- The Effect of Working Noise Exposure and Military Background on the Hearing Threshold.
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Kyoo Sang Kim, Ho Keun Chung
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Korean J Prev Med. 2003;36(2):137-146.
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- OBJECTIVES
Impaired hearing is a prevalent occupational hazard, not only in industry, but also in the armed forces. In military life, noise has unusual characteristics, and constitutes a serious hazard to hearing. The aim of this study was to analyze the hearing threshold data in order to compare the hearing loss among shipyard workers, representing different workers, and a military service background. METHODS: A cross-sectional audiological survey, combined with a questionnaire study, was conducted on a stratified random sample of 440 shipyard workers, with long-term exposure to noise. The employees were divided into four groups, according to their working and military service backgrounds, in relation to their exposure to noise. RESULTS: As expected, the working and military noise exposure group (Group I) had significantly poorer hearing than the other groups. The high frequencies (2-8 kHz) showed the greatest difference in terms of poorer hearing in both ears. The prevalence of noise-induced hearing loss (NIHL) was highest in Group I. A logistic regression analysis was applied to determine the dependence of the NIHL in relation to age, smoking, drinking, working duration, ear protection, past history of ear diseases, and working and military service backgrounds, on the noise exposure. The important factors found to be related to the NIHL, in relation to noise exposure were: age, work duration, and working and military service backgrounds. The adjusted odds ratio estimates for NIHL in the right ear were 4.5 times greater (95% CI 1.7-11.6) for the military noise exposed group, and 7.9 times greater (95% CI 2.0-31.3) for the working noise exposed group than in the controls. The hearing thresholds at the pure-tone average and 4 kHz were significantly increased with age and work duration with both the working and military service backgrounds. CONCLUSIONS: From these results, specific preventive programs were planned, which should be assessed by epidemiological surveillance of the military noise exposed population.
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Summary
- Factors Affecting the Use of Medical Services by Workers with Respiratory Diseases.
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Yeon Soon Ahn, Jae Seok Song, Seong Kyu Kang, Ho Keun Chung
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Korean J Prev Med. 2002;35(1):49-56.
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- OBJECTIVES
To identify the relationship between the use of medical services by workers with three types of respiratory diseases (total respiratory diseases, acute upper respiratory infections and chronic lower respiratory diseases) and exposure to hazardous agents after controlling for other factors affecting medical services use, such as characteristics of the enterprises (scale, industry type) and employee demographics (sex, age). METHODS: The study population comprised 28,882 workers who had undergone general or special medical examinations at the industrial health center at least once between Jan 1995 and Dec 1997 and had possessed medical insurance during the period. We combined medical examination data with medical insurance data in order to analyze the relationship between exposure to hazardous agents and respiratory diseases. RESULTS: Among the 28,882 study subjects, 17,454 employees (60.4%) used medical services more than once during 3-year study period, owing to more than one kind of respiratory diseases. In logistic regression analysis, sex, age and the size of the enterprises proved to be significant variables on the use of medical services for all three types of respiratory disease: The use of medical services increased with employee age. Women used more medical services than men and the employees in the large-scale enterprises used more services than employees in small-scale enterprises. However, exposure to dust or organic solvents did not affect medical service use due to total respiratory diseases or acute upper respiratory infections. Only in the case of chronic lower respiratory diseases did workers exposed to dusts (OR=1.12, 95% CI=1.01 -1.24) or organic solvents (OR=1.19, 95% CI=1.05-1.35) use more medical services than those not exposed. CONCLUSIONS: Workers exposed to dusts or organic solvents are particularly apt to suffer from chronic lower respiratory diseases and use medical services more often than those not exposed. That is, chronic exposure to hazardous agents such as dusts and organic solvents is believed to be harmful and to cause respiratory symptoms and diseases.
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Summary
- Understanding the Occurrence of Lung Cancer in Foundry Workers through Health Insurance Data .
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Yeon Soon Ahn, Jae Seok Song, Seong Kyu Kang, Ho Keun Chung
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Korean J Prev Med. 2000;33(3):299-305.
