• Title/Summary/Keyword: Case-crossover study

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Short-term Effect of Air Pollution on Respiratory Disease in Seoul : A Case-Crossover Study (서울지역 대기오염이 호흡기계질환에 미치는 단기영향에 관한 환자교차연구)

  • Lee, Young-Ju;Lee, Jong-Tae;Shin, Dong-Chun;Im, Hyoung-June;Cho, Soo-Hun;Ju, Young-Su
    • Journal of Preventive Medicine and Public Health
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    • v.34 no.3
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    • pp.253-261
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    • 2001
  • Objectives : To evaluate the hypothesis that air pollution could increase emergency room visits for respiratory diseases, and if so, to quantify the strength of association between those. Methods : We compiled daily records of hospital emergency room visits for respiratory diseases in Seoul, from November 1. 1955 to October 31. 1996, by using medical utilization data of unscheduled visits. In addition, air quality and weather data for the same period was collected. And a case-crossover design was applied by adopting conditional logistic regression analysis to determine the relationship between air pollutants and emergency room visits for respiratory diseases. In particular, the control periods were chosen by a bidirectional paired matching technique 7, 14, and 21 days before and after the case periods. Results : Only ozone was associated with the increased number of emergency room visits for respiratory diseases. The relative risk according to a 30ppb increase of ozone concentration (24hr mean, lagged 1day) was 1.91(95% confidence interval = 1.78-2.05). Conclusion : There was a statistically significant association between the ambient ozone and daily emergency room visits for respiratory diseases.

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Zolpidem Use and Risk of Fracture in Elderly Insomnia Patients

  • Kang, Dong-Yoon;Park, So-Young;Rhee, Chul-Woo;Kim, Ye-Jee;Choi, Nam-Kyong;Lee, Joong-Yub;Park, Byung-Joo
    • Journal of Preventive Medicine and Public Health
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    • v.45 no.4
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    • pp.219-226
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    • 2012
  • Objectives: To evaluate the risk of fractures related with zolpidem in elderly insomnia patients. Methods: Health claims data on the entire South Korean elderly population from January 2005 to June 2006 were extracted from the Health Insurance Review and Assessment Service database. We applied a case-crossover design. Cases were defined as insomnia patients who had a fracture diagnosis. We set the hazard period of 1 day length prior to the fracture date and four control periods of the same length at 5, 10, 15, and 20 weeks prior to the fracture date. Time independent confounding factors such as age, gender, lifestyle, cognitive function level, mobility, socioeconomic status, residential environment, and comorbidity could be controlled using the case-crossover design. Time dependent confounding factors, especially co-medication of patients during the study period, were adjusted by conditional logistic regression analysis. The odds ratios and their 95% confidence intervals (CIs) were estimated for the risk of fracture related to zolpidem. Results: One thousand five hundred and eight cases of fracture were detected in insomnia patients during the study period. In our data, the use of zolpidem increased the risk of fracture significantly (adjusted odds ratio [aOR], 1.72; 95% CI, 1.37 to 2.16). However, the association between benzodiazepine hypnotics and the risk of fracture was not statistically significant (aOR, 1.00; 95% CI, 0.83 to 1.21). Likewise, the results were not statistically significant in stratified analysis with each benzodiazepine generic subgroup. Conclusions: Zolpidem could increase the risk of fracture in elderly insomnia patients. Therefore zolpidem should be prescribed carefully and the elderly should be provided with sufficient patient education.

