• 한국대기환경학회지
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• 제17권5호
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• pp.425-437
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• 2001

This study is based on the uses meta-analysis methodology to examine the statistical consistency and importance of random variation among results of epidemiologic studies between air pollutants exposure and childhood asthma. Studies for this meta-analysis were conducted by reviewing previous results and by asking researcher active in this field for recommendations. Overall, 10 cases of air pollutants exposures and childhood asthma were reviewed. A variety of statistical methods for meta-analysis have been used to assess the combined effects, to identify heterogeneity, and to provide a single summary risk estimate based on a set of simiar epidemiologic studies. In this study, classification of exposure metircs on air environmental epidemiologic studies are reported for (1) aggravation of childhood asthma by a 50 ppb increase SO$_2$(6 individual studies); (2) aggravation of childhood asthma by a 50 ppb increase NO$_2$(5 individual studies); (3) aggravation of childhood asthma by a 50 ppb increase $O_3$(7 individual studies); (4) aggravation of childhood asthma by a 10$\mu\textrm{g}$/m$^3$increase PM$_{10}$ (4 individual studies); (5) aggravation of childhood asthma by a 1 ppm increase CO (2 individual studies); and (6) comparison of results between a Korean study results and this meta-analytic study. Results of this study indicated that an inverse-variance weighted pooling of the hospital admission risk at a 1ppm increment of CO levels was 1.12% (95% CI : 1.01 ~ 1.24). The hospital admission risk was estimated to increase 5% (95% CI : 1.02~1.08), 6%(95% CI : 1.04~1.09), and 5% (95% CI : 1.02~1.09) with each 50ppb increase of SO$_2$, NO$_2$, and $O_3$, respectively. In addition, our results lead to a small but significant elevation in risk of 2% (RR = 1.02, 95% CI = 1.01~1.04) with each 10$\mu\textrm{g}$/m$^3$increase of PM$_{10}$ among 4 individual studies. We found a small elevation in risk of childhood asthma, and pooled results of 10 epidemiologic studies of childhood asthma using increase a cut-off-point levels of air pollutants showed a few pieces of evidence. The results of this meta-analysis suggested that air pollution associated with an increased incidence of childhood asthma. According to this study, relationship between exposure to air pollutants and childhood asthma in Korea seem to be high than results of this meta-analysis.sis.

• Journal of Preventive Medicine and Public Health
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• 제40권2호
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• pp.108-113
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• 2007

When conducting large-scale cohort studies, numerous statistical issues arise from the range of study design, data collection, data analysis and interpretation. In genomic cohort studies, these statistical problems become more complicated, which need to be carefully dealt with. Rapid technical advances in genomic studies produce enormous amount of data to be analyzed and traditional statistical methods are no longer sufficient to handle these data. In this paper, we reviewed several important statistical issues that occur frequently in large-scale genomic cohort studies, including measurement error and its relevant correction methods, cost-efficient design strategy for main cohort and validation studies, inflated Type I error, gene-gene and gene-environment interaction and time-varying hazard ratios. It is very important to employ appropriate statistical methods in order to make the best use of valuable cohort data and produce valid and reliable study results.

• 한국산업보건학회지
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• 제26권3호
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• pp.237-252
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• 2016

Objectives: This study was conducted in order to improve the current understanding of rare earths(RE) and to provide supporting data for establishing occupational health policies by reviewing the toxicological data and issues caused by the use of RE compounds in various fields. Methods: To evaluate the potential toxicity of RE from the viewpoint of occupational health, we summarized extensive reviews of relevant articles in the toxicology(animals and cells), occupational health and safety, and epidemiologic literature. Results: Although occupational RE exposure occurs extensively from ore mining and refining to end users in various industrial applications, epidemiologic study has not been performed among workers up to now. Bioaccumulation and adverse effects of RE have also been mentioned in ore mining regions and nearby residences, but safety standards for each process are insufficient. Moreover, because new commercial recycling technology will soon be applied to various industries, regulation and policies are needed for preventing abuse of recycling. In the results of animal toxicity for a few REs(mostly cerium, lanthanum, and gadolinium), toxicities of liver, lung, blood, and the nervous system were identified due to oxidative stress, but study of long-term RE exposure is required. Understanding the dual effect for RE and discovery of biomarkers pose a scientific challenge in further mechanism studies. Conclusions: In the future, additional hazard evaluation based on animal experiments is required, alongside continuous research for developing analytical methods and discovering biomarkers. Finally, RE occupational health and safety management needs to be integrated into the sustainable use of these materials.

