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Background: Reduced meal frequency can increase the risk of metabolic syndrome (MetS). However, limited studies have examined the association between meal frequency and skipping meals with MetS. This study aims to analyze the association between main meal frequency and meal skipping with MetS in Korean adults aged ≥ 19 years. Methods: In this study, we included data from 22,699 Korean adult participants from the 2016–2020 Korea National Health and Nutrition Examination Survey (KNHANES). The 24-h dietary recall method was used to classify the participants into three groups based on main meal frequency (one, two, or three meals per day) and seven groups based on the type of main meal they skipped. Multivariable logistic regression analysis was conducted to determine the association between main meal frequency and the types of main meals skipped with the odds of MetS and its associated components. Appropriate estimates were accounted for using sampling weights, stratification, and clustering. Results: The prevalence of MetS in the study population was 33.8%. The average age of the participants was 47.2 years with 42.6% being men, and 57.4% being women. Men who consumed two meals per day had higher odds of MetS than those who consumed three meals per day (odds ratio [OR] 1.16, 95% confidence interval [CI] 1.01–1.33). Women who consumed two meals per day, and skipped breakfast had increased odds of having elevated fasting blood glucose levels (OR 1.18, 95% CI 1.02–1.35), and elevated triglycerides (OR 1.19, 95% CI 1.02–1.39). However, women who skipped dinner had reduced odds of having elevated fasting blood glucose levels (OR 0.74, 95% CI 0.58–0.94). Conclusions: Our findings suggest that meal frequency and the type of main meal skipped may be associated with MetS and emphasize the importance of consuming breakfast to prevent MetS. [ABSTRACT FROM AUTHOR]

Evidence on the association between serum 25-hydroxyvitamin D (25(OH)D) concentration and all-cause and cause-specific mortality in Asians, especially Koreans, is limited. We hypothesized that high concentrations of 25(OH)D are associated with lower all-cause and cause-specific mortality in the general Korean population. This study included 27,846 adults participating in the Fourth and Fifth Korean National Health and Nutrition Examination Survey 2008–2012, followed up through December 31, 2019. Hazard ratios (HR) and 95% confidence intervals (CIs) for mortality from all causes, cardiovascular disease (CVD), and cancer were estimated using multivariable-adjusted Cox proportional hazards regression. The weighted mean serum 25(OH)D of study participants was 17.77 ng/mL; 66.5% had vitamin D deficiency (<20 ng/mL) and 94.2% had insufficient vitamin D (<30 ng/mL). During a median follow-up of 9.4 years (interquartile range, 8.1–10.6 years), 1680 deaths were documented, including 362 CVD deaths and 570 cancer deaths. Serum 25(OH)D levels ≥30 ng/mL were inversely associated with all-cause mortality (HR, 0.57; 95% CI, 0.43–0.75) compared with serum 25(OH)D levels <10 ng/mL. Based on the quartile cutoffs of serum 25(OH)D concentration, the highest quartile of serum 25(OH)D concentration (≥21.8 ng/mL) was associated with the lowest all-cause mortality (HR, 0.72; 95% CI, 0.60–0.85; P trend <.001), and CVD mortality (HR, 0.60; 95% CI, 0.42–0.85; P trend =.006). No association with cancer mortality outcome was found. In conclusion, higher serum 25(OH)D levels were associated with lower all-cause mortality in the general Korean population. An additional association was found between higher quartile of serum 25(OH)D and lower CVD mortality. In this nationally representative sample of Korean adults, we found that higher serum 25-hydroxyvitamin D (25(OH)D) levels were associated with lower all-cause mortality but not with cancer mortality. Quartile analysis of serum 25(OH)D levels revealed an additional significantly inverse relationship with cardiovascular mortality. Maintaining the proper level of serum 25(OH)D through vitamin D supplementation in the general Korean population may have potential benefits in altering mortality risk. [Display omitted] [ABSTRACT FROM AUTHOR]

This study aims to determine the relationship between chewing ability and the nutritional status of the elderly in Korea. This study utilized the data from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted from 2013–2018 for persons who were ≥65 years of age. Of the 7835 subjects, 43.2% had chewing difficulty. Compared to the normal group, the chewing difficulty group had more stress, lower exercise frequency, less snack intake, a lower frequency of eating out, and a higher proportion of food insecurity. The chewing difficulty group had significantly lower food intake compared to the normal group, including various food groups such as cereals and grain, potatoes, fruits, meat, and milks and dairy products. The intake of fresh fruits was 24.5% lower and the intake of plant food (fresh fruits and nonstarchy vegetables) was 17.8% lower in the chewing difficulty group compared to the normal group. In addition, the intake of most nutrients (carbohydrates, fat, calcium, phosphorus, sodium, potassium, vitamin A, riboflavin, niacin, and vitamin C) was significantly lower in the chewing difficulty group than in the normal group. The chewing difficulty was significantly associated with undernutrition (OR = 1.63). In conclusion, chewing ability is closely related to food and nutrient intake among the elderly, which can decrease the quantity and quality of diet and is also related to undernutrition. Therefore, it is necessary to develop customized nutrition programs and aging-friendly food products that consider the chewing ability of the elderly. [ABSTRACT FROM AUTHOR]

Sarcopenia is a well-known age-related disease that can lead to musculoskeletal disorders and chronic metabolic syndromes, such as sarcopenic obesity. Numerous studies have researched the relationship between sarcopenia and various risk factors, leading to the development of predictive models based on these factors. In this study, we explored the impact of physical activity (PA) in daily life and obesity on sarcopenia prediction. PA is easier to measure using personal devices, such as smartphones and watches, or lifelogs, than using other factors that require medical equipment and examination. To demonstrate the feasibility of sarcopenia prediction using PA, we trained various machine learning models, including gradient boosting machine (GBM), xgboost (XGB), lightgbm (LGB), catboost (CAT), logistic regression, support vector classifier, k-nearest neighbors, random forest (RF), multi-layer perceptron, and deep neural network (DNN), using data samples from the Korea National Health and Nutrition Examination Survey. Among the models, the DNN achieved the most precise accuracy on average, 81%, with PA features across all data combinations, and the accuracy increased up to 90% with the addition of obesity information, such as total fat mass and fat percentage. Considering the difficulty of measuring the obesity feature, when adding waist circumference to the PA features, the DNN recorded the highest accuracy of 84%. This model accuracy could be improved by using separate training sets according to gender. As a result of measurement with various metrics for accurate evaluation of models, GBM, XGB, LGB, CAT, RF, and DNN demonstrated significant predictive performance using only PA features including waist circumference, with AUC values at least around 0.85 and often approaching or exceeding 0.9. We also found the key features for a highly performing model such as the quantified PA value and metabolic equivalent score in addition to a simple obesity measure such as body mass index (BMI) and waist circumference using SHAP analysis. [ABSTRACT FROM AUTHOR]

Studies have reported inconsistent results regarding the relationship between serum vitamin E levels and depressive symptoms. Furthermore, the potential modulating role of age and sex has been underexplored. We conduct an age- and sex-stratified investigation of the association between serological vitamin E status and depressive symptoms in a large nationwide sample. Data from the Korean National Health and Nutrition Examination Survey were analyzed (n = 4448). The participants were stratified into four groups according to age (<65 vs. ≥65 years) and sex. Each group was divided into tertiles of vitamin E/total lipid ratio, and Patient Health Questionnaire-9 (PHQ-9) scores were compared among the tertiles via multivariable linear regression analyses. The relationship between dietary supplement use and the proportions of tertiles was assessed in each group. With the middle tertile as the reference group, the low tertile of vitamin E/total lipid ratio was associated with increased PHQ-9 scores in younger females and older males after adjusting for all covariates, while the high tertile showed no significant associations with PHQ-9 scores in any group. The low tertile was associated with increased adjusted mean PHQ-9 scores by 0.53 and 1.02 compared to the middle tertile in younger females and older males, respectively. Dietary supplement use was related to higher vitamin E/total lipid ratio in all four groups. In conclusion, younger females and older males with a low vitamin E status showed worse depressive symptoms. These individuals may benefit from dietary interventions to prevent depressive symptoms. [ABSTRACT FROM AUTHOR]