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- CONCLUSIONS: To investigate the difference in the occurrence of lung cancer between foundry workers and non-foundry workers by comparing the number of workers diagnosed with lung cancer through health insurance data. METHODS: The study population was comprised of 28,884 workers who had undergone at least one general or special medical examination between January 1995 and December 1997 at the occupational health center. All of the subjects had health insurance during this period. We combined the medical examination data with the health insurance data to compare the number of foundry workers diagnosed with lung cancer and the number of non-foundry workers diagnosed with lung cancer. RESULTS: Seven workers were diagnosed with lung cancer among the 1,591 foundry workers, compared to twelve workers among the 27,293 non-foundry workers (odds ratio: 10.04, 95% confidence interval: 3.95-25.55). The seven foundry workers diagnosed with lung cancer were all exposed to dust, and six out these seven workers were engaged in finishing or shake-out processes. CONCLUSIONS: Although the information for this study was obtained from health insurance data, which has limitations such as accuracy and completeness, the number of foundry workers diagnosed with lung cancer was significantly higher than that of non-foundry workers. Therefore, a well-designed cohort study should be followed to confirm the higher lung cancer rates in foundry workers.
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Summary
- Skin diseases of male workers in painting workplace.
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Jae Beom Park, Kyung Jong Lee, Jae Yeon Jang, Ho Keun Chung
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Korean J Prev Med. 1997;30(4):830-839.
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- Painting is risky work to occupational skin disease. This research was carried out to investigate the prevalence of occupational skin disease in painting department of a shipyard company in June 1996. Dermatological examination, self-administered questionnaire survey, compositional analysis of solvents used in painting and cleaning were conducted. Exposed group(n=379) was selected randomly in painting department and control group(n=151) was selected in those who had not exposed to paints or solvents. Exposed group was divided into two groups by substance to contact ; painters contact to paints and organic solvents and workers contact to cleaners mainly composed of organic solvents. The prevalence of contact dermatitis(11.9%) is significantly elevated compared with control group(2.6%), and age adjusted odds ratio(OR) is 4.95 (95% confidence interval[CI]: 1.75-14.03). The prevalence of Tinea pedis, the most common skin disease, in exposure group is 48.0%, and its age-adjusted odds ratio(OR) is significantly elevated compared with control group (OR:3.17, 95% CI:2.06-4.88). Pompholyx is also significantly elevated in prevalence(11.9%) and age-adjusted OR(OR:6.69, 95% CI:2.05-21.87). There were no difference in the prevalence of contact dermatitis, Tinea pedis, and pompholyx by use of protector, work type, and duration of employment in painting department. In exposure group, 71.1% suffer from contact dermatitis improved in vacation or holiday and 68.9% of them had lesion in exposed area, it suggest that contact dermatitis in exposed group is related to their work. In conclusion, workers in painting department have high risks of contact dermatitis, Tinea pedis, and pompholyx. A health policy should be provided to prevent skin disease among painting department.
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Summary
- Respiratory Health of Foundry Workers Exposed to Binding Resin.
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Jung Keun Choi, Chang Ok Rhee, Do Myung Paek, Byung Soon Choi, Yong Chul Shin, Ho Keun Chung
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Korean J Prev Med. 1994;27(2):274-285.
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- The effects of resin on the respiratory health have been investigated in 309 workers from four iron and steel foundries and the results compared with those from 122 workers who were not significantly exposed to resin gas and silica dust at the same industries. Phenol-formaldehyde resin was used in the core making and molding processes and workers were exposed to their decomposition products as well as to silica dist containing particulates The subjects were grouped according to formaldehyde, dust and other gas exposures, and smoking habits were considered also in the analysis. Standardized respiratory symptom questionnaire was administered by trained interviewers. Chest radiograph, pulmonary function tests, and methacholine challenge tests were done. Environmental measurements at the breathing zone were carried out to determine levels of formaldehyde, respirable dust and total dust. Foundry workers had a higher prevalence of symptoms of chronic bronchitis with chronic phlegm and chronic cough when exposed to dust. Exposure to gas was significantly associated with lowered FEV1 and obstructive pulmonary function changes. Exposure to formaldehyde and phenol gas was associated with wheezing symptom among workers, but FEV1 changes after methacholine challenge were not significantly different among different exposure groups. When asthma was defined as the presence of bronchial hyperreactivity with more than 20% decrease in FEV1 after methacholine challenge, 17 workers out of 222 tested had asthma. Fewer asthmatic workers were found among groups exposed to for maldehyde, gas and dust, which indicates a healthy worker effects in a cross-sectional study. The concentration of formaldehyde gas ranged from 0.24 to 0.43 ppm among studied foundries. The authors conclude that fornaldehyde and phenol gas from combust resin is probably the cause of asthmatic symptoms and also a selection force of those with higher bronchial reactivity away from exposures.
