South Korea has the highest policy priority for working hour regulations because it has longer annual working hours than other Organization for Economic Development Co-operation and Development countries and has fewer holidays. According to the results of the Working Conditions Surveys between 2006 and 2020, in 2020, 6% of wage earners worked for > 52 hours weekly. The percentage of workers exceeding 52 hours weekly has decreased over time; however, disparities exist based on age, industry, occupation, company type, and company size, particularly in service-, arts-, and culture-related occupations and workplaces with fewer than 5 employees. South Korea’s working hours system is greatly influenced by the 52-hour weekly maximum; sometimes, a maximum of 64–69 hours, including overtime, is theoretically possible. To ensure healthy working hours, it is important to actively protect workers who fall through the cracks, such as those in businesses with fewer than 5 employees.
Citations
There are several types of shift work in Korea: rotating shift, 24-hour shift, day-night shift, fixed night work, and.so on. As a result of analyzing the 8th Korea National Health and Nutrition Examination Survey and the 6th Korean Working Condition Survey, Korean shift workers accounted for 11.6%–13.9% of wage workers. Weekly working hours of shift workers were 57.69 ± 1.73 (24-hours shift) and 49.97 ± 0.67 (fixed night shift), which were significantly longer than day workers. To prevent health consequences of night work, many countries regulate the working hours of night work not to exceed 7–9 hours a day. However, Korea does not regulate working hours for night work, and some occupations may work more hours than the prescribed overtime hours. To prevent health consequences and reduce working hours for Korean night shift workers, it is necessary to regulate the working hours of night shift workers by law.
Citations
Recently, irregular working hours have become controversial issues in Korea. The health impact of irregular working hours on the work-related musculoskeletal pain (MSP) is scarcely researched before. We sought to investigate the association between irregular working hours and work-related MSP among South Korean workers.
This study used data from the sixth Korean Working Conditions Survey in 2020. The prevalence of work-related MSP was analyzed using the χ2 test. A multiple logistic regression analysis was conducted to assess the association between irregular working hours and work-related MSP. We conducted stratified analysis by gender, weekly working hours, and workers’ control over their working hours. We calculated the adjusted odds ratios (ORs) of work-related MSP for irregular working hours combined with weekly working hours.
The OR for work-related MSP was significantly higher in the population with irregular working hours than in the population with regular working hours (OR: 1.43, 95% confidence interval [CI]: 1.29–1.58). Irregular and long (> 52 hours/week) working hours have the highest risk of work-related MSP in both genders (in men, OR: 3.48 [95% CI: 2.53–4.78]; in women, OR: 2.41 [95% CI: 1.46–4.00]).
Irregular working hours were associated with work-related MSP in Korea. The association was magnified with long working hours. Reform of the Korean Labor Standards Act leading to increase irregular working hours may induce adverse health outcome.
Citations
In the manufacturing industry, work-family conflict (WFC) is related to working hour characteristics. Earlier studies on the relationship between working hour characteristics and WFC in the manufacturing industry have been limited to some regions in Korea. No study has addressed the data on a national scale. Thus, this study investigated the impact of weekly working hours, weekend work, and shift work on WFC using national-scale data.
This study was based on the fifth Korean Working Conditions Survey of 5,432 manufacturers. WFC consists of 5 variables; WFC1 “kept worrying about work”; WFC2 “felt too tired after work”; WFC3 “work prevented time for family”; WFC4 “difficult to concentrate on work”; WFC5 “family responsibilities prevented time for work”. As WFC refers to the inter-role conflict between the need for paid work and family work, WFC has been measured in two directions, work to family conflict (WTFC: WFC1, 2, 3) and family to work conflict (FTWC: WFC4, 5). With these WFC variables, we conducted multiple logistic analyses to study how working hours, weekend work, and shift work impact WFC.
Korean manufacturers’ prolonged working hours increased all aspects of WFCs. Odds ratios (ORs) of WFCs based on working hours (reference of under 40 hours) of 41–52, 53–60, over 61 were 1.247, 1.611, 2.279 (WFC1); 1.111, 2.561, 6.442 (WFC2); 1.219, 3.495, 8.327 (WFC3); 1.076, 2.019, 2.656 (WFC4); and 1.166, 1.592, 1.946 (WFC5), respectively. Shift-work in the WFC2 model showed a significantly higher OR of 1.390. Weekend work ‘only on Saturday’ had significant ORs with WFC2 (1.323) and WFC3 (1.552).
An increase in working hours leads to the spending of less time attending to problems between work and family, causing both WTFC and FTWC to increase. As weekends, evenings, and nighttime are considered to be family-friendly to people, working on weekends and shift-work were highly correlated to WTFC.
