Increased risk of thyroid cancer in female residents nearby nuclear power plants in Korea: was it due to detection bias?

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.

What causes the experience of discrimination in non-regular workers?

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.

The Relationship between Shift Work and Work-related Injuries among Korean Workers / 대한산업의학회지

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.

Relationship between Workplace Physical and Chemical Hazard Exposures and Mental Health Problems in Korea / 대한산업의학회지

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.

Association between Physical Workload and Work-related Back Pain: A Nationwide Study / 대한산업의학회지

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.

Prevalence of Baker's Asthma among Workers in an Industrial Bakery / 대한산업의학회지

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.

Heart Rate Variability of Carbon Disulfide Poisoned Subjects after Exposure Cessation / 대한산업의학회지

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.

The Association of Carbon Disulfide Poisoning with Heart Rate Variability / 대한산업의학회지

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.

Multilevel Analysis of Risk Factors Related to Musculoskeletal Symptoms among Caterers for Elementary School Lunch Services / 대한산업의학회지

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.

Investigation of Occupational Dermatological Problem with Additives in Polypropylene Manufacturing Process / 대한산업의학회지

OBJECTIVES: To investigate the causative agents for the dermatological problems associated with the polypropylene manufacturing process. METHODS: The study subjects consisted of 44 male workers involved in the polypropylene manufacturing process. Twenty-seven of them had been exposed to additives, and the remaining 17 had not. Among the 27 exposed, 10 had been exposed previously, and 17 are currently being exposed through their duties. Patch test were performed with three different concentrations, 0.1%, 1% and 10% of 10 different additives that was diluted with Vaseline. RESULTS: 18 subjects (41%) had positive reactions to the patch tests. Exposed group had a higher reaction rate (51.9%) than the control group (23.5%). When the positive reactions were further classified, 7, 6 and 5 were compatible with probably irritant, probably allergic, and multiple hypersensitivity reactions respectively. The most frequent reactions were from Ultranox-626 followed by Millad 3988, Armoslip-E and Songstab Sc-100. CONCLUSIONS: When considering the significantly higher probability of an allergic reaction rate among the currently exposed group compared to non- or previously-exposed groups, the nature of dermatological problems in a polypropylene plant is probably allergic. Ultranox-626, Millad3988, Armoslip-E and Songstab Sc-100 were the main causatives agents found in the process.

Distribution of Blood pressure and Current State of Life Style Modification on Male Workers in a Large Factory: Analysis According to JNC-6 Guideline / 대한산업의학회지

OBJECTIVES: To describe the distributions of blood pressure level and risk group, and the current state of life style modification in the population of a large factory. METHODS: We surveyed 1,088 workers in a large factory from June 2002 to August 2002. Information related to hypertension was collected through a questionnaire and medical examination. We classified the blood pressure level and risk group using JNC-VI criteria, and the current state of life style modification and medication according to the blood pressure level in the entire study population. REULTS: The prevalence of hypertension was 30.1% in all workers. The distribution of blood pressure level was 656 (60.3%) in normal stage, 160 (14.7%) in high normal stage, 190 (17.5%) in stage 1, 67 (6.1%) in stage 2, and 15 (1.4%) in stage 3. The numbers of workers in risk groups A, B and C were 296 (27.2%), 690 (63.4%) and 102 (9.4%), respectively. Among all workers, 432 (39.7%) needed to modify their lifestyle; 106 of whom (24.5%) needed to go on hypertensive drug medication. Overweight subjects were more common in stage 2 than in other stages (p=0.02). The numbers of smokers and low-exercisers were signigicantly lower in the higher blood pressure group than the lower blood pressure group (p<0.01). Alcoholic drinking was evenly distributed in all blood pressure level. CONCLUSION: The prevalence of hypertension was 30.1% in all workers. The most common stage of blood pressure level was normal, followed by stage 1, high normal stage, stage 2, stage 3. The number of subjects in risk group B was more than that in the other risk groups. We recommend total worker education and the practice of lifestyle modification.