Background: Chronic kidney disease (CKD) has a significant impact on global health. Studies have shown that subclinical thyroid dysfunction may be related to CKD, but the association between subclinical thyroid dysfunction and CKD in the general population is unclear. We aimed to evaluate the risk of CKD according to thyroid function status in a large cohort. Methods: We analyzed data from a nationwide, population-based, cross-sectional survey (KNHANES VI). A total of 3,257 participants aged ≥ 19 years who underwent thyroid and kidney function assessments were included in this study. CKD was defined as an estimated glomerular filtration rate < 60 mL/min/1.73 m2 and/or urine albumin-creatinine ratio ≥ 30 mg/g. The risk of CKD according to thyroid function status was assessed using logistic regression, adjusted for potential confounders. Results: Overall, 6.7% of the participants had CKD. There were no significant differences in thyroid-stimulating hormone and free thyroxine levels between the groups with and without CKD. The proportion of participants with CKD was significantly different among the thyroid function status groups (p = 0.012) and tended to increase significantly in the following order: subclinical hyperthyroidism (1.5%), euthyroidism (6.6%), and subclinical hypothyroidism (12.6%) (p for trend < 0.001). Subclinical hypothyroidism was a significant risk factor for CKD, even after adjusting for sex, age, household income, education, smoking, alcohol consumption, walking activity, abdominal obesity, hypertension, low high-density lipoprotein cholesterol, elevated triglycerides, hyperglycemia, free thyroxine, and thyroid-peroxidase anibody (odds ratio 2.161, 95% confidence interval 1.032–4.527, p = 0.041). Conclusion: Subclinical hypothyroidism is an independent predictor of CKD in the general population. [ABSTRACT FROM AUTHOR]

Vitamin D deficiency is prevalent in Korea and an insufficient vitamin D status increases the risk of various chronic diseases including metabolic syndrome (MetS). We examined the relationship between serum 25-hydroxyvitamin D (25(OH)D) levels, dietary vitamin D intake, and MetS. The 2013–2014 Korea National Health and Nutrition Examination Survey's (KNHANES) included participants (n = 4.541; 1145 men; 1368 women) who were aged ≥19. In men, higher serum 25(OH)D levels were correlated with significantly increased protein intake (p = 0.032) and saturated fatty acid intake (p = 0.006), but significantly decreased fat intake (p = 0.027), monounsaturated fatty acid intake (p = 0.005), and polyunsaturated fatty acid intake (p = 0.003), and significantly decreased serum triglycerides levels (p = 0.002), whereas women had no association with any dietary intake or biochemical markers. Furthermore, our study found a significant negative correlation between abdominal obesity (OR, 0.970; CI, 0.946, 0.994) and hypertriglyceridemia (OR, 0.974; CI, 0.950, 0.998) and serum 25(OH)D levels in men, as well as a significant decrease in hypertriglyceridemia (OR, 0.980; CI, 0.961, 0.999) with vitamin D intake. However, women had a significantly negative correlation between serum LDL cholesterol (β, −1.751; p = 0.018) and vitamin D intake. By increasing the vitamin D intake and serum 25(OH)D levels, Korean adults could reduce their risk of MetS-related factors. [ABSTRACT FROM AUTHOR]

Hypertriglyceridemia is a well‐known risk factor of various chronic diseases including diabetes mellitus, metabolic syndrome, obesity, and cardiovascular diseases. This study aimed to determine dietary patterns and explore the relationship between dietary patterns and hypertriglyceridemia in the Korean adult population. We utilized a cross‐sectional and nationally representative survey, the Korea National Health and Nutrition Examination Survey 2013–2018 database. From 47,217 subjects who participated in the survey between 2013 and 2018, only subjects over 40 years old were included. Subjects lacking 24‐h recall data and data on hypertriglyceridemia and body mass index, and who had implausible energy intake were excluded. A total of 19,806 participants' data were analyzed. Dietary data were based on 24‐h recall data, and dietary patterns were derived using factor analysis. Triglyceride levels greater than 200 mg/dl were considered hypertriglyceridemia, according to the Korean Society of Lipid and Atherosclerosis. Three dietary patterns— "oil and fats & seasoning", "soybean paste and vegetable", and "fruit and whole‐grain"— explained 7.9%, 6.3%, and 5.8% of variation in food intake, respectively. Comparing the lowest and highest dietary pattern score groups after adjusting for potential confounders revealed an inverse relationship between "fruit and whole‐grain" dietary pattern and hypertriglyceridemia in men (odds ratio [OR]: 0.61, 95% confidence interval [CI]: 0.45–0.82, p for trend <.0001); which was only marginal in women (OR: 0.78, 95% CI: 0.58–1.07, p for trend:.628). A diet containing high proportions of fruit and whole‐grain may have preventive effects on hypertriglyceridemia in middle and older aged Korean adults. [ABSTRACT FROM AUTHOR]

BackgroundSeveral studies have shown that adherence to the Mediterranean diet is associated with a lower risk of depression; however, little is known about the Asian population. This study investigated the relationship between adherence to the Mediterranean diet and depression in a sample of the South Korean population.MethodsIn total, 5,849 adults from the 2014 and 2016 Korea National Health and Nutrition Examination Surveys were included in the study. The Mediterranean diet adherence was measured using a modified alternate Mediterranean diet score (mMED) developed to adjust for Korean dietary patterns. The mMED scores using the Food Frequency Questionnaire were divided into four categories (0–2, 3–4, 5–6, and 7–9 points). Subjects with depression were defined as having moderate-to-severe depressive symptoms using the Patient Health Questionnaire-9, with a cutoff value of 10. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). A subgroup analysis was performed based on sex.ResultsThe results of logistic regression analysis indicated that individuals with higher mMED were 42–73% less likely to report depression compared to individuals with the lowest mMED [ORs (95% CIs) =0.58 (0.37–0.90), 0.50 (0.31–0.80), 0.27 (0.15–0.47)] after adjusting for socio-demographic and health-related variables. In women, individuals with mMED of 7–9 had 71% lower odds of depression [ORs (95% CIs): 0.29 (0.13–0.64)]. In men, individuals with mMED of 5–9 had 55% [ORs (95% CIs): 0.45 (0.23–0.91)] to 79% [ORs (95% CIs): 0.21 (0.08–0.57)] lower odds of depression.ConclusionThis study suggests that adherence to the Mediterranean diet is inversely associated with depression in both men and women among Korean adults. This study provides evidence that a Mediterranean diet is crucial in preventing depressive symptoms in Asian populations.

Objectives: This research aims to confirm the association between dyslipidemia, oral health behaviors, and periodontal disease according to age groups. Method and materials: This cross-sectional study used collected data from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted from 2012 to 2015 with 17,004 adults. Complex samples logistic regression analysis confirmed the relevant factors of oral disease. Results: Hypo high-density lipoprotein cholesterol (HDL-C) related to periodontal disease in two groups (under 40 and over 40 years old). In the over-40 age group, the level of low-density lipoprotein cholesterol (LDL-C) was associated with periodontal disease; toothbrushing frequency and usage of interdental hygiene products were associated with periodontal disease. Conclusions: Better HDL-C level in all age groups, management of LDL-C level, tooth-brushing at least twice a day, and additional use of interdental hygiene products in the over-40 age group were associated with better oral health. Thus, public and oral health professionals should emphasize the relationship according to age group during health care education and share relevant information. [ABSTRACT FROM AUTHOR]

PURPOSE The purpose of this study was to examine the association between objectively measured physical activity and metabolic syndrome in Korean adults and older adults. METHODS A total of 2,191 adults and older adults from the Korea National Health and Nutrition Examination Survey from 2014 to 2017 were analyzed. Participants were categorized into three groups (‘Inactive’, ‘Active’, ‘Highly active’) according to physical activity guidelines. A chi-square test was performed to confirm whether the physical activity guidelines were met according to metabolic syndrome and the difference between metabolic syndrome according to age group. Logistic regression was used to predict the relationship between physical activity and metabolic syndrome. RESULTS The prevalence of metabolic syndrome differed according to whether physical activity guidelines were met in older adults, and the prevalence of metabolic syndrome and its risk factors varied according to age group. Compared to the Inactive group, the odds ratios (OR) for metabolic syndrome were 0.73 (95% confidence interval [CI]: 0.56–0.95) and 0.65 (95% CI: 0.47–0.88) in adults in the Active and Highly active groups, respectively; and 0.46 (95% CI: 0.28–0.78) and 0.39 (95% CI: 0.22–0.69) in older adults in the Active and Highly active groups, respectively. CONCLUSIONS As the level of physical activity increased, the OR of having metabolic syndrome and its risk factors decreased: this relationship was stronger in older adults than in adults. Therefore, physical activity guidelines should be met to prevent and manage metabolic syndrome.

