• Health Policy and Management
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• v.32 no.1
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• pp.45-52
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• 2022

Background: There are regional variations in the incidence of coronavirus disease 2019 (COVID-19), which means that some regions are more exposed to the risk of COVID-19 than others. Therefore, this study aims to investigate regional variations in the incidence of COVID-19 in Korea and identify risk factors associated with the incidence of COVID-19 using community-level data. Methods: This study was conducted at the districts (si·gun·gu) level in Korea. Data of COVID-19 incidence by districts were collected from the official website of each province. Data was also obtained from the Korean Statistical Information Service and the Community Health Survey; socio-demographic factor, transmission pathway, healthcare resource, and factor in response to COVID-19. Community risk factors that drive the incidence of COVID-19 were selected using a least absolute shrinkage and selection operator regression. Results: As of June 2021, the incidence of COVID-19 differed by more than 80 times between districts. Among the candidate factors, sex ratio, population aged 20-29, local financial independence, population density, diabetes prevalence, and failure to comply with the quarantine rules were significantly associated with COVID-19 incidence. Conclusion: This study suggests setting COVID-19 quarantine policy and allocating resources, considering the community risk factors. Protecting vulnerable groups should be a high priority for these policies.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.1
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• pp.355-361
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• 2015

Background: Deletion types of genetic variants of glutathione S-transferase (GST) M1 and T1, the GSTM1 null and GSTT1 null which are risk factors for certain cancers, have been ubiquitously found in human populations but their worldwide distribution pattern is unclear. Materials and Methods: To perform a meta-analysis, a systematic search for the literature on GSTM1 and GSTT1 null genotypes was done to identify 63 reports for 81 human populations. Relationships between the GSTM1 and GSTT1 null genotype frequencies and the absolute latitude of 81 populations were tested by Spearman's rank correlation coefficient. Results: A significant positive correlation was detected between the GSTM1 null genotype frequency and the absolute latitude (r=0.28, p-value <0.05), whereas the GSTT1 null genotype frequency and absolute latitude showed a significant negative correlation (r= -0.41 p-value <0.01). There was no correlation between the frequencies of GSTM1 and GSTT1 null genotype in each population (r= -0.029, p-value=0.80). Conclusions: Latitudinal clines of the distribution of the GSTM1 and GSTT1 null genotypes may be attributed to the result of gene-environmental adaptation. No functional compensation between GSTM1 and GSTT1 was suggested by the lack of correlation between the null frequencies for GSTM1 and GSTT1.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.433-438
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• 2018

This study examined the effects of ambiguity aversion on the self-protection and self-insurance efforts using a two-period model to consider the time difference between making an effort and occurring loss, which is in contrast with the existing one-period model. The loss follows a binary distribution while the distribution is ambiguous. The distribution depends on the state variable. First, the effort of ambiguity averse individuals is not always greater than that of ambiguity neutral ones. Second, the effects of absolute ambiguity aversion (AAA), which does not appear in one-period model, were observed. Not-increasing AAA is a sufficient condition to increase the efforts of ambiguity averse individuals compared to those of ambiguity neutral ones. In addition, the change in effort also depends on the probability function of the state. Lastly, the results hold even when the individual is risk neutral or risk loving. As a result, ambiguity aversion needs to be considered independently with risk aversion.

• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.264-273
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• 2016

The insulation of a building envelope influences the hygrothermal performance as well as the thermal performance of the building. While most of Korean wood frame houses have an interior insulation system, the exterior insulation system with high thermal performance has recently been applied. While it can be effective in energy savings for better insulation performance, without consideration of the moisture, condensation and mould growth can occur. Therefore, in this study, hygrothermal behaviour, water content, and mould growth were analyzed using hygrothermal simulation of an exterior wall of a wood frame house with which the interior insulation and exterior insulation systems were applied. The wall layer included Wall A (Interior insulation) and Wall B (Exterior insulation). The U-values were identified as 0.173 and $0.157W/m^2K$, respectively. The total water content and OSB absolute water content of Wall A were confirmed to be higher than those of Wall B, but the absolute water content did not exceed the reference value of 20%. The moisture content of the two walls was determined to be stable in the selected areas. However, mould growth risk analysis confirmed that both Wall A and Wall B were at risk of mould growth. It was confirmed that as the indoor setting temperature decreased, the mould index and growth rate in the same area increased. Therefore, the mould growth risk was affected more by indoor and outdoor climate conditions than by the position of the insulation. Consequently, the thermal performance of Wall B was superior to that of Wall A but the hygrothermal performances were confirmed to be similar.

