Comparison of work-related musculoskeletal symptoms between male cameramen and male office workers.

BACKGROUND: Previous studies have classified cameramen's job as physiologically heavy work and identified the risk factors of work-related musculoskeletal disorders (WRMDs) in cameramen. However, those studies limited their research subjects to cameramen. In this study, we compared the frequency and severity of WRMDs between cameramen and office workers. METHODS: A total of 293 subjects working in four broadcasting companies in Korea were recruited. A questionnaire survey was conducted for a month, starting in October 2016. The subjects were divided into cameramen and office workers according to their occupation. We compared the frequency and severity of WRMDs and ergonomic risk assessment results between the two groups. RESULTS: The high-risk WRMD group had a higher proportion of cameramen than office workers. Moreover, the high ergonomic risk group also had a higher proportion of cameramen than office workers for WRMDs in the upper extremities and waist+lower extremities. In the multivariable-adjusted model comparing cameramen and office workers, the odds ratio (OR) with 95% confidence interval (95% CI) for high-risk WRMDs was 3.50 (95% CI: 1.92-7.72) for the upper extremities and 3.18 (95% CI: 1.62-6.21) for the waist and the lower extremities. The ORs by body parts were 3.11 (95% CI: 1.28-7.57) for the neck, 3.90 (95% CI: 1.79-8.47) for the shoulders, and 4.23 (95% CI: 1.04-17.18) for the legs and feet. CONCLUSIONS: Our study suggests that cameramen are at high risk of WRMDs. Workplace improvements and management of the neck, shoulders, and lower extremities, which are susceptible to WRMDs, are necessary to prevent musculoskeletal disorders among cameramen.

Comparison of sleep quality based on direction of shift rotation in electronics workers.

BACKGROUND: Previous studies have reported the effects of direction of shift rotation on sleep, however, the findings are inconsistent. In this study, we investigated sleep quality related to direction of shift rotation using large-scale data from shiftwork-specific health examinations of electronics workers. METHODS: This study included 4750 electronics workers working in a rotating 3-shift system who completed a medical examination for shift workers survey from January 1 to December 31, 2014, at a general hospital. The subjects were categorized into one of two groups according to direction of shift rotation. We compared sleep quality index between the subjects who worked in forward rotation and backward rotation systems. RESULTS: Backward rotation was positively associated with prevalence of poor sleep quality. In the multivariable-adjusted model, when comparing backward rotation to forward rotation, the odds ratio (OR) with 95 % confidence interval (95 % CI) for poor sleep quality was 1.95 (1.58-2.41). After stratifying by gender, the ORs (95 % CIs) for poor sleep quality in male and female was 1.92 (1.47-2.49) and 2.13 (1.47-3.08), respectively. In subgroup analyses, backward rotation was significantly associated with poor sleep quality in workers ≥30 years of age compared with workers <30 years of age (adjusted OR 2.60 vs. 1.89, respectively; P for interaction <0.001). CONCLUSIONS: Our study supports that a backward rotation system is associated with poor sleep quality. Forward rotation systems should be considered to reduce sleep problems.

Risk factors of work-related upper extremity musculoskeletal disorders in male cameramen.

OBJECTIVE: The aim of this study is to determine the risk factors related to upper extremities work-related musculoskeletal disorders (WRMSDs) in cameramen. METHODS: A questionnaire survey was performed on 166 cameramen in a broadcasting station. The questionnaire consisted of questions on the general characteristics, the health behavior, work type and duration, physical burden, ergonomic posture, and musculoskeletal symptoms. Definition of musculoskeletal disorders was based on NIOSH criteria. RESULTS: The positive rate of WRMSDs symptoms by parts of the body was turned out to be the highest in the shoulder (14.5%) and the lowest in arm and elbow (6%). Logistic regression analysis revealed that symptoms in the shoulders increased with BMI (OR = 3.62, 95% CI = 1.03-12.71), physical burden (OR = 9.29, 95% CI = 1.72-61.78 in the very hard group) and ergonomic factors (OR = 4.50, 95% CI = 1.03-19.68). Ergonomic factors were only related to the symptoms of hand and wrist (OR = 10.21, 95% CI = 1.02-102.20). WRMSDs symptoms, in the whole upper extremities, were higher in the 50 or older age group (OR = 5.86, 95% CI = 1.03-33.26), higher BMI group (OR = 3.26, 95% CI = 1.28-13.53), non-exercise group (OR = 2.37, 95% CI = 1.24-12.59), high physical burden group (OR = 7.6, 95% CI = 1.34-52.74), and high grade ergonomic risk group (OR = 4.82, 95% CI = 1.29-16.06). CONCLUSION: The most serious musculoskeletal disorders of male cameramen were shoulder pain. Ergonomic factors and physical burden were the most significant factors affecting WRMSDs in cameramen in this study. Cameramen should be educated to be able to improve the ergonomic occupational environment and to set up preventive measures against the risk factors during work.

