The Korea National Health and Nutrition Examination Survey as a Primary Data Source

This study is to assess how missing values in socioeconomic status (SES) variables were handled in the Korean Journal of Family Medicine (KJFM) article using the Korea National Health and Nutrition Examination Survey (KNHANES) data and to estimate the rate of missing SES variables from the 4th KNHANES. We searched all original articles published in the KJFM from 2007 to 2011 and identified those that used KNHANES as their primary source of data. None of the 11 articles which presented KNHANES SES variables took into account of omitions in the analysis. The estimated rate of missing data on education, household income, marital status, and occupation data of the 4th KNHANES was 0.3 (0.05)%, 2.7 (0.2)%, 0.5 (0.1)%, and 9.4 (0.9)%, respectively. When all four variables were used simultaneously, the rates increased to 11.8 (0.9)%. Respondents with missing household income tended to be older (P < 0.001), less educated (P < 0.001), and more likely to be unemployed (P < 0.001), and widowed (P < 0.001). A similar relationship was shown for missing occupation data. Omissions in SES variables in KNHANES were related to certain characteristics of study participants. Researchers using KNHANES data should keep in mind the possible bias which can be introduced by missing SES values.

OBJECTIVESIn South Korea, there are two nationwide health surveys conducted by the Korea Centers for Disease Control and Prevention: the Korea Community Health Survey (KCHS) and Korea National Health and Nutrition Examination Survey (KNHANES). The two surveys are directly comparable, as they have the same target population with some common items, and because both surveys are used in various analyses, identifying the similarities and disparities between the two surveys would promote their appropriate use. Therefore, this study aimed to compare the estimates of six variables in KCHS and eight variables in KNHANES over a six-year period and compare time series stability of region-specific and sex- and age-specific subgroup estimates.METHODSData from adults aged 19 years or older in the 2010-2015 KCHS and KNHANES were examined to analyze the differences of estimates and 95% confidence interval for self-rated health, current smoking rate, monthly drinking rate, hypertension diagnosis rate, diabetes diagnosis rate, obesity prevalence, hypertension prevalence, and diabetes prevalence. The variables were then clustered into subgroups by city as well as sex and age to assess the time series stability of the estimates based on mean square error.RESULTSWith the exception of self-rated health, the estimates taken based on questionnaires, namely current smoking rate, monthly drinking rate, hypertension diagnosis rate, and diabetes diagnosis rate, only differed by less than 1.0%p for both KCHS and KNHANES. However, for KNHANES, estimates taken from physical examination data, namely obesity prevalence, hypertension prevalence, and diabetes prevalence, differed by 1.9-8.4%p, which was greater than the gap in the estimates taken from questionnaires. KCHS had a greater time series stability for subgroup estimates than KNHANES.CONCLUSIONSWhen using the data from KCHS and KNHANES, the data should be selected and used based on the purpose of analysis and policy and in consideration of the various differences between the two data.

Trends in Fermented Food Consumption and Sodium Intake from Fermented Foods for Korean Adults Using the Korea National Health and Nutrition Examination Survey (KNHANES) (P18-025-19)

This study developed and validated a short form (SF) using activities of daily living (ADL) outcome measures from the Korea National Health and Nutrition Examination Survey (KNHANES) that can minimize survey administration burden for clinicians. This study utilized secondary data from the 2005 KNHANES with 422 community-dwelling stroke survivors. The KNHANES data were collected from April to June 2005 in South Korea. We created a 7-item SF from the 17 ADL questions in the survey using item response theory (IRT) methodologies. The precision and validity of the SF were compared to the full questionnaire of ADL items and the EuroQol-5D total score. Among the 17 ADL questions, 14 questions demonstrated unidimensional construct validity. Using IRT methodologies, a set of 7 items were selected from the full bank. The 7-item SF demonstrated good psychometric properties: high correlation with the full bank ( r = .975, p < .001), good internal consistency (Cronbach's α = .93), and a high correlation with the EuroQol-5D total score ( r = .678, p < .001). These findings indicate that a well-developed SF can precisely measure ADL performance capacity for stroke survivors compared to the full item bank, which is expected to reduce the administration burden of the KNHANES.