Research on Classical Crossover Arrangement Methods of Arias in Operas - Focused on Una Furtiva Lagrima, an Aria of an Opera called L'Elisir d'Amore - (오페라 아리아의 크로스오버 편곡기법 연구 - 오페라 사랑의 묘약 중 아리아 Una Furtiva Lagrima를 중심으로 -)

  • Shin, Del La;Shin, You-Ho
    • Journal of Korea Entertainment Industry Association
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    • v.14 no.6
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    • pp.151-160
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    • 2020
  • In the past, musicians followed strict patterns written by composers when playing classical music. However, since the development of postmodernism, which puts an emphasis on unique individualities and various ways of thinking, following the strict patterns of classical music unquestioningly became less significant. Classical music was thought to be difficult to follow and enjoy for most people. Thus, musicians have found ways to keep the dignity of classical music but added familiarity in order to popularize arias in operas. They created classical crossover music and this type of music enabled people to enjoy easy access to classical music. However, not many studies focus on arrangement methods of changing classical music into crossover music. The goal of this study is to research on arrangement methods of crossover music based on the findings from precedent researches on operas. This study focused on analyzing musical structure including chords, rhythms and compositions of musical instruments. According to the analysis, original classical songs and popera, which is a type of crossover music, share similarities in terms of rhythms and chords. However, there are differences when it comes to compositions of musical instruments. In case of a jazz version, it uses AfroCuban rhythm as well as Bolero rhythm which is a part of ballad and jazz acoustic instruments are mainly used. Also, in order to reduce the feeling of classical music and to differentiate the jazz version from the original version, a lot of tension is used in voicing. This study can be helpful for any researches related to arrangements of classical crossover music.

Correlation of Primary Spontaneous Pneumothorax and Air Pollution in Adolescents

  • Gu, Byung Mo;Ko, Ho Hyun;Ra, Yong Joon;Lee, Hee Sung;Kim, Hyoung Soo;Lee, Hong Kyu
    • Journal of Chest Surgery
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    • v.54 no.1
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    • pp.53-58
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    • 2021
  • Background: We aimed to investigate the characteristics of primary spontaneous pneumothorax (PSP) in adolescents and to analyze the relationship between the occurrence of PSP and air pollutants. Methods: Data pertaining to age, sex, body mass index, smoking status, initial pneumothorax volume, presence of bullae, treatment methods, and city of residence were retrospectively obtained from January 2010 to December 2014. We investigated the association between short-term exposure to air pollutants (SO2, NO2, O3, CO, and PM10) and the occurrence of PSP using a case-crossover design with conditional logistic regression. Results: We collected information from 598 patients who were admitted for PSP, with a mean follow-up duration of 62.9 months. The majority (91.1%) of the patients were male. In the case-crossover design, conditional logistic regression showed that no air pollutant was associated with the occurrence of pneumothorax. The results were consistent across all city subgroups (Anyang, Gunpo, Uiwang, and Gwacheon). Conclusion: In our study, the incidence rate of pneumothorax was 153.8 per 100,000 person-years in male adolescents and 16.7 per 100,000 person-years in female adolescents. The case-crossover design showed that PSP in adolescents is unlikely to be related to air pollution.

Measurement of Hydrogen Crossover by Gas Chromatograph in PEMFC (고분자전해질 연료전지에서 기체 크로마토그래프에 의한 수소투과도 측정)

  • Jeong, Jaejin;Jeong, Jaehyeun;Kim, Saehoon;Ahn, Byungki;Ko, Jaijoon;Park, Kwonpil
    • Korean Chemical Engineering Research
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    • v.52 no.4
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    • pp.425-429
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    • 2014
  • Until a recent day, degradation of PEMFC MEA(membrane and electrode assembly) has been studied, separated with membrane degradation and electrode degradation, respectively. But membrane and electrode were degraded coincidentally at real PEMFC operation condition. During simultaneous degradation, there was interaction between membrane degradation and electrode degradation. Hydrogen permeability was used often to measure degradation of electrolyte membrane in PEMFC. In case of hydrogen permeability measured by LSV(Linear Sweep Voltammetry) method, the degradation of electrode decrease the value of hydrogen crossover current due to LSV methode's dependence on electrode active area. In this study hydrogen permeability was measured by gas chromatograph(GC) when membrane and electrode degraded at the same time. It was showed that degradation of electrode did not affect the hydrogen permeability measured by GC because of GC methode's independence on electrode active area.

