The Association Between the Number of Consecutive Night Shifts and Insomnia Among Shift Workers: A Multi-Center Study.

There is a need to determine the optimal limit of consecutive night shift work to reduce insomnia caused by the accumulation of sleep problems among night shift workers. This study aimed to investigate the prevalence of insomnia caused by consecutive night shifts and evaluate the night shift duration that worsens insomnia the most, using a large amount of medical examination data. Night shift profiles and baseline demographics data of three hospitals were collected from January 2015 to December 2017.

Psychological well-being of South Korean employees in different occupational classes.

We compared the mental health of waged Korean workers in different occupational classes. This was a secondary analysis of data from the fifth Korean Working Conditions Survey, conducted in 2017. Men who were "Unskilled manual workers" were more likely to report poor psychological well-being; however, analysis that adjusted for multiple factors (including work stressors and stress relievers) indicated that status as an "Unskilled manual worker" was not associated with poor psychological well-being.

Association of poor psychological well-being with co-exposure to psychosocial factors at work in Korean regular workers.

Background: This study evaluated the association of co-exposure to different psychosocial factors with poor psychological well-being of Korean regular workers.

Methods: This was a secondary analysis of data from the fifth Korean Working Conditions Survey, conducted in 2017. Multiple logistic regression was used to determine adjusted odd ratios (aORs) and 95% confidence intervals for poor psychological well-being associated with self-reported psychosocial factors.

Astigmatism Associated with Allergic Conjunctivitis in Urban School Children.

Introduction: We first examined the association of an ocular refractive error with allergic conjunctivitis in school children and then examined this association in children attending a suburban school and an urban school.

Methods: We enrolled 426 children attending a primary school in a suburban area and 550 children attending a primary school in an urban area which had a higher level of air pollution. Allergic conjunctivitis was defined as the diagnosis of this condition at any time during a child's life.