Background: The prevalence of obesity was estimated based on self-reported height and weight recorded in the Community Health Survey (CHS), a nationwide survey which began in 2008. This study was conducted to evaluate the extent and consistency of underestimation in obesity and overweight prevalences in CHS compared to the Korea National Health and Nutrition Examination Survey (KNHANES) data. Methods: In this study, we compared the prevalence estimates of obesity and overweight among Korean adults aged 20 and over using 2010 KNHANES and 2010 CHS data. In contrast to KNHANES data, where subjects' height and weight were actually measured, CHS data relied on subjects' self-reported height and weight. Results: Compared to KNHANES, CHS underestimated the obesity and overweight prevalence by 8.6%P and 7.8%P, respectively. Height (men: -0.9 cm, women: -1.7 cm) was overestimated while weight (men: 0.5 kg, women: 1.1 kg) and body mass index (men: 0.4 kg/m, women: 1.0 kg/m) were underestimated in CHS compared to KNHANES data. The overestimation of height was greater as age increased and weight was underestimated by more than 1.0 kg among men

The Korea National Health and Nutrition Examination Survey (KNHANES) is a representative survey of the Korean population, providing evidence for health policy and health interest statistics. The survey is conducted annually, and the 10th cycle, 1st year (2025) survey is currently underway. In health examination of KNHANES, blood samples are collected from people aged 10 years or older, and urine samples are collected from people aged 6 years or older. To support research related to various public health concerns based on the general population, the National Bank of Korea (NBK) has been operating the KNHANES biobank project since 2005 and has distributed high-quality biospecimens collected through KNHANES. To date, biospecimens from a total of 95,455 participants have been deposited, with approximately 35,500 biospecimens available as of December 2024. This biobank provides serum, plasma, and extracted DNA to researchers in officially approved projects. Recently, urine specimens have also become available. Additionally, genotyping data (> 833,000 genetic markers) for ~19,300 participants generated from the KoreanChip are available. The vast epidemiological data linkage derived from KNHANES will provide valuable insights into public health issues. Researchers can access the resource through NBK’s online platform (HuBIS_Desk, https://biobank.nih.go.kr/Desk/).

Although sarcopenia and insulin resistance are closely related, there is limited evidence regarding how they interact to influence mortality across different population groups. The purpose of this study was to examine the relationship between skeletal muscle mass and insulin resistance and its impact on mortality and cardiovascular disease risk using large-scale national data from Korea and the United States. We analysed data from the National Health and Nutrition Examination Survey (NHANES) 1999-2006 and 2011-2018 and the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2011, with mortality follow-up through to 2019. Cox regression models were used to assess the effects of muscle mass (appendicular skeletal mass index, ASMI) and insulin resistance on all-cause and major adverse cardiovascular and cerebrovascular events (MACCE)-related mortality. Mediation analysis was performed to examine direct and indirect effects. The study included 8036 participants from NHANES and 14 449 from KNHANES. The sarcopenia group demonstrated a lower homeostasis model assessment for insulin resistance and better metabolic indices than the normal group despite having a higher mortality rate. Insulin resistance positively correlated with muscle mass (r = 0.203, p < 0.001 in the NHANES; r = 0.143, p < 0.001 in the KNHANES), and both insulin resistance and sarcopenia were identified as independent risk factors for all-cause and MACCE-related mortality. When the participants were categorized into four groups based on the presence or absence of insulin resistance and sarcopenia, those with both conditions exhibited the highest risk of all-cause mortality (hazard ratio [HR]: 2.30, 95% confidence interval [CI]: 1.72-3.08 in the NHANES; HR: 2.60, 95% CI: 2.14-3.16 in the KNHANES) and MACCE-related mortality among the groups (HR: 3.18, 95% CI: 1.99-5.08 in the NHANES; HR: 2.47, 95% CI: 1.66-3.69 in the KNHANES). Mediation analysis revealed that low muscle mass was associated with decreased insulin resistance but directly increased both all-cause mortality and MACCE-related mortality (NHANES: total natural direct effects [TNDE], HR: 2.08, 95% CI: 1.57-2.76; KNHANES: TNDE, HR: 1.69, 95% CI: 1.28-2.23). This study found that low ASMI was inversely associated with insulin resistance and positively associated with mortality risk in both cohorts. These findings, consistent across two large national studies, highlight the complex relationships between muscle mass, insulin sensitivity and mortality. Further studies are needed to assess the underlying mechanisms and clinical implications of these associations. Clinicaltrials.gov ID: NCT05616013.

