• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.22.1-22.9
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• 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
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• v.13 no.1
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• pp.17-22
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• 2022

Background: This study aimed to identify work-related risk factors, including long working hours and night/shift work, for unmet health care need using data of a representative panel of Korean adults. Methods: Associations between work-related factors and unmet health care need were analyzed using data of 3,440 participants (10,320 observations) from the 2011-2013 Korean Health Panel Study. A generalized estimating equation was used for the analysis of repeated measures. Results: The prevalence of unmet health care was 16.6%. After adjusting sex, age, socioeconomic status, work characteristics, and working more than 60 hours per week (odds ratio [OR]: 1.43, 95% confidence interval [CI]: 1.23-1.65) or 50-59 hours per week (OR: 1.26, 95% CI: 1.08-1.46) instead of 40-49 hours per week and night/shift work (OR: 1.27, 95% CI: 1.06-1.51) were associated with unmet health care need. Conclusion: Long working hours and night/shift work are risk factors for unmet health care need among the Korean working population.

• Korean Journal of Community Nutrition
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• v.18 no.5
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• pp.467-477
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• 2013

This study examined the health-related factors and nutritional status of 89 single women workers in their 20's who work night and day shift at the take-out coffee shops and the 89 single women office workers. The results of the study are summarized as follows: The shift-workers showed lower rate of office tenure (p < 0.001), income (p < 0.001), job satisfaction (p < 0.05), weight (p < 0.05), and higher rate of weight change (p < 0.001) than the non shift-workers. The shift-workers showed lower rate of of exercise (p < 0.001), sleeping hours (p < 0.01), and good health condition (p < 0.01), and higher rates of smoking (p < 0.001), presence of disease (p < 0.001), gastric and intestinal illnesses (p < 0.001) than the non shift-workers. More than 88.8% of the shift workers answered that they ate alone (p < 0.001). The shift workers showed lower rate of regularity of meal (p < 0.001), balanced diet (p < 0.001), and mealtime (p < 0.001), and higher rate of skipping breakfast (p < 0.001), consumption of salty and spicy food (p < 0.001), and overeating (p < 0.01) than the non shift-workers. The shift workers consumed (p < 0.001) less frequently rice, soup and side dishes, and more frequently noodles and snack, bread than the non-shift-workers. The shift workers showed lower rate of consumption of beer (p < 0.01), and higher rate of consumption of coffee (p < 0.001), tea (p < 0.01) and soju (p < 0.001) in once a week or more intakes than the non-shift-workers. The shift workers showed higher rate of consumption of carbohydrates (p < 0.05), and calcium (p < 0.05) and lower rate of consumption of protein (p < 0.05), fiber (p < 0.05), vitamin C (p < 0.05), and folate (p < 0.05) intakes than the non-shift-workers.

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

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.2
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• pp.126-133
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• 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 the Korean Society of Safety
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• v.37 no.6
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• pp.118-127
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• 2022

This study analyzes the characteristics of occupational accidents of food delivery via motorcycle in terms of accident probability and work-days. Depending on their employment status, food-delivery workers were divided into "employed" workers (who work for restaurants) and "special-type" workers (who work for delivery platforms). Collected data include occupational accident-information during the last two years (1,468 cases for employed workers and 4,899 cases for special-type workers) and their risk information such as age, work experience, accident location, season of the accident, and weather conditions. The study finds that special-type workers had a significantly higher accident probability for the younger age group (80.8%), while employed workers had more accidents in both 20's or younger (34.9%) and 50's or older (25.4%). The number of work-days-lost was higher for special-type workers with less work experience, and it decreased with increasing work experience. Moreover, the chance for accidents was higher at night time (55%) than for day time (45%) for special-type workers as well as for employed workers. The number of work-days-lost was higher in foreign workers (180.79 days) than in Korean workers (121.44 days). Accident probability (30.7%) and work-days-lost (136.2 days) was higher in winter than in other seasons. In addition, accidents-per-day was higher on snowy days (12.7 cases per day) than rainy (8.1) and windy days (7.1). In addition, it was found that deadly accidents mainly caused injuries to face, head, and chest, while non-deadly accidents affected mainly the legs and feet. This study enables the development of better policies to prevent accidents of food delivery workers.

