Annals of Occupational and Environmental Medicine

Choong Ryeol Lee

17 Articles

The effect of diabetes on 4-year changes of hearing thresholds in male workers exposed to noise in a single company: a longitudinal study: Dae Yun Kim, A Ram Kim, Joo Hyun Sung, Choong Ryeol Lee, Jiho Lee; Ann Occup Environ Med 2019;31:e11. Published online June 28, 2019; DOI: https://doi.org/10.35371/aoem.2019.31.e11

Abstract PDF PubReader ePub: Background
Recently, several studies have assessed the association between diabetes and hearing impairment. However, the effect of diabetes on hearing impairment is not well known in diabetic patients exposed to noise, a typical cause of hearing impairment. The aim of this study is to longitudinally analyze the effect of diabetes on hearing impairment in workers exposed to similar noise levels from 2013 to 2017 who had experienced little change in their working conditions.
Methods
The study subjects included 2,087 male workers exposed to noise in a single company and who underwent health examinations at the same hospital in Ulsan city in 2013 and 2017. Hearing impairment was defined that a pure-tone average of pure-tone audiometry (PTA) thresholds at 1,000, 2,000, 3,000, and 4,000 Hz was 25 dB and over in both ears. Statistical analyses were conducted using χ² tests, ANOVA, and Cox proportional hazard models. We analyzed covariates that might affect hearing impairment, including age; working period; levels of total cholesterol, triglyceride, and serum creatinine; smoking and alcohol history; and noise level.
Results
The average PTA thresholds and their average changes between 2013 and 2017 were significant in the diabetes mellitus (DM) group than those in the normal and impaired fasting glucose group. Among the subjects with the same status of fasting glucose group in 2013 and 2017, the adjusted hazard ratios for incident hearing impairment among those in the DM group compared to normal group were 3.35 (95% confidence interval [CI], 1.54–7.29) in the left ear and 5.66 (95% CI, 2.01–15.98) in the right ear.
Conclusions
This study suggested that the risk of hearing impairment in the DM group was significantly higher than that in the normal group in both ears, even when exposed to similar noise levels.

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The Characteristics of Tinnitus and Hearing Threshold: In Workers with Noise Induced Hearing Loss from a Hospital Setting: Nam Jeong Kim, Hyoung Ouk Park, Chang Sun Sim, Choong Ryeol Lee, Young Joo Kwon, Ji Ho Lee; Korean Journal of Occupational and Environmental Medicine 2012;24(4):431-440. Published online December 31, 2012; DOI: https://doi.org/10.35371/kjoem.2012.24.4.431

OBJECTIVES
This study was carried out to define the relationship between the characteristics of tinnitus and hearing threshold (puretone and speech) in workers with noise induced hearing loss (NIHL).
METHODS
A total of 189 cases(378 ears) from workers with compensation claims for NIHL during 2004-2009 were investigated. Various factors, including age, work carriers, body mass index (BMI), blood pressure, noise exposure level of worksite hearing threshold, speech discrimination score, pitch match, and loudness of tinnitus were analyzed.
RESULTS
The average hearing threshold of all subject was 44.2 dBHL, puretone audiometry thresholds in subjects with tinnitus were lower than the non-tinnitus group (except at 8000 Hz). Using speech audiometry, the tinnitus group showed a lower speech recognition threshold and speech discrimination score. The tinnitus group also had an average tinnitus frequency of 4195.2 Hz, loudness of 73.6 dB, and tinnitus sensation average of 6.0 dBSL. These frequencies of tinnitus were in the lowest puretone audiometry frequencies. Tinnitus loudness had a strong relationship with puretone and speech audiometry thresholds.
CONCLUSIONS
In cases beyond moderate hearing loss, the tinnitus group had a better puretone (except 8000 Hz) and speech hearing status, and most comfortable loudness (MCL) level. In addition, puretone and speech audiometry thresholds increase with tinnitus loudness.

