Comparison of estimates and time series stability of Korea Community Health Survey and Korea National Health and Nutrition Examination Survey

OBJECTIVESWe aimed to explore trends in the prevalence and management of obesity, hypertension, diabetes, and hypercholesterolemia in Korean adults from 1998 to 2018 using data from the Korea National Health and Nutrition Examination Survey (KNHANES).METHODSThe study participants included 79,753 individuals aged ≥ 30 years who had participated in the health examination and health interview of the first (1998) to the seventh (2016-2018) KNHANES. The prevalence and management as well as annual percent change (APC) in chronic diseases were analyzed using SAS and the Joinpoint software program.RESULTSThe prevalence of obesity in men significantly increased from 26.8% in 1998 to 44.7% in 2018 (APC=1.9, p<0.001), whereas that in women decreased slightly from 30.5% in 1998 to 28.3% in 2018 (APC=-0.5, p<0.001). The prevalence of hypertension in men was 33.2% in 2018, with no significant change, whereas that in women slightly decreased to 23.1% in 2018 (APC=-0.9, p<0.001). The prevalence of diabetes in men increased slightly from 10.5% in 2005 to 12.9% in 2018 (APC=1.6, p<0.001), whereas that in women remained at approximately 8%, with no significant change. The prevalence of hypercholesterolemia in both men and women increased 3-fold in 2018 (20.9% in men [APC=8.2, p<0.001] and 21.4% in women [APC=7.1, p<0.001]) compared to that in 2005. The awareness rate, treatment rate, and control rate of hypertension and hypercholesterolemia increased 2-3 fold. Regarding diabetes, the treatment rate increased, but the control rate did not change.CONCLUSIONSOver the past 20 years, the prevalence of obesity (in men), diabetes, and hypercholesterolemia has increased and management indicators, such as the awareness rate, treatment rate, and control rate of chronic diseases, have improved continuously.

The Korea National Health and Nutrition Examination Survey (KNHANES) is a population-based cross-sectional survey designed to assess the health related behavior, health condition, and nutritional state of Koreans (http://knhanes.cdc.go.kr/). It was conducted as a tri-annual survey for the first 3 cycles, implemented in 1998, 2001, and 2005. Beginning with the 4th cycle of 2007, it was converted to an annual survey. The 2011 data was recently opened to the public, and is free for all researchers who want to use it. The KNHANES provides a rich source of data which are easy to access and can be quickly obtained. Its ethical problems are minimal and there are no adverse effects in conducting the study. Using the KNHANES saves time, money, and personnel that would otherwise be spent collecting data, and provides a larger and higher-quality database beyond the capacity of any one individual researcher. Further, because the study participants are representative of the Korean population, the results have external validity. Therefore, this data is helpful to young investigators. In fact, the portion of submitted articles to the Korean Journal of Family Medicine (KJFM) using the KNHANES as the primary source of data is significant. Specifically, one article in 2007, three articles in 2008, four articles in 2009, three articles in 2010, five articles in 2011, and five articles in 2012 used the KNHANES data as their primary data source, totaling 21 articles (6.2%) among 338 original articles during the previous five years. However, there are several points investigators should keep in mind when using the KNHANES data. First, the KNHANES data are open to the public and there is no systematic process to control the research topic assignment. Many researchers might investigate the same topic simultaneously, especially popular topics like obesity and metabolic syndrome. Before deciding on the study topic, a thorough search of the database like Medline, EMBASE, and the abstracts of related conferences are needed. Once the topic is decided upon, the article should be submitted as soon as possible. Otherwise someone else may publish a similar study from the same dataset before you do. Second, investigators must be familiar with the huge and complex data structure and study design of the KNHANES. Non-response and multi-stage probability sampling should be taken into account by using survey statistics to estimate the data of the whole Korean population. Despite this, lots of studies submitted to KJFM using the KNHANES do not apply sampling weight in their analysis. In such a case the estimated association might be biased and revision is required. Third, the KNHANES is a secondary data source like the Korea Youth Risk Behavior Web-based Survey and the Community Health Survey, and has the same limitations that they have.1) The main purpose of the KNHANES is to produce national statistics, not to answer a specific research question. Therefore, the particular information the investigator wants may not be collected. For these reasons, the dataset should be examined carefully to confirm that it includes the necessary data. There also exists a potential for errors or mistakes in the data, even with its rigorous documents control system. Missing data is also a problem in the KNHANES.2)