Citations
Long working hours causes several health risks, but little is known about its effects on the liver. This study aimed to examine the correlation between working hours and abnormal liver enzyme levels.
We used data from the Korea National Health and Nutrition Examination Survey IV–VII. For the final 15,316 study participant, the information on working hours was obtained through questionnaires, and liver enzyme levels, consisting of serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), through blood tests. The relationship between weekly working hours and abnormal levels of liver enzymes was analyzed using multiple logistic regression, and a trend test was also conducted.
In male, working ≥ 61 hours per week was significantly associated with elevated AST and ALT levels compared with working 35–52 hours per week. Even after adjusting for covariates, the odds ratios (ORs) of abnormal AST and ALT increased by 1.51 (95% confidence interval: 1.20–2.05) and 1.25 (1.03–1.52), respectively, and a dose-response relationship was observed. This association was more prominent among the high-risk group, such as those aged > 40 years, obese individuals, worker on non-standard work schedule, pink-collar workers, or temporary worker. No correlation was observed in female.
Long working hours are associated with abnormal liver function test results in male. Strict adherence to statutory working hours is necessary to protect workers’ liver health.
Citations
Long working hours are known to account for approximately one-third of the total expected work-related diseases, and much interest and research on long working hours have recently been conducted. Additionally, as the prevalence of prediabetes and the high-risk group for diabetes are increasing worldwide, interest in prediabetes is also rising. However, few studies have addressed the development of type 2 diabetes and long working hours in prediabetes. Therefore, the aim of this longitudinal study was to evaluate the relationship between long working hours and the development of diabetes in prediabetes.
We included 14,258 prediabetes participants with hemoglobinA1c (HbA1c) level of 5.7 to 6.4 in the Kangbuk Samsung Cohort Study. According to a self-reported questionnaire, we evaluated weekly working hours, which were categorized into 35–40, 41–52, and > 52 hours. Development of diabetes was defined as an HbA1c level ≥ 6.5%. Hazard ratios (HRs) and 95% confidence intervals (CIs) for the development of diabetes were estimated using Cox proportional hazards analyses with weekly working 35–40 hours as the reference.
During a median follow-up of 3.0 years, 776 participants developed diabetes (incidence density, 1.66 per 100 person-years). Multivariable-adjusted HRs of development of diabetes for weekly working > 52 hours compared with working 35–40 hours were 2.00 (95% CI: 1.50–2.67). In subgroup analyses by age (< 40 years old, ≥ 40 years old), sex (men, women), and household income (< 6 million KRW, ≥ 6 million KRW), consistent and significant positive associations were observed in all groups.
In our large-scale longitudinal study, long working hours increases the risk of developing diabetes in prediabetes patients.
Citations
Because income and working hours are closely related, the health impact of working hours can vary according to economic status. This study aimed to investigate the relationship between working hours and the risk of poor self-rated health according to household income level.
We used the data from the Korea National Health and Nutrition Examination Survey VI and VII. The information on working hours and self-rated health was obtained from the questionnaire. After stratifying by household income level, the risk of poor self-rated health for long working hour group (≥ 52 hours a week), compared to the 35–51 working hour group as a reference, were calculated using multiple logistic regression.
Long working hours increased the risk of poor self-rated health in the group with the highest income, but not in the group with the lowest income. On the other hand, the overall weighted prevalence of poor self-rated health was higher in the low-income group.
The relationship between long working hours and the risk of poor self-rated health varied by household income level. This phenomenon, in which the health effects of long working hours appear to diminish in low-income households can be referred to as the ‘poor worker’s long working hours paradox’. Our findings suggest that the recent working hour restriction policy implemented by the Korean government should be promoted, together with a basic wage preservation to improve workers’ general health and well-being.
Citations
Adolescent smoking and drinking are influenced by parental supervision. This study aimed to investigate the gap in adolescent smoking and drinking experience rates and age at initiation according to maternal working hours.
Data from 1,580 adolescents aged 12–18 years and 1,172 working mothers of double-parent or single-mother households were selected from the Korean National Health and Nutrition Examination Survey (KNHANES) VI & VII data. Figures on adolescents' smoking and drinking rates and their ages at imitation were used. Maternal working hours were divided into < 40 hours, 40–52 hours, and > 52 hours to analyze whether smoking and drinking experience rates and age at initiation differ according to maternal working hours and by the child's sex. Maternal age, education level, household income, occupation, shift work, current smoking status, monthly drinking frequency and child's obesity, stress recognition and depressive mood were adjusted for in the statistical analyses.