Thin-Section CT Findings of Arc-Welders' Pneumoconiosis

OBJECTIVE: To describe the thin-section CT findings of arc-welders' pneumoco-niosis. MATERIALS AND METHODS: Eighty-five arc-welders with a three to 30 (mean, 15)-year history of exposure underwent thin-section CT scanning. The extent of abnormalities detected was correlated with the severity of dyspnea and pulmonary function tests. For comparison, images of 43 smoking males (mean 25 pack-year) who underwent thin-section CT for other reasons (smokers' group) were also analyzed. RESULTS: Fifty-four welders (63.5%) and six smokers (14.0%) showed positive findings. Predominant thin-section CT findings were poorly-defined centrilobular micronodules (30/54, 55.6%), branching linear structure (18/54, 33.3%), and ground-glass attenuation (6/54, 11.1%). In the smokers' group, poorly-defined micronodules were found in four patients, branching linear structures in one, and ground-glass attenuation in one. In welders, the extent of abnormalities seen on thin-section CT showed no significant correlation with the severity of dyspnea or the results of pulmonary funotion test. CONCLUSION: Poorly-defined centrilobular micronodules and branching linear structures were the thin-section CT findings most frequently seen in patients with arc-welders' pneumoconiosis. Less commonly, extensive ground-glass attenua-tion was also seen

Thin-Section CT Findings of Arc-Welders' Pneumoconiosis

OBJECTIVE: To describe the thin-section CT findings of arc-welders' pneumoco-niosis. MATERIALS AND METHODS: Eighty-five arc-welders with a three to 30 (mean, 15)-year history of exposure underwent thin-section CT scanning. The extent of abnormalities detected was correlated with the severity of dyspnea and pulmonary function tests. For comparison, images of 43 smoking males (mean 25 pack-year) who underwent thin-section CT for other reasons (smokers' group) were also analyzed. RESULTS: Fifty-four welders (63.5%) and six smokers (14.0%) showed positive findings. Predominant thin-section CT findings were poorly-defined centrilobular micronodules (30/54, 55.6%), branching linear structure (18/54, 33.3%), and ground-glass attenuation (6/54, 11.1%). In the smokers' group, poorly-defined micronodules were found in four patients, branching linear structures in one, and ground-glass attenuation in one. In welders, the extent of abnormalities seen on thin-section CT showed no significant correlation with the severity of dyspnea or the results of pulmonary funotion test. CONCLUSION: Poorly-defined centrilobular micronodules and branching linear structures were the thin-section CT findings most frequently seen in patients with arc-welders' pneumoconiosis. Less commonly, extensive ground-glass attenua-tion was also seen

The Percentiles of Body Mass Index and Trend of Obesity in Schoolage Children in Seoul

PURPOSE: Many authors have reported that obesity is a serious health problem in schoolage children and adolescents and recently obese children are increasing. Accurate diagnosis is needed to estimate the prevalence rate and trend of obesity. We studied body mass index(BMI) percentile for age and sex as a reliable and valid screening for adiposity. METHODS: We measured weight and height of 33,329 schoolage children to estimate obesity according to body mass index(weight in kilograms/height in meters2) and different standard weight. We also calculated BMI percentiles according to age and sex. We defined obesity for screening purposes as body mass index(BMI) equal to or in excess of the 95th percentile for age and sex. We also compared the prevalence of obesity according to a different standard weight. RESULTS: The mean value of body mass index(BMI) increases with age and tends to be slightly higher for male than female subjects. The 95th percentiles of body mass index(BMI) ranges from 18.9kg/m2 to 28.2kg/m2 for both males and females. No significant differences were apparent in the mean value of body mass index for each year. CONCLUSION: The percentile curves of body mass index(BMI) will help pediatricians to determine the relative ranking of patients compared with large sample of healthy schoolage children. Further studies are needed to define a useful criteria for defining obesity using body mass index(BMI) in childhood and adolescence. A longitudinal study and nationwide sampling will be required to overcome the limitation of this cross-sectional study.

Development of Questionnaire for Evaluating Health Effect Associated with Air Pollution / 예방의학회지

This study was conducted to develope and evaluate the reliability and the validity of a questionnaire in order to determine the applicability as a screening tool for estimating environmental exposure and health effects related to air pollution. The questionnaire was developed with adopting some items of others such as ISAAC or ATS-DLD. And then we performed test-retest to 89 middle school students and their mothers at interval of three months. Cohen's Kappa values, weighted Kappa values, Spearman's correlation coefficients, and Pearson's correlation coefficients for each item were computed as reliability coefficients. The validity coefficients and validity coefficient bounds were also obtained by simply using these reliability coefficients. As results, Kappa ranged broadly from 0.10 to 0.61 of the items 'diet', 0.52~0.79 of the environmental tobacco smoke, 0.39~0.44 of the functional categories of surrounding environment, and 0.54~0.63 of the using transportation systems; these items were regarded as confounding factors. For items related to health outcomes, Kappa ranged from -0.02 to 0.37 in the respiratory system of past medical history, and from 0.11 to 0.55 in the current health status. But Kappa of the others were over 0.60. In conclusion, if some items can be corrected or modified, the questionnaire developed in this study can be used as a tool for evaluating environmental exposure and health effects associated with air pollution.

