• Journal of Physiology & Pathology in Korean Medicine
• /
• v.18 no.2
• /
• pp.344-348
• /
• 2004

This study regarded irregular life styles such as nigh-shifts as contrary to the norm advised in the rules of Yang-saeng to analyze the problems brought about in relation to the concept of 'Yin-deficiency syndrome'. Yin-deficiency survey was given to sales workers on a big shopping mall in Seoul to compare the measurements of daytime workers to those of nigh-shift workers. The measurement of complaining symptoms related to Yin-deficiency of daytime workers and night-shift workers were compared, In comparison of the daytime workers and the night-shift workers, night-shift workers showed higher measurements than the daytime workers in the item of irritable fever on the five Hearts, flushing of the zygomatic region in the afternoon, tidal fever, dizziness, insomnia, yellow and scanty urination, and constipation. Especially tidal fever, insomnia, and constipation showed statistically significant difference. The total of ten items consisting of Yin-deficiency-related symptoms showed statistically significant high score in night-shift workers than the daytime workers. 'Factors for deficiency-type Heat' consisting of irritable fever on the five Hearts, flushing of the zygomatic region in the afternoon, tidal fever, and dried mouth and throat showed statistically significant high score in night-shift workers than the daytime workers. 'Accompanying factors' consisting of night sweats, emaciation, dizziness, insomnia, yellowish and scanty urination, and constipation also showed statistically and significantly high score in night-shift workers than the daytime workers. From the above results that night-shift workers show high degree of Yin-deficiency than daytime workers, and those overworking irregularly also show high degree of Yin-deficiency than those who work for adequate amount of time regularly implies that sitting up at night for work and sleeping at daytime, excessive work, and irregular life styles all function as high-risk factor for Yin-deficiency.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.33 no.2
• /
• pp.126-133
• /
• 2023

Objectives: This study was conducted to find out the prevalence and risk factors of anemia according to shift work. Methods: Data from the Korean National Health and Nutrition Survey (2016-2020) were used. 9,787 workers were divided into shift workers and non-shift workers. The work type between 6AM-6PM was defined as day work, and other work types were defined as shift work. A chi-square test was used to indicate the distribution of risk factors expected to affect shift work in both frequency and percentage. Multiple logistic regression analysis was performed to find out the relationship between anemia prevalence and shift work. Results: As a result of analysis, multiple logistic regression analysis of anemia prevalence and shift work, the OR (95% CI) of male workers on shift work was 2.186 (1.139 to 4.194) and there was a statistically significant difference. Conclusions: In conclusion, anemia in male shift workers should be considered a possibility of health problems. In the future, research based on various data collection should be conducted for research to reveal various causes or diseases of anemia in the future.

• Journal of Preventive Medicine and Public Health
• /
• v.28 no.1 s.49
• /
• pp.103-121
• /
• 1995

An investigation on psychophysiological health and social well-being of shift workers been carried out on workers of a automobile manufacturing plant in Ulsan, for 1 month from April, 1993. This cross-sectional survey compared shift workers(n=544) with day workers(n=115). Each subject completed a questionnaire about his personal habit, background, shift schedule, sleep and eating patterns, subjective digestive symptom and psychological well-being and distress using the General Well-Being Schedule(GWB) by self administrated questionnaire that was developed for the U.S. Health and Nutrition Examination Surveys (HANES I). Chi-square analysis was used for discontinuous data and the t-test was used for continous data to determine whether differences noted between the two groups. In terms of sleep quality, a greater percentage of shift workers frequently had trouble getting back to sleep once awakend(p<0.01), and a greater percentage of shift workers awakend tired or sleepy frequently more often than day workers(p<0.05). In rating the quality of their sleep, more shift workers rated their sleep fair to poor than day workers, and greater percentage of shift workers felt tired or sleepy at work two or more times per week(p<0.01) and a much higher percentage of shift workers felt tired or sleepy after work every days(p<0.01). In terms of sleep patterns, a much higher percentage of day workers reported uninterrupted sleep per 24hours than shift workers. The shift workers reported different eating patterns from day workers but there were no statistically significant and rate of their appetite. Thirteen percent of day workers reported the best appetite but only 6.6% of shift workers had the best appetite. The gastric complaints is more frequent in shift workers than day workers(p<0.01). Among subscores in General Well-Being Schedule, anxiety, depression, positive well-being and vitality subscale of shift workers were lower than those of day workers(p<0.05) and general health and self control subscale of shift workers were lower than .those of day workers but there were no statistical significant difference. Based on these study result, it could be concluded that the shift work has significant effects on some psychophysiological conditions of the workers.