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The Relationship Between Tinnitus Frequency and Speech Discrimination in Patients With Hearing Loss
Joo Hyung Oh, Taehun Lim, Joon Bum Joo, Ju Eun Cho, Pona Park, Jong Yang Kim
Korean Journal of Otorhinolaryngology-Head and Neck Surgery.2023; 66(3): 156. CrossRef
Efficiency Improvement of the Hearing Test Procedure Using Linear Regression
Heonzoo Lee, Sejin Kim, Rayoung Park, Sungsu Lee, Hyong-Ho Cho, Yonggwan Won
Journal of Digital Contents Society.2022; 23(12): 2489. CrossRef

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The General Characteristics and Results of the Cold Provocation Test in the Risk Group of HAVS: Jae Kook Yoon, Chang Sun Sim, Myoung Soon Oh, Joo Hyun Sung, Ji Ho Lee, Choong Ryeol Lee, Yangho Kim, Cheol In Yoo, Hun Lee; Korean Journal of Occupational and Environmental Medicine 2012;24(3):207-216. Published online September 30, 2012; DOI: https://doi.org/10.35371/kjoem.2012.24.3.207

Abstract PDF

OBJECTIVES
The cold provocation test for diagnosing the vascular component in hand-arm vibration syndrome (HAVS) is likely to be accepted as an objective test, and a few studies have been performed. However, controversy has continued regarding the diagnostic performance of this method. Although objective methods such as plethysmography and laser doppler flowmetry have been studied, they have not received as much attention as other diagnostic methods. Therefore, our study aim was to spread the awareness of HAVS by reporting the results of the cold provocation test in a hand-transmitted vibration exposure group.
METHODS
The study subjects were 549 workers who had been exposed to hand-transmitted vibrations and reported symptoms in their hands. While the subject immersed both their hands in 10degrees C water for 10 minutes, the skin temperature of 10 fingers was recorded from pre-immersion time to 20 minute postimmersion including 10 minutes immersion time. The recovery rates were calculated from the recorded skin temperatures. The 'decreased recovery rate' criteria were less than 30% at 5 minutes post-immersion and 60% at 10 minute post-immersion.
RESULTS
Of the subjects, 69.1% and 30.9% had more severe symptoms in the right and left hands, respectively. The mean finger skin temperature of the right hand after cold-water immersion for 10 minutes was approximately 10degrees C, which increased gradually with time, but they did not reach the baseline temperature at 20 minutes post-immersion. The deviations of the skin temperature in the subjects were higher in the recovery phase than in the baseline and cold immersion phase. The 3rd finger of both hands showed the lowest 5-minute recovery rate among the fingers examined, and the left 4th finger and right 3rd finger showed the lowest 10-minute recovery rate. Of the subjects, 37.6% and 10.4% of subjects showed a lower recovery rate at 5 and 10 minutes in at least one finger, respectively, while 10.2% showed a lower recovery rate at both 5 and 10 minutes simultaneously in at least one finger.
CONCLUSIONS
The larger deviations in the recovery phase than in the other phases indicated that interindividual differences are more prominent in the recovery phase. There might be no benefit in observing the finger skin temperature for an additional 10 minutes after 10 minutes post-immersion. Overall, approximately 10% of the subjects in the HAVS risk group had HAVS.

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Technetium-99m hand perfusion scintigraphy (Raynaud’s scan) as a method of verification in hand arm vibration syndrome: a review
Taewoong Ha, Hyeoncheol Oh, Jungwon Kim
Annals of Occupational and Environmental Medicine.2022;[Epub] CrossRef
Trend of Human Vibration Research in Korea
Hee-Sok Park
Journal of the Ergonomics Society of Korea.2013; 32(4): 293. CrossRef

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Comparison of the Standard Threshold Shift Criteria for Evaluating Hearing Conservation Programs: Chang Sun Sim, Kyoung Sook Jeong, Yu Jung Kim, Na Ri Choy, Choong Ryeol Lee, Hun Lee, Jong Pil Jung, Ok Hyun Kim, Yo Weon Lee, Seung Rim Yang, Sung Soo Oh, Ji Ho Lee; Korean Journal of Occupational and Environmental Medicine 2006;18(3):179-188. Published online September 30, 2006; DOI: https://doi.org/10.35371/kjoem.2006.18.3.179

