• Nutrition Research and Practice
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• v.12 no.3
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• pp.258-264
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• 2018

BACKGROUND/OBJECTIVES: Diet quality scores or indices, based on dietary guidelines, are used to summarize dietary intake into a single numeric variable. The aim of this study was to examine the association between the modified diet quality index for Koreans (DQI-K) and mortality among Health Examinees-Gem (HEXA-G) study participants. SUBJECTS/METHODS: The DQI-K was modified from the original diet quality index. A total of 134,547 participants (45,207 men and 89,340 women) from the HEXA-G study (2004 and 2013) were included. The DQI-K is based on eight components: 1) daily protein intake, 2) percent of energy from fat, 3) percent of energy from saturated fat, 4) daily cholesterol intake, 5) daily whole-grain intake, 6) daily fruit intake, 7) daily vegetable intake, and 8) daily sodium intake. The association between all-cause mortality and the DQI-K was examined using Cox proportional hazard regression models. Hazard ratios and confidence intervals were estimated after adjusting for age, gender, income, smoking status, alcohol drinking, body mass index, and total energy intake. RESULTS: The total DQI-K score was calculated by summing the scores of the eight components (range 0-9). In the multivariable adjusted models, with good diet quality (score 0-4) as a reference, poor diet quality (score 5-9) was associated with an increased risk of all-cause mortality (hazard ratios = 1.23, 95% confidence intervals = 1.06-1.43). Moreover, a one-unit increase in DQI-K score resulted in a 6% higher mortality risk. CONCLUSIONS: A poor diet quality DQI-K score was associated with an increased risk of mortality. The DQI-K in the present study may be used to assess the diet quality of Korean adults.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.4839-4842
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• 2014

Background: Although the Cox's proportional hazard model is the popular approach for survival analysis to investigate significant risk factors of cancer patient survival, it is not appropriate in the case of log-term disease free survival. Recently, cure rate models have been introduced to distinguish between clinical determinants of cure and variables associated with the time to event of interest. The aim of this study was to use a cure rate model to determine the clinical associated factors for cure rates of patients with breast cancer (BC). Materials and Methods: This prospective cohort study covered 305 patients with BC, admitted at Shahid Faiazbakhsh Hospital, Tehran, during 2006 to 2008 and followed until April 2012. Cases of patient death were confirmed by telephone contact. For data analysis, a non-mixed cure rate model with Poisson distribution and negative binomial distribution were employed. All analyses were carried out using a developed Macro in WinBugs. Deviance information criteria (DIC) were employed to find the best model. Results: The overall 1-year, 3-year and 5-year relative survival rates were 97%, 89% and 74%. Metastasis and stage of BC were the significant factors, but age was significant only in negative binomial model. The DIC also showed that the negative binomial model had a better fit. Conclusions: This study indicated that, metastasis and stage of BC were identified as the clinical criteria for cure rates. There are limited studies on BC survival which employed these cure rate models to identify the clinical factors associated with cure. These models are better than Cox, in the case of long-term survival.

• Nutrition Research and Practice
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• v.12 no.5
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• pp.396-405
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• 2018

BACKGROUND/OBJECTIVES: This prospective study examined gender-specific associations between egg intake and the risk of developing type 2 diabetes using data from a large-scale cohort study. SUBJECTS/METHODS: A total of 7,002 Korean adults (40-69 years) without type 2 diabetes at baseline were analyzed. Dietary intake was evaluated by a food frequency questionnaire administered at baseline (2001-2002) and the second follow-up examination (2005-2006). Type 2 diabetes was diagnosed as a fasting glucose concentration ${\geq}126mg/dL$ or current use of glucose-lowering medications or insulin injection. Multivariate Cox proportional hazard models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for incident type 2 diabetes according to egg consumption or cholesterol intake. RESULTS: During a 14-year follow up period, 857 subjects developed type 2 diabetes. In men, frequent egg intake (2- < 4 servings/week) was associated with a 40% lower risk of developing type 2 diabetes than infrequent egg intake (0- < 1 serving/week) (HR = 0.60, 95% CI: 0.37-0.97), whereas no association between egg intake and incidence of type 2 diabetes was observed in women (HR = 0.61, 95% CI: 0.27-1.37). There was no association between cholesterol intake and risk of incident type 2 diabetes in either men or women. CONCLUSIONS: Egg consumption was inversely related to the risk of incident type 2 diabetes in men, but not in women, suggesting gender differences in the relationship between diet and disease risk.