The odds for adolescents' smoking behavior were significantly higher with increasing maternal working hours in boys but not in girls. The odds for adolescents' drinking behavior were not significantly higher in both boys and girls. Regardless of the child's sex, there were no significant differences in the age of smoking and drinking initiation according to maternal working hours.
Adolescents of mothers who work long hours are at a higher risk of being exposed to smoking. Thus, our society needs to share the burden of raising children, which is concentrated on women, and employers and governments should support policies that can help prevent long working hours.
Citations
The intention to quit smoking is one of the most important factors in smoking cessation. Long working hours is also a constant issue, and many studies have shown an association between the working hours and diseases, including cardiovascular and gastrointestinal diseases. This study evaluated the relationship between working hours and the intention to quit smoking among Korean male office workers, and blue collar workers for comparison.
This study was based on the Seventh Korea National Health and Nutrition Examination Survey (2016–2017). A total of 1,389 male workers were smokers, and then office workers and blue collar workers were selected. Logistic regression was used to calculate the odds ratio (OR) for the intention to quit smoking according to smoking-related characteristics and working hours after adjusting for age group, body mass index (kg/m2), marital status, household income (quartile), educational level, drinking, exercise, smoking-related characteristics (smoking initiation age, smoking amount, and attempt to quit smoking more than 1day in the past year) and working hours.
The percentage of workers who had the intention to quit smoking in 6 months was higher in office workers (38.9% for office workers and 29.4% for blue collars,
Working more than 52 hours per week was positively related with a lower intention to quit smoking among currently smoking male office workers. Further studies are needed considering more work-related variables such as job stress and physical load.
Citations
Sleep disorders are common and serious problems for mental health. This study investigated the relationship between spouses' weekly working hours (SWWH) and sleep problems by using the data from the 5th Korean Working Conditions Survey.
Data from 14,921 wage workers were used in the 5th Korean Working Conditions Survey. General and occupational characteristics, sleep problems are included in the questionnaire. Multivariate logistic regression analysis was used after adjustment for general and occupational characteristics to find the relationship between SWWH and sleep problems.
Compared to those whose spouses worked less than 40 hours per week, risk of trouble falling asleep, waking up repeatedly while sleeping, and waking up with a feeling of exhaustion and fatigue was significantly higher as SWWH increase among those whose spouses worked 53 or more hours per week (odds ratio [OR]: 1.40, 95% confidence interval [CI]: 1.16–1.70; OR: 1.50, 95% CI: 1.23–1.82; OR: 1.51, 95% CI: 1.24–1.83).
SWWH were related to sleep problems among Korean wage workers.
Citations
Many studies have reported the negative effects of long working hours on various health problems. However, whether hair loss is associated with working hours has been rarely investigated so far. The main purpose of this study is to explore the relationship between long working hours and the development of alopecia among Korean male workers.
A total of 13,391 male workers not to take alopecia medicine in 2013 were followed up to see if they have alopecia medicine after 4 years, and that was used to confirm the alopecia development. Weekly working hours were categorized into three groups: reference working hours (RWH; < 40 hours/week), long working hours (LWH, 40–52 hours/week), and much longer working hours (MLWH; > 52 hours/week). Multiple logistic regression analyses were conducted to investigate the relationship between long working hours and the development of alopecia after adjusting age, marital status, education, monthly household income, smoking, and work schedule within strata of the covariates.
Long working hours was significantly related to the development of alopecia. The adjusted odds ratios (ORs) for the development of alopecia were 1.57 (95% confidence interval [CI]: 1.21–2.05) for LWH group and 1.74 (95% CI: 1.23–2.47) for MLWH group relative to RWH group.
Our findings suggest that unintentional development of alopecia is another potential health consequence of long working hours among Korean male workers. Preventive interventions to promote appropriate and reasonable working hours are required in our society.
Citations
It has been reported that long working hours are hazardous to the workers’ health. Especially, work-related musculoskeletal disorders (WMSDs) have been considered as one of the significant health issues in workplace. The objective of this study was to identify the association between long working hours and work-related musculoskeletal symptoms.
The analysis was conducted using data from the Fourth Korean Working Conditions Survey (KWCS). Subjects of this study were 24,783 wage workers and divided into three groups according to the weekly working hours, which were ≤ 40, 41–52 and > 52 h. The relationship between long working hours and work-related musculoskeletal symptoms was analyzed by multivariate logistic regression method after adjusting for general, occupational characteristics including specific working motions or postures and psychosocial factors.