Background: The prevalence of diabetes is increasing worldwide on a daily basis, thus threatening human health. To help control diabetes, considerable research has focused on factors influencing diabetes. Among these factors, obesity is the major cause of diabetes. In addition, vitamin D, which has numerous physiological functions, has been associated with diabetes and obesity. Accordingly, the present study investigated the influence of obesity and vitamin D on diabetes using the Korea National Health and Nutrition Examination Survey (KNHANES) data; we also investigated whether vitamin D is a moderating variable between obesity and insulin resistance, the hallmark characteristic of diabetes. Methods: KNHANES data from January to December 2010 were used. Physical information was obtained via interviews, physical examinations, and self-administered questionnaire surveys; 25-hydroxyvitamin D levels, along with other factors, were measured using blood tests. Those who did not participate in both the survey and blood test were excluded from the present study. Results: A greater degree of insulin resistance was associated with a vitamin D deficiency and a higher body mass index (BMI). However, vitamin D did not modify the association between the BMI and insulin resistance. Conclusion: Although this study aimed to investigate the modulatory action of vitamin D on the association between BMI and insulin resistance, it did not provide evidence of a significant relationship. Insulin resistance was increased in patients with a vitamin D deficiency or a higher BMI. Regular physical activity, especially outdoor activities, as well as vitamin D consumption, are recommended to correct for vitamin D deficiency.

BackgroundCorrectional institution inmates have reduced access to dental care; however, a quantitative assessment of their oral health condition has not yet been performed in South Korea. Therefore, this study aimed to assess dental caries and compare the prevalence of dental caries and associated factors between inmates and the general South Korean population.MethodsThe dental records of two detention centers in South Korea were retrospectively analyzed to assess the clinical oral health condition of inmates using the Decayed, Missing, and Filled Teeth (DMFT) index and self-reported questionnaire. These data were compared with similar data obtained from the Korea National Health and Nutrition Examination Survey (KNHANES) for the general South Korean population.ResultsIn total, 642 inmates were analyzed and compared with 13,345 KNHANES participants in the KNHANES. The inmate and KNHANES groups demonstrated significant intergroup differences, with a higher prevalence of untreated caries, DMFT, decayed teeth (DT), and missing teeth (MT) values among the inmates. The prevalence of untreated caries decreased according to the history of dental pain in the inmate group but increased in the KNHANES group. The decrease in DMFT with a history of dental pain was significant only in the inmate group. Furthermore, self-rated oral health was significantly associated with prevalence of untreated caries, DMFT, DT, MT, and filled teeth (FT) in the inmate group but with prevalence of untreated caries, DMFT, DT, and MT in the KNHANES group. It was found that this is because there is an interaction effect by the group.ConclusionsThe oral health of the inmate group was significantly poorer than that of the general group. Since DMFT, DT, MT, and FT values and prevalence of untreated caries in the inmate group were significantly related to their self-rated oral health, suggesting that self-rated oral health should be incorporated into the dental health screenings of correctional institution inmates.

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 R 2 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. (Korean J Nutr 2013; 46(2): 186 ~ 196)

IntroductionCholesterol is an irreplaceable nutrient in pulmonary metabolism; however, studies on high-density lipoprotein cholesterol (HDL-C) levels have shown conflicting results regarding lung function. Therefore, we investigated the association between lung...

