OBJECTIVES: The physical activity paradox suggests that occupational physical activity (OPA), unlike leisure-time physical activity (LTPA), may detrimentally impact health. We explored the relationships of OPA and LTPA with work ability (WA) and health-related productivity loss (HRPL). METHODS: This study included 5,501 workers in Korea who were recruited in 2021 through a web-based cross-sectional questionnaire. The questionnaire was utilized to quantify OPA and LTPA in metabolic equivalents, while WA and HRPL were also measured. Non-parametric regression, using a generalized additive model (GAM), was employed to visualize the relationships of LTPA and OPA with WA and HRPL. Mean differences in WA and HRPL, in relation to OPA and LTPA, were examined using linear regression models. These models were adjusted for covariates including sex, age, body mass index, education level, alcohol consumption, smoking history, insomnia, occupation, hours worked, and income. RESULTS: The GAM and linear regression analyses revealed that higher LTPA corresponded with higher WA and lower HRPL. In contrast, as OPA increased, WA decreased and HRPL increased. However, within the group with high OPA, HRPL was not significantly lower in the high-LTPA subgroup relative to the low-LTPA subgroup (mean difference=1.92%, p=0.343). This pattern was especially pronounced among workers aged 60 years and older, with an increase in HRPL observed with increasing LTPA among the respondents with high OPA. CONCLUSIONS High LTPA levels were associated with elevated WA and diminished HRPL. In contrast, higher levels of OPA were associated with lower WA and higher HRPL.

The Korean Work, Sleep, and Health Study (KWSHS) was launched in 2022 as a longitudinal panel study to examine the interactions between work conditions, sleep health, and labour market performance among the Korean workforce. Baseline data were collected from 5,517 participants aged 19 to 70, encompassing diverse occupations. Follow-up surveys occur biannually, accommodating seasonal variations in sleep and health dynamics. To ensure stability, refreshment samples were integrated in later waves, maintaining a cohort size of 5,783 participants in wave 5. Key data include socio-demographics, employment characteristics, sleep patterns, health outcomes, and workplace performance. Early findings highlight critical associations, such as the adverse effects of occupational physical activity on productivity, the impact of emotional labour on health-related productivity loss, and the significance of sleep disruptions on mental health. The cohort’s design enables detailed analyses of longitudinal and cross-sectional trends, offering insights into how changing work environments influence health and productivity. The KWSHS could serve as a vital resource for evidence-based interventions aimed at improving occupational health and productivity in Korea's evolving labour landscape. Data access is available through the study’s principal investigator upon request.

The Korean Work, Sleep, and Health Study (KWSHS) was launched in 2022 as a longitudinal panel study to examine the interactions between work conditions, sleep health, and labour market performance among the Korean workforce. Baseline data were collected from 5,517 participants aged 19 to 70, encompassing diverse occupations. Follow-up surveys occur biannually, accommodating seasonal variations in sleep and health dynamics. To ensure stability, refreshment samples were integrated in later waves, maintaining a cohort size of 5,783 participants in wave 5. Key data include socio-demographics, employment characteristics, sleep patterns, health outcomes, and workplace performance. Early findings highlight critical associations, such as the adverse effects of occupational physical activity on productivity, the impact of emotional labour on health-related productivity loss, and the significance of sleep disruptions on mental health. The cohort’s design enables detailed analyses of longitudinal and cross-sectional trends, offering insights into how changing work environments influence health and productivity. The KWSHS could serve as a vital resource for evidence-based interventions aimed at improving occupational health and productivity in Korea's evolving labour landscape. Data access is available through the study’s principal investigator upon request.