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Summary
- A study to the workers exposed to organic solvents by neurobehavioral tests.
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Seong Kyu Kang, Ho Keun Chung, Jeong Pyo Hong, Ki Woong Kim, Young Sook Cho
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Korean J Prev Med. 1993;26(2):210-221.
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- In order to evaluate the confounding factors of neurobehavioral tests and the neurobehavioral effects in the workers exposed to organic solvents, NCTB was carried out on 100 workers. 46 workers had never been exposed to neurotoxic substances, and the others were being exposed to the solvents, mainly toluene. Simple reaction time, digit symbol, Santa Ana dexterity test and persuit aiming were different with age in non exposure group. Simple reaction time was carried out well in males, and digit symbol and persuit aiming were in females. There was no difference at educational level when the subject was educated over 12 years. Santa Ana dexterity and Benton visual test differed according to exposure level to toluene, however simple reaction time didn't. The acute neurotoxic effect was not excluded in this study. But, NCTB could be used to evaluate and prevent neurobehavioral changes in workers exposed to neurotoxic solvents in Korea.
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Summary
- Serum protein concentrations and electrophoretic patterns by categories of small opacity profusions in coal workers' pneumoconioses.
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Jeong Pyo Hong, Ho Keun Chung
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Korean J Prev Med. 1991;24(1):1-7.
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- The concentrations of serum proteins fractions and their electrophoretical patterns were investigated in 135 patients with coal workers' pneumoconiosis who participated in confirmative examination for pneumoconiosis in December 1989. Their radiographical profusions were classified as 1/0 or more. Agarose film and phosphoric acid-sodium hydroxide buffer(pH 8.6) were used for electrophoresis. Concentration of each protein fractions and electrophoretical patterns seemed to be equivalent to reference values. Serum alpah1- and beta-globulin concentrations, however, were significantly different(p<0.50) among categories of small opacity profusions and showed the lowest level in the group of category 1. Albumin concentrations decreased and alpha2-globulin concentrations increased significantly(p<0.05) in the group of complicated with pulmonary tuberculosis. gamma-globulin concentrations were not varied by category of profusions nor by pulmonary tuberculosis complication.
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Summary
- Concentrations of lead, iron and zinc in blood of coal workers' pneumoconiosis patients.
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Ho Chun Choi, Ho Keun Chung, Hae Jeong Kim
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Korean J Prev Med. 1989;22(4):486-494.
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- Lead, iron, and zinc concentrations in whole blood were determined by atomic absorption spectrophotometry, using a simple one-step dilution procedure, which were measured in 3 groups, 98 officers unexposed to dust or to metal, 58 coal miners without pneumoconiosis, and 113 coal workers' pneumoconiosis (CWP) patients. The results were as follows; 1. The precisions (C. V.%) of lead, iron, and zinc in blood were 12.65+/-6.95%, 1.47+/-1.25% and 6.35+/-3.34%, respectively. 2. Lead and zinc in blood showed the log-normal distribution unlike iron in blood which showed normal distribution. 3. Lead, iron, and zinc concentrations in blood of 3 groups were follows. There was significant difference of concentration far zinc in blood by groups statistically. 4. The difference of lead, iron, and zinc concentrations in blood was not significant (p>0.05) by profusion on chest radiographs.
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Summary
- Survival Rate of Hospitalized Coal Workers' Pneumoconiosis Patients: According to Characteristics at the Time of Hospitalization.
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Kyoung Yong Rhee, Ho Keun Chung
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Korean J Prev Med. 1989;22(1):81-89.