A SMR study of Korean public servants / 예방의학회지

In Korea, sudden deaths of middle-aged and older male workers who are the responsible persons at home as well as workplace, have aroused social concern. Besides, U.N. has reported recently that mortality of Korea male in 40-50's was one of the highest among newly developed countries in 1992. Not much is, however, known about the nature of the work contributing to the mortality of different groups of workers. Therefore, this study was done to examine mortality of public servants, comprising about 5% of all the employed in Korea, according to their job titles and grades. The datas of 1753 official deaths, comprised 323 (only disease-oriented deaths) applicants of survivors' compensation, were used to examine age-adjusted Standardized Mortality Ratios(SMRs) according to their job titles, grades, tenures and cause of deaths. Controlling age and sex difference was conducted using 26,950,481 general population, 95,340 general deaths and 864,560 working public servants. All the groups were aged 20-64, who were being observed January - December in 1993, at the same time. Results and discussions are as follows. 1. SMRs standardized by general population was significantly low (SMR 44.9 CI 42.8-52.7) for all job titlses. Of public servants, 90.0% was graduated from high school, although 17.5% in general population. The distinction of social status such a education may produce a strong healthy worker effect. Besides, SMRs for different tenure groups showed a steady increase as tenure increases. This suggests that the magnitude of healthy-worker effect may be greater with increasing tenures. 2. SMRs standardized by own public servants was significantly elevated for workmen(SMR 121.0, CI 110.2-132.6) in solitue. When SMRs for different grade of workmen was examined, 9th(SMR 124.2, CI 104.4-146.7) and 10th(SMR 137.9 CI 120.8-156.8)grade, lower grade in workmen, showed significantly elevated SMRs. Of workmen, 57.0% were graduated from high school and 50.1% in 9th grade, as well. These mean that low economic states made up social class, education may increase mortality rate. 3. Of SMRs according to all causes of death, only policemen on 'cause of death related hypertensive disease'(SMR 282.5, CI 121.6-556.7) was significantly high except for 'cause of death related other signs, symptoms and ill-defined conditions'. 4. When SMRs on cause of death related hypertensive disease for different grade of policemen was examined, senior policemen(SMR 241.9), in charge of the front service, showed elevated SMR, in spite of statistical no significance. Especially, the working hour of senior policemen is quite long and also the work schedule is even more irregular for policemen. The results of this study showed that mortality for different jobs differed, and it differed also for different grades in the same job. This difference in mortality may reflect the difference in the nature of job contents, and further studies are warranted to elucidate which job characteristics are responsible.

Carpal Tunnel Syndrome among workers in a condom industry / 예방의학회지

The objectives of this study are to investigate the prevalence of occupation related carpal tunnel syndrome(CTS) among workers in a condom industry; to analyse the sensitivity and specificity of clinical signs or symptoms such as hand diagram, Tinel's sign and Phalen's sign in carpal tunnel syndrome; and to test vibration threshold test using audiometry as a technically easy and noninvasive method in the diagnosis of carpal tunnel syndrome in stead of nerve conduction velocity(NCV). The study group was divided into exposed group(39 cases)and non-exposed group(48 cases) based on whether or not excessive use of wrist movements exist. 1. There are statistically significant differences in symptoms and signs of carpal tunnel syndrome such as hand diagram, Tinel's sign and Phalen's sign between exposed and non-exposed group(p<0.05). 2. Six cases(9 hands) were confirmed as carpal tunnel syndrome by NCV. Five cases(7 hands) belonged to exposed group, 1 case(2 hands) to nonexposed group. As there are significant differences in prevalence of carpal tunnel syndrome between two groups(p<0.05), excessive use of wrist in occupation is a risk factor of carpal tunnel syndrome. 3. When we use NCV as a gold standard in the diagnosis of carpal tunnel syndrome, sensitivity and specificity of hand diagram, Tinel's sign and Phalen's sign is as followed; hand diagram; sensitivity 88.9%, specificity 84.2%. Tinel's sign; sensitivity 55.6%, specificity 72.8%. Phalen's sign; sensitivity 14.3%, specificity 88.4%. Among above clinical signs and symptoms, hand diagram is the best clinical screening test. 4. The differences of vibration threshold between median and ulnar nerve at the same time are useful in the diagnosis of carpal tunnel syndrome but the time change of vibration threshold of median nerve over time are not sensitive enough. It is concluded that vibration threshold between median and ulnar nerve at the same time can be used as a supplementary or alternative criterion to indicate that the nerve dysfunction is located in the carpal tunnel.

