• Journal of Preventive Medicine and Public Health
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• v.56 no.5
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• pp.458-466
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• 2023

Objectives: The association between long sleep duration and mortality is frequently attributed to the confounding influence of comorbidities. Nevertheless, past efforts to account for comorbidities have yielded inconsistent outcomes. The objective of this study was to evaluate this relationship using a large prospective cohort in Korea. Methods: The study included 114 205 participants from the Health Examinees Study, who were followed for a median of 9.1 years. A composite comorbidity score was developed to summarize the effects of 21 diseases. Using Cox proportional hazards regression, hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause, cancer, and cardiovascular mortality associated with sleep duration were estimated. These estimates were adjusted for socio-demographic factors, lifestyle factors, body mass index, and comorbidity score. Additionally, a stratified analysis by subgroups with and without comorbidities was conducted. Results: Throughout the follow-up period, 2675 deaths were recorded. After all adjustments, an association was observed between a sleep duration of 8 hours or more and all-cause mortality (HR, 1.10; 95% CI, 1.01 to 1.20). However, no such association was detected in the stratified analysis for the subgroups based on comorbidity status. Conclusions: Long sleep duration was found to be associated with all-cause mortality among Koreans, even after adjusting for comorbidities. Additional studies are required to explore the mechanism underlying the association between sleep duration and major causes of mortality.

• 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.

• Parasites, Hosts and Diseases
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• v.45 no.2 s.142
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• pp.149-152
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• 2007

A cohort was established for evaluation of cancer risk factors in Sancheong-gun, Gyeongsangnam-do, Korea. As one of the cohort studies, stools of 947 residents (403 males and 544 females, age range: 29-86 years) were screened for Clonorchis sinensis eggs using both Kato-Katz method and formalin-ether sedimentation technique. The overall egg positive rate of C. sinensis was 37.7% and individual EPG (eggs per gram of feces) counts ranged from 24 to 28,800. Eight egg positive residents voluntarily joined a process of collection of the passed worms after praziquantel treatment. A total of 158 worms were recovered from 5 of the 8 treated persons, ranged from 3 to 108 in each individual. The worms were $15-20 mm{\times}2-3 mm$ in size, and showed brown-pigmented, red, or white body colors. This is the first collection record of C. sinensis adult worms from humans through anthelmintic treatment and purgation. The adult worms of C. sinensis may be paralyzed by praziquantel and then discharged passively through bile flow in the bile duct and by peristaltic movement of the bowel.

• Journal of Preventive Medicine and Public Health
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• v.45 no.1
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• pp.14-20
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• 2012

Objectives: The aim of this study was to evaluate and quantify the risk of both individual and combined health behaviors on premature mortality in middle aged men in Korea. Methods: In total, 14 533 male subjects 40 to 59 years of age were recruited. At enrollment, subjects completed a baseline questionnaire, which included information about socio-demographic factors, past medical history, and life style. During the follow-up period from 1993 to 2008, we identified 990 all-cause premature deaths using national death certificates. A Cox proportional hazard regression model was used to estimate the hazard ratio (HR) of each health risk behavior, which included smoking, drinking, physical inactivity, and lack of sleep hours. Using the Cox model, each health behavior was assigned a risk score proportional to its regression coefficient value. Health risk scores were calculated for each patient and the HR of all-cause premature mortality was calculated according to risk score. Results: Current smoking and drinking, high body mass index, less sleep hours, and less education were significantly associated with all-cause premature mortality, while regular exercise was associated with a reduced risk. When combined by health risk score, there was a strong trend for increased mortality risk with increased score (p-trend < 0.01). When compared with the 1-9 score group, HRs of the 10-19 and 20-28 score groups were 2.58 (95% confidence intervals [CIs], 2.19 to 3.03) and 7.09 (95% CIs, 5.21 to 9.66), respectively. Conclusions: Modifiable risk factors, such as smoking, drinking, and regular exercise, have considerable impact on premature mortality and should be assessed in combination.

