• Journal of Korean Academy of Oral Health
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• v.42 no.4
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• pp.101-108
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• 2018

Objectives: The Korea National Health and Nutrition Examination Survey (KNHANES) is a national surveillance system that has been assessing the health and nutritional status of Koreans since 1998. Based on the National Health Promotion Act, the surveys have been conducted by the Korea Centers for Disease Control and Prevention (KCDC). Methods: An oral examination as part of The National Health and Nutrition Examination was proposed to calculate the sample design and survey participation. The surveying system was presented by classifying the measurement environment, screening, and survey items by year, and the merits and limitations of using the data were suggested by examining the status of survey quality management and the process of disclosing raw data. Results: This nationally representative cross-sectional survey samples approximately 10,000 individuals each year and collects information on oral examinations and oral health interviews. Data for the oral health component of KNHANES was obtained to assess the oral health status of Koreans and determine the prevalence of dental caries and periodontitis. The oral health data quality control of KNHANES was composed of three parts: "Education Program" and "Field Training Program" for quality control of oral health examiners (dentists) by the professional academy, and "Data management" by the KCDC. After completion of the three-step data check, the indicators of dental caries, periodontal disease, and oral health behavior were published in the National Health Statistics. Conclusions: To achieve the goals of oral health indicators, we will continue to monitor so that we can use it as basic data for oral policies and carry out various linkage analyses related to oral diseases.

• Journal of Korean society of Dental Hygiene
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• v.19 no.5
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• pp.689-698
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• 2019

Objectives: The study aimed to investigate the relationship between depression and number of present teeth in Korean elderly individuals. Methods: Data for this cross-sectional survey was obtained from the records of the sixth Korea National Health and Nutrition Examination Survey (KNHANES). The subjects were 1,199 Korean elderly individuals above 65 years of age. The survey and examination data were used for the independent variables. The KNHANES included health status, nutrition survey, and oral examination. $x^2-test$ was performed to identify the characteristics of depression and number of teeth present according to the characteristics of the study subjects. Logistic regression analysis was also performed to identify the relationship between depression and number of teeth present. The statistical significance level wa sset at 0.05. Results: The prevalence of depression in the subjects was 14.8%. There were statistically significant differences in the prevalence of depression, depending on gender (p<0.001), education level (p=0.001), income (p=0.001), spouse status (p<0.001), and alcohol consumption (p=0.020). The association between depression and the number of teeth present showed statistically significant difference after adjustment (p=0.040). Conclusions: Depression in elderly individuals was closely related to the number of teeth present. Therefore, public health policies for improving oral health should be established to prevent depression.

• Korean Journal of Community Nutrition
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• v.24 no.1
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• pp.1-17
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• 2019

Objectives: This study was performed to compare the dietary life of single- and non single-person households in the Korea National Health and Nutrition Examination Survey (KNHANES). Methods: A nationally representative sample of 20,421 19-64-year-olds who had 24-hour recall data was taken from the 2014-2016 Korea National Health and Nutrition Examination Survey (KNHANES). Single- and non single-persons were compared for nutrient intake, dietary behaviors, food consumption patterns, nutrition education and confirm nutrition label. Results: The dietary intakes of dietary fiber and iron were lower in single-person households than in non single-person households. The lower the level of education and income, the lower the nutrient intake of single-person households. In the case of those aged 19 to 29, the breakfast skipping rate was higher in single-person households than in non single-person households. The higher the education level, the higher the breakfast skipping rate and the eating out frequency in the single-person households. In the food intake survey, the frequency of healthy food intake in single-person households was much lower than that of non single-person households. The confirmation rate of nutrition labeling was lower in single-person households than in non single-person households. Conclusions: This study shows that single-person households have poorer health-nutritional behaviors than multi-person households. Therefore, a nutrition education program based on the data of this study needs to be developed for health promotion of single-person households.