Abstract PDF: OBJECTIVES
Workers from a factory was selected to compare 8 standard threshold shift criteria with the Korean diagnostic criteria of noise-induced hearing loss for this cohort study.
METHODS
From 1990 to 1999, 491 workers at a manufacturing company with complete record of the hearing test covering the range of 0.5~6 kHz for 10 consecutive years were finally selected. Eight standard threshold shift criteria (15 dB once, NIOSH (1972), 10 dB average 3~4 kHz, OSHA STS, AAOHNS, 15 dB twice, 15 dB 1~4 kHz, OSHA STS twice) along with the Korean standard for diagnosing the noise-induced hearing loss (the average hearing threshold at 0.5, 1 and 2 kHz) were compared to calculate the degree of the threshold shift and the minimum time required to detect the change.
RESULTS
Those workers showing at least one positive shift in the 'once'criteria of NIOSH (1972) were 92.5%; the 'average'criteria of 10 dB average 3~4 kHz were 35.8%; 'twice'criteria of 15 dB twice were 44.4%. The duration from the baseline to the year showing the first positive shift was from 3.2 +/- 3.1 years (NIOSH, 1972) to 6.0 +/- 2.1 years (OSHA STS twice). The percentage of true positive shift ranging from 20.4% (AAO-HNS) to 69.8% (NIOSH, 1972). There were 10 (2%) which met the Korean diagnostic criteria of noise-induced hearing loss.
CONCLUSIONS
Currently the concept of hearing threshold shift in diagnosing the hearing loss was adopted in Korea thus in this study we determined the validity and the effect of the various hearing threshold shift criteria and showed that NIOSH (1972) criteria was the best of all. In the future, hearing data from various manufacturing workers should be compared to thoroughly evaluate the threshold shift criteria and to establish adequate standard for Korean workers.

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Evaluation of Ototoxicity by Mixed Organic Solvents Using the Upper Limit of Hearing: Ji Ho Lee, Cheol In Yoo, Choong Ryeol Lee, Hun Lee, Young Hee Choi, Nam Jung Kim, Yangho Kim; Korean Journal of Occupational and Environmental Medicine 2004;16(4):391-400. Published online December 31, 2004; DOI: https://doi.org/10.35371/kjoem.2004.16.4.391

Abstract PDF: OBJECTIVES
This study evaluated the ototoxicity by mixed organic solvents on workers'hearing using the upper limit of hearing(ULH).
METHODS
Seven hundred ninety-seven male workers in the ship building industry who were evaluated by interview with an upper limit of hearing from August 2000 to July 2002 were enrolled in the study. The subjects were divided into 3 groups according to exposure profile and job: officers, field supporters, and painters. To assess the ototoxicity of mixed organic solvent exposure on hearing, with regard to confounders, the general liner model was used.
RESULTS
After controlling for the possible confounders, such as age, career, noise exposure level, tinnitus, alcohol intake, and smoking, the estimated mean for ULH of the painter group was higher than that of the officer and the field supporter groups. These differences of mean ULH were at the borderline of statistically significance(p=0.069).
CONCLUSIONS
The results of this study suggest that a relatively lower level of mixed organic solvent chronically affected the hearing organ or auditory pathway. ULH seems to be a useful method for early detection of the ototoxicity of organic solvents.

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Relationship of Biological Indices of Manganese with Pallidal Index on MRI in Liver Cirrhotics: Younghee Choi, Neung Hwa Park, Jung Woo Shin, Hyo Kyung Kim, Sung Ryul Kim, Tae Heum Jeong, Ji Kang Park, Hun Lee, Cheol In Yoo, Choong Ryeol Lee, Ji Ho Lee, Yangho Kim; Korean Journal of Occupational and Environmental Medicine 2004;16(2):129-138. Published online June 30, 2004; DOI: https://doi.org/10.35371/kjoem.2004.16.2.129

Abstract PDF: OBJECTIVES
The objectives of this study were to clarify which biological manganese exposure indices reflect the pallidal signal intensities in magnetic resonance imaging (MRI) in liver cirrhotics.
METHODS
We examined whole blood, plasma, RBC and urinary manganese concentrations, as well as, brain MRI in 22 cirrhotic patients and 10 healthy controls. From MRI scans we calculated the signal intensity of the globus pallidus using the pallidal index (PI), the ratio of the globus pallidus to subcortical frontal white-matter signal intensity in axial T1-weighted MRI planes multiplied by 100. In addition, we studied the relationships between PI and other measurements.
RESULTS
The high signal intensity in the globus pallidus on T1-weighted MRI was observed in 18 (81.8%) patients. There was a significant correlation between whole blood and RBC manganese concentration, and PI on MRI. According to multiple linear regression, whole blood and RBC manganese concentration reflected PI on MRI better the other indices did.
CONCLUSIONS
Whole blood and RBC manganese concentrations could be useful as biological manganese exposure indices that reflect PI on MRI.

