BACKGROUND: The Korea Radiation Effect & Epidemiology Cohort METHODS: Using the KREEC-R raw data, we calculated age standardized rates (ASRs) of female thyroid cancer and re-analyzed the results of survey on the use of medical services. We also marked the administrative districts of residents who received the Radiation Health Research Institute (RHRI) health examinations and those in which thyroid cancer case occurred as per the Chonnam National University Research Institute of Medical Sciences (RIMS) final report on maps where the locations of NPPs and 5 km-radii around them were also indicated. And we compared the incidence rates of Radiation-induced cancer measured between the first period when RHRI health examinations were not yet implemented, and the second period when the RHRI health examinations were implemented. RESULTS: The ASR for the far-distance group, which comprised residents living in areas outside the 30 km radius of the NPPs, increased rapidly after 2000; however, that of the exposed group, which comprised residents living within a 5 km radius of the NPPs, started to increase rapidly even before 1995. The frequencies of the use of medical services were significantly higher in the intermediate proximate group, which comprised residents living within a 5–30 km radius of the NPPs, than in the exposed group in women. In case of female thyroid cancer, the second period ASR was higher than the first period ASR, but in case of female liver cancer and female stomach cancer no significant difference were observed between the periods. On map, many administrative districts of residents who received RHRI health examinations and most administrative districts in which thyroid cancer case occurred on RIMS final report were outside 5 km-radii around NPPs. CONCLUSIONS: We could not find any evidence supporting the assertion that detection bias influenced the increased risks of female thyroid cancer observed in the exposed group of the KREEC-R study, as opposed to the control group.
Academies and Institutes ; Bias (Epidemiology) ; Cohort Studies ; Epidemiology ; Female ; Humans ; Incidence ; Jeollanam-do ; Korea ; Liver Neoplasms ; Neoplasms, Radiation-Induced ; Nuclear Power Plants ; Radiation Effects ; Radius ; Stomach Neoplasms ; Thyroid Gland ; Thyroid Neoplasms

BACKGROUND: Discrimination based on type of employment against non-regular workers is still a social issue. However, there are few studies on job factors that affect the discrimination experience in each type of employment or the association between discrimination and health impact indicators. This study examined occupational health characteristics according to discrimination experience and relating factors that affect discrimination experience. METHODS: This study used the 4th Korean Working Conditions Survey (2014) provided by the Korea Occupational Safety and Health Agency. Among the 50,000 workers, 7731 non-regular wage workers were selected as study population. To examine differences in discrimination experience, we used a t-test on occupational risk factors, occupational stress, occupational characteristics, health impact indicators. To identify the factors that affected discrimination experience, we performed binomial logistic regression analysis. RESULTS: The discrimination experience rate was significantly higher in male, aged less than 40 years old, above high school graduate than middle school graduate, higher wage level, shorter employment period and larger company's scale. As factors related to discrimination experience, they experienced discrimination more as occupational stress was higher and when they were temporary or daily workers rather than permanent workers, work patterns were not consistent, and the support of boss was low. It showed that physical, musculoskeletal, and mental occupational risk scores and subjective job instability were higher and work environment satisfaction was lower in discrimination experienced group. CONCLUSIONS: The present study showed that the demographic and occupational factors were complexly related to discrimination experience in non-regular workers. The experience of discrimination had increased when occupational stress was higher, they were temporary or daily workers rather than permanent workers, work patterns were not consistent, and their boss' support was low. Improving various relating factors, (e.g. occupational stresses, employment status and occupational characteristics), this would ultimately expect to improve non-regular workers' discrimination.
Discrimination (Psychology)* ; Employment ; Humans ; Korea ; Logistic Models ; Male ; Occupational Health ; Risk Factors ; Salaries and Fringe Benefits