The rapid increases in childhood obesity and physical inactivity are linked to the incidence of diabetes among young individuals. However, few studies have evaluated the prevalence of diabetes among this population. Therefore, we used Korea National Health and Nutrition Examination Survey (KNHANES) data to evaluate the prevalence and management of diabetes and pre-diabetes among young Koreans. We evaluated KNHANES data (2005–2014) from 10–29-year-old individuals. Individuals were considered eligible if they had completed the health examination and the health interview survey, and we excluded individuals with missing data regarding fasting glucose or glycated haemoglobin levels. Among the 100,101 potentially eligible individuals who participated in KNHANES (2005–2014), we included 83,577 (37,677 male and 45,900 female) individuals. The overall prevalences of diabetes and pre-diabetes among 10–19-year-old individuals were 0.2% and 11.9%, respectively. Among 20–29-year-old individuals, the prevalences of diabetes and pre-diabetes were 0.9% and 9.6%, respectively. The overall rates of diabetes awareness during the study period were 36.6% for 10–19-year-old individuals and 50.8% for 20–29-year-old individuals. However, the prevalence of diabetes and pre-diabetes had noticeably increased at the 2013–2014 KNHANES: 0.6% and 25.9% among 10–19-year-old individuals, and 0.8% and 19.2% among 20–29-year-old individuals. The prevalence of diabetes and pre-diabetes is rapidly increasing among Korean teenagers and young adults. Pre-emptive interventions to diagnose and treat diabetes and pre-diabetes are needed to improve glycaemic control among this population.

Socioeconomic inequalities in conventional cigarette smoking are well established in developed countries. The aim of this study was to investigate socioeconomic inequalities in e-cigarette use in Korea, in comparison with inequalities in conventional cigarette use. Data from the Korea National Health and Nutrition Examination Survey (KNHANES) and the Korea Community Health Survey (KCHS) were analyzed. The years of data collected were 2013 to 2016 for the KNHANES and 2014 to 2016 for the KCHS, respectively. The age-adjusted prevalence of ever and current e-cigarette use and conventional cigarette use was calculated according to socioeconomic status indicators, including education, occupation, and income. The prevalence of ever e-cigarette use in men increased from 12.1% in 2013 to 19.2% in 2016 in the KNHANES, and from 13.4% in 2014 to 17.9% in 2016 in the KCHS. Ever and current e-cigarette use was concentrated among current smokers and was much more prevalent among men and also more common among younger age groups in men and women. There was higher prevalences of conventional cigarette use among men and women with less education, manual occupational class and lower income, with the differences more pronounced for women. There was higher ever and current use of e-cigarettes among women with less education, manual occupational class and lower income, but among men there was much less difference in e-cigarette use by these indicators of socio-economic status.

Trends in diabetes prevalence among Korean adults based on Korean National Health and Nutrition Examination Surveys III–VI

