• Journal of Korean society of Dental Hygiene
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• v.19 no.1
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• pp.131-140
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• 2019

Objectives: The purpose of this study was to evaluate the association between asthma and dental caries by using data from the Korean National Health and Nutrition Examination Survey (KNHANES), from 2013 to 2015. Methods: The study included 11,731 subjects who were ${\geq}19$ years of age and analyzed their demographic-, socioeconomic-, health-, and oral health care-related data. The chi-squared test and logistic regression analysis were conducted using complex sample analyses to examine the relationship between asthma and dental caries. Results: Compared with the control group, the risk for dental caries in the asthma group was 1.207 times higher, regardless of various confounding factors (p<0.001). In the asthma group, the mean DMFT score was significantly higher than that in the control group (p<0.001). After adjusting for confounding factors, the mean number of DMFT in subjects with asthma was 7.67, which was higher than that in subjects without asthma (7.28) (p<0.001). Conclusions: The study results show that asthma may be a risk factor for dental caries. Therefore, in order to prevent dental caries in asthma patients, oral hygiene education is important.

• Journal of Korean society of Dental Hygiene
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• v.22 no.6
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• pp.503-512
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• 2022

Objectives: This study aimed to study the association between unmet dental treatment and depression in the dental area of the elderly. Methods: The data was from the 7th period of the National Health and Nutrition Examination Survey. Multiple logistic regression analysis was performed to evaluate the relationship between depression and unmet dental treatment when confounding factors such as income quintile and smoking were considered. Statistical software, SAS 9.4 version was used. Results: After correcting all confounding factors, the analysis showed that the experience of unmet dental treatment was 2.73 times more likely among depressed men and 2.52 times more likely among depressed women (p<0.05). Conclusions: The results of this study suggested that we should consider that depression in the elderly can affect unmet dental treatment regardless of gender.

• Journal of Korean Neurosurgical Society
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• v.43 no.5
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• pp.227-231
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• 2008

Objective : Earlier reports have revealed that the incidence of posttraumatic hydrocephalus (PTH) is higher among patients who underwent decompressive craniectomy (DC). The aim of this study was to determine the influencing factors for the development of PTH after DC. Methods : A total of 693 head trauma patients admitted in our hospital between March 2004 and May 2007 were reviewed. Among thee, we analyzed 55 patients with severe traumatic brain injury who underwent DC. We excluded patients who had confounding variables. The 33 patients were finally enrolled in the study and data were collected retrospectively for these patients. The patients were divided into two groups: non-hydrocephalus group (Group I) and hydrocephalus group (Group II). Related factors assessed were individual Glasgow Coma Score (GCS), age, sex, radiological findings, type of operation, re-operation and outcome. Results : Of the 693 patients with head trauma, 28 (4.0%) developed PTH. Fifty-five patients underwent DC and 13 (23.6%) developed PTH. Eleven of the 33 study patients (30.3%) who had no confounding factors were diagnosed with PTH. Significant differences in the type of craniectomy and re-operation were found between Group I and II. Conclusion : It is suggested that the size of DC and repeated operation may promote posttraumatic hydrocephalus in severe head trauma patients who underwent DC.

• Journal of the Korea Safety Management & Science
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• v.16 no.3
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• pp.257-266
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• 2014

This study was planned to investigate the effect of the exposure to hazard factors on work environment satisfaction. Existing researches about job satisfaction have focused on the general working conditions, such as working hours, wage, human relationship, job task and so on. Korean Working Conditions Survey was used for this study because that relevant questions were included. The effect of the exposure to hazard factors on work environment satisfaction may be produced by hierarchical regression analysis because of comparison with existing model for work environment satisfaction. The exposure to hazards factors were statistically significant effect on work environment satisfaction after adjusting other confounding variables, such as gender, age, educational level, job security, work hour, work load, work autonomy, social support, etc. This study has some limitation because that KWCS was cross sectional survey. Some researches about the causal effect and its mechanism may be suggested as future study.