Effects of Air Pollution on Asthma in Seoul: Comparisons across Subject Characteristics (서울지역 대기오염이 천식에 미치는 급성영향: 연구대상의 특성에 따른 비교)

  • Kim, Sun-Young;Kim, Jai-Yong;Kim, Ho
    • Journal of Preventive Medicine and Public Health
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    • v.39 no.4
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    • pp.309-316
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    • 2006
  • Objectives: Korean epidemiological studies have used reduced samples according to the subject's characteristics, such as the health services provided, the historical note with asthma, and age, to examine the acute effect of air pollution on asthma using the Korean National Health Insurance records. However, there have been few studies on whether the effects shown in these reduced samples are different from those of all samples. This study compared the effects of air pollution on asthma attacks in three reduced samples with those of entire samples. Methods: The air pollution data for $PM_{10},\;CO,\;SO_2,\;NO_2,\;and\;O_3$, and weather conditions including temperature, relative humidity, and air pressure in Seoul, 2002, were obtained from outdoor monitoring stations in Seoul. The emergency hospital visits with an asthma attack in Seoul, 2002 were extracted from the Korean National Health Insurance records. From these, the reduced samples were created by health service, historical notes with asthma, and age. A case-crossover design was adopted and the acute effects of air pollution on asthma were estimated after adjusting for weather, time trend, and seasonality. The model was applied to each reduced sample and the entire sample. Results: With respect to the health service, the effects on outpatients were similar to those for the total sample but were different for inpatients. These similar effect sizes were also observed in the reduced samples according to the historical note with asthma and age. The relative risks of $PM_{10},\;CO,\;SO_2,\;NO_2,\;and\;O_3$, among the reduced and entire samples were 1.03, 1.04-1.05, 1.02-1.03, 1.04-1.06, and 1.10-1.17, respectively. Conclusions: There was no clear evidence to show a difference between the reduced samples and the entire samples.

Estimation of the National Burden of Disease and Vulnerable Population Associated with Natural Disasters in Korea: Heavy Precipitation and Typhoon

  • Han, Hyun-Jin;Kim, Jong-Hun;Chung, Soo-Eun;Park, Jae-Hyun;Cheong, Hae-Kwan
    • Journal of Korean Medical Science
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    • v.33 no.49
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    • pp.314.1-314.15
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    • 2018
  • Background: Despite its growing significance, studies on the burden of disease associated with natural disasters from the perspective of public health were few. This study aimed at estimating the national burden of disease associated with typhoons and torrential rains in Korea. Methods: During the period of 2002-2012, 11 typhoons and five torrential rains were selected. Mortality and morbidities were defined as accentual death, injury and injury-related infection, and mental health. Their incidences were estimated from National Health Insurance Service. Case-crossover design was used to define the disaster-related excess mortality and morbidity. Disability-adjusted life years (DALYs) were directly assessed from excess mortality and morbidity. Results: The burden of disease from typhoons increased with the intensity, with 107.7, 30.6, and 36.6 DALYs per 100,000 per event for strong, moderate, and weak typhoons, respectively. Burden of disease from torrential rains were 56.9, 52.8, and 26.4 DALYs per 100,000 per event for strong, moderate, and weak episodes, respectively. Mental disorders contributed more years lived with disability (YLDs) than did injuries in most cases, but the injury-induced YLDs associated with strong typhoon and torrential rain were higher than those of lower-intensity. The elderly was the most vulnerable to most types of disaster and storm intensities, and males younger than 65 years were more vulnerable to a strong torrential rain event. Conclusion: The intensity of torrential rain or typhoon was the strongest determinant of the burden of disease from natural disasters in Korea. Population vulnerable may vary depending on the nature and strength of the disasters.