• Journal of the Korea Safety Management & Science
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• v.14 no.2
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• pp.91-101
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• 2012

To decrease employees' job stress in the viewpoint of occupational health is very important to improve the productivity and quality of labor. In this study, the job stress, and it's influence on job commitment and organizational commitment were investigated by the questionnaire survey of 259 industrial workers. As results, the majority of workers were under job stress resulted from job demand, job control, and coworker's support. The work times per a week and night work had significant relationships with job demand, and the maximum negative relationship between the work times per a week and job continuous commitment was found. Job demand had the significant relationship with job affective and normative commitment, and job control had the significant relationship with job normative commitment and organizational affective commitment. Moreover, job affective and normative commitment had the significant relationship with organizational continuous commitment. Finally, it was found that cyclic organic chain was composed of work times per a week, night work, salary, job demand, job control, job affective and normative commitment, and organizational affective and continuous commitment. The results of this study indicates that reducing cyclic organic chain is urgently necessary to increase employees' job satisfaction and company commitment.

• Journal of Korean Public Health Nursing
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• v.30 no.3
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• pp.495-511
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• 2016

Purpose: The present study was performed to describe the prevalence of various types of smoking statuses and to identify factors associated with different types among Korean wageworkers. Methods: The prevalence of hardcore smoking, daily smoking, and intermittent smoking was assessed in 2,126 wage workers from the Sixth Korea National Health and Nutrition Examination Survey. The associations of these three types of smoking statuses with sociodemographic characteristics, health conditions, and occupation-related characteristics were also examined in a multinomial logistic regression. Results: In men, the prevalence of hardcore smoking and daily smoking were 11.4% and 30.2%, respectively; and in women, the daily smoking prevalence was 5.6%. The education level was strongly associated with men's hardcore smoking and women's daily smoking. The household income and marital status were associated with women's daily smoking. Among occupation-related characteristics, the regularity of work and night work were associated with men's intermittent smoking. Night work was also associated with women's daily smoking. Employment condition was associated with women's intermittent smoking. Conclusion: The socioeconomic status and health conditions, compared with occupation-related factors, were found to have more influence on smoking. Therefore, antismoking programs that focus on individual characteristics should be developed for Korean wageworkers.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.4
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• pp.566-572
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• 2015

Objectives: The major objective of this study was to analyze insomnia after the change to consecutive day shift from day and night shift in a motor assembly factory. Materials: Data were collected at before and after shift system change through a survey conducted by a labor union. We analyzed transition of PSQI(Pittsburgh Sleep Quality Index) among 222 workers by separating the day shift week and night shift week. The cut-off point of insomnia was 8.5 on the PSQI. Results: Mean PSQI in the day shift week significantly did not decrease, going from $6.36{\pm}3.23$ to $6.46{\pm}3.00$(p=0.612 by paired t-test), Mean PSQI for night shift week significantly decreased from $8.31{\pm}3.36$ to $6.19{\pm}3.18$(p<0.001 by paired t-test). However, mean PSQI in the day shift week increased from $6.33{\pm}3.83$ to $7.11{\pm}2.86$ in ${\geq}50$ years(p=0.085, by repeated measured ANOVA). Mean PSQI score in the night shift week improved more in the married group(from $8.38{\pm}3.27$ to $6.12{\pm}3.18$) than in the non-married group(from $7.82{\pm}3.27$ to $6.12{\pm}3.18$)(p=0.038, by repeated measured ANOVA). Conclusions: The change to consecutive day shift improved insomnia in night shift. However, insomnia in the day shift week was worsened among those more than 50 years old.

• Journal of the Korean Home Economics Association
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• v.30 no.1
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• pp.87-98
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• 1992

This study was undertaken to investigate protein effects on the adaptation of shift work. Since biorhythms differ according to the time of day, an investigation of the change of metabolism during day-shift and night-shift was undertaken by dividing twenty 3-shift worker into two groups: dormitory diet group and milk & egg supplemented group. Between the two groups, estimations were made on the concentrations of serum protain, albumin, cholesterol and cortisol and the excretion of vanilymandelic acid(VMA), creatinine and nitrogen in urine. The results are summarized as follows: 1. Serum ingredients were gathered from workers at 6:00-7:00h and 14:00-15:00h on the day of their change from morning shift(6:00-14:00h) to night shift(22:00-6:00h). On examnation of the serum ingredient it was found that, in dormitory diet group only the concentrarion level of serum albumin showed a change of rhythm adapted to night work, and in the milk & egg supplemented group the concentration levels of serum protein, albumin and cholesterol all showed a change of rhythm adapted to night work. Serum cortisol of both groups showed the same rhythm as during morining shfits, which implied nonadatation to night work, but the concentration was observed to be lower. 2. Excretion of urinary VMA and nitrogen were higher during night work than during morning work: they were also higher on the 6th day than on the 1st, in comparing the two groups, excretion of VMA was higher among the dormitory diet group, whereas the opposite was ture for excretion of nitrogen among the milk & egg supplemented group. There was no sign of difference in excretion of cretinine among the two experiment groups.