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

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

While the prevalence of musculoskeletal disorders has recently increased among Korean workers employed in highly physically and psychologically demanding jobs, the relation among these domains remains relatively unexplored. We examined 2,037 subway workers in Seoul, that collected data via questionnaire survey on musculoskeletal symptoms and the work environment, administered in 2009, 2012, and 2015. Generalized estimating equation (GEE) analysis was used for statistical analysis. After conducting GEE analysis by adjusting for the sociodemographic and occupational characteristics, we found the prevalence of musculoskeletal symptoms significantly increased in cases with high Depression, Anxiety and Stress Scales (DASS) scores compared with low DASS scores, especially on shift workers. An integrated management method that considers ergonomic and mental health factors, should be used to better manage musculoskeletal symptoms in subway workers.

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