노인인구에서 음주와 대장직장암 발생간의 연관성에 관한 코호트연구

임회정,박병주,Lim, Hoi-Jeong,Park, Byung-Joo 대한예방의학회 2008 예방의학회지 Vol.41 No.1

Objectives : We examined the association between alcohol consumption and incidence of colorectal cancer in elderly Koreans. Methods : The cohort members (n=14,304) consisted of 4,834 males and 9,470 females derived from the Korea Elderly Pharmacoepidemiologic Cohort (KEPEC), a population-based dynamic cohort. They were aged 65 years old or older and lived in Busan between 1993-1998; they were beneficiaries of the Korean Medical Insurance Corporation (KMIC). Baseline information was surveyed by a self-administered, mailed questionnaire. This study population was restricted to 14,304 participants who reported alcohol drinking habits on the questionnaire and had not been diagnosed with colorectal cancer at baseline. The adjusted hazard ratios (aHR) of status, type, frequency and daily average amount of alcohol consumption were computed with Cox's proportional hazard model, with the never-drinkers as a reference group and controlling for age and gender. Results : After 4.82 person-years of mean follow-up 112 cases of colorectal cancer occurred. The incidence densities of colorectal cancer were 161 (95% CI=123-200) for never-drinkers, 219 (95% CI=125-339) for ex-drinkers, and 137 (95% CI=84-189) for current-drinkers per 100,000 person-year. The status, type, frequency, and daily average amount of alcohol consumption were not significantly related to the incidence of colorectal cancer after controlling for age and gender. Conclusions : There was no significant association between alcohol consumption and colorectal cancer among elderly people after controlling for age and gender.

대한치과교정학회지(KJO)와 미국교정학회지(AJODO)에서 사용된 통계기법의 비교분석 및 고찰 : 1999-2003

임회정 대한치과교정학회 2004 대한치과교정학회지 Vol.34 No.5

본 연구는 1999-2003년 사이에 출판된 대한치과교정학회지(KJO)의 논문 247편과 American Journal of Orthodontics and Dentofacial Orthopedics (AJODO)의 논문 250편들이 사용하고 있는 통계기법들을 연도별로 조사, 비교하였다. 각각의 저널에서 어떠한 통계기법들이 자주 사용되었는지, 최근들어 통계기법의 변화가 있었는지, 자주 쓰이는 통계기법들에 대한 주의할 점을 고려했는지, 어떠한 고급통계기법을 사용하였는지를 살펴보았다. KJO는 이 기간 동안의 모든 논문을 연구대상으로 하였고 AJODO는 각 해마다 50편의 논문을 original article이면서 통계기법을 사용한 논문들 중에서 무작위로 추출하였다. 빈번히 사용된 통계기법은 KJO의 논문에서는 t-검정, 분산분석, 상관분석, 비모수분석 회귀분석, χ²-검정, 요인 분석의 순이었고 AJODO의 논문에서는 t-검정, 분산분석, 비모수분석 상관분석, 회귀분석, χ²-검정 요인분석의 순이었다. 5년 동안의 통계기법의 변화를 살펴본 결과 KJO에서는 유의한 변화를 관찰할 수 없었으나(χ² = 17.38, p = 0.6881) AJODO에서는 유의한 변화를 관찰할 수 있었다(χ² = 42.41, p = 0.0397). 각 통계분석에 해당하는 가정의 점검을 간과한 경우가 있었으며 통계분석 전에 이상치 등의 자료의 탐색이 필요하며 소표본일 경우 좀 더 다른 통계적 접근 방법이 필요하다. 고급통계기법으로는 KJO에서는 인자분석과 판별분석을 통해 부정교합자에게 적용이 가능한 골격유형의 감별기준을 도출하였고 AJODO에서는 다기관센터를 통한 임상시험에서 ITT분석을 실시하였으며 생존분석 및 GEE분석을 실시하였다. 단순한 통계기법만으로는 정확한 자료의 분석이 행해졌다고 보기는 어렵고 자료와 가설에 맞는 단변수 분석후의 다변량 통계 분석 방법을 통하여 정확한 결론을 유추해 내는 노력이 필요하다. 치과학 분야의 자료의 특성중 하나는 서로 상관관계가 높으며 반복 측정치를 가지는 것인데 올바른 통계기법을 도입하여 그 결과에 대한 바른 해석을 할 수 있도록 해야 하겠다. The purpose of this study was to investigate the changes and types of statistical methods used in the Korean Journal of Orthodontics (KJO) and the American Journal of Orthodontics and Dentofacial Orthopedics (AJODO) from 1999 to 2003. The frequency of use, transitions, assumption check of statistical methods and types of advanced statistical methods were examined from each journal. The study consisted of 247 articles published in the KJO and randomly chosen 50 articles per year which were original articles and used statistical methods. T-test, analysis of variance (ANOVA), correlation analysis, nonparametric analysis, regression analysis, chi-square test, factor analysis, were the order of statistical methods most frequently used in the KJO, while t-test, ANOVA, nonparametric analysis, correlation analysis, regression analysis, chi-square test. factor analysis, were the order of statistical methods used in the AJODO. The changes of statistical methods observed in the KJO were not significant (χ²=17.4, p=0.6881), but the changes observed in the AJODO was seen to be significant (χ²=42.4, p=0.0397). Some of the studies examined had overlooked the assumptions of the statistical methods employed. Data investigation such as outlier should be performed before analysis and alternative statistical approaches are applied for a small sample size. Types of advanced statistical methods were factor analysis and discriminant analysis in the KJO and Intention-To-Treat (ITT) analysis in clinical trials through multi-center, survival analysis and Generalized Estimating Equations (GEE) in the AJODO. Appropriate analysis approaches and interpretations should be applied for the correlated and repeated measurements of the orthodontic data set.