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Mental Disorders and Fitness for Work in Korea: Choong Ryeol Lee, Yang ho Kim, Cheol In Yoo, Ji Ho Lee, Hun Lee; Korean Journal of Occupational and Environmental Medicine 2003;15(3):224-236. Published online September 30, 2003; DOI: https://doi.org/10.35371/kjoem.2003.15.3.224

Abstract PDF

OBJECTIVES
This study investigated the actual state of people with mental disorders in Korea, in order to present an alternative proposal for their work fitness and vocational rehabilitation.
METHODS
The authors conducted this study through a review of statistics on the prevalence of mental disorder, labor laws, and the literatures related with work fitness and vocational rehabilitation of people with mental disorders.
RESULTS
According to recent surveys, about 3 million people in Korea are likely to have mental disorders which could lead to discrimination in social life and dishonor in occupational career, either in the present or near future. Therefore, evaluation of work fitness and vocational rehabilitation for persons with mental disorders are important. At present, work fitness for psychiatric patients is evaluated without suitable guidelines regarding the kinds and severity of mental disorders that impede work capacity. Furthermore, mental disorder-specific fitness for work is not under consideration.
CONCLUSION
It is true that most psychiatric patients have some limitation in performing their job. However, judging from the results of some research, proper displacement, apprehension of co-workers, and adjusted workplace could help them complete their tasks properly despite their troublesome psychiatric symptomatology. The government must help all citizens to do their best in their social life, and show a deep interest in the employment of all disabled people including those with psychiatric disorders. Above all we have to change our attitudes and preconceptions against people with mental disorders. Some labor laws, which presently impede employment of people with psychiatric disorders, need to be revised in their favor. Future work capacity evaluation should be done on the basis of ability to function in the workplace rather than symptomatology.

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The Relations among Attitude, Competency, and Appropriateness of Work on Student Suicide in Health Teachers
Jae Soon Yoo, Dallong Han, Chul-Gyu Kim
The Journal of Korean Academic Society of Nursing Education.2016; 22(4): 473. CrossRef
The Stigma of Mental Illness in Korea
Jong-Ik Park, Mina Jeon
Journal of Korean Neuropsychiatric Association.2016; 55(4): 299. CrossRef
Employment Discrimination Against Schizophrenia
Mary V. Seeman
Psychiatric Quarterly.2009; 80(1): 9. CrossRef

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Epidemiologic Characteristics of Hand-Arm Vibration Syndrome through Occupational Disease Surveillance System in Busan, Ulsan, Kyungnam Province: Young hee Choi, Cheol In Yoo, Ji Ho Lee, Choong Ryeol Lee, Hun Lee, Young Wook Kim, Chang Ho Chae, Sang Baek Koh, Euna Kim, Lu Jin Lee, Yang ho Kim; Korean Journal of Occupational and Environmental Medicine 2003;15(3):261-268. Published online September 30, 2003; DOI: https://doi.org/10.35371/kjoem.2003.15.3.261

Abstract PDF: OBJECTIVES
The objectives of this study were to estimate the epidemiologic characteristics of hand-arm vibration syndrome (HAVS) due to occupational exposure of hand transmitted vibration and to identify the occupations and industries where such exposures arises, and the main sources of exposure.
METHODS
In April 2001 the Busan, Ulsan, and Kyung-Nam Province occupational disease surveillance system was established to measure the incidence and prevalence of work-related HAVS and other occupational diseases in these Korean provinces. Occupational physicians of nine hospitals in Busan, Ulsan, and Kyung-nam Province were involved in this project between April 2001 and November 2002. Physicians collected information through questionnaires and interviews. Information gathered included age, occupation, types of vibration tools used and presence of subjective symptoms such as vibration-induced white finger (VWF), numbness and tingling.
RESULTS
A total 192 cases were reported with 188 males and 4 females. The shipbuilding industry was the most common type of industry and grinders were the most common source of exposure. Symptoms of neurological disorder were more common than those of vascular disorder.
CONCLUSIONS
The authors concluded that exposure to hand transmitted vibration is common and that HAVS is one of the most common occupational diseases in Korea. However, the range and extent of hand transmitted vibration and the overall prevalence of HAVS in Korea is still unknown. More extensive research on this syndrome in order to priorite necessary preventive measures is required.