• Annals of Occupational and Environmental Medicine
• /
• v.35
• /
• pp.4.1-4.11
• /
• 2023

Background: Shift work has been shown to increase the risk of cardiovascular disease (CVD) based on several evidences. The classic risk factors of CVD include age, hypertension, smoking, obesity and diabetes. Recently, the serum homocysteine level has been reported to be a valuable indicator of CVD risk. This study aimed to determine the variation in serum homocysteine level as a cardiovascular risk indicator among female workers according to shift work. Methods: The data of regular health examination of workers at an electronic manufacturing services company in Yeongnam region, South Korea in 2019 were examined in this study. The investigation was based on a cross-sectional study conducted on 697 female workers (199 day workers and 498 shift workers). The sociodemographic and biochemical characteristics were compared between day workers and shift workers. Through a logistic regression analysis, the odds ratio (OR) of the increased serum homocysteine level in relation to shift work was determined. Results: Compared to female day workers, female shift workers showed significantly higher level of serum homocysteine (8.85 ± 2.16 vs. 9.42 ± 2.04 μmol/mL; p = 0.001). The OR of day workers against shift workers was 1.81 (95% confidence interval [CI]: 1.25-2.63). With the adjustment of variables that may influence the level of serum homocysteine, the adjusted OR was 1.68 (95% CI: 1.09-2.60). Conclusions: The serum homocysteine level was significantly higher in shift workers than in day workers. It is thus likely to be a useful predictor of CVD in shift workers.

• Korean Journal of Occupational Health Nursing
• /
• v.7 no.2
• /
• pp.155-163
• /
• 1998

In order to investigate the effects of rotating shift work on the subjective characteristics of sleep and mental depression questionnaire survey was carried out on 405 shift workers and 153 nonshift workers who were nurses employed. in three university hospital. The questionnaire forms used in this study were the self rating depression scale(SDS) and circadian type questionnaire(CTQ) factor R(rigidity/flexbility of sleeping habit) and factor V(inability/ability to overcome drowsiness). The results were as follows ; 1. Mean score of CTQ R in shift workers was significantly lower than that in nonshift workers, however, no significant difference in CTQ V was observed between two groups. 2. Mean score of SDS was significantly higher in shift workers(44.1) than in nonshift workers(39.8). 3. Mean self rating depression scale scores of pervasive affect, physiologic equivalents and psychological equivalents were significantly higher in shift workers than in nonshift workers. 4. In shift worker, mean SDS score was the highest in confusion and followed by diurnal variation, retardation, and indeciveness in the descending order. In nonshift worker, that score was the highest in decreased libido and followed by confusion, and indeciveness in the descending order. 5. Circadian type questionnaire scores was significantly and negatively correlated with significantly and negatively correlating with Self-rating depression scale scores(r=-0.473).

• Safety and Health at Work
• /
• v.9 no.4
• /
• pp.421-426
• /
• 2018

Background: The purpose of this study was to investigate the effect of shift work on occupational safety in various industrial sectors. The study analyzes the effects of shift work on the health of workers by considering factors such as the workplace environment and welfare. Methods: Focusing on the $4^{th}$ Korean Working Conditions Survey, this study used an ordinary least-square multiple regression analysis. The dependent variable was the annual frequency of injuries reported by workers. Independent variables were categorized as demographic, shift work, workplace environment, and welfare variables. The analysis was conducted on two levels: 1) Shift work and nonshift work groups were compared, and 2) Shift work was compared with fixed and rotating shifts. Results: For the entire group, age, a low level of education, work hours, and daily and dispatch work negatively impacted the frequency of injuries. Shift work was negatively affected by workplace environment and welfare factors. In the shift group, the frequency of injuries was lower than that of regular workers, and the higher the autonomy in the choice of work hours, the lower the frequency of injuries. Furthermore, shift workers in Korea have more extended work hours (49.25 h/week) than other workers (46.34 h/week). Conclusion: Overall, welfare factors such as workplace satisfaction and worke-life balance reduced the frequency of injuries. The effect of shift work was limited, but it was confirmed that shift worker autonomy could reduce the frequency of injuries.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.30 no.3
• /
• pp.321-330
• /
• 2020

Objectives: The purpose of this study was to compare vitamin D levels, sleep quality, and anxiety symptoms between shift workers and daytime workers and analyze the mediating effect of vitamin D and sleep quality between shift work and anxiety symptoms. Methods: The subjects of the study were 6744 people who received a medical examination while working for an electronics manufacturing company in 2016. We evaluated their shift work, vitamin D levels, sleep quality, and anxiety symptoms with blood samples and questionnaires. Chi-square test, t-test and path statistical analysis were performed. Results: The shift workers had significantly higher symptoms of anxiety than the day workers, significantly lower levels of vitamin D in the blood, and significantly poorer quality of sleep. The results of the pathway analysis confirmed that blood vitamin D and sleep quality had a mediating effect between shift work and anxiety symptoms. Conclusions: Shift workers should be constantly paying attention to mental health effects such as anxiety symptoms. Shift workers should also be alerted of the risk of vitamin D deficiency, encouraged about sun exposure and vitamin D intake, and required to undergo training and counseling on sleep hygiene.

