- Evaluation of Puretone Threshold Using Periodic Health Examination Data on Noise-exposed Workers in Korea .
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Kyoo Sang Kim, Yangho Kim, Jung Keun Choi, Jung Sun Park, Young Han Moon
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Korean J Prev Med. 1999;32(1):30-39.
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- OBJECTIVES
This study was carried out to evaluate hearing impairment judgement and to investigate the differences in various diagnostic criteria for noise-induced hearing loss (NIHL) among workers who required for close observation (C). METHODS: Out of 731,029 workers who had taken the specific periodic health examination in 1994, we used the audiometric data on 37,999 workers (C) eliminating the employees who had previous otologic problems. Many investigators have being using different criteria for the evaluation of hearing impairment. In this study, we used the criteria of early (1989-1994), current, compensation for NIHL in Korea, 2-, 3-, 4-divided classification and hearing loss at 4,000 Hz and compared the evaluation results. RESULTS: The prevalences of C and workers who had occupational disease (D1) diagnosed for NIHL were 11.1 % and 0.44 %. There were significant difference in the prevalences of C and D1 depending on different province of Korea. Pure tone averages (PTAs) were not appropriately applied in their evaluation. 97% of workers whom we studied on were below the level of mild hearing loss judged by ISO standard. However, there were wide variations in the prevalence rate of mild hearing loss by diagnostic criteria. Thus, there were different judgements in determining the degree of NIHL depending on which diagnostic criteria were utilized. PTAs were found 20.54 (Rt) and 20.74 (Lt) when the method of 3-divided classification was applied for audiometric data. The degree of hearing impairment of the left ear was more severe than that of right ear. The prevalence of normal hearing threshold below 20 dB was 75.4% and the range of difference in both ear was below 10 dB. Right sided hearing threshold levels were 21.08 dB (500 Hz), 18.44 dB (1,000 Hz), 22.09 (2,000 Hz) and 52.36 dB (4,000 Hz). There was typical high frequency loss (C5-dip at 4,000 Hz) above 30 - 40 dB in normal hearing level. The increasing trend in hearing threshold level was gradually decreased by the increase of PTAs. The difference between PTAs and threshold at 4,000 Hz was about 10 dB. CONCLUSIONS: We could found that PTAs in the previous examination were not appropriately evaluated. This study revealed that they did not use unique criteria for managing the workers of NIHL. For the prevention of NIHL, it was found that the quality control on diagnosis and comprehensive management program were required, especially for those of hearing loss (C).
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Summary
- Carpal Tunnel Syndrome among workers in a condom industry.
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Joong Koo Kang, Do Myung Paek, Young Jung Lee, Hyeo Il Ma, Mi A Song, Hong Ki Lee, Jung Keun Choi
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Korean J Prev Med. 1996;29(3):507-520.
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- 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.
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Summary
- Medical Surveillance of Glass Fiber Workers in Korea.
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Se Wi Lee, Kyoo Sang Kim, Jung Keun Choi, Yang Ho Kim, Seong Kyu Kang, Kyuong Suk Choi, Young Hahn Moon
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Korean J Prev Med. 1996;29(2):187-198.
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- The industrial use of MMMF(man-made mineral fibers), has been increasing, particularly since the banning of most asbestos products. Fibrous minerals can cause health abnormalities currently associated with occupational exposure to glass fiber. This study was conducted to evaluate health risks of glass fiber manufactory workers within the country. we examined questionaries, physical examination including auscultation, chest x-ray, pulmonary function test for 488 male workers, to go through their dermal itching symptoms and respiratory evaluation. we had the results as follows. 1. In 45% of the workers itching had been expressed at their entrance. At that time we was investigating, 18.5% had itching, and most of them complained it when they fall asleep and night. The frequent itching site is waist and groin, upper and lower extremity in order, and it had been expressed mainly during summer and winter. 2. As the results of ventilatory functions test, 6.0% were obstructive type, 1.0% were restrictive type. so, glass fiber exposures should be controlled or elimination by protective devices in the workplace. 3. The means of FVC, FFV1, FFV1% were in normal range. As the comparison of ventilatory functions by age groups, MMF was decreased significantly for the group, 50 years old and more than other groups. And the comparison by the serving periods at glass fiber producing factory, MMF was decreased for the workers had worked for 11-15 years. Therefore, MMF be more sensitive index in the evaluation of ventilatory impairments caused by glass fiber workers.
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Summary
- Bronchial Hyperresponsiveness in Workers Exposed to Isocyanates.
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Kyeong Sook Choi, Kyoo Sang Kim, Byung Soon Choi, Jung Keun Choi, Se Hui Lee, Young Hahn Moon
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Korean J Prev Med. 1996;29(1):103-112.
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- We studied the association of nonspecific bronchial hyperresponsiveness with general characteristics, exposure concentration, respiratory symptoms, chest x-ray findings, past histories and pulmonary function. We determined bronchial hyperresponsiveness by methacholine challenge test. And we conducted a respiratory symptom questionnaire and performed spirometry on 111 workers occupationally exposed to isocyanates in various industries. About 21.6% of subjects had bronchial hyperresponsiveness. No significant differences were observed between the hyperresponsive and non-responsive group with respect to age, sex, employment period, height, and smoking histories cough and breathlessness were significantly associated with the bronchial hyperresponsiveness. The hyperresponsive group had more experience of bronchitis and asthma in the past than the non-responsive group. The lower FEV1 and FEV1 % were closely related with bronchial hyperresponsiveness. Bronchial hyperrespoosiveness seems to be associated with some of respiratory symptoms, past histories and pulmonary function parameters in workers exposed to isocyanates.
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Summary
- A Comparative Study on Evaluation Methods of Permanent Impairment in Korea.
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Chang Ok Rhee, Jung Keun Choi, Mi A Son, Ok Ryun Moon
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Korean J Prev Med. 1994;27(3):627-651.
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- In this study, literature review was done to examine and compare the current status and problems of different evaluation approaches toward permanent impairment in Korea. Alternatives and improvements in the current approaches in Korea were suggested. Series of cases were also examined to compare different approaches applied to the real cases, using 105 cases from a hospital data and another 207 cases from insurance company data. The main findings of the literature review are as follows; 1. The current evaluation methods of permanent impairment in Korea are grouped into two categories, grading and rating. Grading of impairments are expressly specified in 17 various statutes. 2. In Grading methods, the rigid system of 14 different grades has been adopted uniformally for the convenience of administration, which may not be, appropriate or valid from medical and scientifical aspect. 3. The advantage of McBride method is assessment of occupational disability rate. However the classified compensable occupations are only 280 and limited to manufacturing industries in 1960s' of U.S.A., which is not appropriate to current Korean circumstances. Especially, the job list does not include managerial officers or mental workers. 4. AMA Guides is the scientific and reasonable method for the assessment of physical impairment rate. However compensation and reparation of impairment case is difficult because this method cannot assess the disability rate according to occupation, age, etc. The results of cases comparative study are as follows: 5. The physical impairment could be compared in 167 out of total 312 cases and for the cases of complex impairment, McBride method underestimate physical impairment rate compared with AMA method. 6. When disability rate was assessed, occupation was considered the compensation of only 85 cases, and age was used in only 21 cases. This was because occupation and age compensation in McBride method are unreasonable. 7. The most ideal alternative is to assess physical impairment according to AMA method and then to develop a compensation method appropriate for the circumstances of Korea society.
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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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KSPM