PurposeVitamins exert its effect through different isoforms. The isoform conversion phases involved are affected outside factors. Here, we investigated the correlation between serum retinol, α-tocopherol, and serum inflammatory markers using stratified data acquired from 2016 to 2018 Korea National Health and Nutrition Examination Survey (KNHANES).Materials and MethodsThis study was based on data acquired from the 7th edition (2016–2018) of the Korea National Health and Nutrition Examination Survey, consisting of survey data on smoking and alcohol drinking, serum retinol level, serum α-tocopherol level, high-sensitivity C-reactive protein (hs-CRP), and baseline characteristics.ResultsThere was a negative correlation between serum retinol and hs-CRP in alcohol drinking men. There was a negative correlation between serum retinol and hs-CRP in the alcohol-nonsmoking female group. There was a positive correlation between α-tocopherol and hs-CRP in the nonsmoking and alcohol-drinking group. There was a positive correlation between α-tocopherol and hs-CRP in the nonsmoking and alcohol-drinking female group. There was positive correlation between vitamin A and E and metabolic syndrome. The lowest vitamin A level was observed in subjects with all five metabolic syndrome criteria matched.ConclusionThere was a negative correlation between serum retinol and hs-CRP and positive correlation between α-tocopherol and hs-CRP. Absorption and secretion of serum retinol are affected by inflammation status through retinol-binding protein. Alcohol acts as a competitive inhibitor of vitamin A oxidation through alcohol dehydrogenase and ALDH activity. Smoking causes inflammation and induces reactive oxygen species scavenging system and increases cytochrome p450 levels. These factors may have contributed to the observed findings. Metabolic syndrome subjects increased as the levels of vitamin A and vitamin E increased. Since obesity is inversely related to ALDH activity, we postulate that patients with metabolic syndrome may also have low ALDH activity, especially in the Asian population. Future studies are warranted to study the efficacy of ALDH or ALDH inducers in patients with vitamin A deficiency or metabolic syndrome.

The Korea National Health and Nutrition Examination Survey (KNHANES) is a national health survey that is conducted annually to assess the health and and health-related behaviors of Korean population. To utilize KNHANES data to studies of mortality risk factors, the Korea Disease Control and Prevention Agency (KDCA) constructed a database linking KNHANES data to cause-of-death statistics in Statistics Korea, made available to researchers since 2020. The KNHANES data were linked to the Cause of Death Statistics based on resident registration numbers for subjects aged 19 years or older who agreed to link the data. The linkage rate between 2007-2015 National Health and Nutrition Examination Survey and 2007-2019 Cause of Death Statistics was 97.1%. In the linked dataset, the total death rate was 6.6%, of which neoplasms accounted for the highest death rate (32.1%), followed by circulatory system disease (22.7%) and respiratory system disease (11.5%). The linked dataset was made available through the Research Data Center of the KDCA after a review of the research proposal, and will be made available after periodical updates.

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). This nationally representative cross-sectional survey includes approximately 10 000 individuals each year as a survey sample and collects information on socioeconomic status, health-related behaviours, quality of life, healthcare utilization, anthropometric measures, biochemical and clinical profiles for non-communicable diseases and dietary intakes with three component surveys: health interview, health examination and nutrition survey. The health interview and health examination are conducted by trained staff members, including physicians, medical technicians and health interviewers, at a mobile examination centre, and dieticians’ visits to the homes of the study participants are followed up. KNHANES provides statistics for health-related policies in Korea, which also serve as the research infrastructure for studies on risk factors and diseases by supporting over 500 publications. KCDC has also supported researchers in Korea by providing annual workshops for data users. KCDC has published the Korea Health Statistics each year, and microdata are publicly available through the KNHANES website (http://knhanes.cdc.go.kr).

To improve the usefulness of the Korea National Health and Nutrition Examination Survey (KNHANES) and address emerging health issues, we propose a framework for a rotating survey for the KNHANES, aiming to satisfy the diversification of survey domains or items and minimize the response burden on survey participants simultaneously. To establish a rotating survey system for the health survey of the KNHANES, the research was conducted in the following 5 steps: 1) review and analysis of health survey for the 5th to 9th KNHANES, 2) first consultation with experts in each domain of health topics, 3) drafting a framework for the rotating system of the KNHANES, 4) second expert consultation, and 5) proposal of the final draft. Core items in all domains are surveyed annually. In the health behaviors domain, after classifying all topics into 5 groups in consideration of the interrelationships between topics, the 6-year survey cycle (rotating items) was established by assigning the survey cycle differently to 2 years (2 groups) or 3 years (3 groups). The annual average numbers of survey items for 6 years is 197 items (fixed items 179, rotating items 18). Health literacy, digital health, and infectious disease have been proposed as emerging new health issues to be included in the KNHANES. By implementing a rotating survey system, it is expected to reduce the response burden of the survey participants, to increase the efficiency of the survey, and to produce timely health statistics.