• Korean Journal of Biological Psychiatry
• /
• v.24 no.2
• /
• pp.59-67
• /
• 2017

Shift workers experience a disruption in the circadian sleep-wake rhythm, which brings upon adverse health effects such as fatigue, insomnia and decreased sleep quality. Moreover, shift work has deleterious effects on both work productivity and safety. In this review, we present a brief overview of the current literature on the consequences of shift work, especially focusing on attention-associated cognitive decline and related behavioral changes. We searched two electronic databases, PubMed and RISS, using key search terms related to cognitive domains, deleterious effects, and shift work. Twenty studies were eligible for the final review. The consequences of shift work can be classified into the following three categories extracted from the literature review : 1) work accidents ; 2) commuting accidents such as car accidents that occur on the way to and from work ; and 3) attendance management at work (i.e., absenteeism, tardiness, and unscheduled early departure). These cognitive and behavioral consequences of shift work were also found to be associated with sleep disorders in shift workers. Thus, improvements in the shift work system are necessary in order to enhance workers' health conditions, work productivity, and safety.

• Korean Journal of Occupational Health Nursing
• /
• v.12 no.1
• /
• pp.5-18
• /
• 2003

The purpose of this study was to survey working conditions of women workers. We conducted a field survey of 504 manufacturing company with many women working from May 13 to June 29, 2002. We focused on only 3 categories of metal, textile and electronics industry. The result were as follows : 1. Subjects were constituted metal 27.0%, textile 37.9% and electronics industry 35.1%. Size distribution was small scale(<50 workers) 38.1%, medium(50-299 workers) 50.2% and large(${\geq}300$ workers) company 11.7%. Women workers' proportion was 43.6% of total workers, 63.8% of total contractors. 2. A medical examination enforcement of contractors workers was very poor in comparison with that of employees(p<0.001). 3. A 53.8% of total companies have conducted shiftwork system and 2-crew 2-shift(12 hours shift system) ranked first, 56.1%(151 companies). 4. Only 61.3% of total companies conducted more than 90 days as legal standard of a maternity leave and only 2.6% of total companies had a day nursery. In conclusion, many strategies for women workers are needed by companies and government. For example, the raising of understanding about maternity protection, social support insurancing of woman worker and occupational health system improvement for contractors and small size companies.

• Journal of Nutrition and Health
• /
• v.51 no.6
• /
• pp.567-579
• /
• 2018

Purpose: This study examined the mediation effects of dietary habits, nutrient intake, daily life in the relationship between the working hours of Korean shift workers and metabolic syndrome. Methods: Data were collected from the sixth (2013-2015) Korea National Health and Nutrition Examination Survey (KNHANES). The stochastic regression imputation was used to fill missing data. Statistical analysis was performed in Korean shift workers with metabolic syndrome using the SPSS 24 program for Windows and a structural equation model (SEM) using an analysis of moment structure (AMOS) 21.0 package. Results: The model fitted the data well in terms of the goodness of fit index (GFI) = 0.939, root mean square error of approximation (RMSEA) = 0.025, normed fit index (NFI) = 0.917, Tucker-Lewis index (TLI) = 0.984, comparative fit index (CFI) = 0.987, and adjusted goodness of fit index (AGFI) = 0.915. Specific mediation effect of dietary habits (p = 0.023) was statistically significant in the impact of the working hours of shift workers on nutrient intake, and specific mediation effect of daily life (p = 0.019) was statistically significant in the impact of the working hours of shift workers on metabolic syndrome. On the other hand, the dietary habits, nutrient intake and daily life had no significant multiple mediator effects on the working hours of shift workers with metabolic syndrome. Conclusion: The appropriate model suggests that working hours have direct effect on the daily life, which has the mediation effect on the risk of metabolic syndrome in shift workers.

