• Journal of Preventive Medicine and Public Health
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• 제39권2호
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• pp.123-129
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• 2006

Objectives : The incidence of colorectal cancer increased greatly among the elderly in Korea, but the relationship between smoking and colon cancer remains controversial. Few studies have targeted Asian elderly people. We analyzed the smoking status, the amount smoked, and the smoking duration as risk factors of colorectal cancer to determine their association and causality. Methods: The cohort members (n=14, 103) consisted of 4,694 males and 9,409 females, and they were derived from the Korea Elderly Phamacepidemilogic Cohort (KEPEC), which was a population-based dynamic cohort. They were aged 65 years or more and they lived in Busan Metropolitan City between from 1993-1998; they were beneficiaries of the Korean Medical Insurance Corporation (KMIC). The baseline information was surveyed by a self-administered mailed questionnaire; after 8.7 person-years of mean follow up period, 100 cases of colorectal cancer occurred. The adjusted relative ratio (aRR) of smoking status, the smoking amount and the smoking duration were calculated from the Cox's proportional hazard model with the never-smokers as a reference group and the Cox model controlled for age, gender, precancerous lesions of CRC, medication history of NSAIDs & antibiotics, the alcohol drinking status and BMI. Results : Compared with the never smokers, the aRRs were 2.03 (95% CI=1.02-4.03) and 1.36 (95% CI=0.80-2.32) for the ex-smokers and current smokers, respectively. Statistical significant trends were not observed for the dose-relationship among the elderly, either for the mean daily amount smoked (p for trend=0.28) or for the total amount (p for trend=0.15). Still, the aRRs were 1.51 (95% CI=0.97-2.34) for the elderly who smoked less than 40 years and 2.35 (95% CI=1.16-4.74) for the elderly who had 40 years or more of smoking (p for trend=0.06). Smokers who started smoking before the age 20 had an increased aRR of 2.15 (95% CI=1.17-3.93) compared to the never smokers. Conclusions : After controlling for age, gender, precancerous lesion of CRC, medication history of NSAIDs & antibiotics, the alcohol drinking status and BMI, smoking increases the risk of colorectal cancer among elderly people. The age when starting smoking is also important.

• 한국산업보건학회지
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• 제32권3호
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• pp.268-278
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• 2022

Objectives: This study aimed to establish a control group based on the big data from National Health Insurance Service. We also presented presented the number of incidences for each cancer, and analyzed the cancer incidence rate among Korean workers. Methods: The cohort definition was separated by 'baseline cohort', 'dynamic cohort', and 'fixed- industry cohort' according to the definition. Cancer incidence was calculated based on the Korean Standard Classification of Disease code. Incidence rate was calculated among the group of all workers and public officials. Based on the study subjects and each cohort definition, the number of observations, incidences, and the incidence rate according to sex and age groups was calculated. The incidence rate was estimated based on the incidence per 100,000 person-year, and 95% confidence intervals calculated according to the Poisson distribution. Results: The result shows that the number of cancer cases in the all-worker group decreases after the age of 55, but the incidence rate tends to increase, which is attributed to the retirement of workers over 55 years old. Despite the specific characteristics of the workers, the trend and figures of cancer incidence revealed in this study are similar to those reported in previous studies of the overall South Korean population. When comparing the incidence rates of all workers and the control group of public officials, the incidence rate of public officials is generally observed to be higher in the age group under the age of 55. On the other hand, for workers aged 60 or older, the incidence rates were 1,065.4 per 100,000 person-year for all workers and 1,023.7 per 100,000 person-year for civil servants. Conclusions: This study analyzed through health insurance data including all workers in Korea, and analyzed the incidence of cancer of workers by sex and age. In addition, further in-depth researches are needed to determine the incidence of cancer by industry.

• Journal of Periodontal and Implant Science
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• 제47권2호
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• pp.96-105
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• 2017

Purpose: The National Health Insurance Service-National Sample Cohort and medical checkup data from 2002 to 2013 were used to evaluate the association between periodontal surgery for the treatment of periodontitis (PSTP) and vasculogenic erectile dysfunction (VED). Methods: Bivariate and multivariate logistic regression analyses were applied to a longitudinal retrospective database to assess the association between PSTP and VED while adjusting for the potential confounding effects of sociodemographic factors (age, household income, insurance status, health status, residence area, and smoking status) and comorbidities (diabetes mellitus, angina pectoris, cerebral infarction, and myocardial infarction). Results: Among the 7,148 PSTP within the 268,296 recruited subjects, the overall prevalence of VED in PSTP was 1.43% (n=102). The bivariate analysis showed that VED was significantly related to PSTP (odds ratio [OR], 1.99; 95% confidence interval [CI], 1.38-2.06; P<0.001), and this was confirmed in the multivariate analysis after adjusting for sociodemographic factors and comorbidities (OR, 1.29; 95% CI, 1.06-1.58; P=0.002). Conclusions: Subjects with a history of periodontal flap surgery had a significantly higher risk of VED, after adjusting for potential confounding factors. Further studies are required to identify the key mechanisms underlying the association between severe periodontal disease and VED.