• Journal of Nutrition and Health
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• v.45 no.6
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• pp.600-612
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• 2012

Nutritional researchers world-wide are using large-scale sample survey methods to study nutritional health epidemiology and services utilization in general, non-clinical populations. This article provides a review of important statistical methods and software that apply to descriptive and multivariate analysis of data collected in sample surveys, such as national health and nutrition examination survey. A comparative data analysis of the Korea National Health and Nutrition Examination Survey (KNHANES) was used to illustrate analytical procedures and design effects for survey estimates of population statistics, model parameters, and test statistics. This article focused on the following points, method of approach to analyze of the sample survey data, right software tools available to perform these analyses, and correct survey analysis methods important to interpretation of survey data. It addresses the question of approaches to analysis of complex sample survey data. The latest developments in software tools for analysis of complex sample survey data are covered, and empirical examples are presented that illustrate the impact of survey sample design effects on the parameter estimates, test statistics, and significance probabilities (p values) for univariate and multivariate analyses.

• Korean Journal of Health Education and Promotion
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• v.29 no.3
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• pp.23-34
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• 2012

Objectives: This study aims to compare the contents of physical activity questions of Korean National Health and Nutrition Examination Survey(KNHANES), and to propose suggestions for improvement. Methods: Questions measuring physical activity prevalence of adults in the KNHANES from KNHANES I(1998) to the first year of KNHANES V(2010) were compared. Results: The questions used in each survey showed some problems in consistency and appropriateness. Major issues identified are as follows. First, the questions in each survey were not consistent, and would be inappropriate to make time series comparisons. Second, the purpose of physical activity was not clear. Third, the examples of physical activities suggested in the questions were not appropriate. Fourth, the intensity of physical activity were not adequately described. Fifth, by excluding walking from the moderate-intensity physical activity category, the prevalence of moderate-intensity physical activity could be underestimated. Sixth, it is difficult to measure the total amount of physical activity performed in one day because answers from the other domains cannot be clearly differentiated. Conclusions: The physical activity questions in the KNHANES questionnaire should be improved so that they are consistent with the purpose of survey, the respondents can easily understand the contents of the questions, and the questions can measure all physical activity performed in the different domains.

• The Journal of the Korean dental association
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• v.58 no.1
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• pp.28-37
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• 2019

This study aimed to introduce what Korea national oral health surveys are and examine recent oral health status in Korean children. Korea Government has implemented national oral health-related surveys during the past two decades. The surveys with oral health examination are Korean Children's National Oral Health Survey (KCNOHS) since 2000 in 5-year-old and 12-year-old children and Korea National Hhealth and Nutrition Examination Survey (KNHANES) since 2007 aged 1 year and more. KCNOHS provides the information about the distribution of prevalence of dental caries, gingival health, behavioral factors, and dental clinic demands etc. KNHANES has huge amount of health data for representative Korean population including oral health and general conditions. Based on KCNOHS, the prevalence of dental caries and its experience has decreased steadily, and the status of oral hygiene and preventive treatment called sealents has been also improved after the year of 2000. However, there is still a gap to reach to those of Western developed countries. Therefore, more effective oral health policy plans and strategies for Korean children and adolescents are needed to prevent and manage for dental caries in private and clinical field of dentistry with public sector.

• Journal of Korean society of Dental Hygiene
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• v.15 no.5
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• pp.925-932
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• 2015

Objectives: The aim of this study is to investigate the relationship between diabetes mellitus and oral disease in the Korea adults by using the representative data of Korea National Health and Nutrition Examination Survey (KNHANES) V. Methods: Using data from a cross-sectional survey of Korea National Health and Nutrition Examination Survey V. The subjects were 5,602 adults over 19 years old. The survey data and the examination data are used for the independent variables. KNHANES included health status, nutrition survey, and oral examination. The health status was obtained by a self-reported questionnaire of the study subjects and direct interview was carried out on economic status, prevalence rate, and use of medical services. Results: The regular dental checkup of diabetes patients was significantly lower than the general population. Regular dental visits allow adults to receive early diagnosis and obtain restorative care at the first visit. The regular annual oral examination is very important to prevent and manage the chronic diseases including diabetes mellitus. Conclusions: Diabetes mellitus can be fully prevented and managed by the regular annual dental checkup. The establishment of the regular dental checkup system can prevent and manage the complication due to diabetes mellitus and other chronic diseases.

