Secular trends in grip strength among Korean adults according to socioeconomic factors: the 2014-2022 Korea National Health and Nutrition Examination Survey.

Hand grip strength (HGS), a simple measure of upper limb muscle function, can be used to assess overall muscular strength, and reduced HGS in patients with poor renal functions has been observed. This study examined the associations between renal function and HGS, a surrogate marker of muscular strength, among a stratified sample of Korean adults. This study obtained data from the Korea National Health and Nutrition Examination Survey from 2014 to 2018, a cross-sectional and nationally representative survey conducted by the Korea Centers for Diseases Control and Prevention. In men, low muscle strength (LMS) and normal muscle strength (NMS) were defined as HGS < 28.9 kg and HGS ≥ 28.9 kg, respectively. In women, LMS and NMS were considered as HGS < 16.8 kg and HGS ≥ 16.8 kg, respectively. Of the 25,746 subjects in this study, there were 3603 (14.0%) and 22,143 (86.0%) subjects who displayed LMS and NMS, respectively. Subjects with estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 had a higher risk of developing LMS than those with eGFR ≥ 60 mL/min/1.73 m2 after adjusting for age (odds ratio, 1.772; 95% CI, 1.498–2.096); the significant differences remained after adjusting for other factors including age. Similar tendencies were shown in men and women when analyzed according to gender; however, the risk of developing LMS was higher in men than in women. Results showed that decreased renal function was likely to contribute to an increased prevalence of LMS based on HGS. This association may assist in developing better strategies to estimate renal function in clinical or public health practice.

Kim, YK, Lee, HB, and Lee, SH. Trends in mean hand grip strength, cutoff value, and prevalence of low hand grip strength: An analysis of 2014-2019 Korea National Health and Nutrition Examination Survey (KNHANES) data. J Strength Cond Res 39(8): e967-e973, 2025-The European Working Group on Sarcopenia in Older People 2 (EWGSOP2) defines probable sarcopenia as low muscle strength detected by hand grip strength (HGS). According to this guideline, cutoff for low HGS is determined using a T -score of -2.5 based on age group showing the highest HGS (aged 30-39 years). Our hypothesis is that temporal changes in mean HGS of Koreans may lead to changes in the cutoff values for low HGS and the prevalence of probable sarcopenia as defined by the EWGSOP2 guidelines. We analyzed trends of HGS using 6 years of Korea National Health and Nutrition Examination Survey data. We used the EWGSOP2 guidelines to set yearly cutoff values for low HGS and calculated the prevalence of low HGS. The cutoff value for low HGS and the prevalence rate of low HGS in individuals aged 70 years or older were analyzed using linear regression and trend analysis. We observed a significant decreasing trend from 2014 to 2019 in annual cutoff values for low HGS, ranging from 24.5 to 30.9 kg in men and 13.1-17.3 kg in women. Correspondingly, the prevalence of low HGS (probable sarcopenia) varied significantly from 10.4 to 34.2% in men and 9.1-20.8% in women, indicating notable year-to-year fluctuations ( p < 0.001). While pooling multiyear data reduces some variability, it does not fully address fluctuations in prevalence of probable sarcopenia. To enhance the reliability and clinical relevance of low HGS cutoff values, future guidelines should integrate outcome-based criteria with normative data, ensuring adaptability to temporal trends and population-specific characteristics.

PurposeMuscles play an important role in energy metabolism. Several studies have investigated the association between muscle mass and metabolic syndrome (MetS), reporting conflicting results. However, studies concerning the association between muscle strength and MetS are limited. We aimed to investigate the association between relative handgrip strength (HGS) and MetS in Korean adults.Participants and methodsWe analyzed data from 5,014 Korean adults aged ≥20 years (2,472 men and 2,542 women) who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) VI (2014–2015).ResultsThe increasing quartiles of relative HGS (defined as the sum of both hands’ HGS divided by body mass index) were inversely associated with the risk of MetS in both men and women (OR, 0.37; 95% CI, 0.30–0.45, vs OR, 0.19; 95% CI, 0.14–0.27, respectively) after multivariable adjustment for age, region of residence, smoking status, heavy alcohol consumption, regular exercise, family income, and education level. On multivariable logistic regression analyses, participants with the highest relative HGS had a significant decrease in relative risk of MetS, compared with those with the lowest relative HGS. The multivariable-adjusted ORs (with 95% CIs) for MetS in quartiles 1, 2, 3, and 4 were 1.00, 0.72 (0.55–0.94), 0.34 (0.26–0.46), and 0.22 (0.15–0.32) in men and 1.00, 0.50 (0.36–0.68), 0.26 (0.17–0.40), and 0.16 (0.09–0.27) in women, respectively.ConclusionRelative HGS showed a highly significant inverse association with the risk of MetS in Korean adults, and it can be a novel biomarker for assessing the risk of MetS.