• 한국치위생학회지
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• 제11권4호
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• pp.511-522
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• 2011

Objectives : The purpose of this study was to provide some information on the development of oral health care programs geared toward diabetics and ways of promoting their oral health. Methods : The subjects in this study were 586 diabetics who were selected from the 2009 third-year raw data of the 4th(2007~2009) National Health & Nutrition Survey. The data were analyzed with the statistical package SPSS 12.0 to grasp the influence of their sociodemographic characteristics and oral health behaviors on the presence or absence of periodontal diseases and missing tooth. Results : 1. Periodontal diseases were twofold more prevalent among the men than the women(p<0.01). By age, those who were in their 60s had 1.11-fold more periodontal diseases than those who were in their 70s and up(p<0.05). 2. The men and women were similar to each other in the number of missing tooth. By age, the number of missing tooth got smaller in proportion to decrease in age. By income, the number of missing tooth was 1.48-fold larger among the patients who earned an income of one million won or less than those who earned an income of two million won or more(p<0.01). Conclusions : The above-mentioned findings suggest that prospective cohort studies should be implemented to present prediction models of periodontal diseases and diabetes instead of merely sticking to cross-sectional studies. And oral health programs should be developed based on the findings of cohort studies to encourage diabetics to care about their oral health, and in which way they should be helped to promote their oral health should carefully be considered.

• Clinical and Experimental Pediatrics
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• 제62권4호
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• pp.126-130
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• 2019

Purpose: In this meta-analysis, relevant case-control and cohort studies were pooled to evaluate the association between preeclampsia and the risk of autism spectrum disorders (ASDs) in children. Methods: A search for relevant studies in major databases, including Web of Science, PubMed, and Scopus, was performed up to May 2018. The odds ratios (ORs) or rate ratios (RRs) with 95% confidence intervals (CIs) were extracted from eligible studies to determine the association among studies. Results: The pooled estimates of ORs and RRs indicated a significant association between preeclampsia and ASD [(OR, 1.36; 95% CI, 1.12-1.60) and (RR, 1.30; 95% CI, 1.20-1.41)]. Conclusions: Despite existing controversy, our findings indicated that preeclampsia was associated with an increased risk of ASD among children.

• Communications for Statistical Applications and Methods
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• 제26권2호
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• pp.163-173
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• 2019

Simon's two-stage designs are frequently used in phase II single-arm trials for efficacy studies. A concern of safety studies is too many patients who experience an adverse event. We show that Simon's two-stage designs for efficacy studies can be similarly used to design a two-stage safety study by modifying some of the design parameters. Given the type I and II error rates and the proportion of adverse events experienced in the first stage cohort, we prescribe a procedure whether to terminate the trial or proceed with a stage 2 trial by recruiting additional patients. We study the relationship between a two-stage design with a safety endpoint and an efficacy endpoint as well as use simulation studies to ascertain their properties. We provide a real-life application and a free R package gen2stage to facilitate direct use of two-stage designs in a safety study.

• Journal of Periodontal and Implant Science
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• 제47권5호
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• pp.264-272
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• 2017

Purpose: This study evaluated trends in tooth extraction due to acute and chronic periodontal disease (PD) using data from the National Health Insurance Service-National Sample Cohort for 2002-2013. Methods: A random sample of 1,025,340 individuals was selected as a representative sample of the population, and a database (DB) of diagnostic and prescription codes was followed up for 12 years. We used multivariate logistic regression analysis to assess the incidence of total extraction (TE), extraction due to periodontal disease (EPD), and immediate extraction due to periodontal disease (IEPD) according to sociodemographic factors (sex, age, household income, health status, and area of residence). Results: The incidence of tooth extraction was found to be increasing, and at a higher rate for TE in PD patients. In 2002, 50.6% of cases of TE were caused by PD, and this increased to 70.8% in 2013, while the number of cases of IEPD increased from 42.8% to 54.9% over the same period. The incidence rates of extraction due to acute and chronic PD increased monotonically. We found that the incidence rates of TE, EPD, and IEPD were all 2-fold higher among patients with high income levels and those who were not beneficiaries of health insurance. Conclusions: The rates of TE, EPD, and IEPD have been steadily increasing despite dental healthcare policies to expand public health insurance coverage, increasing the accessibility of dental clinics. Moreover, the effects of these policies were found to vary with both income and education levels. Consistent patient follow-up is required to observe changes in trends regarding tooth extraction according to changes in dental healthcare policies, and meticulous studies of such changes will ensure optimal policy reviews and revisions.