ObjectivesWe aimed to investigate the effect of obstructive sleep apnea (OSA) on hearing ability.MethodsWe retrospectively reviewed the population-based survey data collected by the Korean National Health and Nutrition Examination Survey between January 1, 2019 and December 31, 2020. The data included 3,575 participants who completed the STOP-BANG questionnaire (SBQ) and pure-tone audiometry. OSA risk was assessed using the SBQ, and the hearing level was compared between the risk groups.ResultsAmong the 3,575 participants, 2,152 (60.2%), 891 (24.9%), and 532 (14.9%) were classified as being low, intermediate, and high risk, respectively. The intermediate- and high-risk groups showed significantly worse hearing levels than the low-risk group. When age and sex were adjusted, the hearing level did not differ between the risk groups.ConclusionThe study found that the presence of OSA minimally affected hearing level. Because hearing loss due to hypoxic damage develops over a long period of time, further research on the association between the duration of OSA, rather than the presence or severity of OSA, and hearing loss is needed.

Although there is evidence that mercury (Hg) exposure may be a potential risk factor for cardiovascular disease (CVD), few nationwide epidemiological researches have analyzed the association between blood Hg concentration and serum high-sensitivity C-reactive protein (hs-CRP) level as a biomarker of CVD. The present population-based national study was performed with data from the 2016–2017 National Health and Nutrition Examination Survey. In the total sample of 3,773 adults aged ≥20 years, the serum hs-CRP concentrations were 1.03 mg/L among participants in the lowest quartile of blood Hg level and 1.18 mg/L among those in highest quartile. The trend for the prevalence of a risky (>1.0 mg/L) hs-CRP level (moderate risk and high risk) was significantly related to an increased quartile blood Hg concentration. After adjustment for confounders, participants with the highest quartiles of blood Hg had increased odds of a risky (>1.0 mg/L) hs-CRP level (adjusted odds ratio = 1.34; 95% confidence interval, 1.02–1.77) compared with those with the lowest quartile of blood Hg. These findings demonstrate that a high blood Hg level increases the concentration of serum hs-CRP, a sensitive marker of chronic low-grade inflammation, and imply that the increased body burden associated with high blood Hg is a potential risk factor in the development of many inflammatory diseases, including CVD.

This study aimed to evaluate the prevalence, trends, and risk factors of early chronic obstructive pulmonary disease (COPD) by using a nationally representative sample. The datasets of the Korea National Health and Nutrition Examination Survey 2010–2019 were used, where 80,860 individuals were identified; of these, 9,045 participants aged 40–49 years who underwent spirometry with no missing data were analyzed. Early COPD was defined as forced expiratory volume in 1 s /forced vital capacity ratio < the lower limit of normal (2.5th percentile) in individuals aged <50 years without a history of asthma, inhaler therapy, or persistent respiratory symptoms. The prevalence and trend of early COPD were estimated according to features such as smoking status and pack-years. Joinpoint regression analysis was used to analyze the significant annual change in the trend according to sex, smoking status, and pack-years. A complex sample multivariable-adjusted regression model was used to identify factors affecting early COPD. The estimated population size during 2010–2019 was 82,326,178. Early COPD was present in 4.5% of patients (6.5% of men and 2.3% of women). It was present in 7.7% of current smokers, followed by former and never smokers. Among smokers with ≥ 10 pack-years, early COPD was present in 8.2%, whereas it was present in 2.6% of smokers with < 10 pack-years. Joinpoint regression analyses found a recent decrease in the trend of prevalence in males who were former and current smokers. The multivariable-adjusted logistic regression model showed that being male, lower educational level, smoking status, and pack-years were factors that affected the presence of early COPD. Continued surveillance of this pre-disease condition is required, and further research are warrant. [ABSTRACT FROM AUTHOR]

In recent years, the incidence of hypertension diseases has increased dramatically, not only among the elderly but also among young people. In this regard, the use of machine learning methods to diagnose the causes of hypertension diseases has increased in recent years. In this article, we have improved the prediction of hypertension detection using Mahalanobis distance-based multivariate outlier removing of Korean national health data named by the KNHANES database. The study identified a variety of risk factors associated with chronic hypertension. Chronic disease is often caused by many factors, not just one. Therefore, it is necessary to study the detection of the disease taking into account complex factors. The paper is divided into two modules. Initially, the data preprocessing step that uses a tree classifier-based feature selection, and to remove multivariate outlier using Mahalanobis distance from KNHANES data. The next module applies the predictive analysis step to detect and prediction of hypertension. In this study, we compare the accuracy, mean standard error (MSE), F1-score, and area under the ROC curve (AUC) for each classification model. The test results show that the proposed RF-MAH algorithm has an accuracy, F1-score, MSE and AUC outcomes of 99.48%, 99.62%, 0.0025 and 99.61%, respectively. Following these, the second-best outcomes of an accuracy rate of 99.51%, MSE of 0.0028, F1-score of 99.58%, and AUC of 99.65% were achieved by XGBoost with the MAH model. The proposed method can be used not only for hypertension but also for the detection of various diseases, such as stroke and cardiovascular disease. It is planned to support the identification and decision-making of high-risk patients with various diseases. [ABSTRACT FROM AUTHOR]

Background: Air pollutants can influence local and systemic inflammation, oxidative stress and microbiome composition. Therefore, air pollution may potentially represent an unexplored modifiable risk indicator for periodontitis. The aim of the current cross-sectional study was to investigate the epidemiological association between outdoor air pollution and periodontitis in a representative sample of the South Korean population. Methods: A total of 42,020 individuals, which were representative of 35.2 million South Koreans, were examined. The mean annual levels of particulate matter of 10 μm (PM10), ozone, sulfur dioxide (SO2), nitrogen dioxide (NO2) and humidity, were studied. Periodontitis was defined according to the Community Periodontal Index (CPI ≥ 3). Simple and multiple regression analyses using four different models were applied. Results: Every 5-μg/m3 increase in PM10 (OR = 1.17; 95% confidence interval—CI: 1.11–1.24) and of 0.005 ppm in ozone levels (OR = 1.4; 95% CI: 1.00–1.30) were positively associated with periodontitis prevalence. Conversely, every 5% increase in humidity (OR = 0.94; 95% CI: 0.90–0.99) and 0.003 ppm increase in NO2 levels (OR = 0.93; 95% CI: 0.89–0.96) were inversely associated with periodontitis occurrence. Conclusions: In this nationally representative population several air pollutants were found to be associated with periodontitis occurrence. Hence, the present results suggest that air pollution may be a new modifiable risk indicator for periodontitis. [ABSTRACT FROM AUTHOR]

Objective: Adults may experience unmet medical needs for various reasons. The purpose of this study was to examine the effect of food security on unmet medical needs according to the presence of children in the household of adults, as well as to identify the medically vulnerable group considering individual and household characteristics. Methods: This study was conducted using data from the National Health and Nutrition Examination Survey for 2013–2015 and 2019–2020. The subjects of the study were 23,069 adults 19 years of age or older, and were divided into two groups according to whether or not children were included in the household. In order to observe the association between food security and unmet medical needs, multiple logistic regression analysis was performed. In addition, a subgroup analysis was performed in consideration of individual and household characteristics. Results: When food security was unstable for households with children, or without children, there was a high correlation with unmet medical needs. Considering individual and household characteristics, in groups with lower age and household income level, or higher number of members in household and subjective health status, food security was strongly correlated with unmet medical needs in households with children. Contrarily, households without children showed a high correlation in the opposite characteristics of households with children, excluding household income level. Conclusion: Food security was highly correlation with unmet medical needs regardless of whether or not children were included in the household. However, according to the individual and household characteristics of households with and without children, the relationship between food security and unmet medical needs was found to be different. Therefore, it is necessary to prepare a health policy that can increase access to medical services in consideration of food security and individual and household characteristics depending on whether or not children are included in the household. [ABSTRACT FROM AUTHOR]

