• 대한예방의학회:학술대회논문집
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• 1994.02a
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• pp.417-425
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• 1994

Although animal studies have been used most often for quantitative risk assessment, it is generally recognized that well-conducted epidemiologic studies would provide the best basis for estimating human risk. However, there are several features related to the design and analysis of epidemiologic studies that frequently limit their usefulness for quantitating risks. The lack of accurate information on exposure in epidemiologic studies is perhaps the most frequently cited limitation of these studies for risk assessment. However. other features of epidemiologic study design, such as statistical power, length of follow-up, confounding, and effect modification, may also limit the inferences that can be drawn from these studies. Furthermore, even when the aforementioned limitations are overcome, substantial uncertainty exists concerning the choice of an appropriate statistical (or biologic) model for extrapolation beyond the range of exposures observed in a particular study. This paper focuses on presenting a review and discussion of the methodologic issues involved in using epidemiologic studies for risk assessment. This review concentrates on the use of retrospective, cohort, mortality studies of occupational groups for assessing cancer risk because this is the most common application of epidemiologic data for quantitative risk assessment (QRA). Epidemiologic data should not be viewed as a panacea for the problems inherent in using animal bioassay data for QRA. Rather, information that can be derived from epidemiologic and toxicologic studies complement one another, and both data sources need to be used to provide the best characterization of human risk.

• Journal of Preventive Medicine and Public Health
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• v.34 no.2
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• pp.119-126
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• 2001

Air pollution epidemiologic studies are intrinsically difficult because the expected effect size at general environmental levels is small, exposure and misclassification of exposure are common, and exposure is not selective to a specific pollutant. In this review paper, epidemiologic study designs and analytic methods are described, and two nationwide projects on air pollution epidemiology are introduced. This paper also demonstrates that possible confounding issues in time-series analysis can be resolved and the impact on the use of data from ambient monitoring stations may not be critical. In this paper we provide a basic understanding of the types of air pollution epidemiologic study designs that be subdivided by the mode of air pollution effects on human health (acute or chronic). With the improvements in the area of air pollution epidemiologic studies, we should emphasize that elaborate models and statistical techniques cannot compensate for inadequate study design or poor data collection.

• Journal of Preventive Medicine and Public Health
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• v.33 no.1
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• pp.125-133
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• 2000

Objectives : This study uses meta-analysis methodology to examine the statistical consistency and importance of random variation among results of epidemiologic studies of occupational electromagnetic field exposure and leukemia. Methods : Studies for this meta-analysis were identified from previous reviews and by asking researcher active in this field for recommendations. Overall, 27 studies of occupational electromagnetic field exposures and leukemia were reviewed. A variety of meta-analysis statistical methods have been used to assess 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 occupational epidemiologic studies are reported for (1) job classification (20 individual studies); (2) leukemia subtypes (13 individual studies); and (3) country (27 individual studies). Results : Results of this study, an inverse-variance weighted pooling of all the data leads to a small but significant elevation in risk of f 1% (OR=1.11, 95% CI : $1.06\sim1.16$) among 27 occupational epidemiologic studies. Publication bias was assessed by the 'fail-safe n' that may be not influence for all combined results exception a few categories, ie, 'power station operators' and 'electric utility workers' by job classification on occupational study. And ail combined odds ratio results were similar for fixed-effects models and random-effects models, with slightly higher risk estimates for the random-effects model in situations where there was significant heterogeneity, ie, Q-statistic significant (p<.05). Conclusions : We found a small elevation in risk of leukemia, but the ubiquitous nature of exposure to electromagnetic fields from workplace makes even a weak association a public health issue of substantial power to influence the present overall conclusion about relationship between electromagnetic fields exposure and leukemia.

• Journal of Preventive Medicine and Public Health
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• v.26 no.2 s.42
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• pp.192-201
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• 1993

Epidemiologic investigation was conducted on January, 1993 in Seoul to identify the cause of an infant methemoglobinemia. Field investigation of the area of outbreak, survey of household and family members, analysis of ground water, and blood tests of involved family members were performed. Following results were obtained On analyzing the quality of the ground water on patient's household high levels of nitrate was found indicating contamination of water as the cause of a methemoglobinemia outbreak. On analysing the quality of the ground waters on seven other places within the neighborhood five were contaminated by nitrate in concentration that exceeded the permissible limit implying presence nearby source of contamination. Sources of contamination were thought to be originating from human waste in conventional bathroom facilities, chicken manure used in nearby orchards and plant fields or fertilizers. But the results of water analysis with presence of bacteria or E.coli, concentration of potassium, phosphate and the past history of diarrhea among family members, chicken manure suggested the most possible source of contamination. To evaluate the health status of members in the neighborhood past history was reviewed revealing no prior existence of patient with cyanosis and 65 people in the neighborhood had normal levels of methemoglobin concentration in their blood. Conclusively, the ground water on patient's household was contaminated with nitrate and despite provision of adequate water supply, family members of the patient along with their distrust in the water supply system had used ground water as their source of drinking water resulting of methemoglobinemia. Many suburban area of Seoul and country side thought to be having similar problems concerning contaminated ground water supply and dormant outbreak of patients as a result of the drinking of the contaminated water. Epidemiologic investigation and water analysis of ground waters are advised.