OBJECTIVES: The aim of this study was to evaluate the relationship between shift work and work-related injuries in a representative sample of Korean workers. METHODS: We used data from the Korean Working Condition Survey of 2006. The participants were 7,075 Korean workers 15 to 64 years of age. Logistic regression was employed to estimate the relationship between shift work and work-related injury using the SAS version 9.2 program. RESULTS: Shift work was significantly related to work-related injuries compared to non-shift workers(OR 2.40, 95% CI=1.65~3.48). When personal and occupational risk factors were accounted for, shift work had a statistically meaningful relationship with work-related injuries compared to non-shift work(OR 1.79, 95% CI=1.20~2.66). CONCLUSIONS: In this study, shift workers appear to have a higher risk of work-related injuries compared to non-shift workers. Work-related injuries in shift workers could be attributed to circadian rhythm disorder and sleep problems. Suitable arrangements that ensure flexible working times are needed for shift workers. Further study will be needed to identify and mitigate work-related injuries among shift workers.
Chronobiology Disorders ; Dietary Sucrose ; Humans ; Logistic Models ; Phenothiazines ; Risk Factors

OBJECTIVES: To date, no population-based epidemiological studies have estimated the association between physical workload (standing or walking, carrying heavy loads, carrying people, repetitive hand or arm movements, wearing protective equipment) and work-related back pain in Korea. The purpose of this study was to evaluate the relationship between physical workload and work-related back pain using a nationwide survey. METHODS: We analyzed data obtained from working men and women age 15 to 64 (n=10,043) who participated in the 2006 national working condition survey of random sample workers in Korea. Using both simple and multiple logistic regression analysis, the association between physical workload and work-related back pain was evaluated. RESULTS: Carrying heavy loads, repetitive hand or arm movements, and wearing protective equipment were associated with an increased risk of work-related back pain. CONCLUSIONS: This study identifies that an increased risk of work-related back pain related to the nature and intensity of the physical workload of the general working population in Korea. We also found a strong association between repetitive hand or arm movements and back pain.
Arm ; Back Pain ; Female ; Hand ; Humans ; Korea ; Lifting ; Logistic Models ; Male ; Walking

OBJECTIVES: Mental health and work efficiency are adversely affected by exposure to physical and chemical hazards in the workplace. This study is the first large scale evaluation of the relationship between physical and chemical hazard exposure in the workplace in relation to the mental health of Korean workers. METHODS: A national survey of a random sample of workers (n=10,043) was conducted between June and September 2006 in Korea. Physical and chemical hazards in the workplace were considered if exposure occurred over more than a quarter of the time spent at work. Mental health problems were defined as work-related depression, anxiety or insomnia. We analyzed whether physical and chemical hazards were independent risk factors for work-related mental health problems by multiple logistic regression analysis after adjusting for age, gender, employment type, education, occupation, duty schedule, work hours, smoking, and alcohol consumption. RESULTS: The mean age of surveyed workers was 42 years and 58% were male. A total of 7.8% of workers had work-related mental health problems. Exposure to high temperature, mist, fumes, dust, chemicals, and radiation were associated with an increased risk of work-related mental health problems. CONCLUSIONS: This study reaffirmed that physical and chemical hazard exposure in the workplace significantly elevates the risk of work-related mental health problems.
Anxiety ; Appointments and Schedules ; Depression ; Dust ; Employment ; Hot Temperature ; Humans ; Korea ; Logistic Models ; Male ; Mental Health ; Occupations ; Risk Factors ; Sleep Initiation and Maintenance Disorders ; Smoke ; Smoking ; Vibration