• Genomics & Informatics
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• v.14 no.4
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• pp.138-148
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• 2016

The success of genome-wide association studies (GWASs) has enabled us to improve risk assessment and provide novel genetic variants for diagnosis, prevention, and treatment. However, most variants discovered by GWASs have been reported to have very small effect sizes on complex human diseases, which has been a big hurdle in building risk prediction models. Recently, many statistical approaches based on penalized regression have been developed to solve the "large p and small n" problem. In this report, we evaluated the performance of several statistical methods for predicting a binary trait: stepwise logistic regression (SLR), least absolute shrinkage and selection operator (LASSO), and Elastic-Net (EN). We first built a prediction model by combining variable selection and prediction methods for type 2 diabetes using Affymetrix Genome-Wide Human SNP Array 5.0 from the Korean Association Resource project. We assessed the risk prediction performance using area under the receiver operating characteristic curve (AUC) for the internal and external validation datasets. In the internal validation, SLR-LASSO and SLR-EN tended to yield more accurate predictions than other combinations. During the external validation, the SLR-SLR and SLR-EN combinations achieved the highest AUC of 0.726. We propose these combinations as a potentially powerful risk prediction model for type 2 diabetes.

• Korean Journal of Health Education and Promotion
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• v.32 no.5
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• pp.73-81
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• 2015

Objectives: We tried to confirm physical activity of 1,000 Kcal per week was a meaningful point in controlling coronary artery disease risks in female older adults. Methods: Participants were 66 female older adults recruited from senior welfare center. Participants were provided with accelerometer (e-step, Kenz, Japan) for measuring daily energy expenditure. Graded exercise test was done for measuring aerobic fitness. Blood glucose and lipid were analyzed. Framingham risk score was calculated based on blood glucose, blood lipid, and smoking. These variables were compared between the group expended more than 1,000 Kcal/week and the group with energy expenditure below 1,000 Kcal/week. Results: The group expended over 1,000kcal/week showed to be superior to the counterpart group in following variables; AC(Abdominal Circumference), %BF, $HR_{rest}$(resting heart rate), $VO_{2peak}$, FBG, LDL-C, TG, BDI-II, QOL, AR(Absolute Risk), RR(Relative Risk). Conclusions: The group expended over 1,000 Kcal/week was likely to have less probability in CAD than group expended less than 1,000 Kcal/week. The result of this study suggests the important role of active daily life that can be replaced with that of regular exercise especially for those who are not available to do structured exercise.

• Nutrition Research and Practice
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• v.6 no.3
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• pp.246-253
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• 2012

The Framingham risk score (FRS) has been used to assess the risk of a cardiovascular event and to identify patients for risk factor modifications. Therefore, the purpose of this study was to evaluate the relationship of the FRS with dietary intake and inflammatory biomarkers. We conducted a cross-sectional study of 180 men ($49.2{\pm}10.2$ years) with MS. Serum levels of high sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6), and adiponectin were examined. Participants were asked to complete the food frequency questionnaire (FFQ) using the previous 1 year as a reference point. The absolute cardiovascular disease (CVD) risk percentage over 10 years was calculated to estimate the FRS, which was classified as low risk (< 10%), intermediate risk (10-20%), and high risk (> 20%). Mean intake of polyunsaturated fatty acids was lower in subjects who had > 20% FRS than in subjects who had < 10% FRS ($3.7{\pm}1.9$ g/day vs. $4.7{\pm}1.9$ g/day; P < 0.05). Significant differences in the Index of Nutritional Quality of protein, phosphorus, iron, vitamin A, vitamin $B_1$, niacin, vitamin $B_6$, and vitamin C were observed between the > 20% FRS group and the < 10% FRS group (P < 0.05). IL-6 concentrations were significantly lower in subjects with a < 10% FRS than in subjects who were 10-20% FRS or > 20% FRS ($0.91{\pm}0.26$ vs. $1.48{\pm}033$ vs. $2.72{\pm}0.57$ pg/mL, respectively; P < 0.05). IL-6 and dietary intake of polyunsaturated fatty acids together explained 6.6% of the variation in FRS levels in a stepwise multiple regression model. Our results provide some evidence that dietary intake in the higher CVD risk group was inferior to that in the lower risk group and that dietary fat intake and IL-6 were associated with FRS and MS in Korean men.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.8
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• pp.3377-3381
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• 2014