• Sleep Medicine and Psychophysiology
• /
• v.7 no.2
• /
• pp.96-101
• /
• 2000

Objectives: Through comparing sleep variables and autonomic activities among three shifts in shift workers, the authors intended to clarify which shift is most tolerable and to identify the characteristics of their psychological and physical problems. This study is also expected to help shift workers to adapt themselves to their work more effectively. Methods: Fifty one shift workers took part in this study. They were working in a rapidly rotating system in which they worked for 3 days in one shift with one day off between each shift. Based on a sleep diary, sleep latency (SL), sleep period time (SPT), and number of wake after sleep onset (NWASO) were estimated and compared among the three shifts. In assessing sleepiness, Epworth sleepiness scale (ESS) and visual analogue scale (VAS) were used. To evaluate mood states among the three shifts, profile of mood states (POMS) was administered. Heart rate variability (HRV), and the level of adrenaline and noradrenaline were measured to assess autonomic activities. HRV included low frequency power (LF), high frequency power (HF), and LF/HF. Results: SPT was significantly lengthened during the evening shift and SL was shortened during the night shift. The workers showed a drop in alertness at wake-up during morning shift and a drop in alertness at work during night shift. During night shift the subjects complained of physical fatigue and cognitive decline. Comparison of HRV showed that parasympathetic activity was most prominent during the evening shift. Secretion of adrenaline and noradrenaline decreased during the evening shift, though statistically not significant. Conclusion: We found that the evening shift was most tolerable among the three shifts. It is recommended that morning light exposure be done during the morning shift and nocturnal light exposure during the night shift.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.1 no.1
• /
• pp.77-97
• /
• 1994

The circadian system represents a temporal order which is mediated by the mutual coupling of oscillators and by the synchronizing effects of zeitgebers. It is known that well-being of man depends partly on the maintenance of this order, and that repeated or long lasting disturbances to it such as shift work will Cause harmful effects. This study was a quasi-experimental study to test the effect of shift directions for the clinical nurses on the circadian rhythm. Fourteen nurses working at the general units of Y hospital were selected according to the established criteria. Fourteen subjects were assigned to a weekly shift but the directions of shift work were phase delay first and then phase advance or vice versa. Oral temperature, total sleeping time, frequency of sleep-wake cycle, fatigue, mental performance, and physical symptom were measured during these days except holidays. The data collection period was from April 26, 1993 to July 3, 1993. MANOVA and Wilcoxon signed rank test were used for statistical analysis. The results are summarized as follows. 1. Having worked on evening and night shifts in either phase delay or phase advance schedules, temperature rhythms of shift workers were gradually adapted to the new sleep-wake cycles. A complete adaptation to work on the night shift was achieved the sixth day of the night shift in the phase delay schedule compared to the partial adaptation to the work on the night shift in the phase advance schedule. Accordingly, by putting evening shift between day and night shifts, it will be possible for circadian rhythm to adapt easily to the night shift. 2. There were differences in the total sleeping time, frequency of steep-wake cycle, fatigue, and physical symptom except for mental performance between night shift and day, evening shift. This indicates further that shift workers working on the night shift have a hard time adapting to the shift work compared to the other shifts. 3. Evaluating all the acrophases of temperature rhythm either in phase delay or phase ad-vance schedules, it was shown that night to evening shift in the phase ad-vance schedule revealed the smallest phase move. Also phase advance schedule showed poorer adaptation to shift work than phase delay schedule in connection with total sleeping time, frequency of sleep-wake cycle, fatigue, mental performance, and physical symptom. It is suggested, taken together, these findings reflect that phase delay schedule facilitated the degree of adjustment to the shift work compared to the phase advance schedule.

• Korean Journal of Occupational Health Nursing
• /
• v.11 no.1
• /
• pp.63-80
• /
• 2002

Objectives: The objective of this study is to evaluate the job characteristics of container terminal workers by applying the Job Strain model, and to assess the relationship among the general characteristics, job characteristics and psychosocial distress. Methods: A self-administrated questionnaire survey was performed to the container terminal workers in Pusan. Among the 200 male workers who answered the questionnaires, white-collar workers and blue-collar workers were 100, respectively. Karaseks Job Content Questionnaire was utilized to evaluate the job characteristics and Psychosocial well-being index (PWI) was applied to measure the extent of their psychosocial stress. Results: In white-collar workers, the skill discretion, created skill, decision-making authority, decision-making latitude, psychological job demand, and supervisor support of the job characteristics were significantly high, while in blue-collar workers physical exertion was significantly high. The result of Psychosocial well-being index (PWI) reveals that blue-collar workers were more stressed than white-collar workers, especially, the indices of depression (factor 2), sleeping disturbance and anxiety (factor 3), General well-being and vitality (factor 4) were significantly increased; whereas, in white-collar workers, only the index of social performance and self-confidence (factor 1) was significantly increased. And PWI scores were significantly increased in the lower social support and psychological job demand. By the multiple logistic regression analysis for PWI, blue-collar workers had increased odds ratio of 2.66(95% CI;1.11-6.41) compared with white-collar workers. The unmarried workers increased odds ratio of 3.54(95% CI;1.18-10.62) compared with married workers. And workers who have not own house increased odds ratio of 2.35(95% CI;1.15-4.79) compared with workers who have own house. Particularly, odds ratio of work-shift in blue-collar workers was 11.10(2.14-57.64). Conclusion: Skill discretion, created skill, decision-making authority, decision-making latitude, psychological job demand, and supervisor support were increased in white-collar workers. Decreased skill discretion and increased physical exertion were found in blue-collar workers, which is supported the Job Strain model. Job stress of blue-collar workers was comparatively higher than that of white-collar workers, especially, skill discretion, decision-making authority, decision-making latitude, job insecurity, physical exertion were noticeable factors. Especially, sleeping, smoking, and work shifting turned out to be a main cause that increases stress. Therefore, in order to decrease the job stress, a health promotion program to change the health behaviors should be activated and an organized job stress management program should be introduced. Especially, working condition for blue-collar such as physical exertion and work-shift should be improved.