Character profiles and life satisfaction.

BACKGROUND: There is a surge of interest in subjective well-being (SWB), which concerns how individuals feel about their happiness. Life satisfaction tends to be influenced by individual psychological traits and external social factors. The aim of this study was to examine the relationship between individual character and SWB. METHODS: Data from 3522 university students were analyzed in this study. Character profiles were evaluated using the Temperament and Character Inventory-Revised Short version (TCI-RS). Life satisfaction was assessed using the Satisfaction with Life Scale (SWLS). All statistical tests regarding the correlations between each character profile and life satisfaction were conducted using ANOVAs, t-tests, multiple linear regression models and correlation analyses. RESULTS: The creative (SCT) profile was associated with the highest levels of life satisfaction, whereas the depressive (sct) profile was associated with the lowest levels of life satisfaction. Additionally, high self-directedness, self-transcendence and cooperation were associated with high life satisfaction. The results of gender-adjusted multiple regression analysis showed that the effects of self-directedness were the strongest in the assessment of one's quality of life, followed by self-transcendence and cooperativeness, in that order. All of the three-character profiles were significantly correlated with one's quality of life, and the character profiles of TCI-RS explained 27.6% of life satisfaction in total. Among the three-character profiles, the self-directedness profile was most associated with life satisfaction. LIMITATIONS: Our study was cross-sectional, and self-reported data from students at a single university were analyzed. CONCLUSIONS: The results of this study showed that, among the character profiles, the effects of self-directedness were the strongest for predicting life satisfaction.

Time-dependent association between metabolic syndrome and risk of CKD in Korean men without hypertension or diabetes.

BACKGROUND: The time-dependent association between metabolic syndrome and risk of chronic kidney disease (CKD) is not clear. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: The study cohort was composed of 10,685 healthy men without CKD, hypertension, or diabetes who participated in a health-checkup program at a large work site. PREDICTOR: Metabolic syndrome. OUTCOMES & MEASUREMENTS: CKD was defined as an estimated glomerular filtration rate (GFR) less than 60 mL/min/1.73 m(2). A standard Cox proportional hazards model and a time-dependent Cox model were used to calculate adjusted hazard ratios (HRs) in the CKD model. RESULTS: During 40,616.8 person-years of follow-up, 291 incident cases of CKD developed; 787 patients (7.4%) had metabolic syndrome at baseline and 1,444 (14.4%) developed incident metabolic syndrome during follow-up. After adjustment for age, baseline GFR, gamma-glutamyltransferase level, and uric acid level, metabolic syndrome at baseline was associated with a significantly increased risk of CKD (HR, 1.99; 95% confidence interval, 1.46 to 2.73). Metabolic syndrome over time as a time-dependent variable also predicted the development of CKD (HR, 1.83; [corrected] 95% confidence interval, 1.34 to 2.49) [corrected] The relationship between metabolic syndrome and incident CKD remained significant, even after further adjustment for the homeostasis model assessment of insulin resistance, high-sensitivity C-reactive protein level, current smoking, alcohol consumption, or regular exercise. In addition, there were graded relationships between number of metabolic syndrome traits or quintile of homeostasis model assessment of insulin resistance over time as a time-dependent variable and risk of CKD. Both increased triglyceride and low high-density lipoprotein cholesterol levels among metabolic syndrome traits were associated with significantly increased risk of CKD. These results were effectively unchanged, even after additional adjustment for incident hypertension and incident diabetes. LIMITATIONS: Estimated GFR was used instead of a directly measured GFR to define CKD. CONCLUSION: Metabolic syndrome is an independent risk factor for the development of CKD in Korean men without hypertension or diabetes, even with changes in status of metabolic syndrome over time.

Changes in body weight predict CKD in healthy men.

