly to the global burden of disease. The problem in low- and middle-income countries appears to be exacerbated by a shift in global manufacturing base to these countries and inadequate enforcement of environmental and safety standards. In Ghana, the potential adverse effects on respiratory function associated with occupational wood dust exposure have not been thoroughly investigated.

Sixty-four male sawmill workers and 64 non-woodworkers participated in this study. The concentration of wood dust exposure, prevalence and likelihood of association of respiratory symptoms with wood dust exposure and changes in pulmonary function test (PFT) parameters in association with wood dust exposure were determined from dust concentration measurements, symptoms questionnaire and lung function test parameters.

Sawmill workers were exposed to inhalable dust concentration of 3.09 ± 0.04 mg/m³ but did not use respirators and engaged in personal grooming habits that are known to increase dust inhalation. The sawmill operators also showed higher prevalence and likelihoods of association with respiratory symptoms, a significant cross-shift decline in some PFT parameters and a shift towards a restrictive pattern of lung dysfunction by end of daily shift. The before-shift PFT parameters of woodworkers were comparable to those of non-woodworkers, indicating a lack of chronic effects of wood dust exposure.

Wood dust exposure at the study site was associated with acute respiratory symptoms and acute changes in some PFT parameters. This calls for institution and enforcement of workplace and environmental safety policies to minimise exposure at sawmill operating sites, and ultimately, decrease the burden of respiratory diseases.

Work-Family Conflict means that the demands of work and family roles cannot be met simultaneously, so one cannot concentrate on one’s work or family role. This conflict can negatively affect mental health and cause insomnia symptoms.

This study was conducted on 20,442 subjects. Insomnia symptoms were assessed using the Minimal Insomnia Symptom Scale, and other variables were assessed using the questionnaire method. Logistic regression analyses were performed to evaluate the effect of Work-Family Conflict on insomnia symptoms, and subgroup logistic regression analyses were also performed.

The number of people with insomnia symptoms was 4,322 (15.1%). Compared with Low Work-Family Conflict, the odds ratios (ORs) for the risk of insomnia symptoms were 1.84 (95% confidence interval: 1.56–2.16) in High work-to-family conflict, 1.16 (1.02–1.32) in High family-to-work conflict, and 3.19 (2.87–3.55) in High Work-Family Conflict. The ORs were higher for men than women in High WFC but higher for women than men in High Work-Family Conflict.

The risk of insomnia symptoms was highest in High Work-Family Conflict.

Although many studies have been conducted on worker fatigue and sickness absence, the association between fatigue and sickness absence is unclear in Korean workers. This study was conducted to investigate the effect of worker fatigue on future sickness absence.

The study was conducted on workers who received medical check-ups at a university hospital for two consecutive years (2014–2015). During check-ups in the first year, the Fatigue Severity Scale (FSS) was used to assess fatigue levels, and during check-ups in the second year, sickness absence was surveyed to determine whether they had been absent from work due to physical or mental illness during previous 12 months. The χ² test was used to analyze relationships between sociodemographic and occupational characteristics, fatigue levels, and sickness absence. Odds ratios (ORs) were calculated by logistic regression analysis controlled for confounding factors.

A total of 12,250 workers were included in the study, and 396 (3.2%) workers experienced more than one day of sickness absence during the study period. Adjusted ORs for sickness absence were 3.35 (95% confidence interval [CI]: 2.64–4.28) in the moderate-fatigue group and 6.87 (95% CI: 4.93–9.57) in the high-fatigue group versus the low-fatigue group. For men in the moderate- and high-fatigue groups, adjusted ORs for sickness absence were 3.40 (95% CI: 2.58–4.48) and 8.94 (95% CI: 6.12–13.07), and for women in the moderate- and high-fatigue groups, adjusted ORs for sickness absence were 2.93 (95% CI: 1.68–5.10) and 3.71 (95% CI: 1.84–7.49), respectively.

Worker fatigue is associated with sickness absence during the following 12 months, and this association appears to be stronger for men than women. These results support the notion that sickness absence can be reduced by evaluating and managing work-related fatigue.

Lone workers are generally defined as individuals who work alone without supervision, including self-employed people. While lone workers are considered a vulnerable group in some countries, there is a lack of research on their health status in domestic studies. Globally, the number of lone workers has been increasing, and this trend has been further accelerated since the coronavirus disease 2019 (COVID-19) pandemic with the rise of remote work.