Background: Many factors associated with chronic low back pain (CLBP) have been proposed, including individual, psychosocial, and physical factors. However, these associated factors are still controversial. Purpose: (1) To determine the prevalence of CLBP and (2) to analyze factors associated with CLBP in the general population using a nationally representative sample of South Koreans. Study design: Cross-sectional study. Patient sample: Data from versions IV-1, -2, and -3 of the Korea National Health and Nutrition Examination Survey (KNHANES), which were performed in 2007, 2008, and 2009, respectively (n = 24,871). Outcome measures: Multiple logistic regression analysis was performed to determine the association between several factors (age, gender, alcohol consumption, household income, education level, mid-intensity physical activity, depressive symptoms, vitamin D level, and comorbidities [stroke, ischemic heart disease, knee osteoarthritis, asthma, COPD, cancer history]) and CLBP. Methods: CLBP status was surveyed using a self-reported questionnaire. Demographic, socioeconomic status, comorbidities, and other factors were evaluated from health questionnaires, health and physical examinations, and laboratory tests. To analyze the association between these factors and CLBP, we used multiple logistic regression analysis. Results: Data from 17,038 participants were included in the final analysis, including 2,693 with CLBP and 14,345 without. The prevalence of CLBP was 15.8% in South Korean subjects, with a prevalence of 11.8% in men and 24.5% in women. After regression analysis, we found advanced age, female gender, mid-intensity physical activity, depressive symptoms, stroke, ischemic heart disease, knee arthritis, asthma, COPD, and cancer history were positively associated with CLBP. In contrast, alcohol consumption ≥ 1 drink per month, increased household income, higher education level, and vitamin D insufficiency were negatively associated with CLBP. Conclusions: Our study showed that CLBP was most common in the elderly and women in the general South Korean population. Several individual, socioeconomic, lifestyle, and health-related factors were associated with CLBP. These results demonstrate the influence of these factors on CLBP in the general population and suggest that consideration of these factors may improve the management of CLBP. [ABSTRACT FROM AUTHOR]

Purpose: National big data pertaining to the status of common respiratory diseases is essential to devising appropriate policies to promote proper treatment and prevention of respiratory diseases amid the prolonged coronavirus disease 2019 (COVID‐19) pandemic. The aim of this study is to investigate the prevalence of common respiratory diseases and their association with sociodemographic characteristics, comorbidities, and medical history using 11 years (2008–2018) of the Korea National Health and Nutrition Examination Survey (KNHANES) data, ultimately to present foundational data for policy decision making and disease prevention measures. Methods: Among the participants of the KNHANES survey (2008–2018), 93 028 adults aged ≥40 years who underwent a lung function test were included in this cross‐sectional study. The participants were divided into four groups: Asthma, chronic obstructive pulmonary disease (COPD), asthma + COPD, and no respiratory disease. Their data were analyzed for demographic factors, health behavior, and disease‐related factors. Multiple logistic regression was used to calculate the odds ratio (OR) adjusted for sex, age, household income, educational level, occupation, body mass index (BMI), smoking status, alcohol consumption, physical activity, and comorbidities. Results: Of all participants, 1.83%, 12.63%, and 1.27% had only asthma, only COPD, and asthma + COPD, respectively. With respect to the patients with asthma who also had asthma + COPD, the OR of asthma + COPD was 5.272 in underweight patients and 6.479 in patients aged ≥70 years. Meanwhile, a high association between COPD and asthma + COPD was found in female patients, whereas asthma was more highly associated with asthma + COPD in male patients. Conclusion: The study confirmed that old age, sex, smoking status, BMI, previous history of atopic dermatitis, and lung cancer were independent risk factors for asthma, COPD, and asthma + COPD. The present study demonstrated the need for a multidisciplinary integrative approach to respiratory diseases, and the findings could be used for developing policies for the treatment of COVID‐19 and respiratory diseases and the prevention of infectious diseases. [ABSTRACT FROM AUTHOR]

This study investigated the potential role of dietary factors associated with obesity and metabolic syndrome (MetS) in Koreans. The scoping review method was used to evaluate the studies that utilized the secondary data sets comprising the Korean National Health and Nutrition Examination Survey (KNHANES) and the Korean Genome and Epidemiology Study (KoGES). Articles published between 2012 and 2022 were identified using RISS, KISS, DBpia, PubMed, and ScienceDirect databases. In all, there were 32 published articles on obesity and 119 on MetS. Obesity research included eight articles on nutrients, 12 on food items/food groups, two on dietary patterns, nine on dietary behavior/eating habits, and one on the dietary index. MetS studies comprised 34 articles on nutrients, 43 on food items/food groups, seven on dietary patterns, 25 on dietary behavior/eating habits, and 10 on the dietary index. Carbohydrates, alcohol, and coffee consumption were the most frequently studied dietary factors for obesity and MetS. The primary areas of study were largely focused on nutrients and food items/food groups. Thus, to overcome the paucity of information on the relationship of dietary patterns and dietary indexes with obesity and MetS, there is a need for further research using the KNHANES and KoGES data sets. [ABSTRACT FROM AUTHOR]

A high prevalence of dyslipidemia has recently been shown not only in adults, but also in adolescents. When occurring in adolescence, dyslipidemia is a risk factor for cardiovascular disease in adulthood. This study aimed to identify significant factors affecting dyslipidemia in South Korean adolescents. We used data from the third year of the 8th Korea National Health and Nutrition Examination Survey (KNHANES VIII-3) on 381 Korean adolescents aged 12–18 years. The data were analyzed using frequency analysis, descriptive statistics, the Rao–Scott χ test, the t-test, and univariate and multivariate logistic regression using complex sample analysis. On a weighted population basis, 28.1% of the adolescents among the participants were identified as the group with dyslipidemia. Obesity, waist circumference, serum uric acid, and alanine aminotransferase (ALT) were significantly related to the prevalence of dyslipidemia. Physical activity 4–7 days a week was related to a decrease in the prevalence of dyslipidemia only in male adolescents. The results of this study can be used as evidence for the risk assessment of adolescent dyslipidemia and the establishment of systematic health management guidelines according to risk factors for the prevention of adolescent dyslipidemia.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is distinguished by the buildup of excessive liver fat unrelated to alcohol consumption. However, the role of alcohol consumption on disease progression is debatable. Recently, alcohol flushing syndrome in Asian populations has gained interest, and its role in the risk of developing MASLD is unknown. Therefore, in this cross-sectional study, we investigated the association between alcohol consumption and MASLD in Korean men, considering their alcohol flushing response and utilizing the lipid accumulation product (LAP) score. Data from the Korean National Health and Nutrition Examination Survey (2019–2021) were analyzed. Participants were categorized into non-or-infrequent drinkers and light-to-heavy drinkers and further sub-classified based on alcohol flushing response as non-flushers and flushers. Multivariate logistic regression analysis showed a significant association between alcohol consumption and MASLD risk in both non-flushers (aHR 1.90, 95% CI 1.51–2.40, p < 0.001) and flushers (aHR 2.35, 95% CI 1.94–2.84, p < 0.001) after adjusting for potential confounding factors such as age, exercise, smoking, body mass index, systolic blood pressure, total cholesterol, and fasting plasma glucose. There was a significant interaction between alcohol consumption and alcohol flushing response for MASLD risk (p for interaction < 0.001). These findings emphasize the importance of alcohol flushing as a potential indicator of MASLD risk in Korean men and highlight the need for further research to understand the underlying mechanisms and develop targeted preventive strategies.

