Relationship between job rotation and work-related low back pain: a cross-sectional study using data from the fifth Korean working conditions survey.

BACKGROUND: Job rotation was introduced in various industries as a strategic form of work for improving workers' job skills and health management. This study aims to examine the relationship between job rotation and work-related low back pain (LBP), one of the typical work-related musculoskeletal symptoms of Korean workers. METHODS: We conducted this study using the data of the 5th Korean Working Conditions Survey (KWCS). As the subject of this study, 27,163 wage workers were selected, and classified into three groups according to occupational type (white-collar, service and sales, and blue-collar). In this study, job rotation means to change the work-related activities with other colleagues periodically and work-related LBP was defined as whether there was work-related LBP in the last 12 months. Chi-square test and logistic regression were used to analyze the relationship between job rotation and work-related LBP. RESULTS: Out of 27,163 workers, 2,421 (8.9%) answered that they had job rotation and 2,281 (8.4%) answered that they experienced work-related LBP. According to the results from logistic regression, job rotation was significantly associated with low prevalence of work-related LBP among blue-collar workers (odds ratio [OR]: 0.71, 95% confidence interval [CI]: 0.58-0.88), whereas no significant relationship was observed among white-collar, service and sales groups. In addition, the negative association between job rotation and work-related LBP among blue-collar workers was more pronounced when exposed to ergonomic risk factors (uncomfortable posture OR: 0.79, 95% CI: 0.64-0.98; heavy work OR: 0.74, 95% CI: 0.57-0.96; repetitive work OR: 0.74, 95% CI: 0.60-0.92). CONCLUSIONS: Job rotation was associated with low prevalence of work-related LBP among workers in the blue-collar occupational group in Korea. It is necessary to evaluate the effect of job rotation by occupational type and introduce an appropriate method of job rotation to reduce workers' work-related musculoskeletal symptoms.

Effects of Occupational and Leisure-Time Physical Activities on Insomnia in Korean Firefighters.

Studies have been conducted on the association between physical activity (PA) and sleep, but to the best of our knowledge, a simultaneous analysis of the effects of occupational PA (OPA) and leisure time PA (LTPA) on South Korean firefighters' sleep has never been conducted. This study aims to analyze how OPA and LTPA affect these individuals' risk of suffering from insomnia with-in this specific population of subjects. The study includes data from an online self-report survey in which 9788 South Korean firefighters participated. The survey used the Insomnia Severity Index and the OPA- and LTPA-related characteristics were investigated. The independent two-sample t-test, χ2 test, and multiple logistic regression analysis were performed. Subgroup logistic regression analyses were also completed in accordance with the OPA level. Among 9788 participants, 890 (9.1%) suffered from insomnia. A logistic regression analysis revealed that higher levels of feeling of job loading (FoJL), rising levels of physical strength utilization rate (PSUR), greater frequency levels of occupational activities, and high-intensity LTPA were significantly correlated with an increased risk of insomnia, while execution of LTPA and getting enough rest after LTPA was correlated with a decreased risk. However, the subgroup analysis showed that high-intensity LTPA was correlated with a significantly increased the risk in the group with high OPA, but this did not apply to the group with low OPA. Although the risk of suffering from insomnia was overall significantly higher in the high OPA group, the risk was significantly lower in groups getting enough rest after partaking in LTPA, regardless of the OPA level. Thus, the intensity of exercise programs pre-scribed to groups with high OPA and individuals with higher risks of suffering from insomnia, such as firefighters, police officers, and soldiers, should be considered.

Psychosocial factors affecting sleep quality of pre-employed firefighters: a cross-sectional study.

BACKGROUND: There have been no health-related studies of pre-employed firefighters without firefighter-specific job-related factors (FSJRF). This study aimed to evaluate the sleep quality of pre-employed firefighters and to examine the relationship between sleep quality and psychosocial factors. METHODS: We conducted a self-report questionnaire survey for 602 pre-employed firefighters at 3 Fire Service Academies after brief lecture about sleep. Sleep quality and psychosocial variables such as depression, anxiety, stress and social support were evaluated. The independent 2 sample t-test, χ2 test and multiple logistic regression analysis were used to evaluate the effect of the variables on the sleep quality of pre-employed firefighters. RESULTS: Among a total of 602 people, 347 (57.6%) had good sleep quality and 255 (42.4%) had poor sleep quality. Pittsburgh Sleep Quality Index score of them was 3.29 ± 1.41) and 7.87 ± 2.20), respectively. 24 (4.0%) were evaluated to have insomnia by Insomnia Severity Index. Logistic regression analyses showed that the depression (adjusted odds ratio [aOR]: 5.940, 95% confidence interval [CI]: 3.124-11.292), anxiety (aOR: 4.233, 95% CI: 2.138-8.381), stress (aOR: 2.880, 95% CI: 1.915-4.330) and social support (aOR: 0.959, 95% CI: 0.939-0.980) have a significant effect on sleep quality after adjusted by sex, age, smoking status, drinking status, caffeine intake, past shift working and circadian rhythm type. CONCLUSIONS: Depression, anxiety, stress and social support were associated with sleep quality among pre-employed firefighters. Repeated follow-up studies of pre-employed firefighters are needed to further assess their change of sleep quality and identify the FSJRF that may affect the sleep quality of firefighters.