Recently, a positive association has been reported between hypertension and periodontitis. The authors hypothesized that oral hygiene promotion activities could have an effect on hypertension prevention or the degree of hypertension control. Therefore, this study examines the relationship between oral hygiene behaviors and hypertension using data from a nationally representative survey, the Korea National Health and Nutrition Examination Survey (KNHANES). Using data from the KNHANES (2008 to 2010), 19,560 adults with complete data sets were included. The authors analyzed the relationship of the prevalence and control rate of hypertension and numerous variables, including oral hygiene behavior. As the frequency of toothbrushing increased, the prevalence of hypertension decreased in multivariate analysis after adjusting for various factors, including the presence of periodontitis. In a subgroup analysis, this relationship was also observed in individuals without periodontitis. In particular, systolic blood pressure levels progressively decreased as the frequency of toothbrushing and the number of secondary oral products used increased. The adjusted odds ratio of hypertension prevalence was 1.195 (95% confidence interval 1.033 to 1.383) for individuals who brushed their teeth hardly ever or once daily compared with those who brushed after every meal. Individuals with poor oral hygiene behavior are more likely to have a higher prevalence of hypertension, even before periodontitis is shown. Oral hygiene behavior may be considered an independent risk indicator for hypertension, and maintaining good oral hygiene may help to prevent and control hypertension.

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.

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.

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.

PurposeThe prevalence and burden of asthma is increasing worldwide. In this study, we analyzed 3 different Korean national health survey datasets to determine the general features of adult asthma in Korea and to obtain basic information that would support future strategies for better management of adult asthma.MethodsThe surveys used in this study included the Korea National Health and Nutrition Examination Survey (KNHANES), Korea Community Health Survey (KCHS) and National Health Insurance Service-National Sample Cohort (NHIS-NSC). We investigated annual asthma prevalence, evaluating the rate and risk factors of asthma exacerbation by age and sex, and clinical data of 1,832 patients with asthma who were registered in the Cohort for Reality and Evolution of Adult Asthma in Korea (COREA) were analyzed to elucidate risk factors for asthma exacerbation. We also analyzed another asthma cohort and added it as replication data.ResultsIn the KNHANES database, annual asthma prevalence rates varied from 1.2% to 3.1%. In the KCHS database, overall prevalence increased, with significant regional differences (1.6%–2.1%). The NHIS-NSC indicated a gradual increase in annual asthma prevalence from 4.5% to 6.2%. Interestingly, all 3 surveys indicated the highest prevalence of asthma among elderly women. In addition, elderly women with asthma had a significantly higher risk of asthma exacerbation (odds ratio [OR], 1.87; 95% confidence interval [CI], 1.19–2.93; P=0.006). Approximately 11% of patients were classified as having severe asthma. An asthma cohort analysis identified female sex, low baseline pulmonary function, longer treatment duration, high variability in pulmonary function and significant changes in Asthma Control Test scores as risk factors for asthma exacerbation.ConclusionsThe prevalence of asthma in Korea is consistently high among elderly and female populations. These results should lay the foundation for strategies for effective asthma prevention and management; elderly female patients with asthma should receive particular attention.

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.

This study aimed to examine the association between food insecurity and the prevalence of chronic diseases among older adults in South Korea and to compare the findings with data from the United States (US). We analyzed data from the Korea National Health and Nutrition Examination Survey (KNHANES) V (2010 - 2012) and VI (2013 - 2015) and 4 years (2012 - 2015) of food security questionnaire data. The data of 46,189 National Health and Nutrition Examination Survey participants (1999 - 2016) were subjected to propensity score-matched (PSM) analysis. We included 7,914 individuals from the KNHANES. In the older group (age &gt;65 years), no differences were observed in the prevalence of hypertension, diabetes, chronic kidney disease (CKD), and metabolic syndrome across the income groups. Income, education, and food security had no impact on hypertension, diabetes, and CKD prevalence in the multivariate logistic analysis after PSM. CKD was not associated with food insecurity (odds ratio (OR), 1.26; 95% confidence interval (CI), 0.94-1.26) in the final model using the KNHANES data; however, the U.S. NHANES data showed that an increased risk of hypertension was associated with food insecurity (OR, 1.27; 95% CI, 1.04-1.55). As per the U.S. NHANES data, food insecurity was associated with a high prevalence of hypertension, while as per the South Korean KNHANES data, food insecurity was not found to be associated with CKD, indicating divergent relationships between food insecurity and chronic diseases in the two countries. Further research is needed to explore these differences.