We investigated whether cigarette smoking and dietary acid load (DAL) are associated with a risk of chronic obstructive pulmonary disease (COPD) in healthy, middle-aged Korean men. Healthy men without diagnosed chronic disease (aged 40–64 years) from the KNHANES-VI (2013–2015) were included in the analysis (n = 774) and were subdivided by smoking status and DAL levels, as estimated using the quartile of net endogenous acid production (NEAP). The current smokers tended to have a higher risk of COPD than the never-smokers before and after adjustment. When divided by the DAL quartile, the Q4 group tended to have a higher risk of COPD than the Q1 group. Additionally, the current smokers with lower (Q2), modest (Q3), and the highest NEAP scores (Q4) showed risks of COPD that were more than fourfold higher than those of the never-smokers with the lowest NEAP scores (Q1). The ex-smokers with higher NEAP scores (Q3 and Q4) showed risks of COPD that were more than fourfold higher than those of the Q1 group. Interestingly, the risk of COPD was also more than sixfold higher in the never-smokers with the highest NEAP scores compared to that in the Q1 group. The NEAP scores and smoking status synergistically increased the risk of COPD in healthy, middle-aged Korean men. This suggests that DAL levels are an important factor in the prevention and management of COPD.

Machine Learning is a powerful tool to discover hidden information and relationships in various data-driven research fields. Obesity is an extremely complex topic, involving biological, physiological, psychological, and environmental factors. One successful approach to the topic is machine learning frameworks, which can reveal complex and essential risk factors of obesity. Over the last two decades, the obese population (BMI of above 23) in Korea has grown. The purpose of this study is to identify risk factors that predict obesity using machine learning classifiers and identify the algorithm with the best accuracy among classifiers used for obesity prediction. This work will allow people to assess obesity risk from blood tests and blood pressure data based on the KNHANES, which used data constructed by the annual survey. Our data include a total of 21,100 participants (male 10,000 and female 11,100). We assess obesity prediction by utilizing six machine learning algorithms. We explore age- and gender-specific risk factors of obesity for adults (19–79 years old). Our results highlight the four most significant features in all age-gender groups for predicting obesity: triglycerides, ALT (SGPT), glycated hemoglobin, and uric acid. Our findings show that the risk factors for obesity are sensitive to age and gender under different machine learning algorithms. Performance is highest for the 19–39 age group of both genders, with over 70% accuracy and AUC, while the 60–79 age group shows around 65% accuracy and AUC. For the 40–59 age groups, the proposed algorithm achieved over 70% in AUC, but for the female participants, it achieved lower than 70% accuracy. For all classifiers and age groups, there is no big difference in the accuracy ratio when the number of features is more than six; however, the accuracy ratio decreased in the female 19–39 age group.

This study analyzed the effect of the household type on the prevalence of metabolic syndrome in Koreans utilizing data from the sixth, seventh, and eighth Korea National Health and Nutrition Examination Surveys conducted by the Korea Disease Control and Prevention Agency from 2015 to 2019. The demographic characteristics, metabolic syndrome characteristics according to household type, and risk factors of 25,092 subjects were identified using the Rao–Scott χ2–test and weighted multiple logistic regression results. Furthermore, to understand the effect of the household type on prevalence of metabolic syndrome, the selection bias between the groups was eliminated using the propensity score matching method. The average treatment effect for those treated for metabolic syndrome prior to propensity score matching was higher for single-person households, with 0.353 and 0.268 for single- and multi-person households, respectively. The difference was statistically significant (p < 0.0001). However, after propensity score matching, it was observed to be higher for multi-person households, with 0.290 and 0.316 for single- and multi-person households, respectively. However, the difference was not statistically significant (p < 0.1822). Difference was observed regarding the prevalence of metabolic syndrome by individual characteristics, some of which were considered in previous studies. However, the household type alone did not explain the prevalence of metabolic syndrome. [ABSTRACT FROM AUTHOR]

Background: Several studies have reported an association between anemia and depression. However, whether anemia is independently associated with depression remains controversial. The current study aimed to investigate the association between anemia and depression according to sex in a large national sample population.Methods: Data from the 2014, 2016, and 2018 Korean National Health and Nutrition Examination Survey were analyzed, and 15,472 participants were included in this study. Anemia was defined as a hemoglobin level <13 g/dL in men and <12 g/dL in women. We defined a Patient Health Questionnaire-9 score ≥10 as depression and ≥5 as mild depressive symptoms.Results: The prevalence of depression was significantly higher in women with anemia than in women without anemia (8.9 % vs. 7.0 %, P = 0.036). In women, anemia was significantly associated with depression after adjusting all covariates in multilevel logistic regression analysis (odds ratio, 1.37; 95 % confidence interval, 1.08-1.75; P = 0.011). However, no significant association was observed in men.Limitations: There is a limit to explaining the causal direction, and several factors may not have been considered as confounders. Also, patients with severe diseases were excluded from data acquisition. A structured diagnostic interview, other than the self-report method, was not conducted.Conclusions: The findings of this study suggest that anemia is associated with depression in women but not in men. A decrease in tissue oxygenation, deterioration of physical performance due to anemia, and altered monoamine synthesis due to malnutrition may have an effect on depression. [ABSTRACT FROM AUTHOR]

Background: Patients with low back pain (LBP) often suffer from sleep disorder, and insufficient sleep duration was recognized as a potential risk factor for LBP. Our aim was to explore the exact effect of sleep duration on LBP and the optimal sleep duration to reduce the risk of LBP., Methods: Analyzing data from the Korean National Health and Nutrition Examination Survey (KNHANES), we investigated the association between sleep duration and LBP in individuals aged 50 years and older. We used logistic regression models, interaction stratification analysis, and threshold effect assessment to analyze the relationship between sleep duration and LBP., Results: A total of 6,285 participants, comprising 3,056 males and 3,229 females with a median age of 63.1 years, were enrolled in the study. The association between sleep duration and LBP risk exhibited an L-shaped curve ( p < 0.015) in RCS analysis. In the threshold analysis, the OR of developing risk of LBP was 0.864 (95% CI:0.78-0.957, p = 0.005) in participants with sleep duration <6.55 h. Each additional hour of sleep was associated with a 13.6% decrease in the risk of LBP. No significant association was observed between sleep duration ≥6.55 h and the risk of LBP. The risk of LBP did not decrease further with increasing sleep duration. Results remain robust across subgroups., Conclusion: Our findings indicate that shorter sleep duration is a risk factor for LBP in adults aged over 50 years. We revealed an L-shaped association between sleep duration and LBP, with an inflection point at approximately 6.55 h per day. These results underscore the significance of sleep duration as a factor in the risk assessment for LBP., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Hu, Zhang, Liu, Yang, Liang, Hu, Yuan and Zhao.)

We aimed to examine the correlation between periodontitis and body size phenotypes in 7301 participants without diagnosed chronic diseases in the Korean National Health and Nutrition Examination Survey 2013-2015. The participants were categorized into the following body size phenotype groups based on body mass index and the presence of metabolic syndrome: metabolically healthy normal weight (MHNW), metabolically abnormal normal weight (MANW), metabolically healthy obese (MHO), and metabolically abnormal obese (MAO). The prevalence rates of mild and severe periodontitis were 18.1% and 7.5%, respectively. Patients with periodontitis were older, current smokers, had a lower family income, were less likely to engage in regular tooth brushing or exercise, and had a higher body mass index and glucose levels. Periodontitis was more prevalent in the MANW and MAO groups than in the MHNW and MHO groups. Compared with the MHNW phenotype, the MAO and MANW phenotypes were significantly associated with mild and severe periodontitis, and the MHO phenotype was significantly associated with mild periodontitis. The MANW and MAO phenotypes are independent risk factors for periodontitis in adults without diagnosed chronic diseases. To enhance public health, a greater focus and effective approaches for identifying metabolic disease phenotypes among individuals with periodontal disease may be clinically relevant.

