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.

Purpose: Hepatitis B is a major prognostic factor after hematopoietic stem cell transplantation (HSCT). Currently, no consensus exists regarding the management of various scenarios that can lead to reverse seroconversion of the hepatitis B surface antigen (HBsAg-RS). This study focused on HBsAg-RS, which serves as an indicator of active hepatitis, and aimed to obtain exploratory information on the associated patient and treatment factors. Methods: This single-center retrospective study utilized clinical data extracted from the electronic medical records of Seoul St. Mary’s Hospital, Korea. Patients who underwent HSCT between January 2013 and December 2018 and tested negative for hepatitis B surface antigen (HBsAg) before undergoing HSCT were included. The associations between HBsAg-RS and demographic information, baseline hepatitis B serological markers, and vaccination status were statistically analyzed. Results: This study included 1,344 patients, of whom 83.3% tested positive for the hepatitis B surface antibody (HBsAb) during HSCT. HBsAg-RS occurred in 2.2% of HBsAb-negative patients and 3.0% of HBsAb-positive patients, indicating no significant difference in reactivation rates according to HBsAb status. However, positivity for hepatitis B core antibody (HBcAb) was significantly associated with hepatitis B reactivation (HBsAg-RS rate: 8.0%). The vaccination rates were highest in patients who were negative for both HBsAb and HBcAb and had a transient protective effect. Conclusion The sufficient patient population enabled the identification of an association between baseline HBcAb positivity and the development of HBsAg-RS. Further prospective studies are warranted to determine optimal vac‑ cination strategies for preventing HBsAg-RS.

Purpose: Hepatitis B is a major prognostic factor after hematopoietic stem cell transplantation (HSCT). Currently, no consensus exists regarding the management of various scenarios that can lead to reverse seroconversion of the hepatitis B surface antigen (HBsAg-RS). This study focused on HBsAg-RS, which serves as an indicator of active hepatitis, and aimed to obtain exploratory information on the associated patient and treatment factors. Methods: This single-center retrospective study utilized clinical data extracted from the electronic medical records of Seoul St. Mary’s Hospital, Korea. Patients who underwent HSCT between January 2013 and December 2018 and tested negative for hepatitis B surface antigen (HBsAg) before undergoing HSCT were included. The associations between HBsAg-RS and demographic information, baseline hepatitis B serological markers, and vaccination status were statistically analyzed. Results: This study included 1,344 patients, of whom 83.3% tested positive for the hepatitis B surface antibody (HBsAb) during HSCT. HBsAg-RS occurred in 2.2% of HBsAb-negative patients and 3.0% of HBsAb-positive patients, indicating no significant difference in reactivation rates according to HBsAb status. However, positivity for hepatitis B core antibody (HBcAb) was significantly associated with hepatitis B reactivation (HBsAg-RS rate: 8.0%). The vaccination rates were highest in patients who were negative for both HBsAb and HBcAb and had a transient protective effect. Conclusion The sufficient patient population enabled the identification of an association between baseline HBcAb positivity and the development of HBsAg-RS. Further prospective studies are warranted to determine optimal vac‑ cination strategies for preventing HBsAg-RS.

Purpose: Hepatitis B is a major prognostic factor after hematopoietic stem cell transplantation (HSCT). Currently, no consensus exists regarding the management of various scenarios that can lead to reverse seroconversion of the hepatitis B surface antigen (HBsAg-RS). This study focused on HBsAg-RS, which serves as an indicator of active hepatitis, and aimed to obtain exploratory information on the associated patient and treatment factors. Methods: This single-center retrospective study utilized clinical data extracted from the electronic medical records of Seoul St. Mary’s Hospital, Korea. Patients who underwent HSCT between January 2013 and December 2018 and tested negative for hepatitis B surface antigen (HBsAg) before undergoing HSCT were included. The associations between HBsAg-RS and demographic information, baseline hepatitis B serological markers, and vaccination status were statistically analyzed. Results: This study included 1,344 patients, of whom 83.3% tested positive for the hepatitis B surface antibody (HBsAb) during HSCT. HBsAg-RS occurred in 2.2% of HBsAb-negative patients and 3.0% of HBsAb-positive patients, indicating no significant difference in reactivation rates according to HBsAb status. However, positivity for hepatitis B core antibody (HBcAb) was significantly associated with hepatitis B reactivation (HBsAg-RS rate: 8.0%). The vaccination rates were highest in patients who were negative for both HBsAb and HBcAb and had a transient protective effect. Conclusion The sufficient patient population enabled the identification of an association between baseline HBcAb positivity and the development of HBsAg-RS. Further prospective studies are warranted to determine optimal vac‑ cination strategies for preventing HBsAg-RS.