Several recent prospective studies have reported that obesity is associated with an increased risk for chronic kidney disease (CKD), but it is unknown whether weight gain increases the risk for CKD if one remains within the "normal" category of body mass index (BMI). We prospectively followed a cohort of 8792 healthy men who had no known risk factors for CKD and participated in a comprehensive health evaluation program at a large worksite. During 35,927 person-years of follow-up, 427 new incident cases of CKD (estimated GFR <64 ml/min per 1.73 m(2)) developed. Cox proportional hazards modeling revealed that in both the normal-weight and overweight groups, a U-shaped association between weight change categories and development of CKD was observed after adjustment for age, baseline GFR, baseline BMI, HDL, fasting blood glucose, uric acid, and exercise habits. The lowest risk for CKD was observed among those whose weight changed -0.25 to <0.25 kg/yr (P < 0.001 for quadratic term). Weight change as a time-dependent variable was significantly related to CKD incidence. These relationships remained significant even after further adjustment for Homeostasis Model Assessment of Insulin Resistance, high-sensitivity C-reactive protein, systolic BP, diastolic BP, metabolic syndrome, incident hypertension, or incident diabetes. In summary, increases in body weight are independently associated with an increased risk for CKD, even when the BMI remains within the normal range.

Nonalcoholic fatty liver disease predicts chronic kidney disease in nonhypertensive and nondiabetic Korean men.

In the absence of significant research, we performed a prospective study to examine the association between nonalcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD). The study cohort comprised a total of 8329 healthy men, with normal baseline kidney functions and no proteinuria, working in a semiconductor manufacturing company and its 13 affiliates. Alcohol intake was assessed with a self-reported questionnaire. Biochemical tests for liver and metabolic function and abdominal ultrasonography were done. Chronic kidney disease was defined as either the presence of proteinuria or a glomerular filtration rate (GFR) of <60 mL/min per 1.73 m(2). Cox proportional hazards model was used to estimate hazard ratios in the model for CKD. During 26717.1 person-years of follow-up, 324 men developed CKD. Nonalcoholic fatty liver disease was associated with the development of CKD (crude relative risk, 2.18; 95% confidence interval [CI], 1.75-2.71); and this relationship remained significant even after adjustment for age, GFR, triglyceride, and high-density lipoprotein cholesterol (adjusted relative risk [aRR], 1.55; 95% CI, 1.23-1.95). The association between NAFLD and incident CKD was evident in the NAFLD group with elevated serum gamma-glutamyltransferase (GGT) (aRR, 2.31; 95% CI, 1.53-3.50), even after adjustment for age, GFR, triglyceride, and high-density lipoprotein cholesterol, but not in the NAFLD group without elevated GGT (aRR, 1.09; 95% CI, 0.79-1.50) (P = .008 for interaction). To summarize, NAFLD with elevated GGT concentration was associated with an increased CKD risk among nondiabetic, nonhypertensive Korean men, irrespective of metabolic syndrome.

Incidence and risk factors for metabolic syndrome in Korean male workers, ages 30 to 39.

PURPOSE: There are few prospective data on the incidence of metabolic syndrome. The goals of this study were to define the incidence of and specific risk factors for metabolic syndrome (MetS) in Korean male workers 30 to 39 years of age. METHODS: A prospective cohort study was undertaken involving 4,779 male workers, 30 to 39 years of age, who did not take medication for dyslipidemia or have a history of any malignancy at study entry. Subjects were reexamined annually at a university hospital in Seoul, Korea, over a 3-year period between 2002 to August 2005. A modified National Cholesterol Education Program definition of MetS with body mass index was used instead of waist circumference. Cox proportional hazards models were used to calculate adjusted hazard ratios in separate models for MetS. RESULTS: At the end of the 3-year follow-up period, MetS developed in 708 individuals. The unadjusted incidence density of MetS was 70.5 (95% CI, 65.3 approximately 75.37), and the age-adjusted incidence density of MetS was 76.9 per 1,000 person-years (95% CI, 67.8 approximately 86.1). Among a variety of candidate risk factors, uric acid, weight change, gamma-glutamyltranspeptidase, and alanine aminotransferase were independent risk predictors for MetS. CONCLUSIONS: The high-incidence density of this MetS in Korea may be an indicator of future increases in diabetes and cardiovascular disease.

[Apolipoprotein A-I and B distribution among the employees and their partners in Korea].

