유기용제노출이 직업적 청력손실에 미치는 영향

이지호,고영주,이헌,강정학,유철인,이충렬,김양호 大韓産業醫學會 2000 대한직업환경의학회지 Vol.12 No.4

목적 : 산업 장에서 노출되는 유기용제가 청력역치에 어떠한 영향을 미치는가를 5년 동안의 추적조사를 통하여 파악하고자 하였다. 방 법 : 유기용제와 소음에 동시에 노출된 근로자 43명과 소음노출수준, 연령, 근무경력을 짝짓기 한소음노출군을 대상으로 문진과 이경검사, 소음노출 수준, 유기용제노출수준을 조사하였다. 결과 : 1. 전체 근로자의 각 주파수별 청력역치 변화양상에서 500Hz∼2000Hz에서는 추적기간 동 소음동안 현저한 변화가 없었고, 4000Hz 및 8000Hz에서는 역치가 증가하는 경향을 나타내었다. 2.유기용제와 소음에 동시에 노출된군에서 소음 노출군에 비해 4000Hz 이상에서 청력역치가 높게 나타났으나, 통계적인 유의성은 없었다(p(0.05). 3.반복측정 분산분석 법으로 각 주파수별 평균청력 역치의 연차적 변화에 미치는 영향을 분석한 결과 유기용제 노출은 통계적으로 유의한 영향이 없었으나(p)0.05), 소음노출수준은 250Hz, 2000Hz 및 4000Hz에서, 연령은 250Hz와 500Hz에서 통계학적으로 유의한 영향을 미치는 것으로 나타났다(p(0.05). 4.소음노출군파 동시노출군 각각에서의 청력역치 변화량을 paired t-test로 비교한 결과 250Hz∼4000Hz에서는 통계학적 유의성이 없었으며(p(0.1), 8000Hz에서만 경계치 (p=0.0884)의 유의성을 나타내었다. 5.요인들의 영향을 보정한 상태에서 관찰하기 위해 관찰기간동안의 청력역치변화량을 종속변수로 두고 일반선형모형을 이용하여 주파수별로 관찰한 결과 8000Hz에서만 모델에 통계학적 유의성이 있었으며 (p(0.05), 여기서 소음노출수준이 통계학적으로 유의한 영향을 미치는 것으로 나타났고(p(0.05), 유기용제노출은 경 계수준이 었다(p=0.087). 결론 : 청력에 대한 유기용제의 영향이 소음과 연령에 비해 상대적으로 미미하여 명확한 결론에 이르지는 못하였으나, 다소 영향이 있는 것으로 생각되어 유기용제의 영향에 대한 추가연구가 필요할 것으로 판단된다. 또한 보다 효과적인 근로자들의 청력관리를 위해서는 소음 외 산업 장에서 동시에 노출되는 여러 유해물질들을 고려하여야 할 것이다. 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.