• Journal of Periodontal and Implant Science
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• v.47 no.2
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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.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.149-157
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• 2018

This study was conducted using the National Health and Nutrition Survey data for 2010-2014 to investigate the relationship between pregnancy-related health factors and periodontitis in adult women. Dependent variable was periodontitis, and independent variables, pregnancy-related health factors(duration of lactation and number of pregnancies) were analyzed. Socioeconomic variables and health-related behaviors were corrected by confounding variables. The number of pregnancies and periodontitis were highly correlated after adjusting for various confounding factors [odds ratio for women with 2-3 pregnancies: 2.66 (95% confidence interval(CI): 1.56-4.54); The odds ratio for women with four or more pregnancies 3.02 (95% CI: 1.70-5.36). In conclusion, periodontitis is closely related to the number of pregnancies and this will be used as basic data for development of oral health education programs for women and pregnant women.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.3
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• pp.283-290
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• 2002

Two-level fractional factorial designs are widely used when many factors are considered. When two-level fractional factorial designs are used, some effects are confounded with each other. To break the confounding between effects, we can use fractional factorial designs, called fold-over designs, in which certain signs in the design generators are switched. In this paper, optimal fold-over designs with four-level quantitative and two-level factors are presented for (1) the initial designs without curvature effect and (2) those with curvature effect. Optimal fold-over design tables are provided for 8-run, 16-run, and 32-run experiments.

• The Korean Journal of Applied Statistics
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• v.25 no.1
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• pp.163-181
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• 2012

This paper studies the effect of job training for non-regular employees in the Korea labor market. Using an economically active population data set of statistics Korea, we apply a non-parametric matching and sensitivity analysis method to measure the effect of the training for non-regular employees and to look for the impact of an unobservable variable or confounding factor in regards to the selection effect and outcome effect. In the our empirical results, we conclude that the effect of the training for non-regular employees has a better employment effect for getting a regular job rather than a wage effect; in addition, the impact of unobservable variables or confounding factors do not exercise a statistically strong influence on the baseline ATT.

• Journal of Preventive Medicine and Public Health
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• v.40 no.6
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• pp.454-460
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• 2007

Objectives : Obesity is currently an epidemic in Korea, and sleep duration is thought to be one of the risk factors for obesity. The objective of this study was to test the hypothesis that short sleep duration is associated with obesity in Korean adults. Methods : The data from the 2001 Korean National Health and Nutrition Survey were used, and 6,174 subjects aged $18{\sim}80$ years were included in the analysis. Sleep duration was measured using information obtained from self-reported questionnaires. Obesity, the main outcome variable, was measured according to body mass index. Multiple regression modeling was used to adjust for potential confounding variables. Results : The study results revealed a negative association between sleep duration and body mass index among Korean adults. These associations persisted after controlling for the potential confounding variables. Conclusions : These findings support the hypothesis that sleep duration is associated with obesity in Korean adults. In addition, these observations support earlier experimental sleep studies and provide a basis for future studies on weight control intervention by increasing the amount of sleep.

• Annals of Clinical Neurophysiology
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• v.10 no.1
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• pp.1-12
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• 2008

Intraoperative neuromonitoring (INM) is well known to be useful method to reduce intraoperative complications during the surgery of nervous system lesions. Evoked potentials are most commonly used among the electrophysiological tests. Brainstem auditory evoked potentials are for detecting the problems along the auditory pathways including the eighth cranial nerve and brainstem. Somatosensory evoked potentials are applied for preventing the spinal cord lesions. The INM is affected by many factors. In order to perform an optimal INM, the confounding factors including technical, anesthetical, and individual factors should be kept well under control. INM has frequent electrophysiologic changes during the surgery and it might be helpful to keep one's eyes on which monitoring modalities are reluctant to change during each operation. The skillful monitoring and timely interpretation of electrophysiologic changes can drive the patient to be undergone surgery, even in high surgical risk group.