Approximately 18.4% of subjects worked more than 52 h per week and 26.4 and 16.4% of male subjects and 33.0 and 23.4% of female subjects experienced work-related upper and lower limb pains, respectively, over the last 12 months. Moreover, the prevalence of upper and lower limb pain was increased in both genders as the weekly working hours increased. The odds ratios (ORs) of upper limb pain for those working 41–52 h and more than 52 h per week when adjusted for general, occupational characteristics including specific motions or postures and psychosocial factors were 1.36 and 1.40 for male workers and 1.26 and 1.66 for female workers compared to the reference group, respectively. Furthermore, ORs of lower limb pain for the same weekly working hour groups were 1.26 and 1.47 for male workers and 1.20 and 1.47 for female workers, respectively.
Long working hours were significantly related to work-related musculoskeletal symptoms in Korean wage workers and appropriate interventions should be implemented to reduce long working hours that can negatively affect workers’ health.
Citations
South Korea is one of the countries with the longest working hours in the OECD countries. The aim of this study was to evaluate the effect of working hours on depressive symptoms and the role of job stress factors between the two variables among employees in South Korea.
This study used data from the Korea Working Conditions Survey in 2014. Study subjects included 23,197 employees aged 19 years or older who work more than 35 h per week. Working hours were categorized into 35–39, 40, 41–52, 53–68, and more than 68 h per week. Depressive symptoms were assessed using the WHO’s Well-Being Index with a cut-off score of 13. We calculated prevalence ratios of depressive symptoms according to working hours using log-binomial regression. Through the percentage change in prevalence ratios, we identified the extent of the role of job stress factors that explain depressive symptoms.
The risks of depressive symptoms were significantly higher in people who worked 35–39 h per week (PR: 1.09, CI: 1.01–1.18), 53–68 h/week (PR: 1.21, CI: 1.16–1.25), and more than 68 h/week (PR: 1.14, CI: 1.07–1.21) than 40 h/week, after adjusting for confounding variables. Job stress explained the effects of long working hours on depressive symptoms in about 20–40% of the groups working more than 40 h/week. Among the factors of job stress, social support was 10–30%, which showed the highest explanatory power in all working hours. Reward explained 15–30% in the more than 52 h working group, and reward was the most important factor in the working group that exceeded 68 h.
We showed the working hours could be an independent risk factor for depressive symptoms in employees. To improve workers’ mental health, it is important to strengthen social support in the workplace, to provide adequate rewards as they work, and ultimately to regulate the appropriate amount of working hours.
Citations
Korean teacher’s working conditions are deteriorating. There is concern about the deterioration of teachers’ health and voice disorder is one of the most common problems. Teacher’s vocal health is important for them and their students. The aim of the present study was to investigate working conditions that may affect voice disorders.
In all, 79 primary and secondary schools were randomly selected for a nationwide school system survey (
Teachers who reported voice symptoms more than once a week (fVD) made up 11.6%. In a multiple logistic regression, fVD was significantly associated with female, difficulty in applying for sick leave as needed, music teachers (primary school), and less than 6 h of sleep per day (primary school). The aOR for fVD was 2.72 (0.83–8.10) in the longest working hours group (> 52 h/wk) among the primary school teachers, and 1.90 (0.80–4.73) in the longest class hour group (≥ 20 h/wk), 1.52 (0.90–2.62) in homeroom teachers among the secondary school teachers, but not statistically significant.
Korean teachers’ working conditions are associated with fVDs. The school health system must take steps to prevent and treat voice disorders of teachers.
Citations
The aim of this study was to investigate the association between work-related factors and temporomandibular disorders (TMD) among female full-time employees using representative data from a national population-based survey.
Data from the Fourth Korea National Health and Nutrition Examination Survey IV (2007–2009) were used to analyze 1,612 women. Complex samples logistic regression was applied for adjusting for general characteristics and work-related factors to examine the association between work-related factors and TMD.
The prevalence of TMD was 12.8% in this study population. With respect to age, educational status, marital status, problem drinking, exercise, and stress, there were statistically significant differences in the prevalence of TMD. In logistic regression analyses on complex samples, based on 40 h or less per week, odds ratios (ORs) for respondents who worked 40–48 working hours, 49–60 working hours, and more than 60 h were 1.16 (95% confidence interval (CI) 0.69–1.94), 1.41 (95% CI 0.79–2.54), and 2.43 (95% CI 1.29–4.59), after adjusting for general characteristics, working schedule, employment status, and occupation.
This study found that long working hours were significantly associated with TMD in Korean female full-time employees.
Citations
Workplace health promotion (WHP) strongly requires the employer’s efforts to improve the psychosocial, ergonomic, and physical environments of the workplace. There are many studies discussing the socio-economic advantage of WHP intervention programmes and thus the internal and external factors motivating employers to implement and integrate such programmes. However, the socio-economic impacts of the employer’s multifactorial efforts to improve the work environment need to be adequately assessed.
