• Korean Journal of Veterinary Research
• /
• v.45 no.3
• /
• pp.405-410
• /
• 2005

To analyze and identify selected risk factors for infectious bronchitis virus (IBV) infection in the growing and laying period of laying-hen flocks, a longitudinal field study was conducted with 27 commercial flocks reared in three provinces of Korea during the period from May 2003 to April 2004. Using monitored data for IBV infection status among study flocks we computed the multivariate odds ratios (ORs) and their corresponding confidence intervals (CIs), and population attributable risks (PARs). Multivariate logistic regression showed significant risk increments for: continuous entry of chick (OR=1.9, 95% CI, 0.7-69.1) and operation years of the layer house greater than or equal to 5 years (OR=3.2, 95%CI, 1.6-389.9). No significant interaction was found between variables. The PAR suggested that continuous entry of chick (PAR=32%) and ${\geq}5years$ of house operation (PAR=84%) had the highest impacts on IB presence in laying-hen flocks under study. Of the two significant factors, however, operation year of the layer house lacks an easy applicability in preventing IB control strategies, and the possibility of confounder cannot be ruled out.

• The Journal of Industrial Distribution & Business
• /
• v.14 no.4
• /
• pp.33-46
• /
• 2023

Purpose: During the coronavirus disease-19 (COVID-19) outbreak, mask-wearing is required to protect against and limit the spread of infection, but it can directly affect skin problems. Change in skin condition might be related to mental health. This study explored the association between skin conditions and behavior of skin cares and stress levels during the Covid-19pandemics. Research design, data and methodology: A survey was conducted on 516 adults who were aware of damaged skin due to continuous wearing of masks for a long time during the COVID-19 Pandemic. The study included 164 men and 352 women in the Republic of Korea. Results: Skin conditions and behavior of skin cares associated with stress perceptions. A multiple linear regression model was used adjusting for potential confounder. Conclusion: Since management so far in the COVID-19 Pandemic can cause skin concerns and change the original skin type, it is necessary to redefine and improve the use of skin care, face-washing methods, and functional cosmetics. People with high and low interest in skin type recognition and management were evenly identified, and it was confirmed that stress awareness decreases as awareness of skin care attitude increases.

• Journal of Preventive Medicine and Public Health
• /
• v.57 no.1
• /
• pp.1-7
• /
• 2024

Objectives: Adjusting for potential confounders is crucial for producing valuable evidence in outcome studies. Although numerous studies have been published using the Korea National Health Insurance Claim Database, no study has critically reviewed the methods used to adjust for confounders. This study aimed to review these studies and suggest methods and applications to adjust for confounders. Methods: We conducted a literature search of electronic databases, including PubMed and Embase, from January 1, 2021 to December 31, 2022. In total, 278 studies were retrieved. Eligibility criteria were published in English and outcome studies. A literature search and article screening were independently performed by 2 authors and finally, 173 of 278 studies were included. Results: Thirty-nine studies used matching at the study design stage, and 171 adjusted for confounders using regression analysis or propensity scores at the analysis stage. Of these, 125 conducted regression analyses based on the study questions. Propensity score matching was the most common method involving propensity scores. A total of 171 studies included age and/or sex as confounders. Comorbidities and healthcare utilization, including medications and procedures, were used as confounders in 146 and 82 studies, respectively. Conclusions: This is the first review to address the methods and applications used to adjust for confounders in recently published studies. Our results indicate that all studies adjusted for confounders with appropriate study designs and statistical methodologies; however, a thorough understanding and careful application of confounding variables are required to avoid erroneous results.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.7
• /
• pp.4353-4360
• /
• 2014

This study examined the relationship between the current chewing difficulty and the dental prosthesis needs of the elderly Koreans to improve their oral health status. A total of 1,177 subjects over 65 years who participated in the the Five Korea National Health and Nutrition Examination Survey were examined. An oral examination was conducted to determine the number of missing teeth and dental prosthesis required. A questionnaire was given to measure the sociodemographic characteristics, concerns about oral health, chewing ability and pronunciation ability. Statistical analysis was done using the SPSS 19.0 program. The percentage of the current chewing difficulty in Korean elderly was 42.9%. After adjusting for confounder variables, the odds ratio of the fixed prosthodontics needs were 1.22 (95% CI; 0.74 to 2.02), the odds ratio of partial denture needs were 2.47 (95% CI; 1.71 to 3.56) and the odds ratio of the full denture needs were 2.06 (95% CI; 0.73 to 5.81). The dental prosthesis needs were associated with the current chewing difficulty. Therefore, dental prosthesis support policy and public oral health promotion for the elderly is necessary.