OBJECTIVES: This study was performed to investigate the distribution of apolipoproteins A-I and B among Korean employees and their partners. METHODS: The study population consisted of 7,633 men and women (4,578 men and 3,054 women) residing in Seoul and Kyung-gee Do, with an average age of 43.5 +/- 8.3 years. Blood samples were collected following at least 12 hours of fasting. Apolipoproteins A-I and B were measured using a Behring Nephelometer analyzer. The body mass index (BMI) for each participant was calculated as weight (kg) divided by height squared (m2). Information on health-related behaviors such as exercise, alcohol intake, and smoking habits was collected through self-administrated questionnaires. RESULTS: The mean concentrations of Apo A-I were 132.6 +/- 22.3 mg/dL and 142.9 +/- 24.8 mg/dL in the men and women, respectively. The concentration of Apo A-I increased significantly across all age categories of men. The mean concentrations of Apo B were 101.7 +/- 23.2 mg/dL and 87.8 +/- 23.5 mg/dL in the men and women, respectively, and Apo B increased significantly across all age categories for both the men and women. Exercise and BMI were major determinants for Apo A-I and B levels. The 10th percentile of Apo A-I concentration was 109 mg/dL in the men and 113 mg/dL in the women, and the 90th percentile of Apo B concentration was 131 mg/dL in the men and 118 mg/dL women. CONCLUSIONS: For the prevention of coronary artery disease, we recommend that for individuals in the 10th percentile of concentration for Apo A-I and the 90th percentile of concentration for Apo B, active preventive interventions such as weight loss and exercise should be taken. This study, within its limitations, may be useful for evaluating apolipoprotein A-I and B concentrations in Korean adults.

gamma-Glutamyltransferase as a predictor of chronic kidney disease in nonhypertensive and nondiabetic Korean men.

BACKGROUND: Little research has been done to examine whether gamma-glutamyltransferase (GGT) is prospectively associated with the development of chronic kidney disease (CKD). We performed a prospective study to examine the association between GGT and the risk for the development of CKD. METHODS: The study cohort included a total of 10 337 healthy males with normal baseline kidney functions and no proteinuria. Participants were workers in a semiconductor manufacturing company and its 13 affiliates. CKD was defined as either the presence of proteinuria or a glomerular filtration rate (GFR) of < 60 mL x min(-1) x (1.73(2))(-1). Cox proportional hazards models were used to calculate the adjusted hazard ratios in separate models for CKD. RESULTS: During a follow-up period of 25,774.4 person-years, 366 men developed CKD. After adjustments were made for age, baseline GFR, triglyceride, and HDL-C, the risk for CKD increased with an increasing quartile of serum GGT (p for trend <0.001). The top one fourth of serum GGT vs the bottom one fourth of relative risks for CKD was 1.90 (95% confidence interval, 1.37-2.63). These associations were also apparent in participants who consumed < or = 20 g/day of alcohol and those with normal weight, with values of alanine aminotransferase within reference intervals, or with C-reactive protein < 3.0 mg/L, and participants without metabolic syndrome. CONCLUSIONS: Our findings, which were obtained from a large work-site cohort and excluded individuals with diabetes and hypertension, indicated that serum GGT may be an early predictor for the development of CKD, independent of baseline confounding factors.

The sequential changes in the fasting plasma glucose levels within normoglycemic range predict type 2 diabetes in healthy, young men.

AIMS: We assessed whether the increased sequential changes in the fasting plasma glucose level (FPG) that is still within the normoglycemic range could be a predictor for future diabetes. METHODS: A prospective cohort study was conducted with 5296 male employees, aged 31-44 years. A sequential change in the FPG level was defined as the first follow-up FPG level minus the baseline FPG level. The incident diabetes was assessed at annual examinations during the next 4.1 years. Cox proportional hazard analyses were performed. RESULTS: During the 21,575.5 person-years follow-up among the 5,296 subjects, a total of 156 incident cases of type 2 diabetes occurred (116 cases among the 4,975 normoglycemic subjects and 40 cases among the 321 subjects with impaired fasting glucose). An increase in the FPG level from the baseline to the first follow-up, although still within the normoglycemic range (FPG<100 mg/dl), significantly predicted future diabetes: the multivariate hazard ratios associated with the sequential changes in the FPG of <-3, -3 to 3, 4-6, 7-9, and >9 mg/dl were 0.75, 1.00 (reference), 2.28, 3.28, and 6.10, respectively (p for trend <0.001). CONCLUSIONS: The increase of the sequential changes in the FPG level that were within the normal glucose range was associated with a higher risk for developing diabetes. Thus, conducting assessment for the serial changes in the FPG level may help to identify the young, healthy, normoglycemic individuals at risk for type 2 diabetes.