The study analyzed data from 44,281 participants, excluding unpaid family workers, soldiers, and those with missing data. Lone workers were defined as individuals who reported having no colleagues with the same job at their current workplace. Self-rated health status was categorized as “good” or “poor.”

This study found a statistically significant higher number of lone workers among women compare to men. The largest occupational category for lone workers was service and sales workers, followed by agriculture and fisheries workers. A majority of non-lone workers reported working 40 hours or less per week, while the majority of lone workers reported working 53 hours or more per week. In addition, lone workers had significantly poorer health status evaluations compared to non-lone workers (odds ratio: 1.297; 95% confidence interval: 1.165–1.444).

Further research is needed to investigate the causal relationship between lone work and health, using data collected after the COVID-19 pandemic.

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.

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.

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.

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.

The objective of this study is to investigate the differences in incidence rates of targeted diseases by classification of occupations among construction workers in Korea.

In a subject-based cohort of the Korean Construction Worker’s Cohort, we surveyed a total of 1,027 construction workers. As occupational exposure, the classification of occupations was developed using two axes: construction business and job type. To analyze disease incidence, we linked survey data with National Health Insurance Service data. Eleven target disease categories with high prevalence or estimated work-relatedness among construction workers were evaluated in our study. The average incidence rates were calculated as cases per 1,000 person-years (PY).

Injury, poisoning, and certain other consequences of external causes had the highest incidence rate of 344.08 per 1,000 PY, followed by disease of the musculoskeletal system and connective tissue for 208.64 and diseases of the skin and subcutaneous tissue for 197.87 in our cohort. We especially found that chronic obstructive pulmonary disease was more common in construction painters, civil engineering welders, and civil engineering frame mold carpenters, asthma in construction painters, landscape, and construction water proofers, interstitial lung diseases in construction water proofers.

This is the first study to systematically classify complex construction occupations in order to analyze occupational diseases in Korean construction workers. There were differences in disease incidences among construction workers based on the classification of occupations. It is necessary to develop customized occupational safety and health policies for high-risk occupations for each disease in the construction industry.

In Korea, little research has focused on the relationship between discrimination in the workplace and sleep health. Thus, this study aims to investigate the association between such discriminatory experiences and insomnia, a common sleep disorder, using Korean employees’ data.

This study used data from the 6th Korea Working Conditions Survey. Discrimination experiences due to age, ethnic background, nationality, race, sex, religion, disability, sexual orientation, educational level, hometown, and employment status were investigated. The Minimal Insomnia Symptom Scale estimated insomnia symptoms. The association between discrimination experience and insomnia symptoms were analyzed using survey-weighted logistic regression analysis.

Based on experiences of discrimination over the past 12 months, insomnia symptoms were associated with discrimination experience due to religion (odds ratio [OR]: 3.70; 95% confidential interval [CI]: 1.58–8.69), sex (OR: 2.51; 95% CI: 1.87–3.37), age (OR: 2.30; 95% CI: 1.88–2.81), hometown (OR: 2.07; 95% CI: 1.44–2.97), employment status (OR: 1.69; 95% CI: 1.37–2.10), and educational level (OR: 1.67; 95% CI: 1.31–2.14). Furthermore, the prevalence of insomnia symptoms increased with the number of discrimination experiences.

In this study, discrimination experiences due to religion, sex, age, hometown, employment status, and educational level were significantly associated with insomnia symptoms. Furthermore, as the number of discrimination experiences increased, so did the prevalence of insomnia. Preventing workplace discrimination may improve workers’ sleep health.

The construction workers are vulnerable to fatigue due to high physical workload. This study aimed to investigate the relationship between overwork and heart rate in construction workers and propose a scheme to prevent overwork in advance.

We measured the heart rates of construction workers at a construction site of a residential and commercial complex in Seoul from August to October 2021 and develop an index that monitors overwork in real-time. A total of 66 Korean workers participated in the study, wearing real-time heart rate monitoring equipment. The relative heart rate (RHR) was calculated using the minimum and maximum heart rates, and the maximum acceptable working time (MAWT) was estimated using RHR to calculate the workload. The overwork index (OI) was defined as the cumulative workload evaluated with the MAWT. An appropriate scenario line (PSL) was set as an index that can be compared to the OI to evaluate the degree of overwork in real-time. The excess overwork index (EOI) was evaluated in real-time during work performance using the difference between the OI and the PSL. The EOI value was used to perform receiver operating characteristic (ROC) curve analysis to find the optimal cut-off value for classification of overwork state.