울산 석유화학공단 인근 어린이들의 혈액상변화 및 면역기능

이충렬,유철인,이지호,이헌,김양호 대한산업의학회 2001 대한직업환경의학회지 Vol.13 No.2

목적 : 지역 특성상 휘발성 유기화합물, 분진, 악취 등 환경오염의 영향을 많이 받는 것으로 추정되는 울산석유화학공단 인근 어린이들의 혈액상 변화, 계절 차이에 의한 혈액상 변화와 면역기능에 미치는 영향을 평가하기 위하여 본 연구를 실시하였다. 방법 : 2000년 4월, 7월, 10월 3회에 걸쳐 석유화학공단 인근 A 초등학생 46명(남자 32명, 여자 14명), B 초등학생 97명(남자 49명, 여자 48명)과 교외지역의 A 초등학생 95명(남자 47명, 여자 48명)을 대상으로 일반혈액검사, 백혈구 백분율 검사를 실시하였으며 7월 조사 때는 B 및 C 초등학생 11세 남자 각각 25명을 대상으로 면역학적 기능검사를 실시하였다. 결과 : 3차례에 걸쳐 진행된 검사결과는 계절별로 다른 양상을 보여 주었다. 즉, 총백혈구수, 호중구수, 림프구수는 A와 C 초등학생은 7월 조사에서는 감소되었다 다시 10월 조사 때는 다시 증가하는 경향을 보여주며, B초등학생은 계절별 변화가 거의 없는 것으로 나타났다. 적혈구수는 B와 C 초등학생은 7월 조사시 감소되었다가 10월 조사 때는 다시 증가하는 양상을 보여주나 A 초등학생은 갈수록 감소하는 경향을 보여주었다. 혈색소량의 변화는 적혈구수의 변화와 유사하였다 혈소판수는 모두 7월 조사 때는 감 소되었다가 10월 조사 때는 다시 증가하는 양상을 보여주었다. 조사시기에 따라 각 학교 어린이들간에 혈구세포수의 차이가 있음을 구명하기 위하여 generalized linear model의 repeated measures ANOVA를 시도한 결과 연령과 성을 공변인으로 보정한 후의 P 값에서 조사시기의 차이와 학교간 차이의 교호작용변수(interaction variable)는 모든 혈구세포에서 유의한 것으로 나타났다(P<0.05). 이는 조사시기에 따라 각 학교어린이들간에 혈구세포수의 차이가 유의하게 다르다는 것을 의미한다. 면역기능 평가를 위하여 혈중 immunoglobulin 측정 및 림프구 아형 분포분석을 B 및 C 초등학생 6학년 남학생 각 25명, 총 50명을 대상으로 실시하였으나 모두 정상범위이었고 학교간 차이도 없었다. 결론 : 휘발성 유기화합물 같은 물질에 쉽게 영향을 받을 수 있는 백혈구와 적혈구 등의 혈구세포는 조사시기에 따라 각 학교어린이들간에 혈구세포수의 차이가 유의하게 나타남은 각 학교 어린이들간에 조사시기에 따라 혈구세포수에 영향을 주는 휘발성 유기화합물의 노출량의 차이가 중요한 원인 중 하나일 것으로 추정된다. 향후 혈구세포의 변화의 원인이라 추정되는 휘발성 유기화합물의 기중 농도측정이나 체내 생체지표검사를 통한 노출원 조사를 병행하는 추가적 조사가 필요한 것으로 사료된다. 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 iymphocyte 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 iymphocyte 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.

조선업 근로자의 족부백선 유병률 및 관련 요인

서호석,유철인,이충렬,이지호,김양호,이원신,최지호,성경제,고재경,문기찬 大韓産業醫學會 2002 대한직업환경의학회지 Vol.14 No.4

목적: 울산지역에 소재한 대규모 조선업종 근로자 1,419명을 대상으로 족부백선의 유병률을 조사하고 족부백선의 유병률에 미치는 요인을 조사하여 족부백선의 작업관련성을 알고자 본 연구를 실시하였다. 방법: 근로자 건강진단시 족부백선의 유뮤를 확인하고, 현재 족부백선의 위험인자로 알려져 있는 여러 요인들과 작업, 환경적인 요인들에 대하여 설문조사를 실시하고, 족부백선의 임상적인 양상을 관찰하였다. 결과: 조사결과 족부백선의 유병률은 54.8%로 높게 나타났으며, 직종과 공동목욕탕 이용 유무, 안전화 착용유무, 작업형태, 가족력 유무가 족부백선이 유병률에 영향을 미치는 위험인자로 나타났으나, 다변량 분석결과 가족력과 공동목욕탕 이용만이 통계적으로 유의한 위험인자로 나타났으며(P<0.05), 안전화 착용은 통계적으로 유의하지 않았다. 결론: 이상의 결과에서 사업장내 근로자들의 족부백선의 높은 유병률과 관련된 직접적인 요인은 사업장내의 공동 목욕탕의 이용 여부와 족부백선의 가족력임을 확인할 수 있었으며, 많은 근로자들이 원인으로 지목한 안전화의 착용은 통계적인 유의성은 없었다. 따라서 족부백선이 작업과 직접적으로 관련되었다는 근거는 적은 것으로 보인다. 하지만 일반인보다 높은 유병률을 보이는 것으로 확인된 사업장내 족부백선의 유병률을 감소시키기 위해서는 위험인자로 최종 확인된 작업장 내의 공동 목욕탕의 철저한 위생관리와 함께 가족간의 감염을 예방히기 위한 개인위생관리가 필요하면, 비록 통계적인 유의성은 없었으나 여러 근로자들이 원인으로 지목한 안전화의 개선에도 노력해야 할 것으로 생각한다. Objectives: Recently, tinea pedis has been reprted 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 erc ate intimately related to this skin conditions, there is some controversu 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 result 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 e affected by some variables, including the jov 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 facrors. 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 bats and the personal hugiene of individuals needs to be improved in order to prevent tinea pedis.