Objectives: Adequate nutrition is an important factor to prevent sarcopenia in older adults. The purpose of this study was to identify the regional differences in the association between dietary pattern and muscle strength in older Korean adults. Methods: This study was based on data from the Korea National Health and Nutrition Examination Survey (KNHANES) in 2014–2016. Muscle strength was measured by grip strength, and dietary patterns were derived by a cluster analysis using the k-means algorithm. Multiple logistic regression analyses were applied to determine the associations between factors (dietary patterns and residential areas) and grip strength. Results: Most participants in the rural area group (50.4%) had the Cluster Three dietary pattern (diet dominant in white rice and kimchi), while most people in the urban area group (43.8%) and the metropolitan area group (53.2%) had the Cluster One dietary pattern (diet dominant in fruits and fish). Those having poor hand grip strength represented 25.8% of the total in rural, 20.6% in urban, and 17.9% in metropolitan (p = 0.009) areas. Upon adjustment for socio-demographic characteristics, health behaviors, and co-morbidity, the odds ratio of Cluster Two (diet dominant in meat) was 1.601 (95%, CI: 1.001–2.563, p = 0.050) compared to the Cluster Three dietary pattern, but there was no significant difference in residence. Conclusions: Muscle strength in the elderly was more related to dietary pattern than was residence. Education and support for conveying the importance of protein intake in the elderly are required to motivate adequate nutrition. In addition, these actions should lead to prevention of muscle weakness and further prevent frailty.

BackgroundAnemia, which is a major public health problem worldwide, represents a decline in the oxygenation function, and can therefore be related to low strength. However, hemoglobin cannot repair muscles directly, but is beneficial only in a supportive role. Previous studies on the relationship between handgrip strength and anemia have been controversial. Thus, we aimed to analyze the association between handgrip strength and anemia in Korean adults.MethodsThis cross-sectional study used the 2013–2017 data from the 6th and 7th Korean National Health and Nutrition Examination Survey (KNHANES) that included 16,638 Korean adults, aged ≥19 years, who met the inclusion or exclusion criteria. Differences in sociodemographic factors (sex, age, education, income, and employment), lifestyle factors (alcohol consumption, smoking, and physical activity), and illness and health factors [body mass index (BMI), vitamin intake, iron intake, comorbid illnesses, and handgrip strength] by existence of anemia, were analyzed using the Chi square test. Binary logistic regression analysis was used to measure the association between handgrip strength and anemia, while adjusting for other possible confounders. Subgroup analysis, stratified by sex and age, was performed.ResultsAmong Korean adults aged ≥19 years, 745,296 (7.7%) had anemia. A higher odds ratio, adjusted for other covariates/factors (OR) of anemia occurred in the weak handgrip strength group than in the strong handgrip strength group (OR = 1.92, 95% CI: 1.58–2.33). The subgroup analysis showed a higher OR adjusted for other covariates/factors of anemia in the weak handgrip strength group than in the strong handgrip strength group, regardless of sex or age. However, the association was greater for males (OR = 2.13, 95% CI: 1.35–3.34) and for those aged ≥65 years (OR = 1.92, 95% CI: 1.42–2.58).ConclusionThis study showed a strong association between handgrip strength and anemia that was particularly strong for males and those aged ≥65 years.

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)

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...

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 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)

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.

Diabetes mellitus (DM) is a significant chronic disease, and health burden from DM is increasing. Recently, studies on the relationship between handgrip strength, which is a measuring tool for muscle strength, and type 2 DM were published. However, the results have been conflicting. In addition, few studies that used data from adults in Korea have been conducted. Thus, this study aimed to identify the association between handgrip strength as well as type 2 DM and insulin resistance in adults using data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2014 to 2015. Inflammation is a condition affecting the muscle strength of individuals with type 2 DM; therefore, its mediating effects were also examined.We included 8208 participants aged between 19 and 80 years who had undergone a handgrip test and had received information about type 2 DM. General linear and binary logistic regression models were used to examine the association between handgrip strength and type 2 DM variables. In addition, mediation analysis was conducted to estimate the role of inflammation in the relationship between handgrip strength and type 2 DM.After adjusting for age, sex, education, alcohol consumption, lifetime smoking, obesity, and aerobic physical activity, handgrip strength was inversely associated with fasting glucose, HbA1c, and fasting insulin levels as well as the homeostasis model assessment of insulin resistance (HOMA-IR) score. Multivariable logistic regression analyses showed that handgrip strength was significantly inversely associated with type 2 DM and insulin resistance. The high-sensitivity C-reactive protein (hs-CRP), an inflammation-related biomarker, mediated approximately 10% of the association between handgrip strength and type 2 DM.Using large, well-defined, nationally representative cross-sectional data on adults in Korea, we found that handgrip strength, which is an indicator of muscle strength, was associated with type 2 DM.

