• Tuberculosis and Respiratory Diseases
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• v.62 no.5
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• pp.365-373
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• 2007

Background: Smoking is one of the most important leading causes of morbidity and mortality. Smoking habit is recognized as nicotine dependence, which consists of physical and psychosocial dependence. To evaluate social nicotine dependence, the Kano Test for Social Nicotine Dependence (KTSND) working group developed a new questionnaire, which consists of 10 questions with a total score of 30 in Japan. We examined the social nicotine dependence among healthy adults using the new KTSND questionnaire and evaluated validity of the KTSND questionnaire in Korea. Method: We applied Korean KTSND questionnaire version 2 to employees of hospital, university students and people for medical examination and promotion test. Complete data obtained from the 741 responders were analyzed. Result: The mean age of responders was 31.8 years. Among them, males were 57.8%. Current smokers, ex-smokers, and non-smokers were 13.8%, 12.8%, and 73.4% respectively. According to smoking status, the total KTSND scores of current smokers were significantly higher than those of ex-smokers, and of non-smokers ($17.1{\pm}5.4$ versus $14.3{\pm}5.5$, and $12.3{\pm}5.5$, $p{\leq}0.001$). The total KTSND scores of males were higher than those of females, suggesting that males have a propensity for depending nicotine socially much more than females ($14.3{\pm}5.7$ and $11.7{\pm}5.4$ respectively, p<0.001). Eight of ten questions produced significantly different scores among three different smoking groups. When current smokers were sub-classified by heavy smoking index (HSI) that represented physical nicotine dependence, we did not find a significant difference of KTSND score between low HSI group (<4) and high HSI group (${\geq}4$), This finding suggested that the psychosocial dependence might play a different role from physical nicotine dependence in smoking. Most of the non-smokers (62.5%) had an experience of harmful passive smoking especially in public place. Conclusion: Our study suggested that the KTSND questionnaire could be a useful method to evaluate psychosocial aspects of smoking.

• Journal of Nutrition and Health
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• v.52 no.5
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• pp.488-500
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• 2019

Purpose: This study examined the effects of a mobile app-based program to reduce the dietary sugar intake according to the stages of the behavioral change in dietary sugar reduction in female college students. Methods: The program used in this study can monitor the dietary sugar intake after recording the dietary intake and provide education message for the reduction of dietary sugar intake. In an eight-week pre-post intervention study, 68 female college students were instructed to record all the food they consumed daily and received weekly education information. At pre-post intervention, the subjects were asked to answer the questionnaire about sugar-related nutrition knowledge, sugar-intake behavior, and sugar-intake frequency. For statistical analysis, ANOVA and a paired t-test were used for comparative analysis according Precontemplation (PC), Contemplation Preparation (C P), and A M (Action Maintenance) stage. Results: Significant differences were observed in the frequency of snacking, experience of nutrition education, and preference for sweetness according to the stages of behavior change in dietary sugar reduction. After finishing an intervention, the sugar-related nutrition knowledge score was increased significantly in the stages of Precontemplation (PC) and Contemplation Preparation (C P). The score of the sugar intake behavior increased significantly in all stages. The intake frequency of chocolate, muffins or cakes, and drinking yogurt decreased significantly in the PC stage and the intake frequency of biscuits, carbonated beverages, and fruit juice decreased significantly in the C P stage. Subjects in the PC and C P stages had an undesirable propensity in nutrition knowledge, sugar-intake behavior, and sugar-intake frequency compared to the A M stage, but this intervention improved significantly their nutrition knowledge, sugar-intake behavior, and sugar-intake frequency. Conclusion: This program can be an effective educational tool in the stages of PC and C P, and is expected to further increase the usability and sustainability of mobile application if supplemented appropriately to a health platform program.

• Journal of Intelligence and Information Systems
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• v.21 no.1
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• pp.119-142
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• 2015

