- Cohort Study for the Effect of Chronic Noise Exposure on Blood Pressure among Male Workers.
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Ji Ho Lee, Tae Joon Cha, Jang Rak Kim, Weechang Kang, Seung Rim Yaang, Choong Ryeol Lee, Cheol In Yoo
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Korean J Prev Med. 2002;35(3):205-213.
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Abstract
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Whether exposure to chronic noise induces an increase in blood pressure, or the development of hypertension, has not been established. A cohort study was performed to identify the effects of chronic noise exposure on blood pressure. METHODS: 530 males working at a metal manufacturing factory in Busan, Korea were enrolled for the study. They were monitored for 9 consecutive years, from 1991 to 1999, with an annual health check-up. The subjects were divided into 4 groups, which were determines by noise level categories(NLC) according to noise intensity ; NLC-I: office workers, exposed to noise a level below 60dB(A); NLC-II: field technical supporters or supervisors, frequently exposed to workplace noise, wearing no hearing protection device; NLC-III: workers, exposed to workplace noise below 85 dB(A), wearing ear plugs or muffs; NLC-IV: workers, exposed to workplace noise over 85 dB(A), wearing both ear plugs and muffs. RESULTS: After controlling possible confoundens, such as baseline age, smoking, alcohol intake, exercise, family history of hypertension, systolic(SBP) or diastolic blood pressure(DBP) and changes in BMI (body mass index), the pooled mean for the systolic blood pressures, over the duration of the study period, were 3.8mmHg, 2.0mmHg and 1.7mmHg higher in NLC-IV, NLC-III NLC-II groups, respectively, than in the NLC-I group. There were no significant differences in the diastolic blood pressures between the groups. CONCLUSION: This study suggests that chronic noise exposure increases systolic blood pressure independently, among male workers.
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- Trend of the Changes in the Level of Blood Lead, Urinary Arsenic and Urinary Cadmium of Children in Ulsan: 3-year Follow-up Study.
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Choong Ryeol Lee, Cheol In Yoo, Ji Ho Lee, Hun Lee, Yangho Kim
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Korean J Prev Med. 2001;34(2):166-174.
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Abstract
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To obtain basic data on blood lead level and urinary level of arsenic and cadmium of children living near a petrochemical estate and a suburban area in Ulsan, Korea and to observe the trend of the changes in the level of these metals in these children. METHODS: The study subjects comprised 626 children living near a petrochemical estate and 299 children living in a suburban area of Ulsan. We analyzed the level of lead, arsenic and cadmium using atomic absorption spectrometer. RESULTS: The mean levels of blood lead in children living near the petrochemical estate were 5.25 microgram/dl, 5.24 microgram/dl, and 7.24 microgram/dl in the years 1997, 1999, and 2000, respectively, whereas those of children living in the suburban area were 3.81 microgram/dl, 4.75 microgram/dl, and 7.19 microgram/dl respectively. The mean levels of urinary arsenic in children living near the petrochemical estate were 4.57 microgram/g creatinine, 4.78 microgram/g creatinine, and 6.02 microgram /g creatinine in the year 1997, 1999, and 2000 respectively, whereas those of children living in suburban area were 2.35 microgram/g creatinine, 4.75 microgram/g creatinine, and 7.07 microgram/g creatinine, respectively. The mean levels of urinary cadmium in children living near the petrochemical estate were 1.15 microgram/g creatinine, 1.05 microgram/g creatinine, and 1.71 microgram/g creatinine in the year 1997, 1999, and 2000, respectively, whereas those of the children living in the suburban area were 0.74 microgram/g creatinine, 1.29 microgram/g creatinine, and 1.48 microgram/g creatinine, respectively. There were increasing trends in the level of blood lead, urinary arsenic and cadmium of children in Ulsan, and the differences in the level of these metals were disappearing between the children living in other areas year by year. CONCLUSIONS: These results suggest that the amount of exposure to lead, arsenic, and cadmium is increasing from year to year, and there is a need for periodic biological and atmospheric monitoring of these metals in Ulsan.
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Summary
- Respiratory Health of the Children Living near the Petrochemical Estate in Ulsan.
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Choong Ryeol Lee, Cheol In Yoo, Ji Ho Lee, Yangho Kim
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Korean J Prev Med. 2000;33(2):174-183.
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Abstract
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To evaluate the effect of low-level exposure of air pollutants on the respiratory tract of the children living near the petrochemical estate in Ulsan. METHODS: The study design was cross-sectional, and the study subjects consisted of 150 children(76 boys, 74 girls) living near the petrochemical estate and 100 children(53 boys, 47 girls) living in a suburban area. We investigated respiratory health using self-administered questionnaires(ATS-DLD-78), radiological examination, and pulmonary function test such as FVC and FEV1. RESULTS: There were higher prevalence rates of respiratory symptoms in the children living near the petrochemical estate than the children living in a suburban area. And the results of FVC and FEV1 of 11-years old children living near the petrochemical estate were lower than those of the children living in a suburban area. CONCLUSIONS: Chronic exposure of low-level air pollutants would affect respiratory health of the children. Therefore, further a longitudinal study of respiratory health will be needed for children living near the petrochemical estate in Ulsan.
