• Tuberculosis and Respiratory Diseases
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• v.76 no.4
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• pp.169-174
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• 2014

Background: The Korean Obstructive Lung Disease (KOLD) Cohort Study is a prospective longitudinal study of patients with chronic obstructive pulmonary disease (COPD), asthma, or other unclassified obstructive lung diseases. It was designed to develop new classification models and biomarkers that predict clinically relevant outcomes for patients with obstructive lung diseases. Methods: Patients over 18 years old who have chronic respiratory symptoms and airflow limitations or bronchial hyper-responsiveness were enrolled at 17 centers in South Korea. After a baseline visit, the subjects were followed up every 3 months for various assessments. Results: From June 2005 to October 2013, a total of 477 subjects (433 [91%] males; 381 [80%] diagnosed with COPD) were enrolled. Analyses of the KOLD Cohort Study identified distinct phenotypes in patients with COPD, and predictors of therapeutic responses and exacerbations as well as the factors related to pulmonary hypertension in COPD. In addition, several genotypes were associated with radiological phenotypes and therapeutic responses among Korean COPD patients. Conclusion: The KOLD Cohort Study is one of the leading long-term prospective longitudinal studies investigating heterogeneity of the COPD and is expected to provide new insights for pathogenesis and the long-term progression of COPD.

• Journal of Preventive Medicine and Public Health
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• v.46 no.5
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• pp.271-281
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• 2013

Objectives: Emerging evidence indicates that sleep duration is associated with health outcomes. However, the relationship of sleep duration with long-term health is unclear. This study was designed to determine the relationship of sleep duration with mortality as a parameter for long-term health in a large prospective cohort study in Korea. Methods: The study population included 13 164 participants aged over 20 years from the Korean Multi-center Cancer Cohort study. Information on sleep duration was obtained through a structured questionnaire interview. The hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality were estimated using a Cox regression model. The non-linear relationship between sleep duration and mortality was examined non-parametrically using restricted cubic splines. Results: The HRs for all-cause mortality showed a U-shape, with the lowest point at sleep duration of 7 to 8 hours. There was an increased risk of death among persons with sleep duration of ${\leq}5$ hours (HR, 1.21; 95% CI, 1.03 to 1.41) and of ${\geq}10$ hours (HR, 1.36; 95% CI, 1.07 to 1.72). In stratified analysis, this relationship of HR was seen in women and in participants aged ${\geq}60$ years. Risk of cardiovascular disease-specific mortality was associated with a sleep duration of ${\leq}5$ hours (HR, 1.40; 95% CI, 1.02 to 1.93). Risk of death from respiratory disease was associated with sleep duration at both extremes (${\leq}5$ and ${\geq}10$ hours). Conclusions: Sleep durations of 7 to 8 hours may be recommended to the public for a general healthy lifestyle in Korea.

• 한국사회정책
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• v.24 no.2
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• pp.245-275
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• 2017

It is attempted here to explain change in welfare attitudes for two decades in 10 countries with the cohort effect, especially differences in societal values between generations. It was found that for the last 20 years pro-welfare attitudes of the public has been strengthened, on which the generation has impact, more by the cohort effect than by the age effect, and that the Millennials/Y-generation are the strongest supporters for the state welfare. Value-differences between cohorts, as a background factor for the cohort effect on welfare attitudes, are clear but show a kind of linear trend from the older to the younger cohorts. As for the cohort effect on welfare attitudes, it is expected, at least for the short-term future, in the direction toward supporting the expansion of the state welfare. Korean welfare attitudes show an exceptional pattern - preferring income inequality as incentives, and at the same time, the expansion of governmental welfare responsibility, which echoes recent arguments of contradictoriness and non-class-orientedness of Korean welfare attitudes. Especially, Korean Millennials/Y-G shows this contradictory welfare attitudes the most strongly, which is unique between 10 countries in this study, implying their fierce competition is being internalized. It is expected that the contradictoriness of Korean welfare attitudes may limit its possibility to back up welfare expansion in Korea.

• Journal of Distribution Research
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• v.14 no.1
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• pp.45-65
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• 2009

As a number of people using the internet for their shopping steadily rises, it is increasingly important for retailers to understand why consumers decide to buy products via online or offline. The main purpose of this study is to develop and test a model that enhance our understanding of how consumers respond future online and offline channels for their purchasing. Rather than merely adopting statistical models like most other studies in this field, the present study develops a model that combines double-cohort method with multinomial logit model. It is desirable if one can adopt an overall encompassing criterion in the study of consumer behaviors form diverse sales channels. This study uses the concept of cohort or aging to enable this comparison. It enables us to analyze how consumers respond to online and offline channels as people aged by measuring their shopping behavior for an online and offline retailers and their subsequent purchase intentions. Based on some empirical findings, this study concludes with policy implications and some necessary fields of future studies desirable.

• Korean Journal of Social Welfare
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• v.60 no.2
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• pp.53-76
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• 2008

This study analyze the intergenerational transmission of poverty in Korea, using the first wave of Korea Welfare Panel Study. For this analysis, I produced poverty transition tables across generation and estimated logistic models to explore the effects of parent's poverty on the children's adulthood poverty. As the results, I found that parent's poverty reduced children's education level and then the low education level increased the likelihood that children experience poverty in their adulthood. In other words, parent's poverty might increase children's adulthood poverty through the mediating effects of education level. This mediating effects were also identified in the analyses by group and cohort. From the analyses by group, daughters rather than sons, those from urban rather than rural area, and the older cohort rather than younger cohort showed greater intergenerational transmission of poverty.