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.

ObjectMeasuring handgrip strength is a useful method to evaluate sarcopenia. No study has shown the trends of handgrip strength to weight ratio among Korean adolescents by year. This study aimed to determine the trends of handgrip strength among Korean adolescents using data from the Korea National Health and Nutrition Examination Survey (KNHANES). Data of 2304 adolescents who participated in the KNHANES between 2014 and 2017 were obtained. The handgrip-to-weight ratios were categorized by age, sex, and year.ResultsHandgrip strength in adolescents decreased from 28.67 kg in 2014 to 27 kg in 2017 (P for trend < 0.05). The handgrip-to-weight ratio also decreased from 51.48 in 2014 to 48.18 in 2017 (P for trend < 0.05). The handgrip strength and handgrip-to-weight ratio also decreased among boys and girls over the years 2014–2017 (P for trend < 0.05). The results of the present study indicate that the handgrip-to-weight ratio decreased in Korean adolescents from the years 2014 to 2017, and a declining overall ratio indicates a decrease in the health status among Korean adolescents. Hence, there is a need to review the health status of Korean adolescents.

Background and Objectives: This study aimed to investigate the association between insulin resistance, as measured by the triglyceride–glucose index (TyG index), and hearing impairment in middle-aged women in Korea. Materials and Methods: This cross-sectional survey utilized data from the Korea National Health and Nutrition Examination Survey (KNHANES) IV (2007–2009), specifically from the period after July 21, 2009, when hearing test results became available, and from the KNHANES V (2010–2012). This study was conducted on 5416 women aged 40 to 69 who had completed both the health examination survey and audiometric tests, excluding those with missing data on menopausal status and the use of hormone replacement therapy. Results: In the study group, the prevalence of high-frequency hearing loss according to the TyG index was significantly higher in the mild hearing loss group (OR = 1.29; 95% CI: 1.12, 1.49, p &lt; 0.001) and the moderate hearing loss group (OR = 1.27; 95% CI: 1.09, 1.48, p = 0.002). Conversely, the prevalence of low-frequency hearing loss did not show a significant difference in either the mild hearing loss group (OR = 1.17; 95% CI: 0.99, 1.37, p = 0.065) and the moderate hearing loss group (OR = 1.13; 95% CI: 0.94, 1.35, p = 0.199) Conclusions: Since diabetes can induce hearing impairment in women, it is recommended that women with a high TyG index undergo early hearing tests

BackgroundTo evaluate and analyse the factors associated with health-related quality of life (HR-QoL) in the Korean population aged 50 years and older.MethodsWe used data obtained from the fourth and fifth Korea National Health and Nutrition Examination Survey (KNHANES IV-V) 2007–2012, a national, cross-sectional health examination and survey, for which representative data on the health, nutritional status, and physical activities of the Korean general population are collected by the Korea Centres for Disease Control and Prevention (KCDC). The sampling protocol for the KNHANES was designed to involve a complex, stratified, multistage probability cluster survey of a representative sample of the noninstitutionalized civilian population in South Korea using a cross-sectional design. The association between HR-QoL and socio-economic factors and medical comorbidities in adults aged 50 years and older was investigated using data from the KNHANES IV-V from 2007 to 2012 (n = 17,937). The EuroQol 5-Dimension Questionnaire (EQ-5D) was used to evaluate HR-QoL, and the factors associated with HR-QoL were analysed after adjusting for socio-economic and demographic factors, anthropometric measurements and clinical comorbidities.ResultsHealth status declined with ageing, and low socio-economic status had negative associations with health status. Gender had no association with health status. Among chronic medical conditions, arthritis and depression had significant associations with health status in older people when stratified by age and gender (P < 0.05).ConclusionsThese findings suggest that older people may value the ability to perform daily activities, which may mean that it is necessary to pay more attention to the factors associated with musculoskeletal pain and emotional distress, as well as socio-economic status or chronic diseases.Trial registrationThe Korea National Health and Nutrition Examination Survey (KNHNES) is not a clinical trial registry, but the national health survey conducted by the Government of the Republic of Korea, to gather information on health and nutritional status of Korean population, to plan public health services and health education programs, and to do statistical studies of the efficiency of public health services required for setting up welfare and healthcare policies.