• Journal of Korean Academy of Nursing
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• v.54 no.2
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• pp.139-150
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• 2024

Purpose: This study aimed to identify changes in sleep patterns and fatigue levels during consecutive night shifts among shift nurses and to determine the association between sleep parameters and increased fatigue levels during work. Methods: This prospective observational study employing ecological momentary assessments was conducted using data collected from 98 shift nurses working in Korean hospitals between June 2019 and February 2021. The sleep patterns were recorded using actigraphy. The participants reported their fatigue levels at the beginning and end of each night shift in real time via a mobile link. Linear mixed models were used for the analysis. Results: Nurses spent significantly less time in bed and had shorter sleep durations during consecutive night shifts than on off-duty days, whereas their wake times after sleep onset were much longer on off-duty days than on on-duty days. Fatigue levels were higher on the second and third night-shift days than on the first night-shift days. A shorter time spent in bed and asleep was associated with a greater increase in fatigue levels at the end of the shift than at the beginning. Conclusion: Nurses experience significant sleep deprivation during consecutive night shifts compared with off-duty days, and this sleep shortage is associated with a considerable increase in fatigue levels at the end of shifts. Nurse managers and administrators must ensure sufficient intershift recovery time during consecutive night shifts to increase the time spent in bed and sleeping.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.30.1-30.13
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• 2023

Background: Dysmenorrhea and menstrual cycle changes occur in women working shifts. Circadian rhythm disruption and sleep disturbances associated with shift work leads to health problems. We identified chronotypes and the occurrence of insomnia among newly employed university hospital nurses and investigated the association of these factors with menstrual problems. Methods: We conducted pre-placement health examinations for shift workers using self-reported questionnaires between 2018 and 2020. A total of 463 nurses were included in the study. Sociodemographic data, shift work experience, and information on insomnia were collected from health examination data. In addition, details regarding chronotype, dysmenorrhea, irregular and abnormal menstrual cycles, amenorrhea, and contraceptive use were obtained from the questionnaire. Multiple logistic regression analysis was performed to study the association between chronotype, insomnia, and menstrual problems after controlling for age, body mass index, contraceptive use, amenorrhea, and prior shift work. Results: The prevalence rates of dysmenorrhea, irregular menstrual cycles, and longer menstrual cycles were 23.8%, 14.9%, and 4.1%, respectively. The risk of dysmenorrhea increased in the evening-type (odds ratio [OR]: 3.209; 95% confidence interval [CI]: 1.685-6.113) and those with insomnia (OR: 1.871; 95% CI: 1.074-3.261). Additionally, the risk of an irregular menstrual cycle (OR: 2.698; 95% CI: 1.167-6.237) increased in the evening-type, and the risk of a longer menstrual cycle (OR: 4.008; 95% CI: 1.354-11.864) increased in individuals with insomnia. Conclusions: Our findings suggest that dysmenorrhea is promoted in the evening-type and insomnia individuals. There may be an increased risk of irregular menstrual cycles among evening-type nurses and an increased risk of longer menstrual cycles among those with insomnia. Therefore, factors such as evening-type and insomnia should be considered for the prevention of menstrual problems in women performing shift work.

• Journal of the Korean Society of Food Culture
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• v.34 no.4
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• pp.486-494
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• 2019

There are an increasing number of reports that job related factors are associated with hypertension, sleep deprivation, obesity and diabetes. This study analyzed the relationship of working type, working hours and the prevalence of metabolic syndrome. The study's subjects were 2,777 employees (1,446 males and 1,331 females) over 19 years old and their data was from the Korea National Health and Nutrition Survey (2015). The type of work was divided into day work and shift work. The working hours were divided into less than 40 hours, 40 to 49 hours, 50 to 59 hours and 60 hours or more per week. As a result of this study, the prevalence of metabolic syndrome was 26.4% of the males and 19.1% of the females. Generally there was no relationship between metabolic syndrome and type of work (day work and shift work). As a result of analysis of working hours and metabolic syndrome, the workers who worked 40-49 hr were associated with a decreased prevalence of metabolic syndrome as compared to that of workers who worked less than 40 hr (odds ratio: 0.47, 95% confidence interval: 0.24-0.95, p<0.05). Further, positive relationships were found between the number of work hours and the prevalence metabolic syndrome for specific females who worked over 40 hr/wk. It can be concluded from the results that it is important to help workers avoid metabolic syndrome through setting appropriate work hours.

• Journal of muscle and joint health
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• v.25 no.3
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• pp.196-204
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• 2018

Purpose: The purpose of this study was to contribute to the activation of comprehensive nursing care services by comparing and analyzing the working environment and operational status of comprehensive nursing care wards with general wards. Methods: A questionnaire survey was conducted at hospitals operating comprehensive nursing care services. We collected data on patient characteristics, workforce, working environment, and work support facilities of 40 hospitals voluntarily participating in the survey. The collected data were analyzed by dividing it into an comprehensive nursing care ward and a general ward. Results: Compared with the general ward, the comprehensive nursing care ward had fewer hospitalized patients, but the severity of the patients and the need for nursing were high. The number of nurses, assistant nurses, and ward support workers per patient was higher in the comprehensive nursing care ward than in the general ward, and the implementation rate of night shift fixed system, the fixed shift system, and the preceptor system were higher. In terms of structural environment, comprehensive nursing care wards had more room for interviews. Conclusion: The comprehensive nursing care ward had more nursing staff and provided a better working environment than the general ward, but required additional support for the structural environment.