Objectives: This study aimed to compare the distinct socio-ecological characteristics, nutritional status, and nutrient intake quality of the older adults based on breakfast skipping (EBF, eating breakfast vs. SBF, skipping breakfast). This study also investigated the association between breakfast skipping, socioecological features, and quality of nutrient consumption., Method: From the 8th Korea National Health and Nutrition Examination Survey (KNHANES, 2020), data of 92,093 subjects aged ≥ 65 years old (male: 43,910 and female: 48,183) having data with eating habits, such as nutrient intake and skipping breakfast were analyzed., Results: The average age of SBF was markedly lower than EBF. EBF had a lower employed status, education level, heavy alcohol intake frequency, smoking, and eating out regularly than SBF. Compared to EBF, SBF showed a significantly higher BMI and waist circumference. Moreover, EBF showed a markedly higher average intake in energy, protein, fiber, calcium, and iron compared with SBF, while SBF had a noticeably higher mean intake in fat, saturated fat, and sugar. In addition, SBF had a significantly reduced mean adequacy ratio (MAR, adjusted OR: 0.260 [95% CI: 0.245-0.276]) and the value of index nutritional quality (INQ, adjusted OR: 0.847 [95% CI: 0.799-0.898]) compared with EBF., Discussion: There were distinct socioecological features and nutritional conditions of older adults relying on breakfast skipping; and a strong association between breakfast skipping, socioecological parameters, and nutrient intake quality. These observations provide the significance of breakfast skipping in the nutritional status of older adults and offer fundamental information for nutritional education and implications for older adults., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Taeyun Kim,1 Jehun Kim,2 Jun Hyeong Kim3 1Division of Pulmonology, Department of Internal Medicine, The Armed Forces Goyang Hospital, Goyang-si, South Korea; 2Division of Pulmonology, Department of Internal Medicine, Kosin University College of Medicine, Kosin University Gospel Hospital, Busan, South Korea; 3Division of Pulmonology, Department of Internal Medicine, Busan Veterans Hospital, Busan, South KoreaCorrespondence: Jehun KimDivision of Pulmonology, Department of Internal Medicine, Kosin University College of Medicine, Kosin University Gospel Hospital, 262 Gamcheon-ro, Seo-gu, Busan, 49267, South KoreaTel/Fax +82-51-990-5820Email libertier@gmail.comJun Hyeong KimDivision of Pulmonology, Department of Internal Medicine, Busan Veterans Hospital, 420, Baegyang-daero, Sasang-gu, Busan, 46996, South KoreaTel +82-51-601-6988Fax +82-51-601-6339Email imjune83@gmail.comIntroduction: Few studies have examined the prevalence and associated factors of early chronic obstructive pulmonary disease (COPD) in Asians.Objective: To evaluate the prevalence of early COPD and its associated factors among non-institutionalized middle-aged Korean adults.Methods: A total of 3195 participants aged 40– 49 years from the 2016– 2018 Korea National Health and Nutrition Examination Survey were included in this study. Patients (1) aged less than 50 years, (2) with a minimum of 10 pack-years of smoking, and (3) with forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) below the lower limit of normal were diagnosed with early COPD. The prevalence and odds ratio (OR) for early COPD were measured using multivariate logistic regression analysis, and the demographic data, anthropometric measurements, socioeconomic status, and lifestyle factors were considered covariates.Results: The overall prevalence of early COPD among the middle-aged Korean population was 2.4% (4.4% in men and 0.4% in women), while that in participants with ≥ 10 pack-years was 8.2% (8.1% in men and 11.3% in women). A multivariate logistic regression model showed that male sex, urban residence, chronic sputum production, and hypertriglyceridemia were associated with increased ORs for early COPD in middle-aged, non-institutionalized Korean adults.Conclusion: Early COPD is prevalent among middle-aged smokers in Korea. Efforts are needed to reduce the potential negative effects of early COPD on public health in Korea and other Asian countries.Keywords: early COPD, KNHANES, prevalence

Da-Young Jeong,1 Shin-Hye Kim,1 Moon Young Seo,2 Sin Young Kang,1 Mi Jung Park1 1Department of Pediatrics, Inje University Sanggye Paik Hospital, Seoul, Korea; 2Department of Pediatrics, Uijeongbu Eulji Medical Center, Gyeonggi-do, KoreaCorrespondence: Mi Jung Park; Shin-Hye KimDepartment of Pediatrics, Inje University Sanggye Paik Hospital, 1342, Dongil-ro, Nowon-gu, Seoul, 01757, KoreaTel +82 2 950 8826; +82 2 950 4823Fax +82 2 950 1245; +82 2 950 1246Email pmj@paik.ac.kr; s2635@paik.ac.krPurpose: An adverse lipid profile in adolescence often persists into adulthood, resulting in cardiovascular disease. We aimed to investigate the trends in the prevalence of adverse lipid profiles among Korean adolescents from 2007 to 2018.Patients and Methods: The data were obtained from 9044 adolescents aged 10– 19 years who participated in the Korean National Health and Nutrition Examination Surveys (KNHANES) from 2007 to 2018. Fasting serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) levels were analyzed.Results: Significantly increasing trends in age-standardized prevalence of hypercholesterolemia [from 5.6% to 9.4% in boys (P = 0.004); from 8.1% to 12.4% in girls (P = 0.01)] and hyper-LDL-cholesterolemia [from 4.3% to 8.0% in boys (P = 0.003); from 6.6% to 9.7% in girls (P = 0.035)] were noted in both sexes. In contrast, the prevalence of hypo-HDL-cholesterolemia decreased significantly from 20.0% to 12.5% in boys (< 0.001) and from 12.4% to 6.9% in girls (P < 0.001). There were no significant changes in the prevalence of hypertriglyceridemia and hyper-non-HDL-cholesterolemia in both sexes. Accordingly, the overall prevalence of dyslipidemia showed only a modest decline in boys (from 31.8% to 28.7%) and a stable trend in girls (from 28.9% to 28.2%).Conclusion: The prevalence of hypercholesterolemia and hyper-LDL-cholesterolemia increased and that of hypo-HDL-cholesterolemia decreased among Korean adolescents over the recent 12 years. Further studies are needed to explain these trends and possible associations with lifestyle factors.Keywords: hypercholesterolemia, cholesterol, dyslipidemia, prevalence, KNHANES

Background: The present study investigated the association between two domains of physical activity (occupational physical activity [OPA] and leisure-time physical activity [LTPA]) and sleep duration. Methods: We investigated 3,421 paid workers from the Korea National Health and Nutrition Examination Survey, 2014–2015. Sleep duration was categorized into three categories (short for less than 5 h, optimal for 5–9 h, and long for more than 9 h). OPA and LTPA were defined in terms of answers to relevant questions. Odds ratios were calculated for sleep duration according to each physical activity domain using multinomial logistic regression models. Results: There were 464 subjects (13.6%) who showed short sleep duration, and 169 subjects (4.9%) who showed long sleep duration. Prevalence of OPA and LTPA was higher in male workers than in female workers (for OPA: 3.67% and 1.76%, respectively, p = 0.0108; for LTPA: 16.14% and 6.07%, respectively, p

Background and Objectives: Grip strength is a measure of general health and is associated with oral health. This study aimed to investigate the relationship between the number of teeth and grip strength in Korean adults. Methods and Materials: We recruited adult participants who underwent oral examinations in the Korean National Health and Nutrition Examination Survey (KNHANES) between 2016–2018. When performing the KNHANES oral examination, an experienced dentist performed it according to the oral examination guidelines and recorded the results. A total of 24,269 participants from the 2016–2018 KNHANES were included in this study. Of these, only 16,489 participants underwent oral screening. A total of 3209 were non-adult children and adolescents, and 1781 did not respond to the grip strength test; those who did not respond to the main independent confounder were excluded. The relationships between grip strength, general characteristics, general health, oral health, and the number of remaining teeth were analyzed. There were 11,499 subjects in total in this study, with 4839 males and 6660 females. The age groups were 19–65 years of age, with 8387 subjects, and 65 years and older, with 3112 subjects, and the number of remaining teeth was 0–9 for 936 subjects, 10–19 for 1015 subjects, and 20–28 for 9548 subjects. Results: The probability that the higher the grip strength, the higher the residual number of gingiva was estimated by multinomial logistic regression analysis using complex sampling. The higher the grip strength, the higher the probability of having 20–28 teeth remaining (adjusted odds ratio, 1.59; 95% confidence interval, 1.19–2.13). Conclusions: Maintaining general health is related to maintaining teeth; the higher the grip strength, the higher the number of remaining teeth.