• Journal of Preventive Medicine and Public Health
• /
• v.37 no.2
• /
• pp.182-189
• /
• 2004

Objectives : The objective of this study is to compare the circadian patterns of heart rate variability assessed by 24-hour ambulatory electrocardiographic (ECG) recordings during day shift and night shift among the workers in the 5 days-concecutive-12-hour shift in an automobile factory in Korea. Methods : The study population consisted 300 workers, who were randomly selected among the 8700 total workers in one car factory. To analyse circadian variation, the 24-hour ECG recordings (Marquette) were measured during day shift (08:00-20:00 h) and night shift (20:00-08:00 h). Analysis was performed for all time and frequency domain measures of HRV. 233 workers completed taking 24-hour ECG recordings. Results : This study shows that the 24 hourcircadian variation mainly follows work/sleep cycle rather than day/night cycle among shift workers. This study also shows that among the night shift, the circadian variation between work and sleep cycle decreased compared to the work/sleep cycle among day shift workers. All time and frequency domain parameters (except LF/HF ratio) show significantly different between work and sleep in the day shift and night shift. Conclusion : These changes in heart rate variability circadian rhythms reflect significant reductions in cardiac parasympathetic activity with the most marked reduction in normal vagal activity among the shift workers. Especially, it suggests the circadian rhytm has blunted among the night workers. The quantification of the circadian variation in HRV can be a surrogates of workers' potential health risk, as well as suggests possible mechanisms through which the shift works compromise workers' health.

• Annals of Occupational and Environmental Medicine
• /
• v.35
• /
• pp.22.1-22.9
• /
• 2023

Background: Shift work increases the risk of chronic diseases, including metabolic diseases. However, studies on the relationship between shift work and renal function are limited. The aim of this study was to investigate the association between shift work and a decreased glomerular filtration rate (GFR). Methods: Data were evaluated for 1,324,930 workers who visited the Korean Medical Institute from January 1, 2016 to December 31, 2020 and underwent a health checkup. Daytime workers were randomly extracted at a ratio of 1:4 after matching for age and sex. In total, 18,190 workers aged over 40 years were included in the analyses; these included 3,638 shift workers and 14,552 daytime workers. Participants were categorized into the shift work group when they underwent a specific health checkup for night shift work or indicated that they were shift workers in the questionnaire. The odds ratio was calculated using a conditional logistic regression to investigate the relevance of shift work for changes in GFR. Results: 35 workers in the shift group and 54 in the daytime group exhibited an estimated GFR (eGFR) value of < 60 mL/min/1.73m² (p < 0.01). The difference in eGFR values between two checkups differed significantly depending on the type of work (p < 0.01); the difference in the shift work group (-9.64 mL/min/1.73 m²) was larger than that in the daytime work group (-7.45 mL/min/1.73 m²). The odds ratio for eGFR reduction to < 60 mL/min/1.73 m² in the shift group versus the daytime group was 4.07 (95% confidence interval: 2.54-6.52), which was statistically significant. Conclusions: The results of this study suggest that eGFR decreases by a significantly larger value in shift workers than in daytime workers; thus, shift work could be a contributing factor for chronic kidney disease (CKD). Further prospective studies are necessary to validate this finding and identify measures to prevent CKD in shift workers.

• Safety and Health at Work
• /
• v.11 no.3
• /
• pp.367-371
• /
• 2020

We evaluated the eating pattern, physical activity, and daytime sleepiness level in Chilean shift workers. Fifty, middle-aged adult health workers from a public hospital in Santiago, Chile, were included: a group undergoing shift work (shift workers, including at least one "night shift" and one "long day", n = 33), and day workers under traditional schedule (from 8:00 to 17:00h, n = 17). Body composition, physical activity, and daytime sleepiness levels, and diet characteristics (diet composition, meals' timing, and diet quality) were assessed. Despite similar total energy intake, shift worker showed lower carbohydrate (% of energy) and higher protein intake (both P < 0.01), decreased diet quality, an irregular eating pattern, and delayed meal timing (all P < 0.05). Physical activity and daytime sleepiness levels did not differ between groups. Findings from this first Chilean study in healthcare shift workers support the fact that meal timing and diet quality appear as critical factors for upcoming intervention studies in this group.