• Safety and Health at Work
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• v.11 no.3
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• pp.361-366
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• 2020

Background: This study aimed to identify the validity of breast cancer symptom questionnaire of worker's special health examination and its relationship with breast ultrasonography findings in young female night workers. Methods: The breast cancer symptom questionnaire data of worker's special health examination and breast ultrasonography results in young female shift workers who worked in one electronic manufacture company were collected from 2014 to 2018. Results: Of the 857 workers, 18 had a Breast Imaging Reporting and Database System category 4 or higher. Among other variables, shift work tenure alone was associated with the risk of having a Breast Imaging Reporting and Database System category higher than 4. The sensitivity, specificity, positive predictive value, and negative predictive value of the symptom questionnaire were 16.7%, 87.7%, 2.8%, and 98.0%, respectively. Conclusion: The current breast cancer symptom questionnaire of the worker's special health examination is inappropriate due to its low sensitivity and positive predictive value. In the future, female night workers will need alternative measures for more accurate screening for breast cancer.

• Journal of Biosystems Engineering
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• v.19 no.4
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• pp.291-300
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• 1994

It is desired to operate tractor engines at or near maximum torque much of the time in field operation to increase fuel efficiency. To do this it is necessary to reduce engine speed and to shift gears to higher ratios as frequently as possible. Because of load variations in most drawbar work and inconvenience in gear shift, however, gear-type transmission are usually set in one ratio at unnecessarily high engine speeds, and engine-torque variations are used to compensate for changes in drawbar load. As a result, the most of time the tractor is not operated efficiently in terms of fuel consumption and work output. The objective of this study was to develop an automatic control system which is able to operate a tractor equipped with gear transmission under the optimal condition in terms of fuel efficiency with automatic governor setting and gear shift. An indoor experimental test set which can be used to simulate tractor operation, control engine speed and transmission ratio was developed in the previous paper. In this paper, the performance of the optimal operation system is reported. Through a series of tests, it was found that the automatic control system for optimal operation of tractors with gear transmission had a satisfactory performance.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.199-208
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• 2017

This study investigated the effects of overtime work on the health-related quality of life (HRQoL) of Korean blue-collar workers. This cross-sectional study collected data on 229 Korean blue-collar workers in six small-sized companies from October to November 2015. The data were analyzed using hierarchical multiple regression analysis to estimate the effect of overtime work while considering convergence variables. In the hierarchical regression model, when overtime work variable was included in the model, $R^2$ change was statistically significant. The significant predictors for HRQoL were overtime work (${\beta}=.152$, p=.025), depression (${\beta}=-.192$, p=.003) and night shift work (${\beta}=-.201$, p=.032). The results of this study provide a basic data for establishing optimal working hours standards for improving the quality of life of Korean blue-collar workers.

• Journal of Preventive Medicine and Public Health
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• v.28 no.2 s.50
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• pp.497-510
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• 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
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• v.4 no.4
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• pp.197-200
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• 2013

Background: A variety of sociodemographic factors, such as gender, age, household income, and educational level, influence individuals' likelihood of smoking.Work-related factors may also be linked to smoking behavior.We sought to investigate the relationship between smoking and work environment in South Korea. Methods: We analyzed data from the Fifth Korean National Health and Nutrition Examination Survey to determine whether there was an association between smoking and occupation type (e.g., manual, nonmanual, or service work), night-shift work, and hours worked/week (e.g., <40, 40-48, 49-60, or >60 hours) for 4,685 workers. Regression models were adjusted for sociodemographic variables such as age, recent alcohol consumption, hours slept, educational level, and household income. Results: The prevalence of smoking was 50.1% in men and 7.2% in women. For women, manual workers had 2.34 times [95% confidence interval (CI): 1.02-5.36] greater odds of smoking compared with nonmanual workers, whereas service workers had 2.37 times greater odds (95% CI: 1.28-4.40). Furthermore, women who worked 49-60 hours had 2.21 times greater odds of smoking (95% CI: 1.10-3.75) as compared with women who worked 40-48 hours. Conclusion: Women who work long hours or who are employed in service or manual positions are more likely to smoke. These results indicate a need in South Korea to target these specific groups when creating nonsmoking policies.

• Journal of Korean Academy of Nursing Administration
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• v.21 no.5
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• pp.519-529
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• 2015

Purpose: This study was performed to identify perceptions on fixed night shift system and turnover intention of general hospital nurses and to explore a desirable application plan for a fixed night shift system. Methods: This study was a cross-sectional survey. Participants were 300 nurses working at one general hospital in GyeongGi-Do, Korea. Data were collected from November 3 to 7, 2014, with a structured questionnaires and analyzed using SPSS/PC ver 20.0 programs. Results: Of the participants 73.5% had thought about turnover because of night shifts and the preconditions for desirable fixed night shift system were a payment plan differentiated according to work conditions and an adequate number of nursing staff. Economic and administrative supports like 'raising extra-pay for night shift' and 'increasing the number of paid holidays' were very important for a desirable fixed night shift system. Conclusion: The results indicate that the most important factor for a desirable fixed night shift system to decrease nurses' turnover intention is economic and administrative support according to the needs of the nurses. So nursing managers need to find a desirable fixed night shift system considering nurses' demographic characteristics and organizational characteristics.