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Prevalence and Risk Factors of Tinea Pedis in Workers of Shipbuilding Industry: Ho Seok Suh, Cheol In Yoo, Choong Ryeol Lee, Ji Ho Lee, Yangho Kim, Won Sin Lee, Jee Ho Choi, Kyung Jeh Sung, Jai Kyoung Koh, Kee Chan Moon; Korean Journal of Occupational and Environmental Medicine 2002;14(4):408-417. Published online December 31, 2002; DOI: https://doi.org/10.35371/kjoem.2002.14.4.408

Abstract PDF: OBJECTIVES
Recently,tinea pedis has been reported to be a type of occupational dermatoses because of its high prevalence in specific working conditions.Although there is no doubt that the environment surrounding work places, the usual habits of workers etc are intimately related to this skin conditions, there is some controversy as to whether or not this condition is a real occupational illness and what is the exact cause of the high prevalence of this illness is. In this study, the prevalence of tinea pedis in workers from the shipbuilding industry was investigated andthe risk factors of this disease were evaluated. This study also aimed to verify whether or not tinea pedis is one of the occupational diseases.
METHODS
The results of interviews, questionnaires and clinical findings from 1,419 workers who visited the occupational health center for an annual routine check for their health state were analyzed.
RESULTS
Among the 1,419 workers, 778 workers (54.8%)had tinea pedis. By simple logistic regression analysis,the prevalence of tinea pedis was found to be affected by some variables, including the job category, the types of work,the kinds of footwear, whether or not they were using communal baths in the work places, and a family history of tinea pedis.In contrast, by multiple logistic regression analysis,only utilization of the communal baths in the work places and a family history of tinea pedis turned out to be statistically significant risk factors.
CONCLUSIONS
In this study, the major factors contributing to the high prevalence of tinea pedis are the use of communal baths in the workplace and a positive family history. However, the wearing of safety shoes was not statistically significant. Therefore, tinea pedis could not be confirmed to be an occupational disease. On the basis of these results, a solution to the environmental hygiene of communal baths and the personal hygiene of individuals needs to be improved in order to prevent tinea pedis.

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Evaluation of Finger Skin Temperature by Cold Provocation Test for Diagnosis of Hand-Arm Vibration Syndrome: Cheol In Yoo, Ji Ho Lee, Choong Ryeol Lee, Hun Lee, Young Hee Choi, Yang Ho Kim; Korean Journal of Occupational and Environmental Medicine 2002;14(2):124-133. Published online June 30, 2002; DOI: https://doi.org/10.35371/kjoem.2002.14.2.124

Abstract PDF

OBJECTIVES
Various objective tests have been widely used worldwide for diagnosing the hand-arm vibration syndrome. Among these, the cold provocation test has been frequently used to confirm the presence of Raynaud's phenomenon. This study was carried out in order to evaluate finger skin temperature by cold provocation test(10 degrees C for 10 minute) for the diagnosis of hand-arm vibration syndrome METHODS: Fifty-eight workers who had been exposed to local vibration were examined. Information concerning age, occupation, types of vibration tools used, presence of subjective symptoms such as vibration induced white finger(VWF), and numbness and tingling were collected. The subjects were classified into three groups according to their symptoms(Vascular, Neural, and No symptom group). In order to examine the applicability of the cold provocation test using water at 10 degrees C for 10 minute, we compared finger skin temperature between the groups.
RESULTS
The mean value of the finger skin temperature at 5 minutes and 10 minutes after cold provocation as well as the recovery rate in the vascular group were significantly lower than that seen in the other groups.
CONCLUSIONS
The evaluation of finger skin temperature by cold provocation test is very useful method for the diagnosis of hand-arm vibration syndrome. The test results will assist in confirming the diagnosis of the hand-arm vibration syndrome.

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The Health Effects of Whole Body Vibration
Soo-Jin Lee, Soo-Yong Roh
Journal of the Ergonomics Society of Korea.2013; 32(4): 297. CrossRef

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Hematological Changes and Immunological Function in Children Living Near the Petrochemical Estate in Ulsan: Choong Ryeol Lee, Cheol In Yoo, Ji Ho Lee, Hun Lee, Yang Ho Kim; Korean Journal of Occupational and Environmental Medicine 2001;13(2):127-140. Published online June 30, 2001; DOI: https://doi.org/10.35371/kjoem.2001.13.2.127