• Journal of Chest Surgery
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• v.51 no.1
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• pp.15-21
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• 2018

Background: Prosthetic valve endocarditis (PVE) is a serious complication of cardiac valve replacement, and many patients with PVE require reoperation. The aim of this study was to review our institutional 20-year experience of surgical reoperative valve replacement in patients with PVE. Methods: A retrospective study was performed on 84 patients (mean age, $54.8{\pm}12.7years$; 51 males) who were diagnosed with PVE and underwent reoperative valve replacement from January 1995 to December 2016. Results: PVE was found in 1 valve in 61 cases (72.6%), and in 2 or more valves in 23 cases (27.4%). The median follow-up duration was 47.3 months (range, 0 to 250 months). Postoperative complications occurred in 39 patients (46.4%). Reinfection occurred in 6 cases, all within 1 year. The freedom from reinfection rate at 5 years was $91.0%{\pm}3.5%$. The overall survival rates at 5 and 10 years were $64.4%{\pm}5.8%$ and $54.3%{\pm}7.3%$, respectively. In stepwise multivariable Cox proportional hazard models, older age (hazard ratio [HR], 1.48; 95% confidence interval [CI], 1.05 to 2.10; p=0.027) and cardiopulmonary bypass (CPB) time (HR, 1.03; 95% CI, 1.00 to 1.01; p=0.033) emerged as independent risk factors for death. Conclusion: Older age and a longer CPB time were associated with an increased risk of overall mortality in PVE patients.

• Industry Promotion Research
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• v.5 no.1
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• pp.1-11
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• 2020

The purpose of this study is to analyze the industrial accidents data with survival model. EDA approach is used to explore the relationship between two variables and among three variables for the past 10 years of industrial accidents data. Survival models are also tried. Survival curve drops more rapidly for the business with fewer employees as time goes by. Industrial accidents occur more often as the total number of industrial accidents gets larger and as the number of employees gets smaller. Agriculture, fishing and forestry have a higher level of industrial accidents than construction while service industry and 'transportation·storage and telecommunication' have a fewer number of industrial accidents than construction. Korea Safety and Health Agency's and Ministry of Employment and Labor's involvement were not effective but Civilian's was. Recurrent event data analysis reveals all most the same result as for non-recurrent data analysis.

• Journal of Preventive Medicine and Public Health
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• v.51 no.5
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• pp.248-256
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• 2018

Objectives: Several studies have investigated the effects of serum uric acid (SUA) levels on chronic kidney disease (CKD), with discrepant results. The effect of SUA levels on CKD development was studied in the Korean rural population. Methods: A total of 9695 participants aged ${\geq}40years$ were recruited from 3 rural communities in Korea between 2005 and 2009. Of those participants, 5577 who participated in the follow-up and did not have cerebrovascular disease, myocardial infarction, cancer, or CKD at baseline were studied. The participants, of whom 2133 were men and 3444 were women, were grouped into 5 categories according to their quintile of SUA levels. An estimated glomerular filtration rate of < $60mL/min/1.73m^2$ at the time of follow-up was considered to indicate newly developed CKD. The effects of SUA levels on CKD development after adjusting for potential confounders were assessed using Cox proportional hazard models. Results: Among the 5577 participants, 9.4 and 11.0% of men and women developed CKD. The hazard ratio (HR) of CKD was higher in the highest quintile of SUA levels than in the third quintile in men (adjusted HR, 1.60; 95% confidence interval [CI], 1.02 to 2.51) and women (adjusted HR, 1.56; 95% CI, 1.14 to 2.15). Furthermore, CKD development was also more common in the lowest quintile of SUA levels than in the third quintile in men (adjusted HR, 1.83; 95% CI, 1.15 to 2.90). The effect of SUA was consistent in younger, obese, and hypertensive men. Conclusions: Both high and low SUA levels were risk factors for CKD development in rural Korean men, while only high levels were a risk factor in their women counterparts.

• Journal of Preventive Medicine and Public Health
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• v.53 no.5
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• pp.342-352
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• 2020

Objectives: The aim of this retrospective cohort study was to investigate whether non-alcoholic fatty liver disease (NAFLD) was associated with incident bone mineral density (BMD) decrease. Methods: This study included 4536 subjects with normal BMD at baseline. NAFLD was defined as the presence of fatty liver on abdominal ultrasonography without significant alcohol consumption or other causes. Decreased BMD was defined as a diagnosis of osteopenia, osteoporosis, or BMD below the expected range for the patient's age based on dual-energy X-ray absorptiometry. Cox proportional hazards models were used to estimate the hazard ratio of incident BMD decrease in subjects with or without NAFLD. Subgroup analyses were conducted according to the relevant factors. Results: Across 13 354 person-years of total follow-up, decreased BMD was observed in 606 subjects, corresponding to an incidence of 45.4 cases per 1000 person-years (median follow-up duration, 2.1 years). In the model adjusted for age and sex, the hazard ratio was 0.65 (95% confidence interval, 0.51 to 0.82), and statistical significance disappeared after adjustment for body mass index (BMI) and cardiometabolic factors. In the subgroup analyses, NAFLD was associated with a lower risk of incident BMD decrease in females even after adjustment for confounders. The direction of the effect of NAFLD on the risk of BMD decrease changed depending on BMI category and body fat percentage, although the impact was statistically insignificant. Conclusions: NAFLD had a significant protective effect on BMD in females. However, the effects may vary depending on BMI category or body fat percentage.