• Nutrition Research and Practice
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• v.11 no.6
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• pp.492-499
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• 2017

BACKGROUND/OBJECTIVES: This study aimed to investigate the association of dietary patterns with overweight risk and all-cause mortality in pediatric cancer patients. SUBJECTS/METHODS: Prospective cohort study was undertaken; 83 cancer patients admitted to the pediatric cancer ward at a university hospital in Seoul were included and followed for obesity and death over 24 months. Food consumption data were collected from patients using validated meal order sheets for breakfast, lunch, and dinner at the pediatric cancer ward over 3 days. Using principal component analysis, three dietary patterns were derived from 29 food groups. RESULTS: Eighteen deaths occurred among the patient cohort during the follow-up period. The "spicy & fried meat and fish" dietary pattern was positively associated with overweight risk at both baseline [odds ratio (OR) = 4.396, 95% confidence interval (CI) = 1.111-17.385, P for trend = 0.023] and after 6 months (OR = 4.088, 95% CI = 1.122-14.896, P for trend = 0.025) as well as all-cause mortality (hazard ratios = 5.124, 95% CI = 1.080-24.320, P for trend = 0.042), when comparing the highest and lowest tertiles after adjusting for covariates. The "fish, egg, meat, and fruits & vegetables" dietary pattern was associated with lower overweight risk after 24 months (OR = 0.157, 95% CI = 0.046-0.982, P for trend = 0.084). CONCLUSION: The results imply that dietary patterns might be associated with weight gain and premature death among pediatric cancer patients.

• Korean Circulation Journal
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• v.53 no.1
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• pp.17-30
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• 2023

Background and Objectives: To evaluate the impact of smoking in young adults on the risk of cardiovascular disease (CVD) and the clustering effect of behavioral risk factors such as smoking, obesity, and depression. Methods: A Korean nationwide population-based cohort of a total of 3,280,826 participants aged 20-39 years old who underwent 2 consecutive health examinations were included. They were followed up until the date of CVD (myocardial infarction [MI] or stroke), or December 2018 (median, 6 years). Results: Current smoking, early age of smoking initiation, and smoking intensity were associated with an increased risk of CVD incidence. Even after quitting smoking, the risk of MI was still high in quitters compared with non-smokers. Cigarette smoking, obesity, and depression were independently associated with a 1.3-1.7 times increased risk of CVD, and clustering of 2 or more of these behavioral risk factors was associated with a 2-3 times increased risk of CVD in young adults. Conclusions: In young adults, cigarette smoking was associated with the risk of CVD, and the clustering of 2 or more behavioral risk factors showed an additive risk of CVD.

• Journal of Chest Surgery
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• v.57 no.3
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• pp.302-311
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• 2024

Background: Unexpected conversion to thoracotomy during planned video-assisted thoracoscopic surgery (VATS) can lead to poor outcomes and comparatively high morbidity. This study was conducted to assess preoperative risk factors associated with unexpected thoracotomy conversion and to develop a risk scoring model for preoperative use, aimed at identifying patients with an elevated risk of conversion. Methods: A retrospective analysis was conducted of 1,506 patients who underwent surgical resection for non-small cell lung cancer. To evaluate the risk factors, univariate analysis and logistic regression were performed. A risk scoring model was established to predict unexpected thoracotomy conversion during VATS of the lung, based on preoperative factors. To validate the model, an additional cohort of 878 patients was analyzed. Results: Among the potentially significant clinical variables, male sex, previous ipsilateral lung surgery, preoperative detection of calcified lymph nodes, and clinical T stage were identified as independent risk factors for unplanned conversion to thoracotomy. A 6-point risk scoring model was developed to predict conversion based on the assessed risk, with patients categorized into 4 groups. The results indicated an area under the receiver operating characteristic curve of 0.747, with a sensitivity of 80.5%, specificity of 56.4%, positive predictive value of 1.8%, and negative predictive value of 91.0%. When applied to the validation cohort, the model exhibited good predictive accuracy. Conclusion: We successfully developed and validated a risk scoring model for preoperative use that can predict the likelihood of unplanned conversion to thoracotomy during VATS of the lung.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.1
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• pp.114-126
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• 2016