Abstract PDF: OBJECTIVES
To evaluate the hematological changes and the immunological function of children living near the petrochemical estate in Ulsan.
METHODS
The study subjects comprised of 238 children who consisted of 143 children living near the petrochemical estate and 95 children living in a suburban area. We conducted the hematological examination 3 times, in April, July and October. Also we evaluated the immunological function of some children in July. To confirm differences between schools repeated measures ANOVA of generalized linear model was done controlling age and sex as covariates.
RESULTS
The blood cell counts of children showed differences between schools in accordance with the survey month. The total WBC, neutrophil, and lymphocyte counts of children living in a suburban area decreased in July and increased in October again, but those of some children living near the petrochemical estate did not changed distinctly. The RBC counts of children living in a suburban area decreased in July and increased in October again, but those of some children living near the petrochemical estate decreased as time passed. The changes of the amount of hemoglobin of all study subjects were similar with those of RBC. The platelet counts of all study subjects decreased in July and increased in October again. In the generalized linear model, school was a significant independent variable for the total WBC, RBC, and platelet counts, and sex was a significant independent variable for the RBC counts. Age was a significant independent variable for the lymphocyte and platelet counts. P values of all blood cell were statistically significant in interaction variable between the survey month and school, and those of the total WBC, neutrophil, and lymphocyte counts were statistically significant in interaction variable between the survey month and age. The immunological function showed no significant difference between study groups.
CONCLUSIONS
The total WBC and RBC counts which would be easily affected by volatile organic compounds(VOCs) in the atmosphere showed differences between schools in accordance with the survey month. This suggests that the amounts of exposure to VOCs are different among each school children in different months. To ascertain the hematological changes by VOCs, an additional study evaluating the concentrations of atmosphere of VOCs and biological monitoring of some VOCs is needed.

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Impact of Solvent Exposure on the Occupational Hearing Loss: Ji Ho Lee, Young Ju Go, Hun Lee, Jung Hak Kang, Cheol In Yoo, Choong Ryeol Lee, Yang Ho Kim; Korean Journal of Occupational and Environmental Medicine 2000;12(4):537-546. Published online December 31, 2000; DOI: https://doi.org/10.35371/kjoem.2000.12.4.537

Abstract PDF

OBJECTIVES
This study was to evaluate the impacts of simultaneous exposure to noise and mixed solvents on workers'hearing threshold level (HTL) over five-year period.
METHODS
The study was conducted by interview and annual audiometric test on workers in ship building industry from 1994 to 1998. The cases(workers who exposed to noise and mixed solvent simultaneously) were 43 male workers and controls (workers who exposed to nolle) were selected by matching method with regard to age, sex, carrier, and noise exposure level. To assess the impacts of solvent exposure on hearing threshold level, with considering other factors, general liner model was used.
RESULTS
1. The audiogram of all subjects showed typical sensorineural hearing loss pattern. The mean HTLe were increased at high frequency (4000HB and 8000Hz) for study period. 2. The HTLs of cases were more increased than those of controls at high frequencies (4000Hz and 8000Hz), but there was not statlstical significance. 3. The impact of age on the HTL was statistically significant at 250Hz and 500Hz (p(0.05), and the impact of noise on the HTL was statistically significant at 250Hz, 2000Hz and 4000Hz (p(0.05), but the impact solvent exposure on the HTL was not significant. 4. The changes in HTLs of cases were higher than those of controls at high frequency, there were not statistical significance at 4000Hz, but only at 8000Hz (p=0.087). 5. Statistical analysis of the general linear model implicated that the changes in HTL was impacted by noise exposure bevel significantly (p=0.031) and Impacted by solvent exposure weakly (p=0.087) at 8000Hz.
CONCLUSIONS
The results of this study suggest that workers who simultaneously exposed to noise and mixed solvent were at risk for more affected HTL than those exposed to noise exposure only, but we could not find definitive evidence. Further detailed studies must be made in large number of workers.

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Occupational Hearing Loss in Korea
Kyoo Sang Kim
Journal of Korean Medical Science.2010; 25(Suppl): S62. CrossRef

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The Effect of Noise Exposure and Age on the Changes of Group Mean Hearing Threshold Level: Annual Follow-up Studies for Seven Years: Ji Ho Lee, Choong Ryeol Lee, Cheol In Yoo, Seung Rim Yaang, Ok Hyun Kim, Byung Mann Cho, Su Ill Lee, Don Kyoun Kim; Korean Journal of Occupational and Environmental Medicine 1999;11(2):137-152. Published online June 30, 1999; DOI: https://doi.org/10.35371/kjoem.1999.11.2.137