With the explosive growth in the volume of information, Internet users are experiencing considerable difficulties in obtaining necessary information online. Against this backdrop, ever-greater importance is being placed on a recommender system that provides information catered to user preferences and tastes in an attempt to address issues associated with information overload. To this end, a number of techniques have been proposed, including content-based filtering (CBF), demographic filtering (DF) and collaborative filtering (CF). Among them, CBF and DF require external information and thus cannot be applied to a variety of domains. CF, on the other hand, is widely used since it is relatively free from the domain constraint. The CF technique is broadly classified into memory-based CF, model-based CF and hybrid CF. Model-based CF addresses the drawbacks of CF by considering the Bayesian model, clustering model or dependency network model. This filtering technique not only improves the sparsity and scalability issues but also boosts predictive performance. However, it involves expensive model-building and results in a tradeoff between performance and scalability. Such tradeoff is attributed to reduced coverage, which is a type of sparsity issues. In addition, expensive model-building may lead to performance instability since changes in the domain environment cannot be immediately incorporated into the model due to high costs involved. Cumulative changes in the domain environment that have failed to be reflected eventually undermine system performance. This study incorporates the Markov model of transition probabilities and the concept of fuzzy clustering with CBCF to propose predictive clustering-based CF (PCCF) that solves the issues of reduced coverage and of unstable performance. The method improves performance instability by tracking the changes in user preferences and bridging the gap between the static model and dynamic users. Furthermore, the issue of reduced coverage also improves by expanding the coverage based on transition probabilities and clustering probabilities. The proposed method consists of four processes. First, user preferences are normalized in preference clustering. Second, changes in user preferences are detected from review score entries during preference transition detection. Third, user propensities are normalized using patterns of changes (propensities) in user preferences in propensity clustering. Lastly, the preference prediction model is developed to predict user preferences for items during preference prediction. The proposed method has been validated by testing the robustness of performance instability and scalability-performance tradeoff. The initial test compared and analyzed the performance of individual recommender systems each enabled by IBCF, CBCF, ICFEC and PCCF under an environment where data sparsity had been minimized. The following test adjusted the optimal number of clusters in CBCF, ICFEC and PCCF for a comparative analysis of subsequent changes in the system performance. The test results revealed that the suggested method produced insignificant improvement in performance in comparison with the existing techniques. In addition, it failed to achieve significant improvement in the standard deviation that indicates the degree of data fluctuation. Notwithstanding, it resulted in marked improvement over the existing techniques in terms of range that indicates the level of performance fluctuation. The level of performance fluctuation before and after the model generation improved by 51.31% in the initial test. Then in the following test, there has been 36.05% improvement in the level of performance fluctuation driven by the changes in the number of clusters. This signifies that the proposed method, despite the slight performance improvement, clearly offers better performance stability compared to the existing techniques. Further research on this study will be directed toward enhancing the recommendation performance that failed to demonstrate significant improvement over the existing techniques. The future research will consider the introduction of a high-dimensional parameter-free clustering algorithm or deep learning-based model in order to improve performance in recommendations.

• The Korean Journal of Gastroenterology
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• v.72 no.5
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• pp.271-273
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• 2018