• Journal of Preventive Medicine and Public Health
• /
• v.45 no.5
• /
• pp.316-322
• /
• 2012

Objectives: Abdominal obesity increases mortality and morbidity from cardiovascular disease and there is a possibility that smoking effects obesity. However, previous studies concerning the effects of smoking on obesity are inconsistent. The objective of this study was to examine whether smoking is positively related to abdominal obesity in men with type 2 diabetes. Methods: Subjects consisted of 2197 type 2 diabetic patients who visited Huh's Diabetes Center from 2003 to 2009. Indices of abdominal obesity were defined as visceral fat thickness (VFT) measured by ultrasonography and waist circumference (WC). Overall obesity was defined as body mass index (BMI). Results: Statistically significant differences in WC and VFT by smoking status were identified. However, there was no statistical difference in BMI according to smoking status. Means of WC and VFT were not significantly higher in heavy smokers and lower in mild smokers. Compared to nonsmokers, the BMI confounder adjusted odds ratio and 95% confidence interval for VFT in ex-smokers and current-smokers were 1.70 (1.21 to 2.39) and 1.86 (1.27 to 2.73), respectively. Conclusions: Smoking status was positively associated with abdominal obesity in type 2 diabetic patients.

• Journal of Preventive Medicine and Public Health
• /
• v.28 no.2 s.50
• /
• pp.386-397
• /
• 1995

A cross sectional study was performed to evaluate the neurobehavioral effects of chronic exposure of complex organic solvents, using NCTB(Neurobehavioral Core Test Battery) recommended by WHO(World Health Organization). Forty female shoe factory workers and twenty-two controls matched with age were participated. The tests were performed in the morning before start of work, to exclude the effects of acute exposure. Workers were exposed mainly to toluene, methyl ethyl ketone, n-hexane, cyclo-hexane, dichloroethylene, trichloroethylene, benzene, xylenes etc. The ranges of present solvent exposure of hygienic effect were $0.46\sim0.71$ in the process using adhesives indirectly, and $1.83\sim2.39$ in the process using it directly. We reclassified the subjects, according to cumulative exposure. It showed significantly poorer performances in high exposed group on Santa Ana Dexterity and Benton Visual Retention, compared with control group. After controlling confounder, the significances were still remained. But, further cohort studies, having the information of personal exposure dose from entering a factory, are required to clarify the effects of chronic exposure of complex organic solvents in relation to dose and duration of exposure.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.17
• /
• pp.7463-7466
• /
• 2015

Aims: To analyse the predictors of recurrence, disease free survival and overall survival in cases with endometrial cancer. Materials and Methods: A total of 152 women diagnosed with endometrial cancer were screened using a prospectively collected database including age, smoking history, menopausal status, body mass index, CA125, systemic disorders, tumor histology, tumor grade, lymphovascular space invasion, tumor diameter, cervical involvement, myometrial invasion, adnexal metastases, positive cytology, serosal involvement, other pelvic metastases, type of surgery, fertility sparing approach to assess their ability to predict recurrence, disease free survival and overall survival. Results: In ROC analyses tumor diameter was a significant predictor of recurrence (AUC:0.771, P<0.001). The optimal cut off value was 3.75 with 82% sensitivity and 63% specificity. In correlation analyses tumor grade (r=0.267, p=0.001), tumor diameter (r=0.297, p<0.001) and the serosal involvement (r=0.464, p<0.001) were found to significantly correlate with the recurrence. In Cox regression analyses when some different combinations of variables included in the model which are found to be significantly associated with the presence of recurrence, tumor diameter was found to be a significant confounder for disease free survival (OR=1.2(95 CI,1.016-1.394, P=0.031). On Cox regression for overall survival only serosal involvement was found to be a significant predictor (OR=20.8 (95 % CI 2.4-179.2, P=0.006). In univariate analysis of tumor diameter > 3.75 cm and the recurrence, there was 14 (21.9 %) cases with recurrence in group with high tumor diameter where as only 3 (3.4 %) cases group with smaller tumor size (Odds ratio:7.9 (95 %CI 2.2-28.9, p<0.001). Conclusions: Although most of the significantly correlated variables are part of the FIGO staging, tumor diameter was also found to be predictor for recurrence with higher values than generally accepted.