Data were collected from Swedish company Sandvik Materials Technology (SMT) through a work environment survey in April 2014. Different regression equations were analysed to assess marginal effects of the employer’s efforts on overall labour effectiveness (OLE), informal work impairments (IWI), lost working hours (LWH), and labour productivity loss (LPL) in terms of money.
The employer’s multifactorial efforts resulted in increasing OLE, decreasing IWI and illness-related LWH, and cost savings in terms of decreasing LPL.
Environmental factors at the workplace are the important determinant factor for OLE, and the latter is where socio-economic impacts of the employer’s efforts primarily manifest.
Citations
Self-perceived health, a subjective assessment of one’s health condition, is an important health indicator at the level of quality of life. In this study, working time quality refer to job factors with qualitative aspects of working time. This study was conducted to investigate the association between working time quality and self-perceived health in paid workers in Korea.
In this study, 35,902 paid workers were analyzed based on the 3rd Korean working conditions survey. For independent variables, working time quality (working at night, working in the evenings, working on Sundays, working on Saturdays, and working more than 10 h a day) were set as major job-related variables. Other occupational characteristics were divided into 6 groups and general characteristics were divided into 6 groups, and univariate analysis was conducted with self-perceived health, a dependent variable. Variables that had significance in the univariate analysis were used for multivariate logistic regression analysis.
In the univariate analysis using Chi-square test, variables showing significance in self-perceived health were age, income, education, occupation, employment type, work hours per week, and shift work. Working time quality showed a significant association with self-perceived health. After adjusting for these variables using logistic regression analysis, working at night, working in the evening, working on Sundays, and working more than 10 h a day showed significant association with self-perceived health.
This study showed a statistically significant association between working time quality of employees with self-perceived health.
Citations
Recently, the emergence of long working hours and the associated conditions such as coronary heart disease (CHD) and stroke have gained attention. The aim of this study was to investigate the association between long working hours and the 10-year-risk of CHD and stroke, estimated by Jee’s health risk-appraisal model for ischemic heart disease.
We analyzed data from Koreans who randomly enrolled in Korean National Health and Nutrition Examination Survey 2008–2012 and finally included 13,799 participants. The participants were classified as per their working hours: 0–30 h/week, 31–39 h/week, 40 h/week, 41–50 h/week, 51–60 h/week, 61–70 h/week, 71–80 h/week, and >80 h/week. The risks for CHD and stroke were determined using Jee’s health risk-appraisal model. Multiple logistic regression was used to analyze the association between working hours and 10-year risk for CHD.
The 10-year risks for CHD and stroke were significantly and positively associated with working hours in both men and women. Furthermore, higher risks for CHD and stroke were associated with longer working hours in women.
Long working hours are significantly associated with the risks of CHD and stroke, estimated by Jee’s health risk-appraisal model. This study suggests the need for proper management of working hours to reduce CHD risk and stroke risk in the Korean population.
The online version of this article (doi:10.1186/s40557-016-0149-5) contains supplementary material, which is available to authorized users.
Citations
With the development of technology, extensive use of computers in the workplace is prevalent and increases efficiency. However, computer users are facing new harmful working conditions with high workloads and longer hours. This study aimed to investigate the association between computer use at work and self-reported depressive and anxiety disorder (DAD) in a nationally representative sample of South Korean workers.
This cross-sectional study was based on the third Korean Working Conditions Survey (2011), and 48,850 workers were analyzed. Information about computer use and DAD was obtained from a self-administered questionnaire. We investigated the relation between computer use at work and DAD using logistic regression.
The 12-month prevalence of DAD in computer-using workers was 1.46 %. After adjustment for socio-demographic factors, the odds ratio for DAD was higher in workers using computers more than 75 % of their workday (OR 1.69, 95 % CI 1.30−2.20) than in workers using computers less than 50 % of their shift. After stratifying by working hours, computer use for over 75 % of the work time was significantly associated with increased odds of DAD in 20–39, 41–50, 51–60, and over 60 working hours per week. After stratifying by occupation, education, and job status, computer use for more than 75 % of the work time was related with higher odds of DAD in sales and service workers, those with high school and college education, and those who were self-employed and employers.
A high proportion of computer use at work may be associated with depressive and anxiety disorder. This finding suggests the necessity of a work guideline to help the workers suffering from high computer use at work.
The online version of this article (doi:10.1186/s40557-016-0146-8) contains supplementary material, which is available to authorized users.
Citations
This study is aimed at finding out the relationship between long working hours, one of major job stress elements, and hearing impairment in unexposed workers to occupational and environmental noise.