• 환경영향평가
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• 제13권5호
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• pp.243-250
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• 2004

Recently, concerns about health risks exposed to electromagnetic fields have been brought in the safety of electric power lines. A number of governmental and international organizations have advised to avoid the magnetic field exposure to the schools and residential areas. Some epidemiologic studies showed that electromagnetic fields should not exceed the exposure limits of 2-3mG to the people living near high-voltage transmission lines. In this study, the principles, ranges and survey methods of the assessment for powerfrequency electromagnetic fields were reviewed from the relevant research papers and documents. The ranges of electromagnetic fields were determined from 50m to 100m and have been defined according to the properties of each electric power lines and a new methodology was suggested in this study. It would be necessary to develop and improve specific assessment methods for various high-voltage transmission lines projects.

• 환경영향평가
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• 제14권4호
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• pp.195-202
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• 2005

The health risks from the magnetic fields exposure have been brought out difficulties in the construction of transformer substation. According to several epidemiologic studies and the relevant international organizations, magnetic fields should not exceed the exposure limits of 3mG for the people living near electric power lines. The rigid regulation of the exposure levels for the elementary school and residental areas has been established already in Switzerland and Italy. Since 1998, the environmental impact assessment system in Korea has been reviewed for power-frequency magnetic field by precautionary policies. In this study, the possible application of Prior Environmental Performance Review System for the transformer substation was reviewed from the points of the properties of the powerfrequency magnetic fields. The ranges and survey methods of the assessment for the transformer substation were proposed. The ranges of magnetic fields was between 300m to 500m for the 345kV transformer substation. It is necessary to develop further specific assessment methods for various high-voltage transformer substations.

• Communications for Statistical Applications and Methods
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• 제11권1호
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• pp.181-187
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• 2004

One of objectives in epidemiologic studies is to detect the amount of change caused by a specific risk factor. Risk ratio is one of the most useful measurements in epidemiology. When we perform the inference for this measurement with rare events, the standard approach based on the normal approximation may fail, in particular when there are no disease cases observed. In this paper, we discuss and evaluate several existing methods for constructing a confidence interval of risk ratio through simulation when the disease of interest is a rare event. The results in this paper provide guidance with how to construct interval estimates for risk difference and risk ratio when there are no disease cases observed.

• 한국한의학연구원논문집
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• 제17권2호
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• pp.107-113
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• 2011

Objectives : Sasang typology is extensively studied for the Sasang constitution diagnosis objectification with various data, for example, questionaires, reference materials, etc and analyzed with the several statistical methods. In this study, we used ROC-curve (Receiver Operating Characteristic curve) analysis to diagnose Sasang constitution, which is a kind of epidemiologic research methods and is away from traditional statistical methods. Methods : We collected personality questionnaire which consists of 15 items, from 24 oriental medical clinics. We analyzed the sensitivity and specificity using ROC curve method based on the score of personality questionnaire and also investigated classification accuracy and cut-off value of Sasang constitution. Results : The AUC (area under the ROC curve) value was 0.508 (p=.5511) for Taeeumin, 0.629 (p<.0001) for Soeumin and 0.604(p<.0001) for Soyangin, respectively. so the classification accuracy for Soeumin was highest Soeumin for over 30 points and Soyangin for below 28 points respectively. Conclusions : We suggest that Taeeumin is not classified easily in the ROC-curve analysis. We may classify Soeumin and Soyangin but the accuracy of Sasang constitutional diagnosis is still low.

• Pediatric Infection and Vaccine
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• 제8권2호
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• pp.135-149
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• 2001