부산, 울산, 경남지역 직업병감시체계에서 나타난 수지진동증후근의 역학적 특성

최영희,유철인,이지호,이충렬,이헌,김영욱,채창호,고상백,김은아,이유진,김양호 大韓産業醫學會 2003 대한직업환경의학회지 Vol.15 No.3

목적: 국내에서도 국소진동에 의한 수지진동증후군이 다수 있을 것으로 추정하나 최근에 이에 대한 보고가 적어 부·울·경 직업병감시체계를 통하여 수지진동증후군에 대한 환례를 수집하여 이의 역학적 특성을 밝히고자 본 연구를 실시하였다. 방법: 2001년 44월부터 2002년 12월까지 부산, 울산, 경남지역에 있는 종합병원 9곳을 통하여 특수 건강진단과 산업의학과 외래를 방문한 근로자를 대상으로 진동폭로에 대한 설문조사를 실시하고 이들중에서 수지진동으로 인한 증상을 호소하는 근로자는 이학적 검사와 Stockholm workshop scale을 이용하여 수지진동증후군이 있는지 평가하였다. 결과: 남자 188명, 여자 4명 등 총 192례의 수진진동증후군이 의심되는 환례를 수집하였으며, 업종별로는 조선업에 종사하는 근로자들이 가장 많았다. 국소진동의 주된 폭로원은 그라인더가 가장 많았으며, 혈관장해로 인한 증상보다 감각신경성 장해로 인한 증상을 많이 호소하였다. 결론: 전국적으로 조선업종의 그라인더 사용자를 중심으로 많은 수의 수지진동증후군의 환자가 있을 것으로 추정되며, 이들에 대한 예방대책을 마련하기 위하여 전국규모의 정확한 유병률 조사 및 실태파악이 필요한 것으로 판단된다. Objects: 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-relatd HAVS and other occipational 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 subkective 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 exposire. Symptoms of neurological disorder were more common than those of vascular disprder. 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.

한국 정신장애의 역학 조사 연구[I] : 각 정신장애의 유병률

조맹제,함봉진,김장규,박강규,정은기,서동우,김선욱,조성진,이준영,홍진표,최용성,박종익,이동우,이기철,배재남,신정호,정인원,박종한,배안,이충경 大韓神經精神醫學會 2004 신경정신의학 Vol.43 No.4