This study was performed on 1628 regular, full-time wage workers between the age of 25-64 who indicated in the survey of having no experience of exposure to noise, normal otoscopic findings, and not suffering from diabetes based on the data from the fifth Korea National Health and Nutrition Examination Survey (KNHANES 2010–2012). The average working hours per week was categorized into 40 h and lower group, more than 40 to 48 h group, more than 48 to 60 h group, and more than 60 h group. The groups were defined as suffering from low or high frequencies hearing impairment if the average hearing threshold for 0.5, 1, 2 kHz or 3, 4, 6 kHz in both ears exceeds 25 dB based on the pure tone audiometry. The association between average weekly working hours and hearing impairment was analyzed using logistic regression after gender stratification.
The prevalences of low and high frequencies hearing impairment in male workers were 4.3 and 28.6 %, respectively, which were much higher than female’s prevalence of 2.7 and 11.1 %. For male workers, no significant association was found between average weekly working hours and low and high frequencies hearing impairment. For female workers, odds ratios (OR) of low and high frequencies hearing impairment were 4.22 (95 % confidence interval (CI) 1.09–16.27) and 4.49 (95 % CI 1.73–11.67), respectively, after controlling for several related factors, such as, age, Body Mass Index (BMI), socio-economic status, health-related behavioral, and occupational characteristics variables, in the final model in the group working more than 60 h compared to the group working 40 h and lower. In addition, a dose-response relationship was observed that ORs of low and high frequencies hearing impairment were increased according to increasing average weekly working hours.
The association between long working hours and hearing impairment in both low and high frequencies was significant in Korean female workers with a dose-response relationship. Therefore, the law to change the culture of long working hours should be enacted in order to protect the workers’ health and improve the quality of life in Korean workers.
Citations
The aim of this study was to investigate whether type of work is associated with anxiety and depression using the Hospital Anxiety and Depression Scale (HADS). Additionally, we investigated the impact of number of working hours on anxiety and depression.
A total of 1774 workers participated and completed the HADS to determine their levels of anxiety and depression. All subjects were employed at one of two manufacturing plants for the same company. Of all participants, 222 were employed in office jobs and 1552 in manufacturing jobs.
Results of multivariate logistic regression analysis including age, sex, body mass index, smoking status, alcohol consumption, regular exercise, factory region, and working hours, indicated that employment in an office job was associated with a 2.17-fold increase in the odds of anxiety compared to a manufacturing job (odds ratio [OR] = 2.17; 95 % confidence interval [CI], 1.24–3.80). Office jobs were also associated with a 1.94-fold increase in the odds of depression (OR = 1.94; 95 % CI, 1.34–2.82). In addition, number of hours worked was significantly associated with depression, and working hours significantly modified the effect of office job employment on the risk of depression.
Office job workers had higher levels of anxiety and depression than those working in manufacturing jobs. Our findings suggest that occupational physicians should consider the organizational risks faced by office job employees, and consider the differences in psychological health between office and manufacturing job workers when implementing interventions.
Citations
Previous studies have identified a link between gender and the various risk factors associated with obesity. We examined obesity risk factors in working adults to identify the effects of differences in body mass index (BMI) and percentage body fat (PBF) between women and men.
A total of 1,120 adults agreed to participate in the study. Data from 711 participants, including 411 women and 300 men, were analyzed. Multiple logistic regression analysis was used to estimate the effects of risk factors on obesity and being overweight. In addition, the least-squares (LS) means of both BMI and PBF were estimated by analysis of covariance (ANCOVA) in a generalized linear model.
Increases in BMI and PBF were significantly related to an age > 50 years and long working hours in women after compensating for confounding factors. Using the PBF criterion, the odds ratio (OR) of being overweight or obese in women > 50 years of age who worked for > 9 h a day was 3.9 (95% confidence interval [CI], 1.05–11.00). For BMI, women who were > 50 years of age and worked for > 9 h a day were 3.82 times (95% CI, 1.31–11.14) more likely to be overweight or obese than those who were < 50 years of age and worked for < 9 h a day.
Obesity in working adults was associated with > 50 years of age and long working hours in women. Further studies are needed to investigate the underlying mechanisms of this relationship and its potential implications for the prevention and management of excess weight and obesity.
Citations
This study was conducted in order to evaluate the association between the working hours of Korean employees and the metabolic syndrome and the effects of long working hours on metabolic syndrome based on the 5th Korean National Health and Nutrition Examination Survey (2010-2012).