• Journal of Preventive Medicine and Public Health
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• v.36 no.3
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• pp.209-212
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• 2003

Because of advances of technologies in the field of genmic epidemiology in the recent years, specimen collection, storage and analysis became an essential part of research methodologies. DNA is now being used in epidemiologic studies to evaluate genetic risk factors and specimens other than the fresh whole blood can De used for PCR. Therefore, All nucleated cells, such as buccal swabs and urine specimens, are suitable for DNA analysis. For an unlimited source of genomic DNA, EBV transformation of lymphocytes can be used for immortalization. However, the type of specimen collected in genomic epidemiologic studies will depend on the study where the epidemiologist play a leading role for the design. We also briefly described various finds of analysis for SNP that is an essential part of the genomic epidemiology.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.5
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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.

• Environmental Analysis Health and Toxicology
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• v.31
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• pp.25.1-25.9
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• 2016

Objectives After the initial investigations by the Korea Centers for Disease Control in 2011, over 1000 suspicious cases of humidifier disinfectant (HD) victims were subsequently reported by 2015, and numbers are still increasing dramatically in 2016 in the midst of the prosecutors' office investigation. This study attempts to summarize the current understandings of the related health effects of HD based upon a systemic review of published epidemiologic studies and toxicology investigations. Methods Published studies of HDs were searched through PubMed and TOXLINE under the search words 'humidifier disinfectant,' and related reports were identified from the references and published report list of regulatory agencies including the Korean National Institute of Environmental Research, US Environmental Protection Agency, and EU European Chemicals Agency. Results Case reports and epidemiologic studies have reported the clinical features of severe forms of HD lung damage, together with epidemiologic findings of seasonal occurrence and demographic variations, including the heightened susceptibility of young children. Toxicological studies have reported inhalation toxicities together with positive findings of in vitro genotoxicity studies. Conclusions This study examined unsolved issues based on cases of upper respiratory diseases and diseases of other organs, including cancers, among suspected victims of HDs. These issues should be clarified in future research for the management and prevention of health effects from HDs and chemicals of other related household products.

• Archives of Plastic Surgery
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• v.44 no.2
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• pp.144-149
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• 2017

Background The purpose of this study was to identify the epidemiologic characteristics of hand tendon injuries in children and to compare these with those of adults. Methods This retrospective study was conducted on acute traumatic tendon injuries of the hand treated at our institution from 2005 to 2013, based on medical records and X-ray findings. Age, sex, hand injured, mechanism of injury, tendons and zones injured, number of affected digits, and comorbidities and complications were analyzed. Patients were divided into 2 groups: a pediatric group (${\leq}15years$) and an adult group (>15 years). Results Over the 9-year study period, 533 patients were surgically treated for acute traumatic tendon injuries of the hand. In the pediatric group (n=76), being male, the right hand, the extensor tendon, complete rupture, the middle finger, and glass injury predominated in hand tendon injuries. In the adult group (n=457), results were similar, but injury to the index finger and knife injury were the most common. An accompanying fracture was more common in the adult group and complication rates were non-significantly different. Conclusions This comparative analysis revealed no significant epidemiologic intergroup differences. The belief that pediatric tendon injuries tend to be less severe is misplaced, and careful physical examination and exploration should be conducted in pediatric cases of hand injury.

• Korean Journal of Community Nutrition
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• v.3 no.2
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• pp.273-280
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• 1998

This study was designed to estimate the improvement of Validity for food frequency questionnaire(FFQ) by offering multiple choice portion size in developing a questionnaire. Validity of the two methods(food frequency questionnaire I=FFQ I & Food frequency questionnaire II=FFQ II) was tested in comparison with reference method of the 7-day weighed record(7DWR). Dietary consumption data of the three methods(FFQ I, FFQ II & 7DWR) were collected from 101 female university students for the analysis. Validity was measured in two categories : One was the nutrient intake value from the three methods, the other was the identification of between individual variation within the group. Spearman's rank order correlation test and distribution graphs were used for the analysis. The result showed that individual intake value of the FFQII was closer to that of the 7DWR than that of the FFQ I.Spearman's rank order correlation between the FFQII and the 7DWR did not show any improved correlation. The distribution graphs of nutrient intake derived from both the FFQ I and the FFQII were different from that of the 7DWR. Therefore, it could be suggested that single one portion size food frequency questionnaire is an equally efficient method as a multiple choice food frequency questionnaire to be adopted in epidemiologic studies.

• Journal of Trauma and Injury
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• v.18 no.2
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• pp.94-100
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• 2005

Background: Although trauma has been the major cause of death in korea, there are few reports describing the epidemiologic characteristics of trauma victims according to age-group. Thus, this study aimed to describe the epidemiologic characteristics of trauma victims visiting an urban emergency medical center in Korea. Method: This study was conducted with all trauma victims who visited the emergency departments of Asan Medical Center from April 11, 2005 to May 10, 2005. After the subjects were divided into three groups such as child (${\leq}14$ years old), adult(15-64 years old) and elderly(${\geq}65$ years old), the prehospital courses, injury mechanisms, injury severities and clinical results were compared. Result: Among total 5,927 patients who visited the emergency medical center, 896(15.1%) patients were trauma victims. Although child under the age of 15 comprised 28.7% of the total trauma victims, less severe injuries(injury severity score < 9) accounted for 97.7% of the cases. The hospitalization rate for injury among child was 21.5%. however, although elderly aged 65 comprised only 5.9% of the total trauma victims, more severe injuries(injury severity score ${\geq}9$) accounted for 30.2% of the cases. The hospitalization rate for injury among elderly was 56.4%. Conclusion: Patterns of injury and clinical results by age-group were considerably different. less severe and non-hospitalized injuries were more common in child than other age-groups. while severe and hospitalized injuries were common in elderly.