The Korean Work, Sleep, and Health Study (KWSHS) was launched in 2022 as a longitudinal panel study to examine the interactions between work conditions, sleep health, and labour market performance among the Korean workforce. Baseline data were collected from 5,517 participants aged 19 to 70, encompassing diverse occupations. Follow-up surveys occur biannually, accommodating seasonal variations in sleep and health dynamics. To ensure stability, refreshment samples were integrated in later waves, maintaining a cohort size of 5,783 participants in wave 5. Key data include socio-demographics, employment characteristics, sleep patterns, health outcomes, and workplace performance. Early findings highlight critical associations, such as the adverse effects of occupational physical activity on productivity, the impact of emotional labour on health-related productivity loss, and the significance of sleep disruptions on mental health. The cohort’s design enables detailed analyses of longitudinal and cross-sectional trends, offering insights into how changing work environments influence health and productivity. The KWSHS could serve as a vital resource for evidence-based interventions aimed at improving occupational health and productivity in Korea's evolving labour landscape. Data access is available through the study’s principal investigator upon request.

OBJECTIVES: Occupational stress management is particularly important for successful business operations, since occupational stress adversely affects workers’ health, eventually lowering their productivity. Therefore, this study aimed to investigate the correlation between occupational stress and health-related productivity loss (HRPL) among Korean workers. METHODS: In 2021, 1,078 workers participated in a web-based questionnaire survey. HRPL was measured using the Work Productivity and Activity Impairment Questionnaire, and occupational stress was measured using the Korean Occupational Stress Scale-Short Form. The occupational stress level was divided into tertiles (low, intermediate, and high), and the low occupational stress group was used as the reference group. Using a generalised linear model, differences in labour productivity loss according to the level of occupational stress were tested after adjusting for demographic characteristics such as age, gender, education level, household income, occupation, and underlying medical conditions. RESULTS: Non-parametric regression analysis of HRPL according to occupational stress showed a direct association between occupational stress and HRPL. A statistically significant difference was observed in HRPL between participants with intermediate and high occupational stress and those with low occupational stress. CONCLUSIONS Our results support the hypothesis that high occupational stress is associated with decreased labour productivity.

OBJECTIVES: We conducted this study to investigate the relationship between the blood concentration of cadmium and cognitive function in elderly Koreans. METHODS: This research is a part of the Korean Elderly Environmental Panel Study (KEEPS). A total of 403 subjects were enrolled and analyzed from August 2008 through August 2010. Demographic information and medical histories were obtained using a questionnaire. Blood concentration of cadmium and Mini-Mental State Examination (MMSE) with Functional Activities Questionnaire (FAQ) were evaluated for each subject. RESULTS: The mean age of subjects was 70.67 (SD 5.18, n=403) and 72% were female. The mean blood cadmium level was 1.22 microg/dl (SD 0.56), mean MMSE score was 25.12 out of 30 and mean FAQ score was 2.03 out of 30. Using linear regression analysis to estimate the relationship between blood cadmium concentration and MMSE and FAQ, we observed a significant association between log transformed values of blood cadmium levels and MMSE (p<0.002) or FAQ (p=0.005) scores. After adjusting for age, sex, level of education, alcohol consumption and smoking habits, the relationship between blood cadmium concentration and MMSE and FAQ scores ramained statistically significant (p=0.033 and 0.029, respectively). CONCLUSIONS: These results suggest that blood cadmium concentration is strongly associated with cognitive function and functional activity in the elderly.
Aged ; Alcohol Drinking ; Cadmium ; Female ; Humans ; Linear Models ; Questionnaires ; Smoke ; Smoking