• Journal of Preventive Medicine and Public Health
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• v.45 no.1
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• pp.21-28
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• 2012

Objectives: The aim of this study was to investigate whether a medium to high degree of total physical activity and indoor physical activity were associated with reduced all-cause and cardiovascular mortality among elderly Korean women. Methods: A prospective cohort study was done to evaluate the association between physical activity and mortality. The cohort was made up of elderly (${\geq}65$ years of age) subjects. Baseline information was collected with a self-administered questionnaire and linked to death certificates retrieved from a database. Cox proportional hazard models were used to estimate the hazard ratios (HRs) with 95% confidence interval (CI) levels. Results: Women who did not suffer from stroke, cancer, or ischemic heart disease were followed for a median of 8 years (n=5079). A total of 1798 all-cause deaths were recorded, of which 607 (33.8%) were due to cardiovascular disease. The group with the highest level of total physical activity and indoor physical activity was significantly associated to a reduced all-cause mortality (HR, 0.60; 95% CI, 0.51 to 0.71 and HR, 0.58; 95% CI, 0.50 to 0.67, respectively) compared to the group with the lowest level of total physical activity and indoor physical activity. Additionally, the group with the highest level of total physical activity and indoor physical activity was significantly associated to a lower cardiovascular disease mortality (HR, 0.53; 95% CI, 0.40 to 0.71 and HR, 0.51; 95% CI, 0.39 to 0.67, respectively) compared to the group with the lowest level of total physical activity and indoor physical activity. Conclusions: Our study showed that regular indoor physical activity among elderly Korean women has healthy benefits.

• Korean Journal of Schizophrenia Research
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• v.24 no.2
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• pp.60-67
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• 2021

Objectives: The optimal duration of maintenance treatment for patients with first-episode schizophrenia (FES) remains unclear. We examined the first antipsychotic treatment duration and its association with re-initiation of treatment using a nationwide claim database. Methods: Data from the Health Insurance Review and Assessment Service database in South Korea for 2007-2016 were used. Linear regression analysis and Cox proportional hazard models were used to evaluate the associations between the duration of the first antipsychotic treatment, time to re-initiation of treatment, and occurrence of treatment re-initiation. Results: Of 30,143 patients with FES, 80.4% (n=24,231) received <2 years of the first antipsychotic treatment. In patients who discontinued treatment (n=23,030), the rate of treatment re-initiation was 74.2% (n=17,086). As the duration of the first antipsychotic treatment increased, the time to re-initiation of treatment decreased (β=-0.146, p<0.001); however, the rate of treatment reinitiation was relatively constant (hazard ratio=1.001, p<0.001). Conclusion: Long-term antipsychotic treatment was not significantly associated with the rate of treatment re-initiation but showed a negative association with the time to re-initiation of treatment. Further research is needed to better understand the optimal treatment duration for FES.

• Nutrition Research and Practice
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• v.17 no.6
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• pp.1225-1237
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• 2023

BACKGROUND/OBJECTIVES: Unhealthy dietary behaviors constitute one of risk the factors for chronic and cardiovascular diseases, which are prevalent in middle-aged and older populations. Milk and dairy products are high-quality foods and important sources of calcium. Calcium protects against osteoporosis and cardiovascular disease. Therefore, this study investigated the association of milk and dairy product consumption with cardio-cerebrovascular disease incidence in middle-aged and older Korean adults. SUBJECTS/METHODS: Data were derived from the Ansan-Anseong cohort study, and a total of 8,009 individuals aged 40-69 years were selected and followed up biennially. Cox proportional hazard models were used to examine the association of milk and dairy product consumption with cardio-cerebrovascular disease incidence. RESULTS: During a mean follow-up period of 96.5 person-months, 552 new cases of cardio-cerebrovascular disease were documented. Milk consumers (< 1 serving/day) exhibited a 23% lower risk of cardio-cerebrovascular disease incidence than non-milk consumers (hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.61-0.97; P for trend = 0.842). High yogurt consumption was associated with a 29% lower incidence risk (≥ 0.5 servings/day vs. none: HR, 0.71; 95% CI, 0.53-0.96; P for trend = 0.049), whereas high ice cream consumption was associated with a 70% higher risk of cardio-cerebrovascular disease incidence (≥ 0.5 servings/day vs. none: HR, 1.70; 95% CI, 1.01-2.88; P for trend = 0.070). CONCLUSIONS: This study indicates that less than one serving of milk and high yogurt consumption are associated with a lower cardio-cerebrovascular disease risk in the middle-aged and older populations.