Based on the 5th Korean National Health and Nutrition Examination Survey (2010-2012), 4,456 Korean employees without shift work, aged over 15, who work 30 hours or more per week were targeted in this study. The association between the general characteristics, including age, smoking, alcohol drinking, exercise, and the metabolic syndrome criteria defined by International Diabetes Federation (IDF) and weekly working hours were analyzed. In addition, the association between weekly working hours and the metabolic syndrome of the subjects stratified by gender was analyzed through multiple logistic regression analyses and generalized linear mixed model after adjusting the general characteristics.
In the results of stratified analysis by gender, in male subjects, in comparison with the 30-39 weekly working hours group, there were no significant adjusted odds ratios to the other working hours groups. In female subjects, in comparison with the 30-39 weekly working hours group, there were no significant adjusted odds ratios to the other working hours groups. In addition, no trend associations were observed among weekly working hour groups in both stratified genders.
No significant differences in prevalence of metabolic syndrome of the subjects stratified by gender were found according to weekly increasing working hours. However, due to some limitations of this study, further prospective studies may be necessary for verification.
Citations
The present study investigated the association between long working hours and serum gamma-glutamyltransferase (GGT) levels, a factor influencing the incidence of cardiovascular disease.
Data from the fifth Korean National Health and Nutrition Examination Survey (2010–2011) were used to analyze 1,809 women. Subjects were divided into three groups based on the number of weekly working hours: ≤29, 30–51, and ≥52 hours per week. Complex samples logistic regression was performed after adjusting for general and occupational factors to determine the association between long working hours and high serum GGT levels.
The prevalence of high serum GGT levels in groups with ≤29, 30–51, and ≥52 working hours per week was 22.0%, 16.9%, and 26.6%, respectively. Even after adjusting for general and occupational factors, those working 30–51 hours per week had the lowest prevalence of high serum GGT levels. Compared to those working 30–51 hours per week, the odds ratios (OR) of having high serum GGT levels in the groups with ≥52 and ≤29 working hours per week were 1.56 (95% confidence interval [CI], 1.10–2.23) and 1.53 (95% CI, 1.05–2.24), respectively.
Long working hours were significantly associated with high serum GGT levels in Korean women.
Citations
Many studies have reported an association between overwork and hypertension. However, research on the health effects of long working hours has yielded inconclusive results. The objective of this study was to identify an association between overtime work and hypertension in wage workers 45 years and over of age using prospective data.
Wage workers in Korea aged 45 years and over were selected for inclusion in this study from among 10,254 subjects from the Korean Longitudinal Study of Ageing. Workers with baseline hypertension and those with other major diseases were excluded. In the end, a total of 1,079 subjects were included. A Cox proportional hazards model was used to calculate hazard ratios and adjust for baseline characteristics such as sex, age, education, income, occupation, form of employment, body mass index, alcohol habit, smoking habit, regular exercise, and number of working days per week. Additional models were used to calculate hazard ratios after gender stratification.
Among the 1,079 subjects, 85 workers were diagnosed with hypertension during 3974.2 person-months. The average number of working hours per week for all subjects was 47.68. The proportion of overtime workers was 61.0% (cutoff, 40 h per week). Compared with those working 40 h and less per week, the hazard ratio of subjects in the final model, which adjusted for all selected variables, working 41-50 h per week was 2.20 (95% confidence interval [CI], 1.19–4.06), that of subjects working 51-60 h per week was 2.40 (95% CI, 1.07–5.39), and that of subjects working 61 h and over per week was 2.87 (95% CI, 1.33–6.20). In gender stratification models, the hazard ratio of the females tended to be higher than that of the males.
As the number of working hours per week increased, the hazard ratio for diagnosis of hypertension significantly increased. This result suggests a positive association between overtime work and the risk of hypertension.
Citations
The purpose of the present study was to identify the association between presenteeism and long working hours, shiftwork, and occupational stress using representative national survey data on Korean workers.
We analyzed data from the second Korean Working Conditions Survey (KWCS), which was conducted in 2010, in which a total of 6,220 wage workers were analyzed. The study population included the economically active population aged above 15 years, and living in the Republic of Korea. We used the chi-squared test and multivariate logistic regression to test the statistical association between presenteeism and working hours, shiftwork, and occupational stress.
Approximately 19% of the workers experienced presenteeism during the previous 12 months. Women had higher rates of presenteeism than men. We found a statistically significant dose–response relationship between working hours and presenteeism. Shift workers had a slightly higher rate of presenteeism than non-shift workers, but the difference was not statistically significant. Occupational stress, such as high job demand, lack of rewards, and inadequate social support, had a significant association with presenteeism.
The present study suggests that long working hours and occupational stress are significantly related to presenteeism.
Citations
This study was conducted to determine the number of hours worked per week by full-time wage workers by using the data of the Korean Labor and Income Panel Study (KLIPS), which represents the domestic urban area household, and to determine the association between weekly working hours and the level of self-rated health.