Abstract PDF

This study was carried out to evaluate the effect of noise exposure and age on the changes of group mean hearing threshold level(HTL) over 7-year period. For this purpose, consecutive annual audiometric tests were performed from 1991 to 1997. among 718 male employees of a metal product manufacturing factory. The subjects were divided four groups as follows according to noise level category(NLC). NLC-I officer, exposed noise level was under 60 dB(A) of time weighted average(TWA) NLC-JI technical assistant or engineer, they exposed to workplace noise occasionally NLC-IJJ worker, exposed noise level was below 85 dB(A) of TWA. wore hearing protection device(earmuff or earplug) NLC-IV worker, exposed noise level was over 85 dB(A) of TWA, wore hearing protection device(earmuff and earplug). The results were as follows 1. The improvement of group mean HTL was continued until the fifth year, showing the peak at the third year. The magnitudes of this learning effect were 1.5 - 4.6 dB. 2. The mean HTL of each age group tended to increase after the third year and the tendency was more prominent at 4000 Hz. 3. In noise exposed group(NLC-II, III, and IV), mean HTL increased from the third year after decreasing, meanwhile, in noise free group(NLC-I). it was few changed for the entire period. Among the noise exposure group, the mean HTL of NLC-IV was lower than that of NLC-III and NLC-IV. 4. After learning effect, the mean increase of HTL in noise free group(NLC-I) was 0.4-1.7 dB that suggests aging effect, and that in noise exposure group(NLC-ll, III, and IV) was 0.9 -4.1 dB that suggests noise effect. 5. Statistical analysis of the general linear model implicated that the effect of age was statistically significant at 500, 3000, 4000 and 6000Hz. and the effect of noise exposure was statistically significant at all frequencies except 6000Hz. However, the age * noise interaction was not significant at all frequencies. From these results, it was concluded that the effect of age and noise exposure seems to affect the mean HTL independently and these two factors contribute to an additive effect for the mean HTL change. Furthermore, more concerns should be needed for hearing conservation of low level exposures without any specific protection.

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For 5-years the Longitudinal Study on the Effect of Noise Exposure and Aging to the Changes of Hearing Threshold Level
Chang Ho Chae, Ja Hyun Kim, Jun Seok Son
Journal of Korean Society of Occupational and Environmental Hygiene.2015; 25(4): 573. CrossRef
Prevalence and Risk Factors of Hearing Loss Using the Korean Working Conditions Survey
Kyoo Sang Kim, Oh Jun Kwon
Korean Journal of Audiology.2012; 16(2): 54. CrossRef
Cohort study for the effect of chronic noise exposure on blood pressure among male workers in Busan, Korea
Ji Ho Lee, Weechang Kang, Seung Rim Yaang, Nari Choy, Choong Ryeol Lee
American Journal of Industrial Medicine.2009; 52(6): 509. CrossRef

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Nasal Septum Perforation of Welders: Choong Ryeol Lee, Cheol In Ryu, Ji Ho Lee, Jeong Hak Kang, Seong Kyu Kang, Jung Sun Yang, Yong Cheol Shin; Korean Journal of Occupational and Environmental Medicine 1998;10(3):404-411. Published online August 31, 1998; DOI: https://doi.org/10.35371/kjoem.1998.10.3.404

Abstract PDF

Six cases of nasal septum perforation were found among welders during periodic physical checkup in 1997. Considering the size, shape and margin, the perforations were assumed to have been occurred several years before of which the diameter were 8~15 mm. To investigate the cause of perforation, we reviewed the past history of preemployment, the results of annual working environment survey and the material safety data sheets of welding rods and steels with which they have dealt, and analyzed the concentration of several metals of welding fume and the concentration of blood and urinary chromium. In the result, we presupposed that the nasal septum perforations of welders were due to chronic exposure to low level hexavalent chromium and/or nickel, and report these cases with literatures review.

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Changes of Glycoconjugate Expression in Nasal Respiratory Mucosa of Rats Exposed to Welding Fumes
Gil Nam Jeong, Un Bock Jo, Il Je Yu
Inhalation Toxicology.2007; 19(12): 987. CrossRef
Effects of repeated welding fumes exposure on the histological structure and mucins of nasal respiratory mucosa in rats
Gil Nam Jeong, Gi Jin Jo, Un Bock Jo, Il Je Yu
Toxicology Letters.2006; 167(1): 19. CrossRef

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Type of Anemia Due to Organic Solvents: Choong Ryeol Lee, Cheol In Ryu; Korean Journal of Occupational and Environmental Medicine 1998;10(2):180-188. Published online May 31, 1998; DOI: https://doi.org/10.35371/kjoem.1998.10.2.180

Abstract PDF: The purpose of this study Is whether we can presuppose the correlation between some type of anemia and exposure to organic solvents using some hematologic index such as MCV, RDW and MCHC. The authors conducted the hematological examination of 160 male workers who were exposed organic solvents and those of 167 control workers. The type of anemia was slightly macrocytic anemia, and the RDW was generally homogenous in workers exposed to organic solvents whereas those of control were normocytic and homogenous.