Objectives : This study aims to estimate the prevalence of the DSM-IV psychiatric disorders in Korean population using the Korean version of Composite International Diagnostic Interview (K-CIDI). Methods : Subjects were selected by taking multi-stage, cluster samples of 7,867 adult household residents, 18 to 64 years of age, in ten catchment areas. Total 78 trained interviewers administered the K-CIDI to the selected respondents, from June 1 to November30,2001. Results : Total 6,275 respondents completed the interview. Some 33.5% of respondents reported at least one lifetime disorder, 20.6% reported at least one-year disorder, and 16.7% reported at least one-month disorder. The most common lifetime disorders were alcohol abuse/dependence (17.24%), nicotine dependence/withdrawal (11.19%), specific phobia (5.16%), and major de-pressive disorder (4.25%). The lifetime prevalence of substance abuse/dependence (0.25%) and schizophrenia (0.16%) was very low. Nicotine and alcohol use disorder showed very high male/female ratio. Mood disorder and anxiety disorder were more prevalent among female than male. Conclusion : The prevalence of psychiatric disorders was high. In comparison with other studies, remarkable differences in distributions of psychiatric disorders across the areas and times were observed.

인체 B 림프구 활성화의 신호전달과정에서 IL-4 수용체와 CD40 분자간의 상호작용

이충은,윤석란,변광호 大韓免疫學會 1995 大韓免疫學會誌 Vol.17 No.3

Stimulation of B cells through CD40 antigen has been reported to agument the interleukin-4(IL-4)induced B cell proliferation and differentiation. In order to elucidate mechanisms underlying the synergistic action, we examined the effect of CD40-mediated signal on the IL-4-induced B cell activation. Treatment of dense, resting tonsillar B cells with agonistic anti-CD40 mAb caused a noticeable induction of IL-4 receptor(IL-4R) mRNA expression within hours, which was followed by a significant enhancement of the IL-4-induced surface IL-4R and CD23 expression, suggesting a role of CD40 in amplifying the IL-4-induced signal. Signal interplay between the IL-4 and the CD40 system was further supported by the observation that, in tonsillar B cells, IL-4 plus anti-IgM induced CD40 expression and tyrosine phosphorylation of IL-4R, and that anti-CD40 co-immunoprecipitated the IL-4R and the IL-4R associated tyrosine kinase activity, which implies a possible molecular interaction between IL-4R and CD40. Together these results suggest that there is a cross-talk between CD40-and the IL-4R-mediated signal transduction system during the T cell-dependent B cell activation.

통신상품간 시장잠식현상과 경쟁도입의 효과분석

이상호,정충영,이현우 한국경영과학회 1996 한국경영과학회지 Vol.21 No.1

We consider a consumer self-selection model in which a regulated firm faces two market segmants wig differing valuation of quality of telecommunication services and examine some economic implications from the behaviors of the firm. In the context of a regulated monopolist, even though the results depend on the degree of privatization, the firm could lower the quality of the low-end model and reduce the price of the high-end in order to alleviate cannibalization. This justifies the provision of universal service policy in the telecommunications market. Based on this self-selection model, we also analyze an extended model of product introduction and show that the monopolist will introduce new product with the same introduction time of social planner. However, when we consider competition among firms, the market equilibrium may not guarantee the efficient time of product introduction.

1989-2000년의 5, 12세 한국아동의 치아우식실태에 관한 조사연구

이춘희,최충호,권호근 대한구강보건학회 2003 大韓口腔保健學會誌 Vol.27 No.1

The objective of this study was to analize the change of dental caries prevalence in Korean children and adolescents from 1989 to 2000. National oral examination survey reports in 1989,1991,1995 and 2000 were collected for this purpose The major finding were summerized and the results were as follows : 1. The dft of 5-year-old children in creased from 1989 to 1995 and decreased slightly from 1995 to 2000 the dt decreased or remained constant and the ft increased. 2. The dt of 5-year-olds decreased constantly by 1991 in rural area but in urban area, it remained stable by 1991 and the ft increased in rural and urban area. 3. The DMFT of 12-year-old children increased from 1989 to 2000 the DT decreased of remanined constant and the FT increased, the MT remained below 0.05 4. The DT index of 12-year-olds decreased constantly by 1991 in rural area but in urban area, it remained stable by 1991 and FT index increased in rural and urban area 5. The percentage of caries free and caries experience have increased in rural and urban area. According to results the dft of 5-year-olds and the DMFT of 12-year-olds have increased specially among the component of dft and DMFT dt and DT decreased or remain stable while ft and FT increased constantly which means that the restorative index(ft/dft, FT/DMFT) increased also and the percentage of caries experience increased. Based on this study, preventive approach is more required to lower caries prevalence of korean childeren