STUDY DESIGN: A retrospective study. SUMMARY OF THE LITERATURE REVIEW: The reports comparing short- and long-segment instrumentation are insufficient. OBJECTIVES: To determine the postoperative results and to analyze relative factors affecting results between short- and long-segment instrumentation in thoracolumbar fractures. MATERIALS AND METHODS: From March 2006 to March 2012, 97 patients with thoracolumbar fracture were treated with posterior instrumentation. They were divided into 2 groups, the short- (Group I) and long-segment groups (Group II). To analyze factors affecting results, several factors including age, anterior column height (ACH), and the kyphotic angle were reviewed. For radiologic evaluation, postoperative and follow-up radiographs were evaluated by measuring the kyphotic angle and ACH. Additionally, the presence of complications was reviewed. RESULTS: Groups I and II consisted of 45, 52 cases and had mean ages of 50.3, 55.8 years, respectively. In Group I, the ACH increased from 44.2% to 75.3% postoperatively, and remained 72.8% at follow-up. The kyphotic angle decreased from 19.4degrees to 10.6degrees postoperatively, and remained at 12.8degrees at follow-up. In Group II, the ACH recovered from 41.6% to 76.4% postoperatively, and was 74.8% at follow-up. The kyphotic angle decreased from 21.6degrees to 12.6degrees postoperatively, and was 13.9degrees at follow-up. The canal compromise, age, and comminution were not directly related with results. However, the mean age of the 7 cases showing complications was 72 years, and the 7 cases had severe comminuted fractures. CONCLUSIONS: The short- and long-segment instrumentations of thoracolumbar fractures are not significantly different with respect to the results attained. However, in order to decrease complications, we should pay attention to age and fracture comminution.
Follow-Up Studies ; Fractures, Comminuted ; Humans ; Retrospective Studies

Background: It is well known that the prevalence of obesity in Korea is increasing over time, however it is not known how the trends among occupational groups and sex differ in such increasing trends. This study was designed to provide recent trends of obesity among workers in Korea and to identify whether there were differences among occupational groups. Methods: We used data from the Korean National Health and Nutrition Examination Survey, Phases I to VI (1998–2015), to analyze trends in the prevalence of obesity in adult Korean workers. Obesity was defined as a body mass index of 25 kg/m2 or higher. Occupations were classified into 3 groups: (a) nonmanual workers, (b) service/sales workers, and (c) manual workers. Results: During the period of the Korean National Health and Nutrition Examination Survey Phases I to VI, the prevalence of obesity in male workers increased in all occupations (31.1% to 39.5% in manual workers, 32.3% to 38.2% in service/sales workers, and 25.3% to 39.7% in manual workers). However, female workers did not show any particular tendency toward obesity, except for a significant decrease in the prevalence rate in service/sales workers (30.8% to 23.9%, p for trend = 0.0048). Conclusion The trends of obesity prevalence by sex and occupation were different. For male manual workers, the prevalence rate increased steadily during the data period, while it decreased steadily in female sales/service workers.

OBJECTIVES: Preventing occupational injuries remains a significant challenge in Korea. A positive safety climate can contribute to reducing workplace injuries. However, the impact of safety climate on preventing occupational injuries among the Korean workforce has not been adequately explored. Therefore, this study aimed to investigate the relationship between the perceived safety climate and occupational injuries within the Korean working population. METHODS: This study used baseline data from the Korean Work, Sleep, and Health Study (KWSH). The safety climate was measured using the brief version of the Nordic Safety Climate Questionnaire. Occupational injury was determined by whether injuries or accidents had occurred at workplaces in the past year. Logistic regression analysis was performed to examine the association between the safety climate and occupational injury. RESULTS: Participants who reported an unfavorable workplace safety climate were more likely to experience occupational injuries. Multiple logistic regression analysis revealed that the adjusted odds ratio (OR) for occupational injuries in an unfavorable safety climate was 2.20 (95% confidence interval [CI], 1.38 to 3.51) compared to a favorable safety climate. Specifically, factors such as “not encouraging employees to follow safety rules when on a tight schedule” (OR, 2.02; 95% CI, 1.25 to 3.24) and “not helping each other work safely” (OR, 1.98; 95% CI, 1.17 to 3.25) were significantly associated with occupational injuries. CONCLUSIONS An unfavorable safety climate was associated with increased occupational injuries among Korean workers. Improving the safety climate in the workplace may reduce occupational injuries in Korea.

Previous reports showed that age and socioeconomic factors mediated health-related unemployment. However, those studies had limitations controlling for confounding factors. This study examines age and socioeconomic factors contributing to health-related unemployment using propensity score matching (PSM) to control for various confounding variables.