A Study on the ZEN(禪) style in Contemporary Fashion (현대 패션에 나타난 젠(zen:禪)양식에 관한 연구)

  • 조정미;김예형
    • Journal of the Korean Society of Costume
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    • v.50 no.6
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    • pp.163-175
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    • 2000
  • This study focuses on the Zen style in contemporary fashion which presents itself as one of the dominant cultural phenomena these days. After investigating the basic concepts and features of the Zen style and examining its birth and development, this study moves on to the ways in which it is characteristically applied for the world of fashion. This study is also performed both by the theoretical research on related books and papers for the explication of main concepts and by the practical research on fashion magazines and works of famous fashion designers for the presentation of more detailed illustration. When we are talking about postmodernism, which is a reaction against or a continuation of modernism, as a cultural dominant shown up in the late twentieth century, the Zen style itself can be regarded as a typical representation of postmodernism in fashion. Although the Zen style can be viewed as sharing the basic principles with minimalism which is a main branch of modernism, it is strongly in line with postmodernism (which is human-centered) in that its fundamental idea is based on emotions and feelings of human beings and the purity of natural world. As above, ZEN is a crossover phenomenon between postmodernism and modernism. In this sense, it is said that within the name of postmodernism the Zen style has satisfied our desire to present our inner world of mind with the help of regional philosophy (in this case Oriental one). The four main aspects of the Zen style in fashion are following : simplicity connected with the Oriental moderation, the use of the Oriental silhouette and detail, the destruction of form, and the nature-friendly attitude. These will be under close examination in this study.

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Cohort Study for Investigation of the Causes in Agricultural Injuries and Diseases (농작업재해의 원인구명 및 코호트 구축방안)

  • Lim, Hyun-Sul
    • Journal of agricultural medicine and community health
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    • v.31 no.2
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    • pp.119-144
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    • 2006
  • The Korea rural health study, a large prospective cohort study, the objectives of this study are exploration for potential causes of agricultural injuries and diseases among farmers. Current medical research suggests that they may have higher rates of some traumatic injuries, pesticide poisoning, infectious diseases, musculoskeletal diseases, asthma and other respiratory diseases. This study is designed to identify occupational, lifestyle, and environmental factors of workplace that may affect the rate of diseases in farming population. Round 1, initial cohort recruitment, will begin in 2006 and conclude in 2009. Round 2, follow-up will begin in 2010 and conclude in 2014. Approximately 54,000 persons will be selected to study population. Nested case-control studies and case-crossover studies will be conducted for getting to the bottom of agriculture-related diseases. Recruitment and follow-up are conducted in collaboration with multi-centers. As data on the exposures and health outcomes of this study population are collected and analyzed in 2014. This study will be evaluated by public health experts for effort, achievement, adequacy of performance, efficacy, process of study and so on. The author expects that this cohort study may reduce agricultural injuries and diseases and will provide information that agricultural workers can use in making decisions about their health. Also, this study will be significant basis for strengthening the competitiveness of agriculture in Korea.

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Comparison of Endotracheal Intubation to Transfer - A Study of Simulation Using the SALT - (이송 중 기관내 삽관의 효율성 비교 - SALT를 이용한 시뮬레이션 연구 -)

  • Yun, Seong-Woo;Jung, Jun-Ho;Lee, Hyo-Ju;Choi, Mi-Young
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2022.10a
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    • pp.300-302
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    • 2022
  • The purpose of this study is to compare the speed, confidence, and ease of endotracheal intubation in a transfer posture by using the SALT(Supraglottic Airway Laryngopharyngeal Tube), and a direct laryngoscope to improve the ability to implement professional airway management. The subject of the study was an experimental study by a randomized crossover design, targeting 28 first-class emergency medical technicians working in J-do fire station, and the SPSS 20.0 version was used for data analysis. The endotracheal intubation by using SALT showed a significant difference in speed compared to endotracheal intubation by using a direct laryngoscope(p<.001), and also showed a significant difference in confidence and ease(p<.001). If it is transfer to endotracheal intubation by direct laryngoscope, or in the case of transfer patients, if SALT is used, safe and rapid intubation will be possible.

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