• Clinical and Experimental Pediatrics
• /
• v.63 no.9
• /
• pp.368-372
• /
• 2020

Background: Autism spectrum disorder (ASD) is a neurodevelopmental disorder defined by impairments in social interaction and verbal and nonverbal communication. Purpose: Determine the association between use of assisted reproduction technology (ART) and the risk of ASD among children. Methods: This case-control study included 300 participants (100 cases, 200 controls). The control group included women with a child aged 2-10 years without ASD, while the cases were women with a child aged 2-10 years with ASD. We used a researcher-made questionnaire. Data were analyzed using Stata ver. 14 at the 0.05 significance level. Results: In the univariate analysis, there was significant association between child sex, delivery mode, history of preterm delivery, history of using ART, and maternal age at child's birth and the risk of ASD. After the adjustment for other variables, this association was significant for male sex (2.66; 95% confidence interval [CI], 1.11-4.31; P=0.001) and history of using ART (4.03; 95% CI, 1.76-9.21; P=0.001). Therefore, after the adjustment for confounder variables, there was no significant association between ART and the risk of ASD among children (4.98; 95% CI, 0.91-27.30; P=0.065). Conclusion: After the adjustment for other variables, risk factors for ASD were male sex and history preterm delivery. Thus, there was no significant association between ART and the risk of ASD among children.

• The Journal of the Korean dental association
• /
• v.58 no.2
• /
• pp.68-82
• /
• 2020

Running title: Adequacy of dentist supply Objectives: The proper provision of dentists is very important for delivering the dental care that people need. The purpose of this study is to evaluate the adequacy of dentist supply and to predict the proper supply of dentists in Korea for the next 10 years. Methods and materials: Using the data from 2004 to 2017 in the Statictics Korea, the dental needs were measured as days of admission and the annual total dental care hours in 2020, 2023, 2026 and 2030 were predticted using regression analysis. The dental care productivity (average in-office hours) of dentists was analyzed using regression analysis including age, gender, education level and region as a confounder. The annual care hours were predicted according to seven scenarios based on the percentage of women among dentists, post-dentist education levels, the percentage of dentists in the metropolitan area, aging and retirement age. Results: The needed dentist based on the data in the Statictics Korea will be 27, 288 ~ 27, 311 in 2020, 28,104 ~ 28,1785 in 2023, 28,977 ~ 29,124 in 2026, and 30,174 ~ 30,413 in 2030. On the other hand, the number of dentists in Korea will be 26,945 in 2020, 28,813 in 2023, 30,682 in 2026 and 33,173 in 2030. The adequacy index of dentist supply will be -0.01 in 2020 to +0.10 in 2030. Conclusions: Our data showed that dentists will be adequately supplied in Korea for the next 10 years. Overall, the ratio between dentist versus 1,000 Koreans will be increased from 0.5 in 2019 to 0.7 in 2020, which will meet the mean of OECD countries.

• Imaging Science in Dentistry
• /
• v.48 no.4
• /
• pp.245-254
• /
• 2018

Purpose: To assess the effects of object position in the field of view (FOV) and application of a metal artifact reduction (MAR) algorithm on the diagnostic accuracy of cone-beam computed tomography (CBCT) for the detection of vertical root fractures(VRFs). Materials and Methods: Sixty human single-canal premolars received root canal treatment. VRFs were induced in 30 endodontically treated teeth. The teeth were then divided into 4 groups, with 2 groups receiving metal posts and the remaining 2 only having an empty post space. The roots from different groups were mounted in a phantom made of cow rib bone, and CBCT scans were obtained for the 4 different groups. Three observers evaluated the images independently. Results: The highest frequency of correct diagnoses of VRFs was obtained with the object positioned centrally in the FOV, using the MAR algorithm. Peripheral positioning of the object without the MAR algorithm yielded the highest sensitivity for the first observer (66.7%). For the second and third observers, a central position improved sensitivity, with or without the MAR algorithm. In the presence of metal posts, central positioning of the object in the FOV significantly increased the diagnostic sensitivity and accuracy compared to peripheral positioning. Conclusion: Diagnostic accuracy was higher with central positioning than with peripheral positioning, irrespective of whether the MAR algorithm was applied. However, the effect of the MAR algorithm was more significant with central positioning than with peripheral positioning of the object in the FOV. The clinical experience and expertise of the observers may serve as a confounder in this respect.