Relationship between shift work and liver enzymes: a cross-sectional study based on the Korea National Health and Examination Survey (2007-2015).

BACKGROUND: Shift work has well-known adverse effects on health. However, few studies have investigated the relationship between shift work and hepatic disorders. This study aimed to evaluate the association between shift work and abnormal level of liver enzymes. METHODS: The aggregated data from the 2007-2009, 2010-2012, and 2013-2015 cycles of the Korea National Health and Nutrition Examination Survey was used for this study. The χ2 test and multiple logistic regression analysis were used to assess relationship between shift work and abnormal level of liver enzymes stratified by gender. RESULTS: The odds ratio (OR) of abnormal serum level of alanine aminotransferase (abnormal ALT) in female shift workers was higher with 1.31 (95% confidence interval: 1.00-1.71) compared with day workers after adjusting for covariates. After dividing into subgroups of the shift work pattern, the ORs of abnormal liver enzymes for each pattern compared with day work were not significantly higher. CONCLUSIONS: This study provides limited support for the hypothesis that shift work is related to liver enzyme abnormalities, but offers some evidence in favor of the idea that shift work affects female workers more than males on abnormal ALT. Further studies are needed to define the relationship between shift work and abnormal liver enzymes to be carried out as well as the gender difference in the association.

Relationship between simultaneous exposure to ergonomic risk factors and work-related lower back pain: a cross-sectional study based on the fourth Korean working conditions survey.

BACKGROUND: It is well known that ergonomic risk factors and back pain are related. However, few studies have examined the relationship between simultaneous exposure to these risk factors and back pain in a Korean population. We aimed to investigate the relationship between simultaneous exposure to ergonomic risk factors and work-related lower back pain (LBP) based on the fourth Korean Working Conditions Survey (KWCS). METHOD: The fourth KWCS (2014) was used for this study. Chi-square tests and logistic regression were used to assess relationship between 5 ergonomic risk factors and work-related LBP. We also analyzed the relationship between simultaneous exposure to 2 risk factors and work-related LBP. RESULTS: All 5 ergonomic risk factors (fatigue-inducing and painful posture; lifting or moving people; dragging, pushing, or moving heavy objects; standing posture; and repetitive hand or arm movements) were significantly correlated with work-related LBP in the severe exposure group (adjusted odd ratios [aOR] 5.09, 95% confidence interval [CI] 4.46-5.83; aOR 1.98, 95% CI 1.62-2.42; aOR 2.09, 95% CI 1.82-2.40; aOR 1.79, 95% CI 1.60-2.01; aOR 2.04, 95% CI 1.82-2.30, respectively). When exposed to 2 risk factors simultaneously, the relationship between exposure and work-related LBP was not greater than exposure to only 1 risk factor in our study (usually exposed to 'fatigue-inducing or painful posture' aOR 2.17, 95% CI 2.02-2.34; high exposure to both 'fatigue-inducing or painful posture' and 'dragging, pushing, or moving heavy objects' aOR 2.00, 95% CI 1.82-2.20). CONCLUSIONS: There was a strong relationship between severe exposure to each ergonomic risk factor and work-related LBP. However, when exposed to 2 ergonomic risk factors simultaneously, the relationship between exposure and work-related LBP was not stronger than when exposed to only 1 risk factor in our study.

Factors increasing the risk for psychosocial stress among Korean adults living in rural areas: using generalized estimating equations and mixed models.

BACKGROUND: This study was conducted to analyze the distribution of the psychosocial well-being index among adults living in two rural communities in Korea and to examine its correlation with lifestyle variables such as sleep duration, regular exercise, and sedentary time. METHODS: Using the cohort data of the Atherosclerosis Risk of a Rural Area Korean General Population, this study examined 3631 participants living in Wonju and Pyeongchang in Gangwon Province; their preliminary data were established from 2005 to 2007 while their follow-up data were collected 3 years later. This study investigated demographic characteristics, lifestyle habits, disease history, Psychosocial Well-being Index-Short Form (PWI-SF) scores, sleep duration, regular exercise, and sedentary time during work. Using repeated measures ANOVA, this study examined how the variables and PWI-SF scores changed over the course of 3 years and identified the correlation between them based on mixed model analysis. Afterwards, using the generalized estimation equation, this study identified each variable's risk towards the PWI-SF high-risk group and performed a stratified analysis by occupation after dividing the participants into farmers and non-farmers. RESULTS: The PWI-SF high-risk group was found to be 18.9% of the participants from preliminary data and 15.5% from follow-up data. The odds ratio towards the PWI-SF high-risk group was 1.503 (95% CI 1.241-1.821) in the short sleep duration group and 1.327 (95% CI 1.136-1.550) in the non-regular exercise group. A stratified analysis by occupation showed that middle and long sedentary time in the white-collar group increased the risk toward the PWI-SF high-risk group. CONCLUSIONS: Short sleep duration, no regular exercise, and long sedentary time in the white-collar group were identified as risk factors toward the PWI-SF high-risk group in the rural communities, and policy interventions are needed to address this issue.