• Journal of the Korean housing association
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• v.22 no.1
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• pp.11-23
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• 2011

The purpose of this study is to explore cohort changes in first-time homeownership in Korea. The study collected qualitative data from individual interviews to explore the housing trajectories of different birth cohorts. As a result, Individual interviews facilitated an exploration of the decision making process of first-time homeowner with in a cohort context. The cohorts born in the 1950s seek a sense of security through homeownership, and have strong Korean sentiments of ownership. They tried various means to buy a house, and real estate market boom at that time played a role in the driving force. The cohorts born in the 1960s have less insecurity of tenure than the previous cohorts, but they still feel the need for homeownership. Since the currency crisis in 1997 caused the fluctuation of housing price, the 1960s cohort experienced a dramatic decline and rebound of assets while the previous cohorts had experienced a steady rise in housing prices. Finally, the attitude towards housing in the group of 1970s cohorts has changed from ownershiporiented to use-oriented.

• Child Health Nursing Research
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• v.17 no.4
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• pp.281-287
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• 2011

Purpose: The study was done to explore growth variation in head circumference (HC) in extremely premature infants (EPI) with brain injury. Methods: A retrospective cohort study was conducted with 79 cohort samples from the archives of the catch-up growth project. Mean age of the infants was 29.2 weeks of gestation and mean HC, 27.1 cm at birth. Their HC measurements were retrieved from the archives up to 6 month of corrected age (CA) and analyzed against history of brain injury during hospitalization. Results: Overall growth retardation in HC was observed in the cohort sample compared to longer gestation premature infants. EPI with brain injury showed decreased HC compared to infants without brain injury, and resulting growth variation across 6 month of CA. Highest retardation in HC growth was observed in male infants with brain injury. Conclusion: Extreme preterm birth itself may function as a major obstacle against HC growth toward term age in EPI. Sustainability of brain injury could be observed with higher HC growth retardation after term. Evolutionary favor to female infants may exist in HC growth of EPI. Intensive education on HC monitoring is highly suggested for parents of EPI, particularly with children with brain injury.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.4
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• pp.339-346
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• 2009

The objectives of this study were to introduce spatial interpolation methods which have been applied in recent papers, to apply three methods (nearest monitor, inverse distance weighting, kriging) to domestic data (Ulsan cohort) as an example of estimating the personal exposure levels. We predicted the personal exposure estimates of 2,102 participants in Ulsan cohort using spatial interpolation methods based on information of their residential address. We found that there was a similar tendency among the estimates of each method. The correlation coefficients between predictions from pairs of interpolation methods (except for the correlation coefficient between nearest montitor and kriging of CO and $SO_2$) were generally high (r=0.84 to 0.96). Even if there are some limitations such as location and density of monitoring station, spatial interpolation methods can reflect spatial aspects of air pollutant and spatial heterogeneity in individual level so that they provide more accurate estimates than monitor data alone. But they may still result in misclassification of exposure. To minimize misclassification for better estimates, we need to consider individual characteristics such as daily activity pattern.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.1979-1990
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• 2021

Evacuation Time Estimate (ETE) can provide decision-makers with a likelihood to implement evacuation of a population with radiation exposure risk by a nuclear power plant. Thus, the ETE is essential for developing an emergency response preparedness. However, studies on ETE have not been conducted adequately in Korea to date. In this study, different cohorts were selected based on assumptions. Existing local data were collected to construct a multi-model network by TSIS-CORSIM code. Furthermore, several links were aggregated to make simple calculations, and post-processing was conducted for dealing with the stochastic property of TSIS-CORSIM. The average speed of each cohort was calculated by the link aggregation and post-processing, and the evacuation time was estimated. As a result, the average cohort-based evacuation time was estimated as 2.4-6.8 h, and the average clearance time from ten simulations in 26 km was calculated as 27.3 h. Through this study, uncertainty factors to ETE results, such as classifying cohorts, degree of model complexity, traffic volume outside of the network, were identified. Various studies related to these factors will be needed to improve ETE's methodology and obtain the reliability of ETE results.

• Journal of Sasang Constitutional Medicine
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• v.23 no.2
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• pp.218-229
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• 2011

1. Objectives: This study is to investigate the relationship between Intima Media Thickness(IMT) of common carotid artery and Sasang Constitution. 2. Methods: 839 persons, over 40 years old, participated in community-based cohort of Korea Genome and Epiedemiology Study (KOGES) in Wonju City and Pyeongchang City of South Korea from June 2006 to February 2008. The diagnosis of Common carotid Intima Media Thickness was evaluated by B Mode ultrasonography, cardiovascular risk factors were checked using questionnaire and blood samples. Constitution was verified by a Sasang constitution specialist according to the results of PSSC(Phonetic System for Sasang Constitution), facial photos and a simplified Sasang constitutional questionnaire. Multiple regression analysis and logistic regression analysis were performed with SPSS. 3. Results: There were significantly high values in waist circumference, fasting blood sugar, systolic blood pressure, diastolic blood pressure, triglyceride, HOMA-IR and hsCRP in Taeeumin and low in HDL-cholesterol and adiponectin in Taeeumin. There were significantly high value in Common Carotid Intima Media Thickness in Taeeumin. Age was the significant cardiovascular risk factor irrespective of Sasang constitution in all participants. There was a positive correlation between smoking and Soyangin in all participants and men. There were positive correlations between LDL-cholesterol, BMI and Taeeumin in all participants and men. There were positive correlations between hsCRP and Soeumin in all participants and men. There was significantly high odds ratio of Taeeumin over Soeumin in common carotid Intima Media Thickness. 4. Conclusions: Regimens on cardiovascular diseases should be considered according to Sasang constitution. There are more sensitive risk factor in each constitution; smoking in Soyangin, LDL-cholesterol and BMI in Taeeumin, hsCRP in Soeumin.