• Korean Journal of Community Nutrition
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• v.21 no.3
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• pp.293-300
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• 2016

Objectives: The purpose of the study was to develop a dietary fiber composition table (DFCT) and to assess dietary fiber intakes in Korea National Health and Nutrition Examination Survey (KNHANES). Methods: The DFCT was developed by compiling the food composition tables published by the agencies of Korea, United States, or Japan. When there was no available data from the same species or status (dried, boiled, etc.) of food, the values were imputed by estimating from the same species with different status or substituting familiar species in biosystematic grouping. Using KNHANES VI-2 (2014) microdata and DFCT, intake of dietary fiber of Koreans was estimated. Results: Among the 5,126 food items of DFCT, the proportion of items of which dietary fiber contents were taken from the analytical values of the same foods was 40.9%. The data from the domestic food composition tables was 37.5%, and the data from the foreign tables was 49.6%. The rest was assumed as zero, or estimated with recipe database and nutrition labeling. Mean daily intake of dietary fiber was 23.2 g, and mean intake per 1,000 kcal was 10.7 g in men and 12.6 g in women. The mean percentage of dietary fiber intake compared to adequate intake was higher than 100%. The major food groups contributing to dietary fiber intakes were vegetables and cereals, and the percent contribution were 32.9% and 23.0% of total dietary fiber intakes, respectively. Conclusions: This DFCT could serve as a useful database for assessing dietary fiber intakes and for investigating the association between dietary fiber intakes and noncommunicable diseases.

• Journal of Nutrition and Health
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• v.46 no.2
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• pp.186-196
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• 2013

The objective of this study was to develop a semi-quantitative food frequency questionnaire (FFQ) for an adult population for use in the Korea National Health and Nutrition Examination Survey (KNHANES). The 24-hour recall data for 2,939 subjects aged 19 years and over from the fourth KNHANES first year (2007) were used to extract the items included in the questionnaire. The FFQ items were developed by selection of major dishes based on the cumulative contribution rate, between-person variability based on the cumulative R2 of energy and 14 nutrients (carbohydrate, protein, fat, crude fiber, calcium, phosphorous, iron, sodium, potassium, vitamin A, thiamin, riboflavin, niacin, and vitamin C) and the number of consumers of each dish. In addition, the FFQ items were revised with analysis of 24-hour recall data of the fourth KNHANES second and third year (2008, 2009). Finally, 112 items were included in the FFQ and grouped as follows: rice (5 items), noodles and dumplings (6), breads and rice cakes (8), soups and stews (12), soybeans, eggs, meat and fish (23), vegetables, seaweed and potatoes (27), milk and dairy products (4), fruits (13), beverages (5), snacks (6) and alcoholic beverages (3). The food items of FFQ accounted for an average of 87.0% of energy and 14 nutrient intakes and also accounted for 81.7% of the between-person variability. The frequency range of the FFQ items was classified into nine categories (never or seldom, once per month, 2-3 times per month, once per week, 2-4 times per week, 5-6 times per week, once per day, twice per day and three times per day) and the portion size was divided into three categories (small, medium and large). We expect that this developed dish-based FFQ could be used in assessment of longterm dietary intakes of Korean adults.

• Journal of Preventive Medicine and Public Health
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• v.46 no.2
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• pp.96-104
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• 2013

Objectives: The inherent nature of the Korean National Health and Nutrition Examination Survey (KNHANES) design requires special analysis by incorporating sample weights, stratification, and clustering not used in ordinary statistical procedures. Methods: This study investigated the proportion of research papers that have used an appropriate statistical methodology out of the research papers analyzing the KNHANES cited in the PubMed online system from 2007 to 2012. We also compared differences in mean and regression estimates between the ordinary statistical data analyses without sampling weight and design-based data analyses using the KNHANES 2008 to 2010. Results: Of the 247 research articles cited in PubMed, only 19.8% of all articles used survey design analysis, compared with 80.2% of articles that used ordinary statistical analysis, treating KNHANES data as if it were collected using a simple random sampling method. Means and standard errors differed between the ordinary statistical data analyses and design-based analyses, and the standard errors in the design-based analyses tended to be larger than those in the ordinary statistical data analyses. Conclusions: Ignoring complex survey design can result in biased estimates and overstated significance levels. Sample weights, stratification, and clustering of the design must be incorporated into analyses to ensure the development of appropriate estimates and standard errors of these estimates.