Perceived Occupational Psychosocial Stress and Work-related Musculoskeletal Disorders Among Workers Using Video Display Terminals / 대한산업의학회지

A cross-sectional study was conducted to assess the association between perceived occu-pational psychosocial stress at work and the work-related musculoskeletal disorders (WRMSD) among employees using video display terminals. The study included 111 female telecommunication employees from three companies at ChungBuk province. Cases of WRMSD were defined using symptom questionnaire and physical examination conducted by rehabilitation specialist. Information on demographics, individual factors, and perceived psychosocial stress, were obtained by self-administered questionnaire. For assessing perceived psychosocial stress, we used variables from 'job strain model' proposed by Karasek. Associations between perceived psychosocial stress and WRMSD were assessed by multiple logistic regression models. Forty nine (44% to the total) subjects met our operational definition for WRMSD. Age, seniority, housing load were not associated with WRMSD. Perceived psychosocial stress was associated with WRMSD [odds ratio=3.28, 95% confidence interval: 1.05-10.19]. This study suggests that perceived occupational psychosocial stress is related to the prevalence of WRMSD.

Asthma and Air Pollution in Korea / 한국역학회지

With rapid industrialization and urbanization, environmental pollution has become an urgent health problem. Asthma attack is a common and severe disease, and can be a sentinel event of worsening air pollution. There are, however, few studies about the epidemiolgy of asthma and the association between asthma and low level air pollution in Korea. This study was conducted to describe the trend and pattern of asthma attack and to examine the effect of air pollutants on admission in Korea. Combined data of this study are medical insurance claims for asthma, data from telemetry system of the Ministry of Environment for air pollutants, and air temperatures from monthly weather reports of the Meteorological Administration. To describe the temporal trends of asthma in Korea, insurance claims since 1985 were analized. Age specific asthma visit/admissions per 1000 eligible persons, as well as ratio of asthma visit/admissions over all visit/admissions showed a steady increase in asthma attack in Korea. Asthma prevalence was relatively high among under 5 years and over 50 years of age, and in these age groups asthma was more prevalent among males. The effects of relatively low level air pollution and weather condition on the number of patients who had asthma attacks admitted to hospitals in Seoul area were studied from April 2 to April 24, 1993. Asthma admissions were examined throughout the study period (392 cases), except sunday and holiday(354 cases) and except sunday, holiday and saturday (293 cases), while grouped into three age categories (3 12, over 40, and all age). Following results were obtained through correlation and multiple regression analysis. The number of adimission were significantly correlated with ambient air concentrations of total suspended particles (TSP), sulfur dioxide (SO2) and carbon monoxide(CO). 1) The number of admissions on the same day were significantly correlated with ambient air maximal concentrations of total suspended particcles among persons who were above 40 year old. 2) The effects of maximal daily concentrations of sulfer dioxide(SO2) among persons who were of 3- 12 age were significant when one day lagged asthma admission was compared with the air pollution on the previous day. 3) The number of admissions on 1-day lag were significantly correlated with ambient air maximal daily concentrations of carbon monoxide(CO) among persons who were above 40 year old. The associations between temperatures and number of admissions were not significant in this study. Levels of pollutants were fairly low, the monthly mean being 0.022 ppm for SO2, 0.032 ppm for NO2, 3.2 ppm for CO, 0.015 ppm for 03, and 240 micro gram/m3 for TSP. The mean temperature was 10.6degrees C. These results suggest that concentration of air pollutants lower than those given as guidelines may increase the incidence of asthma attacks.

The Geographic Patterns of The Adult Male Bladder Cancer Patients in Korea: Clue as to the Occupational Exposure / 한국역학회지

We calculated the age specific Proportionate Morbidity Ratio(PMR)' for different areas as the outcome index by using the national cancer registry data(1988 1991) to assess the patterns of stomach cancer and bladder cancer. Also, we calculated 'Manufacturing workers Concentration Index(MCI)' for different areas as the exposure index by using the census data reported in 1980 to assess the relationship between cancer site specific PMRs and MCIs. As a result, we found the significant correlation(r=0.61, p=0.002) between the bladder cancer in the age of 40s and the industrial exposure indicator. Future analytic studies should be fruitful in identifying more occupational risk factors for bladder cancer. Investigation of cancer incidence including geographic variations and difference by age may identify patterns suggesting occupational exposures.