• Journal of Preventive Medicine and Public Health
• /
• v.28 no.2 s.50
• /
• pp.497-510
• /
• 1995

This study was carried out to assess work ability of manufacturing workers and managerial workers. Subjects were 446 manufacturing workers and 278 managerial workers employed in Gumi industrial complex and the observation period was for 1 month(February to March), 1995. In this study, as a questionnaire for the assessment of work ability, we used the Work Ability Index(WAI) which was developed by Institute of Occupational Health in Finland. Major findings obtained from this study were as follows ; WAI was poor in lower economic condition, shift work, irregular diet group(p<0.05). There were no evident trends of WAS in sex, educational level, obesity index, exercise, smoking, and alcohol drinking. In the groups of sensitive to perception of stress, other industrial classification except textile and electronics, the more than 9 hours work, the evident trends of poor WAS were observed(p<0.01). In the groups of $30\sim39$ years old, $40\sim49$ years old, unmarried, high school, shift work, standard body weight, and regular .diet, WAI between manufacturing workers and managerial workers was significantly different(p<0.01) and WAI of managerial worker was worse than that of manufacturing worker.

• Safety and Health at Work
• /
• v.1 no.2
• /
• pp.112-123
• /
• 2010

The paper gives an overview of the problems to be tackled nowadays by occupational health with regards to shift work as well as the main guidelines at organizational and medical levels on how to protect workers' health and well-being. Working time organization is becoming a key factor on account of new technologies, market globalization, economic competition, and extension of social services to general populations, all of which involve more and more people in continuous assistance and control of work processes over the 24 hours in a day. The large increase of epidemiological and clinical studies on this issue document the severity of this risk factor on human health and well being, at both social and psychophysical levels, starting from a disruption of biological circadian rhythms and sleep/wake cycle and ending in several psychosomatic troubles and disorders, likely also including cancer, and extending to impairment of performance efficiency as well as family and social life. Appropriate interventions on the organization of shift schedules according to ergonomic criteria and careful health surveillance and social support for shift workers are important preventive and corrective measures that allow people to keep working without significant health impairment.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.21 no.3
• /
• pp.231-244
• /
• 2008

Purpose: The purpose of this study is to analyze body composition, obesity according to working pattern of working women. The subjects were workers in the automobile manufacturing industry. Methods: The subjects consisted of 514 industrial women workers who had received Korean oriental medicine health examination and submitted questionires about working pattern, during 8 months from April 2005 to November 2005. The body composition was measured by X-scan(Jawon medical, Seoul, Korea). We analyzed the relationship between body composition analysis, obesity and shift pattern with $X^2-test$ using the SPSS Ver. 12.0 Results: Regarding the realationship between body composition and working pattern, shift worker group had a significantly higher level of body weight, ratio of body fat, visceral fat and abdominal fat than normal worker. Conclusion: From this study, we can know that shift work can influence on working women's body composition and obesity.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.29 no.3
• /
• pp.368-374
• /
• 2019

Objectives: To examine the associations of borg's scale with actual heart rates of workers and energy consumption during their physical work. Methods: A total of 72 workers performing physical activities in postal service, ceramic manufacturing, and metal manufacturing participated in heart rate measurement for 1 work shift using the activity meter(A360) and responded to a borg's scale questionnaire. Results: In consistent with previous findings, we presented high correlation between borg's scale and energy consumption measures among workers performing physical activities(r=0.89) while post-work average heart rate showed nearly no correlation with post-work borg's scale (r=0.09). We proposed a set of adjustments when using borg's scale to estimate physical workload for those workers engaged in physical activities during the majority of their work shift. Conclusions: Our findings suggest that a caution should be paid to when using Borg's scale to estimate heart rates during physical activities as well as energy consumption as the product of heart rate measurements.