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Summary
- Hematological Changes of Welders.
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Choong Ryeol Lee, Cheol In Yoo, Ji Ho Lee, Jeong Hak Kang, Hun Lee
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Korean J Prev Med. 1999;32(2):141-146.
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Abstract
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To ascertain whether some result of hematological examination could be as reference data for health management of welders. METHOD: The authors conducted the hematological examination of 1,018 welders and 531 control workers of a shipbuilding industry in Ulsan using automatic blood analyzer. RESULTS: The WBC count of welders was lower than that of control on controlling the age and the duration of employment, but changes of other blood cells were not observed. CONCLUSION: We could use the results of hematological examination such as WBC counts as an indicator for subtle changes of health status of welders.
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Summary
- Urinary Levels of Arsenic, Cadmium, and Zinc of Children in Ulsan Industrial Area.
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Choong Ryeol Lee, Cheol In Ryu, Ji Ho Lee, Sung Ryul Kim, Jin Young Jeong
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Korean J Prev Med. 1999;32(1):1-8.
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We conducted this study to obtain basic data of urinary levels of arsenic, cadmium, and zinc in children of Ulsan industrial area and to evaluate the difference in urinary levels of these metals between industrial area and suburban area. METHODS: The study subjects were composed of 348(male 182, female 166) school children residing in industrial area and 100(male 50, female 50) school children of suburban area. We analyzed urinary levels of arsenic, cadmium, and zinc using atomic absorption spectrophotometer. RESULTS: The geometric means of urinary levels of arsenic, cadmium, and zinc of study participants were 3.69, 0.99, 282.49 microgram/L respectively. The adjusted geometric means of urinary levels of arsenic, cadmium, and zinc of study participants were 3.92, 1.05, 299.92 microgram/g creatinine respectively. CONCLUSIONS: The children residing in industrial area had the higher urinary levels of arsenic and cadmium than suburban children with statistical significance(p<0.01).
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Summary
- Blood Lead Levels of Children in Ulsan Industrial Area.
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Cheol In Yoo, Ji Ho Lee, Choong Ryeol Lee, Sung Ryul Kim, Seon Ho Lee
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Korean J Prev Med. 1998;31(2):240-248.
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- We conducted this study, to obtain basic data of lead concentrations in children of Ulsan industrial area and to evaluate the difference in blood lead levels between industrial area and suburban area. The study subjects were composed of 348 school children residing in industrial area and 100 school children of suburban area. There is no difference in age and sex distribution of study participants between industrial and suburban area. The obtained results were as follows: l. The geometric means of blood lead levels of study participants were 4.90 ng/dl, which is lower than current acceptable value 10 ng/dl. 2. The children residing in industrial area had the higher blood lead levels(5.26 ng/dl) than suburban children(3.81 ng/dl) with statistical significance(P<0.001).
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Summary
- A Study on the Size of Dust in Workplaces of a Shipyard.
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Choong Ryeol Lee, Cheol In Ryu
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Korean J Prev Med. 1998;31(1):104-111.
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- To obtain the basic information that can be used as a factor for explaining the diversity of welders' pneumoconiosis, the authors measured the concentrations of dust according to the size of dust in 71 workplaces of a shipyard where welders' pneumoconiosis have occurred. The concentrations of dust according to the size of dust showed no difference between workplaces regardless of kinds of work.
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Summary
- A Study on the Validity of Filter Paper Method in Estimation of the Amount of Daily Salt Intake.
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Choong Ryeol Lee
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Korean J Prev Med. 1987;20(2):341-351.
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Abstract
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- For the purpose of the determination of the most proper sampling time on using spot urine which can represent the general status of electrolytes in 24 hour urine and for test of the validity of filter paper method which was developed recently in estimation of the amount of daily salt intake, the author investigated this study by different sampling time and various measuring methods in 21 healthy men and 12 women. The summarized results were as follows; 1) The mean excretion amount of urinary electrolytes were Na 3.93 g/l, K 1.47 g/l, and creatinine 1.08 g/l in male, and Na 3.83 g/l, K 1.86 g/l, and creatinine 0.99 g/l in female. 2) In using spot urine for estimation of the amount of daily salt intake, morning urine was the most approximate to that of 24 hour urine in both sexes. 3) There was validity in estimation of daily salt intake by filter paper method using spot urine instead of 24 hour urine. 4) The estimated amounts of daily salt intake in male was higher than the values in female as 16.04-16.22 g and 13.35-13.82 g respectively.
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