내시경 시술 전 일시적으로 항응고제를 중단하는 것은 위장관 출혈의 위험과 혈전색전증의 위험 사이에 적절한 균형을 잡기 어렵기 때문에 논란의 여지가 많다. 와파린은 새로운 경구용 항응고제(direct oral anticoagulant agent, DOAC)보다 임상의에게 더 친숙하고, 효과를 쉽고 빠르게 전환시킬 수 있다는 장점이 있지만 복잡한 약역동학 특징과 좁은 치료적 범위 때문에 관리가 어렵다. 반면, DOAC는 약물의 모니터링 및 용량 조절 없이 정해진 용량으로 처방이 가능하며, 빠르게 작용하고, 반감기가 짧아 관리가 쉽지만 해독제가 없다는 단점이 있다. 이전 연구들에서 DOAC를 복용한 환자들은 와파린을 복용한 환자들보다 시술과 관련되지 않은 위장관 출혈의 위험이 높았다고 보고한 바 있다. 하지만 시술과 관련된 위장관 출혈 위험에 대하여는 알려진 바가 없는 실정이다. 미국이나 유럽 내시경 가이드라인들에서는 저위험 내시경 시술을 받는 환자들에서는 와파린과 DOAC를 유지하도록 권고하고 있으며, 고위험 시술의 경우에는 와파린를 사용하는 환자들에서 헤파린 교량 요법(heparin bridging)을 시행하도록 권고하고 있다. 임상적으로 DOAC를 사용하는 환자들 또한 혈전색전증을 예방하기 위하여 헤파린 교량 요법을 시행해볼 수 있는데, 와파린 및 DOAC의 헤파린 교량 요법과 관련된 출혈 및 혈전색전증 위험의 차이 또한 명확하지 않다. 따라서 저자들은 1) 와파린과 DOAC 치료를 받는 환자들에서의 출혈, 혈전색전증 및 사망의 위험을 비교하고자 하였으며, 2) 13종류의 고위험 내시경 시술 중에서 시술별 위험을 비교하고, 3) 헤파린 교량 요법이 합병증의 발생을 증가시키지 않는지 확인하고자 본 연구를 진행하였다. 일본 대규모 국가 입원 환자 데이터베이스를 이용하여 2014년 4월부터 2015년 5월까지 시술 전 와파린 또는 DOAC(rivaroxaban, apixaban, dabigatran, edoxaban)를 복용하고, 13종류의 고위험 내시경 시술을 시행받은 20세 이상의 성인 환자 총 16,977명을 확인하였다. 고위험 시술은 용종 절제술, 내시경 점막절제술, 내시경 점막하박리술, 협착 부위의 풍선확장술, 내시경 지혈술, 내시경 정맥결찰술, 내시경 주사 경화요법, 내시경 괄약근절개술, 내시경 초음파 유도하 미세침 흡인 검사, 경피적 위루술을 포함하였다. 일대일 성향 점수 매칭 분석(propensity score matching, 나이, 성별, 체질량 지수, 기저 질환, 병원의 규모, 시술의 종류, 약물의 종류를 매칭)을 시행하여 와파린군과 DOAC군에서 시술 위장관 출혈 및 혈전색전증, 사망의 발생을 비교하였다. 또한 경구항혈전제와 헤파린 교량 치료 시행 유무에 따라, DOAC 단독군, 와파린 단독군, DOAC와 헤파린 교량 요법군, 와파린과 헤파린 교량요법군으로 나누어, 하위군(subgroup) 분석을 시행하였다. 5,046쌍이 성향 점수 매칭 분석에 포함되었으며, 와파린군에서 DOAC군보다 통계적으로 의미 있게 위장관 출혈의 비율이 높았다(12.0% vs. 9.9% p=0.02). 혈전색전증 발생률(5.4% vs. 4.7%)과 입원중 사망률(5.4% vs. 4.7%)은 양 군에서 의미 있는 차이는 없었다. DOAC 종류별로 나누어 하위군 분석을 시행하였을 때, 와파린군은 rivaroxaban군에 비하여 위장관 출혈의 비율이 높았으며, rivaroxaban군, dabigatran군에 비하여 혈전색전증의 비율이 높았고, 입원 중 사망률에서는 의미 있는 차이는 없었다. 내시경 시술의 종류로 보정하였을 때 위장관 출혈 및 혈전색전증, 사망률은 DOAC 단독으로 치료한 환자에서보다 와파린과 헤파린 교량 요법(bridging) 또는 DOAC과 헤파린 교량 요법을 시행한 환자에서 높았다. 시술 종류 중에서는 위루관 삽입술에 비하여 내시경 점막하박리술, 내시경 점막절제술 및 내시경 정맥류결찰술, 내시경 주사경화요법을 시행한 환자에서 위장관 출혈의 위험이 가장 높았으며, 하부 내시경 점막절제술, 하부 용종 절제술, 내시경적 유두괄약근절제술 또는 내시경 초음파 유도하 미세침 흡인 검사는 중등도 위험을 보였다.

• Korean Circulation Journal
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• v.52 no.6
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• pp.460-474
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• 2022

Background and Objectives: This study aimed to investigate the association between cardiovascular events and 2 different levels of elevated on-treatment diastolic blood pressures (DBP) in the presence of achieved systolic blood pressure targets (SBP). Methods: A nation-wide population-based cohort study comprised 237,592 patients with hypertension treated. The primary endpoint was a composite of cardiovascular death, myocardial infarction, and stroke. Elevated DBP was defined according to the Seventh Report of Joint National Committee (JNC7; SBP <140 mmHg, DBP ≥90 mmHg) or to the 2017 American College of Cardiology/American Heart Association (ACC/AHA) definitions (SBP <130 mmHg, DBP ≥80 mmHg). Results: During a median follow-up of 9 years, elevated on-treatment DBP by the JNC7 definition was associated with an increased risk of the occurrence of primary endpoint compared with achieved both SBP and DBP (adjusted hazard ratio [aHR], 1.14; 95% confidence interval [CI], 1.05-1.24) but not in those by the 2017 ACC/AHA definition. Elevated on-treatment DBP by the JNC7 definition was associated with a higher risk of cardiovascular mortality (aHR, 1.42; 95% CI, 1.18-1.70) and stroke (aHR, 1.19; 95% CI, 1.08-1.30). Elevated on-treatment DBP by the 2017 ACC/AHA definition was only associated with stroke (aHR, 1.10; 95% CI, 1.04-1.16). Similar results were seen in the propensity-score-matched cohort. Conclusion: Elevated on-treatment DBP by the JNC7 definition was associated a high risk of major cardiovascular events, while elevated DBP by the 2017 ACC/AHA definition was only associated with a higher risk of stroke. The result of study can provide evidence of DBP targets in subjects who achieved SBP targets.