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A Study on the Hematologic Changes of Workers Exposed to Mixed Organic Solvents: Choong Ryeol Lee, Cheol In Ryu; Korean Journal of Occupational and Environmental Medicine 1997;9(4):549-564. Published online December 31, 1997; DOI: https://doi.org/10.35371/kjoem.1997.9.4.549

Abstract PDF: The purpose of this study is to evaluate the hematological changes of workers exposed to mixed organic solvents and to search the organic solvent that bring out these changes. The study participants were 1,605 workers, consisting 1,088 workers (male 989, female 99) exposed to mixed organic solvents and 517 non-exposed workers (male 431, female 86). The authors analyzed the results of complete blood count and differential count of leukocytes of all the workers and examined all of the material safety data sheets of substances with which they dealt and the results of their working environmental surveys during the last 3 years. The results were as follows: 1. The mean values of complete blood count in workers exposed to mixed organic solvents were lower than that of non-exposed workers in WBC, RBC, hemoglobin and hematocrit in cases of male and RBC, hemoglobin and hematocrit in cases of female, but the mean value of platelet count in male exposed workers and WBC count in female exposed workers were higher than those of non-exposed workers. 2. The distribution of differential count of leukocytes showed no difference between exposed workers and non-exposed workers. 3. The correlation coefficients between age and duration of employment and WBC showed statistically a positive value and that between age and duration of employment and RBC, hemoglobin, hematocrit showed a statistically negative value in cases of male exposed to mixed organic solvents. But in cases of female there was no statistical correlation between them. 4. In cases of male the proportions of workers with subnormal levels of WBC, RBC, hemoglobin, hematocrit and platelet according to the standard of classification were high or than those of non-exposed workers. The proportions of exposed workers were 3.6 %, 18.6 %, 5.3 %, 32.7 % and 1.4 % respectively and those of non-exposes workers were 2.8 %, 10.7 %, 2.1 %, 13.9 % and 0.2 % respectively. 5. In cased of female the proportion of workers with subnormal levels of RBC, hemoglobin and hematocrit according to the standard of classification were higher than those of non exposed workers. The proportion of exposed workers were 42.4 %, 55.6 % and 41.4 % respectively and those of non-exposed workers were 10.5 %, 11.6 % and 8.1 % respectively. 6. The number of substances with which workers exposed to mixed organic solvents dealt were about 500, and 22 organic solvents such as xylene, toluene, isopropyl alcohol, 2-ethoxyethanol and 2-ethoxy ethyl acetate were main components of substances according to the material safety data sheet and working environmental surveys during the last 3 years. The authors suspect 2-ethoxyethanol and 2-ethoxy ethyl acetate of the organic solvents, which bring out the hematological changes of workers exposed to mixed organic solvents. As a result of this study, the authors confirmed the hematological changes of workers exposed to mixed organic solvents and recommend : strict management of working environment, working time and the protective equipments of workers exposed to mixed organic solvents.

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A Study on the Urinary Metabolites and Sister Chromatid Exchanges of Peripheral Lymphocytes in Workers Exposed to the Organic Solvents: Don Kyoun Kim, In Kyung Hwang, Cheol In Ryu, Su Il Lee, Kap Yul Jung, Yong Hwan Lee, Choong Ryeol Lee, Won Il Hyun, Suk Bong Kim, Yong Duk Jeon; Korean Journal of Occupational and Environmental Medicine 1990;2(1):75-83. Published online February 28, 1990; DOI: https://doi.org/10.35371/kjoem.1990.2.1.75

Abstract PDF: In order to know the possibility of utilizing the sister chromatid exchanges as an index which could evaliiate the effect of organic solvents on Lhe health in industrial workers, the authors Studied the effects of the inductivity of sister chromatid exchanges in peripheral lymphocyces from 90 female workers espoxed to organic solvents .and 20 lion-exposed female workers. The results obtained were as follows: 1. The frequency of sister chromatid exchanges in peripheral iympnocytes from 90 female workers exposed to organic solvents was significantly increased in comparison with 20 coatiol subiect. 2. The frequency of sister chromatid exchanges was significantly Increased in the workers who were employed in the manufacture of plastic materials than the other manufactures. 3. There were no significant differences in the frequency of sister chrornatid exchanges by carriera of the exposed workers. 4. The correlation between the frequency of sister chromatid exchanges and urinary hippuric acid was significant with the coefficient of 0.5902 showing Y=1.867X+15.188 in which Y indicate the frequency of sister chromatid exchanges per cell and X indicate the urinary hippuric acid concentration by g/l.

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