퇴행성 관절염 환자를 대상으로 새로운 진통제 평가를 위한 임상시험자료의 GEE 분석

임회정,김윤이,정영복,성상철,안진환,노권재,김정만,박병주,Lim, Hoi-Jeong,Kim, Yoon-I,Jung, Young-Bok,Seong, Sang-Cheol,Ahn, Jin-Hwan,Roh, Kwon-Jae,Kim, Jung-Man,Park, Byung-Joo 대한예방의학회 2004 예방의학회지 Vol.37 No.4

Objective : To compare the efficacy between SKI306X and Diclofenac by using generalized estimating equations (GEE) methodology in the analysis of correlated bivariate binary outcome data in Osteoarthritis (OA) diseases. Methods : A randomized, double-blind, active comparator-controlled, non-inferiority clinical trial was conducted at 5 institutions in Korea with the random assignment of 248 patients aged 35 to 75 years old with OA of the knee and clinical evidence of OA. Patients were enrolled in this study if they had at least moderate pain in the affected knee joint and a score larger than 35mm as assessed by VAS (Visual Analog Scale). The main exposure variable was treatment (SKI 306X vs. Diclofenac) and other covariates were age, sex, BMI, baseline VAS, center, operation history (Yes/No), NSAIDS (Y/N), acupuncture (Y/N), herbal medicine (Y/N), past history of musculoskeletal disease (Y/N), and previous therapy related with OA (Y/N). The main study outcome was the change of VAS pain scores from baseline to the 2nd and 4th weeks after treatment. Pain scores were obtained as baseline, 2nd and 4th weeks after treatment. We applied GEE approach with empirical covariance matrix and independent(or exchangeable) working correlation matrix to evaluate the relation of several risk factors to the change of VAS pain scores with correlated binary bivariate outcomes. Results : While baseline VAS, age, and acupuncture variables had protective effects for reducing the OA pain, its treatment (Joins/Diclofenac) was not statistically significant through GEE methodology (ITT:aOR=1.37, 95% CI=(0.8200, 2.26), PP:aOR=1.47, 95% CI=(0.73, 2.95)). The goodness-of-fit statistic for GEE (6.55, p=0.68) was computed to assess the adequacy of the fitted final model. Conclusions : Both ANCOVA and GEE methods yielded non statistical significance in the evaluation of non-inferiority of the efficacy between SKI306X and Diclofenac. While VAS outcome for each visit was applied in GEE, only VAS outcome for the fourth visit was applied in ANCOVA. So the GEE methodology is more accurate for the analysis of correlated outcomes.

치의학 연구에서의 표본크기 산출

임회정(Hoi-Jeong Lim) 대한치과의사협회 2014 대한치과의사협회지 Vol.52 No.9

Sample size determination is critical, but not easy to do. Sample size defined as the number of observations in a sample to be studied should be big enough to have a high likelihood of detecting a true difference between groups. Practical procedure for determining sample size, using G*power and previous dental articles, was shown in this study. Examples involving independent t test, paired t test, one way analysis of variance(ANOVA), and one way repeated measures(RM) ANOVA were used. The purpose of this study is to enable researchers with non statistical backgrounds to use in practice freely available statistical software G*power to determine sample size and power.

치의학 분야에서 SPSS를 이용한 일반화 추정방정식의 단계별 안내

임회정(Hoi-Jeong Lim),박수현(Su-Hyeon Park) 대한치과의사협회 2016 대한치과의사협회지 Vol.54 No.11

The Generalized Estimating Equations (GEE) approach is a widely used statistical method for analyzing longitudinal data and clustered data in clinical studies. In dentistry, due to multiple outcomes obtained from one patient, the outcomes produced from an individual patient are correlated with one another. This study focused on the basic ideas of GEE and introduced the types of covariance matrix and working correlation matrix. The quasi-likelihood information criterion (QIC) and quasi-likelihood information criterion approximation (QICu) were used to select the best working correlation matrix and the best fitting model for the correlated outcomes. The purpose of this study is to show a detailed process for the GEE analysis using SPSS software along with an orthodontic miniscrew example, and to help understand how to use GEE analysis in dental research.