목 적 : 예방접종 사업의 안정화를 위해서는 발생된 이상반응이 적절하게 보고되고, 발견된 이상반응에 대하여 신속하고 정확한 원인 규명을 위한 역학조사를 시행하여 조사된 결과에 따라 적절하게 대응하는 것이 필요하다. 이에 연구자들은 1995년부터 2000년까지 국가 보상을 신청하거나 보고된 예방접종 후 이상반응 감시체계를 통해 보고된 이상반응 사례들을 수집하여 보고 사례와 국가 보상의 변화 양상과 사례의 역학적 특성을 파악하여 이상반응 감시체계의 개선 방향을 제시할 수 있는 기반을 마련하고자 하였다. 방 법 : 1995년부터 1996년까지 예방접종 후 이상반응에 대하여 국가보상신청을 하거나 국립보건원 방역과로 보고된 61건을 대상으로 국가보상 신청시 제출한 자료와 역학조사와 관련된 모든 자료들을 수집, 정리하여 사례들의 역학적 특성들을 파악하였으며, 역학조사 방법과 보상과 관련된 사항들에 대하여 정리 분석하였다. 결 과 : 연도별 보고 건수는 1995년 12명, 1996년 3명, 1998년 12명, 1999년 5명, 2000년 29명으로 총 61명이었으며, 이 중 사망자는 24명(39.3%)이고, 이 중 16명(66.7%)에서 부검이 시행되었다. 보상 심의를 신청한 경우는 36건(59.0%)이었는데, 이 중 17건(47.2%)이 보상받았고, 역학조사를 실시한 경우는 49건(80.3%)이었다. 보고 사례 중 보상 신청 사례는 1995~1998년에는 17건 중 15건(88.2%), 1999~2000년에는 38건 중 15건(76.3%)으로 감소하였으나, 심의 결과 보상을 받는 비율은 1995~1998년 26.6%에서 1999~2000년 53.3%로 증가하였다. 보고 사례 중 역학조사가 이루어진 경우는 1995~1998년에는 17건 중 14건(82.4%), 1999~2000년에는 38건 중 29건(76.3%)으로 역학조사를 실시하는 비율은 감소하였으나 반드시 역학조사가 필요하나 누락되는 경우는 개선되었다. 이상반응 발생을 인지한 후 역학조사에 착수하기까지의 소요시간이 1일 이내인 경우가 1995~1998년에는 전체의 25%에 불과하던 것이 1999년 이후에는 전체의 43.5%로 증가하였다. 전체 이상반응 발생에 있어 남녀간 차이는 보이지 않지만 사망자 21명만을 살펴보면 남자가 14명(66.7%), 여자가 7명(33.3%)으로 남자가 2배나 많았다. 연령별 분포는 정기예방접종이 집중되어 있는 생후 2개월부터 24개월까지가 전체의 75.4%를 차지하고 있다. 접종에서 발병까지의 기간은 전체의 78.4%가 접종 후 일주일 이내에 발생하였다. 결 론 : 보고체계 도입 이후 역학조사가 필요한 경우 대부분에서 조사가 시행되었고, 보고를 받고 신속하게 조사를 착수하는 비율이 증가한 것은 긍정적인 변화로 평가된다. 그러나, 전체적으로 보았을 때 외국에 비하여 감시체계를 통해 보고되는 사례 수가 매우 적어 이상반응의 역학적 양상을 파악함에는 제한점이 있다. 예방접종 사업의 안정성 확보라는 목표를 달성하기 위해서는 무엇보다 보고율 향상을 위한 노력이 경주되어야 할 것으로 생각된다.

• Pediatric Infection and Vaccine
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• 제18권1호
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• pp.61-67
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• 2011

목 적 : 본 연구는 소아에서 보카바이러스와 연관된 하기도 감염증의 역학적인 특성에 대해 알아보고자 하였다. 방 법: 2000년 3월부터 2005년 9월까지 서울대학교 병원과 분당 서울대학교병원에 하기도 감염증으로 입원한 658명의 소아에게서 비인두 흡입 검체를 채취하였다. 다중 역전사 중합효소 연쇄 반응을 이용하여 11종의 바이러스를 조사하였고, 의무기록을 후향적으로 분석하였다. 결 과:전체 호흡기바이러스는 658명의 환아 중 325명(49.4%)에서 검출되었다. 보카바이러스는 62명(9.4%)에서 검출되었으며, 3개월 이상 5세 미만에서 많았다. 보카바이러스가 중복감염이 확인된 것은 37.1%로, 전체 바이러스 양성 환자들의 중복감염률(12.3%)보다 의미 있게 높은 것으로 확인되었다(P =0.000). 또한 늦은 봄부터 이른 여름인 5월부터 7월에 많이 검출되었다. 결 론 : 보카바이러스는 국내에서 소아의 하기도 감염증에서 유병률이 높았고, 특히 늦은 봄부터 초여름에 유행하였다.

• Journal of Preventive Medicine and Public Health
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• 제36권1호
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• pp.77-84
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• 2003

Objectives : Two related cases of Hemolytic-Uremic Syndrome (HUS) were reported to the Korea National Institute of Health in May, 2001. Shiga toxin 2 genes were detected in both stool samples. We suspected an enterohemorrhagic Escherichia coli (EHEC) infection as the cause of the HUS, and conducted an investigation to find the source of the infection and its route of transmission. Methods : We peformed case investigations on these two related HUS cases, and obtained interviews and rectal swabs form the family members and other close contacts. Additionally, we peformed rectal swabs on the cattle raised by the household of the index patient. Results : We found a 20 month old index patient and a 6 year-old cousin had developed HUS, where there had been a 2 day history of contact with the index, and bacteriological examinations for these two patients revealed, indistinguishably, the same E. coli O171. The grandmother of the index patient was found to be asymptomatic, but E. coli O26 was isolated. We also found a probable case in the mother of the cousin. She reported a history of contact with the index, and developed bloody diarrhea of 3 days duration. The test results for the cattle revealed E. coli O26 in one cow, and E. coli O26 and O55 in another. E. coli O26, which was isolated in both cows and the grandmother of the index, were indistinguishably the same. Conclusions : We found that the E. coli O26 in the grandmother had originated from the cows, and that the E. coli O171 found in the index patient had been transmitted to the cousin through person-to-person contact.