PURPOSE: This cross-sectional study aimed to examine the association between self-reported exposure status to second-hand smoke and urinary cotinine level in pregnant nonsmokers. MATERIALS AND METHODS: We recruited pregnant nonsmokers from the prenatal care clinics of a university hospital and two community health centers, and their urinary cotinine concentrations were measured. RESULTS: Among a total of 412 pregnant nonsmokers, the proportions of self-reported exposure to second-hand smoke and positive urinary cotinine level were 60.4% and 3.4%, respectively. Among those, 4.8% of the participants who reported exposure to second-hand smoke had cotinine levels of 40 ng/mL (the kappa value = 0.029, p = 0.049). Among those who reported living with smokers (n = 170), "smoking currently permitted in the whole house" (vs. not permitted at home) was associated with positive urinary cotinine in the univariable analysis. Furthermore, this variable showed a significant association with positive urinary cotinine in the stepwise multiple logistic regression analysis [Odds ratio (OR), 15.6; 95% Confidence interval (CI) = 2.1-115.4]. CONCLUSION: In the current study, the association between self-reported exposure status to second-hand smoke and positive urinary cotinine in pregnant nonsmokers was poor. "Smoking currently permitted in the whole house" was a significant factor of positive urinary cotinine in pregnant nonsmokers. Furthermore, we suggest that a complete smoking ban at home should be considered to avoid potential adverse effects on pregnancy outcomes due to second-hand smoke.
Adult ; Cotinine/*urine ; *Environmental Exposure ; Female ; Humans ; Pregnancy ; Regression Analysis ; *Tobacco Smoke Pollution

OBJECTIVES: To determine the prevalence of baker's asthma due to flour dust in an industrial bakery in Korea. METHODS: Of the 596 active workers, 380 were allocated to a category of either direct exposure (DE) or indirect exposure (IE) to flour dust and completed a modified ISAAC questionnaire. Of the 380 participants, 233 were screened by an occupational physician interview, a skin prick test, and an ELISA for serum-specific IgE antibodies to wheat flour extracts. Selected workers received serial monitoring of peak expiratory flow rate (PEFR), and positive PEFR respondents received a methacholine challenge test. The diagnosis of baker's asthma was confirmed by a specific inhalation challenge with wheat flour extracts. RESULTS: The prevalence of sensitization to wheat flour and baker's asthma was 21.0% (25.9% DE, 13.3% IE) and 3.2% (5.1% DE, 1.8% IE), respectively. DE had an increased risk of sensitization to wheat flour (OR 2.15, 95% CI = 1.03~4.51). Sensitization to wheat flour and the prevalence of baker's asthma correlated significantly (PR 38.63, 95% CI = 6.14~243.22). CONCLUSIONS: These findings indicate a considerable prevalence of baker's asthma among flourexposed workers in Korea. Future studies will be required to survey the situation in flour mill companies and seek ways to protect the health and socioeconomic position of flour industry workers.
Antibodies ; Asthma ; Data Collection ; Dust ; Enzyme-Linked Immunosorbent Assay ; Flour ; Immunoglobulin E ; Inhalation ; Korea ; Methacholine Chloride ; Occupational Exposure ; Peak Expiratory Flow Rate ; Prevalence ; Questionnaires ; Skin ; Triticum

OBJECTIVES: A previous study conducted in 2000 measuring the heart rate variability (HRV) of carbon disulfide (CS2)-poisoned subjects suggested that their HRV was reduced after exposure cessation. However, the study was limited by the following procedural limitations: (1) only 71 CS2-poisoned subjects participated, (2) no females participated, and (3) the CS2-poisoned subjects were older than the controls. This study was therefore conducted to overcome these limitations of the earlier study. METHODS: The study subjects comprised 122 retired workers with CS2 poisoning and the same number of age- and sex-matched controls. Information on individual age, sex, height, weight, smoking history, alcohol drinking, regular exercise, medical and occupational history, chest x-ray, and ECG recording of the two groups was collected though a self-administered questionnaire and a medical examination. Standard Deviation of NN intervals (SDNN), Root-Mean-Square of Successive Differences (RMSSD), Total Power (TP), Low Frequency (LF), High Frequency (HF), and LF/HF ratio were measured as HRV indices for 5 minutes in the sitting position. RESULTS: Univariate analysis revealed that all HRV indices of CS2-poisoned subjects were lower than those of the controls. Multiple linear regression analysis showed that CS2 poisoning had negative association with all HRV indices and that its association with RMSSD was statistically significant (P<0.05). CONCLUSIONS: This study suggests that CS2-poisoned subjects continue to have reduced HRV, even though the exposure has ceased.
Alcohol Drinking ; Carbon Disulfide* ; Carbon* ; Electrocardiography ; Female ; Heart Rate* ; Heart* ; Humans ; Linear Models ; Poisoning ; Questionnaires ; Smoke ; Smoking ; Thorax