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- The authors investigated mortality rate of hospitalized CWP(coal workers' pneumoconiosis) patients. Date, which was composed of age, date of hospitalization, date of death, and radiological findings(profusion of small opacity, type of large opacity, tuberculosis, emphysema, pneumothorax, and cardiac abnormality), was gathered from medical charts and chest x-ray films at the time of hospitalization of CWP patients. Among 738 CWP patients, that were entered survey differently and have followed different period, 160 CWP patients were died during different observational period. Mean value of observational period was 203 weeks, and mean age at hospitalization was 51 years. Because of short observational period, mean survival time could not found. There was statistically significant difference of mortality rate between group of small opacity and that of large opacity. In group of small opacity 5 year survival rate was 0.80 and in group of large opacity that was 0.73. And 80 percentile survival time was 57 months in group of small opacity and that was 40 months in group of large opacity.
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Summary
- Coal Miners' Recognition and Attitude toward Pneumoconiosis in Kangneung Area.
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Ho Keun Chung, Kyung Yong Rhee
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Korean J Prev Med. 1988;21(2):251-266.
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- This study was planned in order to investigate coal miners' recognition and attitude toward pneumoconiosis, and its relationship with related behavior for prevention of pneumoconiosis. Study object was coal miners in Kangneung area, sampled by multistage random proportional sampling, Sample size was 13% of total coal miners in Kangneung area. The results were divided into three parts: (1) descriptive results presented percent distribution, (2) reclassification of knowledge, experiences, and attitude by factor analysis, (3) prediction of health behavior for prevention of pneumoconiosis by discriminant analysis. Knowledge, experiences, and attitude toward pneumoconiosis were classified into nine factors. Knowledge about pneumoconiosis were broken down to two factors and attitude to four factors, and valence, perceived severity were classified into each one factor. According to demographic, socioeconomic characteristics, and factors of knowledge, experiences, attitude about pneumoconiosis, about 62% of behavior of wearing respiratory protector was correctly discriminated. And by the same methods, about 81% of behavior of hospital visit at respiratory symptoms; cough, sputum, chest pain etc. was discriminated correctly.
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- Effect of STEL-toluene on Metabolism of Benzene in Rats.
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Jaehoon Roh, Dong Chun Shin, Jung Gyun Park, Young Hahn Moon, Ho Keun Chung
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Korean J Prev Med. 1988;21(1):152-162.
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- Benzene and toluene, which are widely used aromatic hydrocarbons in workplace, are recently proved to cause health hazards due to their toxic effects. This study investigated the influence of toluene on the urinary excretion of benzene metabolite by administering short term exposure limit(STEL) of these compounds(i.e., 13.8mg/kg of benzene and 108.8mg/kg of toluene) intraperitoneally into Sprague-Dawley rats. After administration, urinary phenol concentration of rat was measured by gas chromatography for every three hours. Data were analyzed by non-parametric statistical methods using Kruskal-Wallis multi-sample test and Mann-Whitney U test. The following results were obtained: 1. Administration of STFL-benzene increased urinary phenol concentration in rats. 2. Urinary phenol concentration was increased logarithmically according to the dosage of benzene. 3. Excretion of phenol in urine was decreased when benzene and toluene were administered simultaneously compared with administering benzene alone. In Summary, these results reveal that administration of STEL of toluene has antagonistic effect of urinary excretion of benzene metabolite in rats.
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Summary
- Relationship between the Measurement Values of the Digitial Dust Indicator and Personal Dust Sampler.
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Young No Yoon, Jeong Joo Lee, Ho Keun Chung, Ho Chun Choi
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Korean J Prev Med. 1987;20(2):255-260.
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- The digital dust indicator (Sibata P-5), one of the direct-reading instruments was evaluated for the respirable dust in the underground coal mine environments. As a reference, respirable dust was determined using three cyclones and/or impactors. All the tests were performed on aerosol in twenty underground coal mines. The coefficients of mass-relative concentration were 0.067+/-0.054 (Mean+/-Standard deviation) (range: 0.006-0.172). The relationship between relative concentration and temperature was not significant statistically. Also, the relationship of relative concentration and relative humidity was not significant. Mass concentration and relative concentration were 5.31+/-5.22 mg/m3 and 162+/-163 CPM (Mean+/-Standard deviation) respectively. The range of mass concentration was 1.22-22.69 mg/m3; relative concentration 16-628 CPM. The relationship of mass concentration and relative concentration was not significant in these ranges.