치의학 분야에서의 메타 분석

임회정(Hoi-Jeong Lim) 대한치과의사협회 2014 대한치과의사협회지 Vol.52 No.8

Recently, importance of meta analysis is increasing in the field of dentistry, since it is not easy to settle controversies arising from conflicting studies. Meta analysis is the statistical method of combining results from two or more individual studies that have been done on the same topic. Merits of meta analysis include an increase in power, an improvement in precision, and the ability to address solution not provided by individual studies. However, it might mislead researchers when variation across studies and publication bias are not carefully taken into consideration. The purpose of this study is to help understand meta analysis by making use of individual results in dental research paper.

치주 영역에서 오렌지 데이터마이닝을 활용한 랜덤 포레스트 모델의 단계별 안내

임회정 ( Hoi-jeong Lim ) 대한예방치과·구강보건학회 2021 大韓口腔保健學會誌 Vol.45 No.4

Objectives: The purpose of this study was to show a procedure for a random forest (RF) analysis which predicts periodontal disease status by using R and Orange Data Mining software, and helps us to understand how to apply the RF technique for dental research. Methods: Oral examination data of the 7th Korea National Health and Nutrition Examination Survey were used. A RF model was adopted to analyze the data where the target variable was periodontal disease status and the features were gender, age, education level, marital status, alcohol consumption level, smoking status, brushing before sleep, hypertension, and diabetes-related variables. Results: The important features of the RF analysis were in the order of age, marital status, and prevalence of hypertension and diabetes. The accuracy of the RF analysis was 73% which is not high enough for use in the clinical field. Conclusions: The RF technique is an ensemble method used to predict periodontal disease status which produces higher accurate outputs than a single method. This study provides a step-by-step guide using Orange Data Mining for researchers who want to study machine learning techniques.

파노라마방사선사진에서의 경동맥 석회화와 초음파영상에서의 경동맥내중막두께의 연관성 연구

윤숙자,김옥수,임회정,김선헌,김민석,강인철,김옥준,강병철,신민호,이재서 대한구강악안면병리학회 2014 대한구강악안면병리학회지 Vol.38 No.2

This study aimed to investigate the association between carotid artery calcification (CAC) on panoramic radiograph and intima-media thickeness (IMT) measured on ultrasound. Panoramic radiographs which were taken from dental patients aged 50 years and older who visited for dental treatment were screened for the presence of CAC. The study group was composed of seven patients (four males and three females, average age 74.4±4.2 yrs) with CAC detected on panoramic radiographs, and the control group eleven patients (seven males and four females, average age 64.5±10.1 yrs) without CAC. All the patients underwent carotid ultrasonography to measure carotid IMT. The IMT was compared between the groups by nonparametric analysis of covariance (ANCOVA). The range of IMT of the study group was 1.10~2.0 mm, while that of the control group 0.60~1.10 mm. The mean of IMT was 1.50±0.34 mm in the study group and 0.85±0.14 mm in the control group, and there was statistically significant difference between the two groups (p<.01). In conclusion, CAC detected on panoramic radiograph might have an association with atherosclerosis

완전 관해후 양측 측두골에 재발한 급성 골수성 백혈병 1예

나애선,임회정,김행재,조용범 대한이비인후과학회 2000 대한이비인후과학회지 두경부외과학 Vol.43 No.6

안면비대칭 3차원 CT 분석

윤숙자,임회정,강병철,황현식 대한구강악안면방사선학회 2007 Imaging Science in Dentistry Vol.36 No.1

Purpose : This study aimed to identify the range of normal facial asymmetry using three-dimensional CT and to develop a simple method of diagnosis of facial asymmetry. Materials and Methods : Twenty eight adults with normal occlusion (16 males and 12 females; mean age 24 years and I month) were selected, whose faces were assessed to be symmetric by an orthodontist. Three-dimensional reconstructions were obtained utilizing spiral CT scans and an oral and maxillofacial radiologist, evaluated nineteen anatomic landmarks in three-dimensional coordinates. Facial asymmetry index of each landmark was caluculated. Results : The range of normal facial asymmetry of each landmark was identified using mean and standard deviation of facial asymmetry index. Conclusions : The range of normal facial asymmetry identified in this study may be used as a diagnostic standard for facial asymmetry analysis. (Korean J Oral Maxillofac Radiol 2007; 37: 45-51)