Background: The incidence of colorectal cancer increases with vitamin D deficiency as shown in recently published studies. In addition, prospective investigations have indicated that low vitamin D levels may be associated with increased mortality of colorectal cancer, especially in stage III and IV cases. However, the exact incidence of vitamin D deficiency and the relation between vitamin D deficiency and osteopenia/osteporosis is still not known. The aim of this study is to identify severity of vitamin D deficiency and absolute risk factors of osteopenia/osteoporosis in colorectal cancer survivors. Materials and Methods: A total of 113 colorectal cancer survivors treated with surgery and/or chemotherapy ${\pm}$ radiotherapy were recruited from medical oncology outpatient clinics during routine follow-up visits in 2012-2013. Bone mineral densitometry (BMD) was performed, and serum 25-OH vitamin D levels were also checked on the same day of the questionnaire. The patients was divided into 2 groups, group A with normal BMD and group B with osteopenia/osteoporosis. Results: The median age of the study population was 58 (40-76). Thirty (30.0%) were female, whereas 79 (70.0%) were male. The median follow-up was 48 months (14-120 months). Vitamin D deficiency was found in 109 (96.5%); mild deficiency (20-30 ng/ml) in 19 (16.8%), moderate deficiency (10-20 ng/ml) in 54 (47.8%) and severe deficiency (<10 ng/ml) in 36 (31.9%). Osteopenia was evident in 58 (51.4%) patients whereas osteoporosis was noted in 17 (15.0%). Normal BMD was observed in 38 (33.6%). No apparent effects of type of surgery, presence of stoma, chemotherapy, radiotherapy and TNM stage were found regarding the risk of osteopenia and osteoporosis. Also, the severity of the vitamin D deficiency had no effect in the risk of osteopenia and osteporosis (p=0.93). In female patients, osteopenia/osteoporosis were observed in 79.5% patients as compared to 60.7% of male patients (p=0.04). Conclusions: In our study, vitamin D deficiency and osteopenia/osteoporosis was observed in 96.5% and 66.4% of colorectal cancer survivors, respectively. There is no defined absolute risk factor of osteopenia and osteoporosis in colorectal cancer survivors. To our knowledge, in the literature, our study is the first to evaluateall the risk factors of osteopenia and osteoporosis in colorectal cancer survivors.

• Journal of the Korean Society of School Health
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• v.22 no.1
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• pp.49-59
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• 2009

Purpose: The aim of this study was to identify the factors related with the intention of smoking abstinence among elementary students in a metropolitan city in Korea. Methods: All the elementary schools in the city were stratified by region, and then schools as a primary sampling units (PSU) were selected by probability proportional to size (PPS) sampling. One class per grade was sampled randomly from 5th and 6th grade in the sampled schools from October to December in 2004. The students completed a standardized self-administered questionnaire anonymously. A total number of 1,712 respondents who did not smoke was included in the final analysis. The dependent variable was an intention of smoking in the future, and it was dichotomized into 'absolutely confident in smoking abstinence' and 'others'. The risk of non-absolute confidence in smoking abstinence was calculated with simple and multiple logistic regression, which were conducted with STATA 9.0 by a design-based analysis considering strata variable, PSU, and sampling weight. Results: In the final model of multiple logistic regression analysis, those who were more likely to have non-absolute confidence in smoking abstinence were male students (OR=2.66, p<0.001); barely attending religious services (OR=3.32, p=0.002) or having no religion (OR=1.95, p=0.027); exposure to environmental tobacco smoke outside home 1${\sim}$2 days per week (OR=1.60, p=0.013); having friends who smoked (OR=1.93, p=0.011); non-absolute confidence in refusing to smoke (OR=5.35, p<0.001); having relatively less negative attitude (OR=2.88, p<0.001), positive attitude (OR=2.35, p<0.001), and indifference (OR=4.05, p=0.034) toward peer smoking; not good relationship with mother (OR=1.52, p=0.016). Conclusion: The factors related with non-absolute confidence in smoking abstinence were coincided with those of smoking among children. The results of this study suggest the smoking prevention education should be applied to the children more actively, especially who are not confident in smoking abstinence in the future.

• Genomics & Informatics
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• v.5 no.3
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• pp.95-101
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• 2007

In this paper, we consider the variable selection methods in the Cox model when a large number of gene expression levels are involved with survival time. Deciding which genes are associated with survival time has been a challenging problem because of the large number of genes and relatively small sample size (n<