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Summary
- Serum Immunoglobulin Levels in Coal Workers' Pneumoconiosis.
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Ho Keun Chung, Yong Hee Cheon, Jeong Pyo Hong
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Korean J Prev Med. 1987;20(2):247-254.
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- Serum Immunoglobulin (Ig)A, IgG, IgM, levels were measured in 99 coal workers' pneumoconiosis (CWP) patients and 12 healthy coal workers and 9 non-miners to compare with each group by the radiological categories, its complications and working period in coal mine. Serum were measured by nephelometry. The findings were as follows: 1) Serum IgA levels were significantly different between three groups of CWP patient, healthy coal worker and non-miner (mean+/-standard deviation: 226.4+/-87.7, 221.3+/-45.1, 170.1+/-65.7 respectively). 2) There were no significant differences of Ig levels among radiological categories of CWP. 3) There were no significant differences of Ig levels among simple pneumoconiosis and its complicated disorders. 4) The three Ig levels were slightly increased in the group of mining years less than 20 years (IgA: r=0.1869, p<0.10 IgG: r=0.2902, p<0.05 IgM: r=0.2889, p<0.05).
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Summary
- A Study on Occupational History of Coal Workers' Pneumoconiosis.
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Ho Keun Chung, Yong Hee Cheon, Kyung Young Rhee, Jeong Pyo Hong
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Korean J Prev Med. 1987;20(1):158-164.
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- The purpose of this study is to analyze occupational history of coal miners with pnemoconiosis. In this study, occupational chracteristics of 49 coal miners with pneumoconiosis were compared with those of 45 coal miners without pneumoconiosis but in similar age category (43-52 years of age) based on interview survey. Various indices on occupational characteristics were developed for the following areas: duration of employment, perception of working condition, working density, dust concentration, temperature, humidity, and experience of respirator wearings. Perception of working condition were measured in 5 points scales but experiences of respirator wearing was measured in 3 points scale. Each index was multiplied by duration of employment. From the analysis, only the experience of respirator wearing showed statistically significant difference between the two groups. Therefore, respirator wearing seemed to be effective in reducing occurrence of pneumoconiosis.
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Summary
- Changes of Forced Vital Capacity and Forced Expiratory Volume in one second of hospitalized Pneumoconiosis Patients.
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Yong Hee Cheon, Ho Keun Chung, Young Hahn Moon, Ho Young Chung
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Korean J Prev Med. 1986;19(2):314-321.
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- Forced vital capacities (FVC's) and forced expiratory volumes in one second (FEV1.0's) of 26 pneumoconiosis patients were checked at admission and were followed up for 10 months through hospitalization. FVC's and FEV1.0's were slightly improved in 10 months after admission. The improvement of FVC's was statistically significant. In the group of large opacities in chest radiographs, FVC's and FEV1.0's were lower than those values in small opacity group at admission but improved more progressively. Similar finding was noted in the group of emphysema; those values were lower at admission but improved more progressively than those of non-emphysema group.
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Summary
- A Study on Sickness Absence.
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Ho Keun Chung
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Korean J Prev Med. 1980;13(1):35-39.
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- The researcher intended to investigate the rate absenteeisms and other related statistics among the workers in a steel and iron industry with the criteria and the recommendation of the International Association on Occupational Health. With the well designed questionnaire and interview, 1,882 workers were surveyed from July the 24th to the 28th, 1978. The results were as follows ; The workers who experienced absence were 16.8% in July. The rate of frequency (spells) was as follow ; the frequency (spells) was 1.34, the duration was 2.29, the frequency (persons) was 101.06 and the lost time was 0.63, respectively. The main causes of sickness absence were general symptoms. such as fatigue (50.8%) and gastro-intestinal symptoms (13.8%). The frequency of sick was highly correlated to the frequency of drinking, the amount of smoking, the physical work-load and the amount of drinking, which was analysed by the stepwize multiple regression analysis. The multiple R due to the above mentioned four variables was 0.320 and the R square was 10.3%.
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