(1) Background: The aim of this study was to evaluate the prevalence of obesity and metabolic syndrome since the COVID-19 pandemic outbreak utilizing representative data on youth aged 2–18 years from the Korean National Health and Nutrition Examination Surveys (KNHANES) conducted in 2019–2020. (2) Methods: The survey consists of three parts: health interviews, health examinations, and nutrition surveys. From the 2019 and 2020 surveys, 1371 (2–9 years = 702 and 10–18 years = 669) and 1124 (2–9 years = 543 and 10–18 years = 581) individuals were included in the analysis. (3) Results: The mean body mass index (BMI) increased significantly among youth aged 2–9 years from 16.53 kg/m2 in 2019 to 17.1 kg/m2 in 2020 (p < 0.01). In youth aged 10–18 years, the BMI was found to increase slightly from 21.25 kg/m2 in 2019 to 21.41 kg/m2 in 2020 (p = 0.64). The increasing prevalence of extreme obesity was significant in girls, especially those aged 2–9 years (p < 0.01). However, extreme obesity had increased in 10–18-year-old boys (p = 0.08). The overall prevalence of metabolic syndrome in adolescents increased from 3.79% to 7.79% during the COVID-19 pandemic (p = 0.01). (4) Conclusions: We observed that the prevalence of obesity and metabolic syndrome among children and adolescents has increased after the COVID-19 outbreak. This is believed to be associated with an increase in the rate of early comorbidities in adulthood. The prevention of the progression of pediatric obesity has recently become an urgent public health concern in Korea.

Background and Aim: The association between thyroid autoimmunity and nonalcoholic fatty liver disease (NAFLD) remains unclear. In this study, we aimed to investigate the relationship between thyroid autoimmunity and NAFLD in a large cohort of euthyroid subjects. Methods: We analyzed clinical and biochemical data from a nationwide, population‐based, cross‐sectional survey (KNHANES VI). A total of 1589 middle‐aged participants aged 45–65 years, with normal thyroid function, were included in this study. NAFLD was defined as a hepatic steatosis index of > 36. We estimated the odds ratios (ORs) for NAFLD according to anti‐thyroid peroxidase antibody (TPOAb) positivity by using logistic regression models, and adjusted for potential confounders. Results: Overall, 24% (n = 378) of the subjects had NAFLD. Subjects with NAFLD showed a higher positivity for TPOAb (11% vs 7%, P = 0.014) compared with those without NAFLD. TPOAb positivity was a significant risk factor for NAFLD [OR 1.668, 95% confidence interval (CI) 1.019–2.730, P = 0.042] even after adjusting for confounding variables, including age, sex, household income, education, smoking, alcohol consumption, walking activity, abdominal obesity, elevated blood pressure, dyslipidemia and hyperglycemia. In addition, TPOAb positivity predicted the risk of advanced liver fibrosis (OR 3.112, 95% CI 1.256–7.713, P = 0.014) in subjects with NAFLD, independent of the confounding variables. Conclusion: In euthyroid subjects, thyroid autoimmunity is associated with NAFLD and advanced liver fibrosis, independent of known metabolic risk factors. Large longitudinal studies in the future will help clarify the causality. [ABSTRACT FROM AUTHOR]

Pterygium, one of the most common eye disorders, is an abnormal fibrovascular proliferation extending from the conjunctiva to the cornea. The mechanism of development in pterygium has not been fully elucidated; however, oxidative stress is suggested to be one of the major causes. Heavy metals such as lead (Pb), cadmium (Cd), and mercury (Hg) enter the human body and induce oxidative stress. However, no study has investigated the association of these heavy metals with pterygium. Therefore, this study aimed to evaluate the associations of environmental exposures to Pb, Cd, and Hg with pterygium in the Korean general adults. We analyzed data from 6,587 adults (≥ 20 years of age) who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) 2008–2011. Pterygium was diagnosed as the presence of a wing-shaped fibrovascular growth. The exposures of Pb, Cd, and Hg were estimated by measuring blood concentrations. The prevalence of pterygium in this study population was 4.0% (348 subjects). After adjusting for potential confounders, the Pb level in blood was found to have a significant dose-dependent association with pterygium (p for trend = 0.001), and its highest quintile (vs. the lowest) had an odds ratio (OR) of 2.22 (95% CI: 1.30, 3.78) for pterygium. The Hg level in blood in the second quintile (vs. the lowest) had an OR of 1.64 (95% CI: 1.04, 2.59) for pterygium. In conclusion, this study suggests that environmental exposures to Pb and Hg in the Korean general adults may be related to the development of pterygium. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the relationship between vitamin D levels and physical activity in adolescents using data from the Korea National Health and Nutrition Survey (KNHANES). The serum vitamin D concentrations were measured between 2008 and 2014 and analyzed. Adolescents aged 13 to 18 years comprised 4527 of the 61,370 participants surveyed. A final dataset including 2811 adolescents was obtained after those with missing data were excluded. Those who did not participate or only participated in 1–3 days of intense physical activity (p < 0.001), moderate physical activity (p = 0.002), and muscular exercise (weight training) (p < 0.001) showed a higher level of vitamin D deficiency than those who performed the same activities 4–7 days per week. Our results showed that most of the adolescents (76%) were vitamin D-deficient, and the risk was higher among high school than middle school students (odds ratio (OR) = 1.70, 95% confidence interval (CI) = 1.40–2.06; p < 0.001) and higher in girls than boys (OR = 1.43, 95% CI = 1.18–1.72; p < 0.001). Reduced participation in physical activity was correlated with vitamin D deficiency. Furthermore, vitamin D deficiency was associated with a lower frequency of participation in all forms of physical activity, and the association increased significantly with an increase in body mass index. [ABSTRACT FROM AUTHOR]

OBJECTIVE: We aimed to investigate the association between low-grade inflammation as indicated by high-sensitivity C-reactive protein (hsCRP) level and organizational factors, such as work hours and shift work. METHODS: We evaluated 7470 young and middle-aged workers who participated in the Korea National Health and Nutrition Examination Surveys from 2015–2018. Work hours were determined from self-reported questionnaires. Shift work was defined as a non-daytime fixed work schedule. An interaction effect between shift work and long work hours on the hsCRP level was estimated using relative excess risk due to interaction (RERI) and attributable proportion (AP) with 95% confidence intervals (CI). RESULTS: Increased hsCRP levels were prevalent in 25.2% of the study population. There was a significant association between long work hours and increased hsCRP, especially among middle-aged men [odds ratio (OR) 1.50 (95% CI 1.20–1.87) for moderately increased hsCRP and OR 1.62 (95% CI 1.14–2.30) for highly increased hsCRP]. There was a significant interaction effect between long work hours and shift work on increased hsCRP among middle-aged workers. The RERI were 0.03 (95% CI 0.02–0.04) and 0.56 (95% CI 0.45–0.68) among middle-aged men and women, respectively. The AP were 0.02 (95% CI 0.01–0.03) and 0.36 (95% CI 0.31–0.40) among middle-aged men and women, respectively. CONCLUSION: There was no significant association between shift work and the level of hsCRP. Long work hours were related to low-grade inflammatory processes, but only in middle-aged workers. There was an interaction effect between long work hours and shift work for increased hsCRP, especially in middle-aged women.

Sarcopenia is a well-known age-related disease that can lead to musculoskeletal disorders and chronic metabolic syndromes, such as sarcopenic obesity. Numerous studies have researched the relationship between sarcopenia and various risk factors, leading to the development of predictive models based on these factors. In this study, we explored the impact of physical activity (PA) in daily life and obesity on sarcopenia prediction. PA is easier to measure using personal devices, such as smartphones and watches, or lifelogs, than using other factors that require medical equipment and examination. To demonstrate the feasibility of sarcopenia prediction using PA, we trained various machine learning models, including gradient boosting machine (GBM), xgboost (XGB), lightgbm (LGB), catboost (CAT), logistic regression, support vector classifier, k-nearest neighbors, random forest (RF), multi-layer perceptron, and deep neural network (DNN), using data samples from the Korea National Health and Nutrition Examination Survey. Among the models, the DNN achieved the most precise accuracy on average, 81%, with PA features across all data combinations, and the accuracy increased up to 90% with the addition of obesity information, such as total fat mass and fat percentage. Considering the difficulty of measuring the obesity feature, when adding waist circumference to the PA features, the DNN recorded the highest accuracy of 84%. This model accuracy could be improved by using separate training sets according to gender. As a result of measurement with various metrics for accurate evaluation of models, GBM, XGB, LGB, CAT, RF, and DNN demonstrated significant predictive performance using only PA features including waist circumference, with AUC values at least around 0.85 and often approaching or exceeding 0.9. We also found the key features for a highly performing model such as the quantified PA value and metabolic equivalent score in addition to a simple obesity measure such as body mass index (BMI) and waist circumference using SHAP analysis.