OBJECTIVES: Mass poisoning by carbon disulfide (CS2) occurred in a viscose rayon factory in Korea. Up until 1998, 830 employees, including 38 who had died, were diagnosed with CS2 poisoning. Among the CS2 poisoned subjects, heart rate variability (HRV) was evaluated to investigate whether the toxic effect of CS2 persists after the exposure has ceased. The dose-response relationship between carbon disulfide exposure and HRV was also evaluated. METHODS: The case group was comprised of 71 retired male workers diagnosed as being CS2 poisoned. The control group was comprised of 127 males of same age-range who had no history of CS2 exposure and cardiovascular diseases. Information on individual age, height, weight, cigarette smoking, alcohol drinking, regular exercise, medical and occupational history, chest x-ray, and ECG recording of the two groups were collected through a self-administered questionnaire and with a medical examination. Time (maximum, average, minimum RR interval) and frequency domain measures (low frequency - LF, high frequency - HF, total power spectrum TPS, and LF/HF ratio) of the two groups were analyzed. CS2 exposure indices of the case group (duration of employment, exposure level per work department, cumulative exposure index and duration of retirement) were investigated. RESULTS: Using a univariate analysis, the frequency domain measures for the case group were significantly lower than those in the control group, except for HF. In the multivariate analysis, previous history of CS2 poisoning was inversely related to all frequency domain parameters and it significantly affected the LF (p<0.05) and the LF/HF ratio (p<0.05). There was no significant dose-response relationship between CS2 exposure indices and HRV parameters in the case group. CONCLUSION: This study suggests that further studies are necessary to evaluate the residual effects of CS2 poisoning even after the CS2 exposure has ceased.
Alcohol Drinking ; Carbon Disulfide* ; Carbon* ; Cardiovascular Diseases ; Electrocardiography ; Employment ; Heart Rate* ; Heart* ; Humans ; Korea ; Male ; Multivariate Analysis ; Poisoning* ; Questionnaires ; Smoking ; Thorax

OBJECTIVES: To examine the complaint proportion and characteristics of musculoskeletal symptoms and to find risk factors of musculoskeletal symptoms among caterers for school lunch services. METHODS: The study subjects were 385 caterers who were working for school lunch services in 71 elementary schools and 114 housewives who had visited a hospital for routine health check-up. A self-recording questionnaire was used to investigate the general characteristics, labor conditions, job stress and nature of musculoskeletal symptom. Caterers were surveyed from September to October in 2003 and the housewives during September by post. The ergonomic risk factors were examined for the caterers of an elementary school in Kyonggi Province in November, 2003. RESULTS: The complaint proportion of self-reported positive musculoskeletal symptoms was 52.0% and that of severe musculoskeletal symptoms was 24.9%. Ergonomic assessment revealed that washing the dishes, carrying the soup containers and cleaning the sewage drain were highly risky activities in terms of repetitive and heavy weight-bearing motions. As for personal factors, the caterers having severe musculoskeletal symptoms had high psychological job demand. As for the workplace factors, the proportion of schools having severe musculoskeletal symptoms was significant higher where each caterer prepared more than 150 lunches. Among schools without school lunchroom, more schools had caterers having severe musculoskeletal symptoms. Using multilevel analysis, we found that the number of lunches to be prepared per caterer was a significant risk factor of severe musculoskeletal symptoms (O.R. 4.67). CONCLUSIONS: This study showed that the number of lunches prepared per caterer has a significant influence on the development of musculoskeletal disorder and that caterers work in an ergonomically highly risky job environment. The study results suggest that the number of caterers be increased to decrease the number of lunches prepared per caterer and the ergonomic environment be improved.
Gyeonggi-do ; Humans ; Lunch* ; Multilevel Analysis* ; Musculoskeletal Diseases ; Questionnaires ; Risk Factors* ; Sewage ; Weight-Bearing