We used data from the 11th KLIPS conducted in 2008. The subjects of this study were 3,699 full-time wage workers between the ages of 25 and 64 years. The association between weekly working hours and self-rated health was analyzed considering socio-demographic characteristics, work environment, and health-related behaviors.
Among the workers, 29.7% worked less than 40 hours per week; 39.7%, more than 40 to 52 hours; 19.7%, more than 52 to 60 hours; and 10.9%, more than 60 hours per week. After controlling for socio-demographic variables, work environment-related variables, and health-related behavior variables, the odds ratio (OR) for poor self-rated health for the group working more than 40 hours and up to 52 hours was calculated to be 1.06 (95% confidence interval (CI), 0.89-1.27) when the group working less than 40 hours per week was considered the reference. The OR for the group working more than 60 hours was 1.42 (95% CI, 1.10-1.83) and that for the group working more than 52 hours and up to 60 hours was 1.07 (95% CI, 0.86-1.33). After stratification by gender and tenure, the OR of the female workers group and that of the group with a tenure of more than 1 year were found to be significantly higher than those of the other groups.
This study showed that workers working more than 60 hours per week have a significantly higher risk of poor self-rated health than workers working less than 40 hours per week. This effect was more obvious for the female workers group and the group with a tenure of more than 1 year. In the future, longitudinal studies may be needed to determine the association between long working hours and various health effects in Korean workers.
Citations
Korea is well known for its long work hours amongst employees. Because workers of the manufacturing industry are constantly exposed to extended work hours, this study was based on how long work hours affect their emotional well-being.
The analysis was done using the secondary Korean Working Condition Survey (KWCS). Long work hours were defined to be more than 48 hours, and they were subcategorized into units of 52 hours and 60 hours. Based on the WHO (five) well-being index, emotional state was subdivided into three groups - reference group, low-mood group, and possible depression group- where 28 points and 50 points were division points, and two groups were compared at a time. Association between long work hours and emotional state was analyzed using binary and multinomial logistic regression analysis.
Working for extended working hours in the manufacturing industry showed a statistically significant increase (
Long work hours have an adverse effect on emotional well-being. A more diversified research towards variables that affect long work hours and emotional well-being and how they interact with each other and their relationship to overall health is imperative.
Citations
The purposes of this study are 1) to measure the prevalence of smoking according to weekly work hours by using data from the Korean Labor and Income Panel Study (KLIPS), and 2) to explain the cause of high smoking prevalence among those with short or long work hours by relative explanatory fraction.
Data from a total of 2,044 male subjects who responded to the questionnaire in the 10th year (2007) and 11th year (2008) of the Korean Labor and Income Panel Study were used for analysis. Current smoking, smoking cessation, continuous smoking, start of smoking, weekly work hours, occupational characteristics, sociodemographic and work-related factors, and health behavior-related variables were analyzed. Log-binomial regression analysis was used to study the relationship between weekly work hours and smoking behaviors in terms of the prevalence ratio.
The 2008 age-adjusted smoking prevalence was 64.9% in the short work hours group, 54.7% in the reference work hours group, and 60.6% in the long work hours group. The smoking prevalence of the short work hours group was 1.39 times higher than that of the reference work hours group (95% confidence interval of 1.17-1.65), and this was explained by demographic variables and occupational characteristics. The smoking prevalence of the long work hours group was 1.11 times higher than that of the reference work hours group when the age was standardized (95% confidence interval of 1.03-1.19). This was explained by demographic variables. No independent effects of short or long work hours were found when the variables were adjusted.
Any intervention program to decrease the smoking prevalence in the short work hours group must take into account employment type, job satisfaction, and work-related factors.
Citations
The aim of this study is to find the association between mothers’ working hours and obesity of their children according to children’s age and gender.
This study used data from the second and third year of KNHANES IV and the first year in KNHANES V (2008–2010). We calculate odds ratio (OR) and 95% confidence interval (CI) by using survey logistic regression to assess association of mother’s working hours with overweight or obesity of her children. The model was adjusted with household income, mothers’ education and obesity and mothers’ job characteristics.
13–18 aged boys whose mothers worked under 40 hours per week were higher risk for obesity and overweight (including obesity) than 13–18 aged boys whose mothers worked 40–48 hours. 6–12 aged girls whose mothers worked 49–60 hours per week were more overweight (including obesity) than girls whose mothers worked 40–48 hours per week. 13–18 aged girls whose mothers worked over 60 hours were more overweight (including obesity) than the reference.
This study showed that girls’ obesity was associated with mothers’ long working hours. Long working hours can influence health of workers’ family.
Citations