[Display omitted] • Dietary spermidine and spermine intake is negatively related with CVD-related and all-cause mortality. • Spermidine and spermine are strongly related to mortality in men and older adults. • Polyamine intake advice for cardioprotection should focus on men and older adults. To evaluate the relationship between dietary polyamine intake and all-cause and cardiovascular disease (CVD)-related mortality in Korean population. A total of 37,715 participants were included in a population-based cohort study. Dietary polyamine intake (µmol/d) were calculated using the average spermidine and spermine content (µmol/g) and daily consumed food components (mg/d) from 12 food groups. Cox proportional hazards examined associations between dietary polyamine and all-cause and CVD-related mortality. Among the participants, 2,080 all-cause and 483 CVD-related deaths occurred. The lowest risk of all-cause and CVD-related mortality was found in the highest tertile of fruit, vegetables, legume, nut and seafood-derived spermidine and spermine intake, after adjusting covariates. The relationship between dietary polyamine intake and all-cause and CVD-related mortality was more pronounced in men and older individuals than in their counterparts. Higher intake of mediterranean-like diet derived polyamine was associated with lower CVD-related and all-cause mortality in Korean adults. [ABSTRACT FROM AUTHOR]

This study aims to determine the relationship between chewing ability and the nutritional status of the elderly in Korea. This study utilized the data from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted from 2013–2018 for persons who were ≥65 years of age. Of the 7835 subjects, 43.2% had chewing difficulty. Compared to the normal group, the chewing difficulty group had more stress, lower exercise frequency, less snack intake, a lower frequency of eating out, and a higher proportion of food insecurity. The chewing difficulty group had significantly lower food intake compared to the normal group, including various food groups such as cereals and grain, potatoes, fruits, meat, and milks and dairy products. The intake of fresh fruits was 24.5% lower and the intake of plant food (fresh fruits and nonstarchy vegetables) was 17.8% lower in the chewing difficulty group compared to the normal group. In addition, the intake of most nutrients (carbohydrates, fat, calcium, phosphorus, sodium, potassium, vitamin A, riboflavin, niacin, and vitamin C) was significantly lower in the chewing difficulty group than in the normal group. The chewing difficulty was significantly associated with undernutrition (OR = 1.63). In conclusion, chewing ability is closely related to food and nutrient intake among the elderly, which can decrease the quantity and quality of diet and is also related to undernutrition. Therefore, it is necessary to develop customized nutrition programs and aging-friendly food products that consider the chewing ability of the elderly.

Studies have reported inconsistent results regarding the relationship between serum vitamin E levels and depressive symptoms. Furthermore, the potential modulating role of age and sex has been underexplored. We conduct an age- and sex-stratified investigation of the association between serological vitamin E status and depressive symptoms in a large nationwide sample. Data from the Korean National Health and Nutrition Examination Survey were analyzed (n = 4448). The participants were stratified into four groups according to age (

Vitamin D deficiency is prevalent in Korea and an insufficient vitamin D status increases the risk of various chronic diseases including metabolic syndrome (MetS). We examined the relationship between serum 25-hydroxyvitamin D (25(OH)D) levels, dietary vitamin D intake, and MetS. The 2013–2014 Korea National Health and Nutrition Examination Survey’s (KNHANES) included participants (n = 4.541; 1145 men; 1368 women) who were aged ≥19. In men, higher serum 25(OH)D levels were correlated with significantly increased protein intake (p = 0.032) and saturated fatty acid intake (p = 0.006), but significantly decreased fat intake (p = 0.027), monounsaturated fatty acid intake (p = 0.005), and polyunsaturated fatty acid intake (p = 0.003), and significantly decreased serum triglycerides levels (p = 0.002), whereas women had no association with any dietary intake or biochemical markers. Furthermore, our study found a significant negative correlation between abdominal obesity (OR, 0.970; CI, 0.946, 0.994) and hypertriglyceridemia (OR, 0.974; CI, 0.950, 0.998) and serum 25(OH)D levels in men, as well as a significant decrease in hypertriglyceridemia (OR, 0.980; CI, 0.961, 0.999) with vitamin D intake. However, women had a significantly negative correlation between serum LDL cholesterol (β, −1.751; p = 0.018) and vitamin D intake. By increasing the vitamin D intake and serum 25(OH)D levels, Korean adults could reduce their risk of MetS-related factors.

Background: The role of serum 25-hydroxyvitamin D [25(OH)D] levels in the development of sarcopenia in non-alcoholic fatty liver disease (NAFLD) remains controversial. We investigated the association between vitamin D levels, occurrence of sarcopenia, NAFLD, and sarcopenia in NAFLD in adults aged >50 years. Methods: This study used data pertaining to 5396 adults aged >50 years (1870 men and 3526 women) from the 2008–2011 Korea National Health and Nutrition Examination Survey. Appendicular skeletal muscle mass adjusted by weight (ASM/Wt) was used to diagnose sarcopenia, and NAFLD was diagnosed using the NAFLD fat score. Results: The lowest quintile of serum 25(OH)D level (4.85–15.26 ng/mL) was associated with an increased occurrence of sarcopenia [odds ratio (OR) 2.65; 95% confidence interval (CI) 1.64–4.27], NAFLD (OR 1.82; 95% CI 1.19–2.96), and sarcopenia in NAFLD (OR 2.25; 95% CI 1.26–4.03) in men. In women, sarcopenia (OR 1.80; 95% CI 1.29–2.51) was also significantly associated with serum vitamin D levels, whereas high levels of vitamin D were not significantly related to NAFLD. Conclusions: Serum vitamin D levels are associated with sarcopenia, NAFLD, and sarcopenia in NAFLD. Vitamin D level can be a useful marker of sarcopenia and NAFLD, especially in men. [ABSTRACT FROM AUTHOR]

Background: Few studies have examined the associations of temporomandibular disorders (TMDs) and tinnitus with health‐related quality of life on a national level. Objective: We aimed to investigate the associations of TMDs, tinnitus and quality of life among the Korean population, aged 19 years or older. Methods: Data were obtained from the fifth Korea National Health and Nutrition Examination Survey (2012; N = 5786). TMDs, tinnitus and health‐related quality of life were assessed using self‐report data from EuroQol‐5 Dimension. Participants were divided into four groups: no TMD and no tinnitus, TMD present but no tinnitus, no TMD but tinnitus present and both TMD and tinnitus present. Results: Among the participants, 21.88% had TMD, 24.93% had tinnitus, and 7.74% had both. The prevalence of most TMD and all types of tinnitus was higher among females than among males. The group with both TMD and tinnitus reported the highest percentage of problems in the usual activity, pain/discomfort and anxiety/depression dimensions. Moreover, the odds ratio (OR) for lower quality of life was significantly higher in the group with both TMD and tinnitus compared to the group without TMD and tinnitus: mobility (OR = 1.527, 95% confidence interval [CI]: 1.014–2.300), pain/discomfort (OR = 2.072, 95% CI: 1.570–2.735), anxiety/depression (OR = 1.692, 95% CI: 1.034–2.767), EQ‐5D score (OR = 1.651, 95% CI: 1.121–2.431) and EQ‐VAS (OR = 1.682, 95% CI: 1.246–2.269). Conclusion: The presence of both TMD and tinnitus has a considerable impact on HRQoL in the Korean population. In our study, the group with both TMD and tinnitus showed lower HRQoL than without TMD and tinnitus group. These results emphasise the need for a multilateral and comprehensive approach to address these disorders and provide baseline data for developing appropriate interventions. [ABSTRACT FROM AUTHOR]