시험 스트레스시 적대감이 혈청 코르티솔 농도와 혈압 및 맥박에 미치는 영향

이충원,박정호 啓明大學校 醫科大學 1995 계명의대학술지 Vol.14 No.4

This study was designed to test the hypothesis that the students with high hostility scores were associated with higher serum cortisol vlevels, and higher responsivity of blood pressure and pulse rate, under the written examination stress in comparison to the students with lower hostility scores. Fifty two medical students gave informed consents to participate in the study. Hostility levels were measured by the Cook-Medley hostility scale, and the response variables were serum cortisol, systolic and diastolic blood pressures, and pulse rates. Coo-Medley hostility scale were administered about one month prior to examination, Serum cortisol levels, systolic and diastolic blood pressures, and pulse rats were measured three times durung the experimental period, about one month before examination, during examination and about one month after examination, respectively. Serum cortisol levels were measured in duplicates by the Coat-A-count radioimmunoassay procedure(??I) and blood presures and pulse rates were measured by two standardized automatic sphygomomanometers. The response variables compatible with the hypothesis were serum cortisol and pulse rate in Cook-Medley hostility tatal scores where serum cortisol concentration of the student with low total scores was 9.43±μ21.82 g/dl and that of the students with high total scores was 9.56 ±2.97 ㎍/dl before examintion. The former showed little changes(9.36±2.34 ㎍/dl) but the latter did a marked increase(11.14±2.14 ㎍/dl) during examination and the serum cortisol levels of both returned to the baseline levels after examination(Period and periodXsubjects effects, p<0.05). And serum cortisol in cynicism subsets and pulse rate in paraniod aliennation subset of Costa et al's two subsets and serum cortisol, systolic blood pressure in social avoidance subset of Barefoot et al's six subsets were compatible with the hypothesis. Serum cortisol levels showed a borderline significance with cynicism subset of Barefoot et al's (0.05<p<0.1). These results suggest that total scores and some subsets of Cook-Medley's hostility scale may be involved in the biomechanism between hostility and coronary heart disease.

푸리에공간에서 위상정보를 이용한 패턴인식과 그 응용에 관한 연구

이원경,이충호 한밭대학교 정보통신전문대학원 2003 정보통신전문대학원 논문집 Vol.1 No.1

This thesis studies on the pattern recognition algorithms in Fourier domain and proposes two improved methods. Three methods are studied on and the performances of them are compared and applied to the pattern recognition of printed numbers in the car-licence plate, and two improved methods are proposed in this application field. The first method which uses the correlation in Fourier domain, and the second method uses only the central part of correlation-images, and the third, phase-only-correlation method, uses only the phase of images. The conventional method which uses the correlation as it is shows the low performance, the proposed method adopted the algorithm which uses the central part only in the correlation-images. In particular, the performance of this method can be improved by applying the algorithm to the black and white images after preprocessing. As well as this method, for the phase-only-correlation method, the performance of recognition can be increased by multiplying an appropriate constant to the amplitude before inverse Fourier transformation. The phase-only-correlation method recognizes the patterns by the magnitude of peak which appears at the center of the image which is obtained by inverse Fourier transformation of the correlation images which consists of phases only. Two methods also shows the high performance in the recognition of numbers which includes noises. In the experimentaion, 10 standard images and 10 number-images in the car-licence plate are used. The black-and-white images from the images and the images with Gaussian noises are also used. The experimental results show the proposed methods are very valid to the recognition of numbers in car-licence plate and they shows higher performance for black-and-white images.