Of the 60 participants analyzed, 28 (46.7%) were classified as the overwork group based on their RHR. ROC curve analysis showed that the EOI was a good predictor of overwork, with an area under the curve of 0.824. The optimal cut-off values ranged from 21.8% to 24.0% depending on the method used to determine the cut-off point.

The EOI showed promising results as a predictive tool to assess overwork in real-time using heart rate monitoring and calculation through MAWT. Further research is needed to assess physical workload accurately and determine cut-off values across industries.

Recently, irregular working hours have become controversial issues in Korea. The health impact of irregular working hours on the work-related musculoskeletal pain (MSP) is scarcely researched before. We sought to investigate the association between irregular working hours and work-related MSP among South Korean workers.

This study used data from the sixth Korean Working Conditions Survey in 2020. The prevalence of work-related MSP was analyzed using the χ² test. A multiple logistic regression analysis was conducted to assess the association between irregular working hours and work-related MSP. We conducted stratified analysis by gender, weekly working hours, and workers’ control over their working hours. We calculated the adjusted odds ratios (ORs) of work-related MSP for irregular working hours combined with weekly working hours.

The OR for work-related MSP was significantly higher in the population with irregular working hours than in the population with regular working hours (OR: 1.43, 95% confidence interval [CI]: 1.29–1.58). Irregular and long (> 52 hours/week) working hours have the highest risk of work-related MSP in both genders (in men, OR: 3.48 [95% CI: 2.53–4.78]; in women, OR: 2.41 [95% CI: 1.46–4.00]).

Irregular working hours were associated with work-related MSP in Korea. The association was magnified with long working hours. Reform of the Korean Labor Standards Act leading to increase irregular working hours may induce adverse health outcome.

Shift work is known to cause changes in the circadian rhythm of the human body and adversely affect not only physical health but also mental health. Some studies have demonstrated the correlation between shift work and thyroid stimulating hormone (TSH), a hormone that changes according to the diurnal rhythm, but few studies have reported the different TSH levels according to the shift work type. This study aimed to investigate changes in TSH according to the shift work type.

This study included 1,318 female workers who had a medical checkup at a university hospital in Changwon from 2015 to 2019. Shift work types were classified as non-shift work, regular 2 shifts, and irregular three shifts, and a TSH ≥ 4.2 mIU/L was defined as abnormal. A general linear model (GLM) was used to compare the TSH levels and the risk of subclinical hypothyroidism in each year, and a binary logistic analysis was performed using a generalized estimation equation (GEE) to compare the risk of subclinical hypothyroidism over the 5-year period.

Of the 1,318 participants included in this study, 363, 711, and 244 were non-shift, two-shift, and irregular three-shift workers, respectively. In the GEE analysis, after adjusting for age, body mass index, smoking, and alcohol consumption, the odds ratios (ORs) were 1.81 (95% confidence interval [CI]: 1.15–2.86; p = 0.011) in 2 shifts and 2.02 (95% CI: 1.23–3.32; p = 0.006) in irregular three shifts, compared to non-shift.

Our results showed that shift work had a higher risk of subclinical hypothyroidism than non-shift work and that there was a significant difference in the risk of subclinical hypothyroidism according to the shift work type. These findings suggest that the shift work type can be considered in future thyroid function tests and evaluations.

Indoor air pollution can cause and exacerbate asthma. We report a previously undescribed case of occupational asthma related to indoor air pollution in a worker at an indoor air gun shooting range and highlight the potential risk of developing occupational asthma in this environment.

A 31-year-old man presented with dyspnea, cough, and sputum and was diagnosed with asthma complicated by pneumonia. Objective evidence of asthma was obtained by performing a methacholine bronchial provocation test. It was suspected that the patient had occupational asthma, which began one month after changing jobs to work within the indoor air gun shooting range. The highest peak expiratory flow (PEF) diurnal variability on working days was 15%, but the highest variation was 24%, with 4 days out of 4 weeks having a variation of over 20% related to workplace exposure. Conversely, the diurnal variability on the rest days was 7%, and no day showed a variation exceeding 20%. The difference in the average PEF between working and rest days was 52 L/min. PEF deterioration during working days and improvement on rest days were noted.

The results obtained from the in-depth analysis of the PEF were adequate to diagnose the patient with occupational asthma. Exposure to indoor air pollution and lead and the patient’s atopy and allergic rhinitis may have contributed to the development of occupational asthma.