• 치위생과학회지
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• 제17권2호
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• pp.160-167
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• 2017

본 연구는 치주질환과 신장질환의 연관성을 알아보기 위한 체계적 고찰이다. Embase, PubMed, The Cochrane Library 데이터베이스에서 2016년 4월 17일 검색을 완료하였다. 문헌의 선택은 코호트 연구 설계를 기준으로 하였으며, 환자군은 치주질환 또는 중증의 치주질환이 있는 대상자로 하였다. 최종 결과는 만성신장질환의 발생이나 신장기능의 저하로 eGFR을 제시한 연구로 하였다. 최종 선정된 문헌의 양적합성을 위하여 Review Manager (RevMan) 통계 분석 소프트웨어를 이용하였다. 고정효과모형 멘텔-헨젤 방법(M-H)을 이용하여 메타분석을 시행하여 치주질환과 만성신장질환의 연관성을 추정하였다. 검색 전략을 이용하여 총 3,018개의 문헌이 검색되었고, 그 중 4개의 문헌이 최종 분석에 포함되어 메타 분석한 결과 치주질환이 만성신장질환 발생위험과 유의한 연관성이 있음이 나타났다(OR, 1.65; 95% CI, 1.44~1.90; p<0.001). 만성신장질환 발생 및 신장기능저하를 예방하기 위해서는 개인의 삶의 질 저하와 의료비용부담을 줄이기 위해 기존에 알려진 전통적 위험인자 외에 만성신장질환에 영향을 미치는 치주질환의 예방 및 관리의 필요성이 크다.

• Journal of Preventive Medicine and Public Health
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• 제36권4호
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• pp.367-372
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• 2003

Objectives : There are many concerns about ginseng as a cancer chemopreventive substance, but there have been few epidemiological studies on ginseng, This study sought to examine the relationships between ginseng intake and cancer incidence in the Kangwha cohort. Methods ; Between March 1985 and December 1999, 2697 males, aged 55 or over, as of 1985, were followed up for their cancer incidence. The cancer incidence rate, standardized incidence ratio and risk ratios were calculated according to ginseng intake. A Cox proportional hazard model was used to adjust for age at entry, smoking, alcohol intake, hypertension, and body mass index. Results & Conclusions : The ginseng intake group had the same cancer (C00-C97) incidences (Standardized Incidence Ratio: SIR=1.11, 95% Confidence Interval=0.97-1.27) and the same risk ratio (RR=1.09, 95% Confidence Interval=0.85-1.41) as the no-intake group. Analyzing the subjects that had followed up from 1990, however, the ginseng intake group had lower cancer incidences at all sites (RR=0.79, 95% Confidence Interval=0.58-1.09). This was a cohort study to try and evaluate the association between ginseng intake and the incidences of cancer, The results of this study provide no clear conclusions on the cancer preventive effects of ginseng. Therefore, further study is needed in the future.

• 한국환경보건학회지
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• 제34권1호
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• pp.1-11
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• 2008

The purpose of this study was to investigate air quality in Chungju, Korea, using data obtained with a local air quality monitoring system. We have utilised cohort studies to investigate the relations between environmental pollution and the health of residents near large industrial complexes since 2004. This study analyzes the $O_3,\;NO_2,\;SO_2,\;CO\;and\;PM_{10}$ concentration in Chungju from 2002 to 2006. Air pollutants are closely related to the number of manufacturing facilities and cars, energy utilization and weather conditions. Generally, the diurnal concentration of air pollutants in Chungju reached the highest level in the morning (about$08:00{\sim}$) and early evening (about$19:00{\sim}$). On the other hand, the diurnal concentration of ozone as recorded gives the highest amount in late afternoon (about$16:00{\sim}$) and lowest in early morning (about$08:00{\sim}$). The concentration of air pollutants in Chungju was highest from winter to spring and lowest during the summer season. On the other hand, the monthly variation of ozone concentration was greatest in June and smallest in December. Also the, $PM_{10}$ concentration posted the highest record in April and the lowest during September. In general, this study analyzed air pollution changes in Chungju as well as in large scale industrial complex regions within Korea such as Ulsan, Pohang, Kwangyang, Sihwa Panwol and Gangneung in Korea. We compared the air quality of Chungju with those of these cites and found that air pollutants except for CO in Chungju was generally lower than large industrial complex regions.