Many cohort studies have reported associations of individual-level long-term exposures to $PM_{10}$ and health outcomes. Individual exposures were often estimated by using exposure prediction models relying on $PM_{10}$ data measured at national regulatory monitoring sites. This study explored spatial and temporal characteristics of regulatory $PM_{10}$ measurement data in South Korea and suggested $PM_{10}$ concentration metrics as long-term exposures for assessing health effects in cohort studies. We obtained hourly $PM_{10}$ data from the National Institute of Environmental Research for 2001~2012 in South Korea. We investigated spatial distribution of monitoring sites using the density and proximity in each of the 16 metropolitan cities and provinces. The temporal characteristics of $PM_{10}$ measurement data were examined by annual/seasonal/diurnal patterns across urban background monitoring sites after excluding Asian dust days. For spatial characteristics of $PM_{10}$ measurement data, we computed coefficient of variation (CV) and coefficient of divergence (COD). Based on temporal and spatial investigation, we suggested preferred long-term metrics for cohort studies. In 2010, 294 urban background monitoring sites were located in South Korea with a site over an area of $415.0km^2$ and distant from another site by 31.0 km on average. Annual average $PM_{10}$ concentrations decreased by 19.8% from 2001 to 2012, and seasonal $PM_{10}$ patterns were consistent over study years with higher concentrations in spring and winter. Spatial variability was relatively small with 6~19% of CV and 21~46% of COD across 16 metropolitan cities and provinces in 2010. To maximize spatial coverage and reflect temporal and spatial distributions, our suggestion for $PM_{10}$ metrics representing long-term exposures was the average for one or multiple years after 2009. This study provides the knowledge of all available $PM_{10}$ data measured at national regulatory monitoring sites in South Korea and the insight of the plausible longterm exposure metric for cohort studies.

• Journal of Preventive Medicine and Public Health
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• v.45 no.5
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• pp.301-308
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• 2012

Objectives: To examine the association between alcohol consumption habit, types of beverages, alcohol consumption quantity, and overall and cancer-specific mortality among Korean adults. Methods: The alcohol consumption information of a total of 16 320 participants who were 20 years or older from the Korean Multicenter Cancer Cohort were analyzed to examine the association between alcohol consumption habit and mortality (median follow-up of 9.3 years). The Cox proportional hazard model was used to estimate the hazard ratio (HR) of alcohol consumption to mortality adjusting for age, sex, geographic areas, education, smoking status, and body mass index. Results: Alcohol drinkers showed an increased risk for total mortality compared with never drinkers (HR, 1.72; 95% confidence interval [CI], 1.38 to 2.14 for past drinkers; HR, 1.21; 95% CI, 1.06 to 1.39 for current drinkers), while past drinkers only were associated with higher risk for cancer deaths (HR, 1.84; 95% CI, 1.34 to 2.53). The quantity of alcohol consumed per week showed a J-shaped association with risk of mortality. Relative to light drinkers (0.01 to 90 g/wk), never drinkers and heavy drinkers (>504 g/wk) had an increased risk for all-cause and cancer deaths: (HR, 1.18; 95% CI, 0.96 to 1.45) and (HR, 1.39; 95% CI, 1.05 to 1.83) for all-cause mortality; and (HR, 1.55; 95% CI, 1.15 to 2.11) and (HR, 2.07; 95% CI, 1.39 to 3.09) for all cancer mortality, respectively. Heavy drinkers (>504 g/wk) showed an elevated risk for death from stomach and liver cancers. Conclusions: The present study supports the existence of a J-shaped association between alcohol consumption quantity and the risk of all-cause and cancer deaths. Heavy drinkers had an increased risk of death from cancer overall and liver and stomach cancer.

• Archives of Plastic Surgery
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• v.46 no.6
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• pp.525-534
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• 2019

Background In microtia patients with bilateral hearing impairment, hearing improvement is crucial for language development and performance. External auditory canal reconstruction (EACR) has been performed to improve hearing, but often results in complications. We performed transcutaneous bone conduction implant (TBCI) surgery in these patients. This study aimed to evaluate the safety and efficacy of TBCI surgery. Methods A retrospective review was performed of five patients who underwent auricular reconstruction and TBCI surgery and 12 patients who underwent EACR between March 2007 and August 2018. Hearing improvement was measured based on the air-bone gap values using pure-tone audiometry over a 6-week postoperative period. We reviewed other studies on hearing improvement using EACR and compared the findings with our results. The surgical techniques for TBCI were reviewed through case analyses. Results Postoperative hearing outcomes showed a significant improvement, with a mean gain of 34.1 dB in the TBCI cohort and 14.1 dB in the EACR cohort. Both gains were statistically significant; however, the TBCI cohort showed much larger gains. Only three of the 12 patients who underwent EACR achieved hearing gains of more than 20 dB, which is consistent with previous studies. All patients who underwent TBCI surgery demonstrated hearing gains of more than 20 dB and experienced no device-related complications. Conclusions TBCI is a safe and effective method of promoting hearing gains in microtia patients with bilateral hearing impairment. TBCI surgery provided better hearing outcomes than EACR and could be performed along with various auricular reconstruction techniques using virgin mastoid skin.