Interplay of Mediterranean-diet adherence, genetic factors, and metabolic dysfunction-associated steatotic liver disease risk in Korea.

BACKGROUNDS: Metabolic dysfunction-associated steatotic liver disease (MASLD) has gained attention owing to its severe complications. This study aimed to explore the interaction between Mediterranean-diet (MD) adherence, genetic factors, and MASLD risk in a Korean population. METHODS: In total, 33,133 individuals aged 40 years and older from the Korean Genome and Epidemiology Study (KoGES) were analyzed. Participants were assessed for MASLD based on criteria and MD adherence measured by the Korean version of the Mediterranean-Diet Adherence Screener (K-MEDAS). Individuals were categorized into two groups based on their MD adherence: high adherence (K-MEDAS > 6) and low adherence (K-MEDAS < 5). Single nucleotide polymorphism (SNP) genotypes were obtained using the Korea Biobank array. Logistic regression was used to examine the single-marker variants for genetic associations with MASLD prevalence. RESULTS: Individuals were categorized into MASLD (10,018 [30.2%]) and non-MASLD (23,115 [69.8%]) groups. A significant interaction was observed between the rs780094 glucokinase regulatory protein (GCKR) gene and K-MEDAS on MASLD (p < 10 - 2 ). Of individuals with K-MEDAS > 6, those carrying the minor allele (C) of the GCKR gene rs780094 exhibited a lower risk of MASLD compared to those without the allele (odds ratio [OR] = 0.88 [0.85-0.91], p-value = 5.54e-13). CONCLUSION: The study identified a significant interaction involving the rs780094 variant near the GCKR gene, with carriers of the minor allele exhibiting a lower MASLD risk among those adhering well to the MD. Dietary habits influence the MASLD risk associated with the rs780094 allele, emphasizing the need for personalized nutrition recommendations.

Associations of Homeostatic Model Assessment for Insulin Resistance Trajectories With Cardiovascular Disease Incidence and Mortality.

BACKGROUND: Whether trends in insulin resistance changes are related to the risk of cardiovascular disease (CVD) incidence and mortality remains unclear. We aimed to examine the association of homeostatic model assessment for insulin resistance (HOMA-IR) trajectories with CVD incidence and mortality. METHODS: Data from 6755 adults aged 40 to 69 years in the Korea Epidemiology and Genome Study were analyzed. During the exposure period (2001-2006), participants were classified into the increasing HOMA-IR trajectory group and the stable HOMA-IR trajectory group using a latent class mixture model. During the event accrual period (2007-2018), information about CVD and mortality were collected. RESULTS: During the median 9.83-year event accrual period, there were 379 (5.6%) new-onset CVD, 535 (7.9%) all-cause mortality, 102 (1.5%) CVD mortality, and 47 (0.7%) major adverse cardiovascular event mortality cases. Compared with the stable HOMA-IR trajectory group, the fully adjusted hazard ratios (95% CIs) for the increasing HOMA-IR trajectory group were 1.59 (1.04-2.44) for incident CVD, 1.87 (1.30-2.69) for all-cause mortality, 2.33 (1.11-4.89) for CVD mortality, and 3.67 (1.38-9.76) for major adverse cardiovascular event mortality. CONCLUSIONS: An increasing HOMA-IR appears to be independently and positively related to incident CVD, all-cause mortality, CVD mortality, and major adverse cardiovascular event mortality. Early lifestyle interventions for individuals with increasing HOMA-IR trend could be a practical strategy to prevent CVD and CVD mortality.

Assessing the Feasibility and Efficacy of Pre-Sleep Dim Light Therapy for Adults with Insomnia: A Pilot Study.

Background: Insomnia is increasingly recognized for its marked impact on public health and is often associated with various adverse health outcomes, including cardiovascular diseases and mental health disorders. The aim of this study was to investigate the efficacy of pre-sleep dim light therapy (LT) as a non-pharmacological intervention for insomnia in adults, assessing its influence on sleep parameters and circadian rhythms. Methods: A randomized, open-label, two-arm clinical trial was conducted over two weeks with 40 participants aged 20-60 years, all of whom had sleep disorders (CRIS, KCT0008501). They were allocated into control and LT groups. The LT group received exposure to warm-colored light, minimizing the blue spectrum, before bedtime. The study combined subjective evaluation via validated, sleep-related questionnaires, objective sleep assessments via actigraphy, and molecular analyses of circadian clock gene expression in peripheral blood mononuclear cells. Baseline characteristics between the two groups were compared using an independent t-test for continuous variables and the chi-squared test for categorical variables. Within-group differences were assessed using the paired t-test. Changes between groups were analyzed using linear regression, adjusting for each baseline value and body mass index. The patterns of changes in sleep parameters were calculated using a linear mixed model. Results: The LT group exhibited significant improvements in sleep quality (difference in difference [95% CI]; -2.00 [-3.58, -0.43], and sleep efficiency (LT: 84.98 vs. control: 82.11, p = 0.032), and an advanced Dim Light Melatonin Onset compared to the control group (approximately 30 min). Molecular analysis indicated a significant reduction in CRY1 gene expression after LT, suggesting an influence on circadian signals for sleep regulation. Conclusions: This study provides evidence for the efficacy of LT in improving sleep quality and circadian rhythm alignment in adults with insomnia. Despite limitations, such as a small sample size and short study duration, the results underscore the potential of LT as a viable non-pharmacological approach for insomnia. Future research should expand on these results with larger and more diverse cohorts followed over a longer period to validate and further elucidate the value of LT in sleep medicine. Trial registration: The trial was registered with the Clinical Research Information Service (KCT0008501).

Association of non-high-density lipoprotein cholesterol trajectories with the development of non-alcoholic fatty liver disease: an epidemiological and genome-wide association study.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) shares common risk factors with cardiovascular diseases. Effects of longitudinal trends in non-high-density lipoprotein (non-HDL) cholesterol on NAFLD development are not understood. This study aimed to assess the relationship between non-HDL cholesterol trajectories and the incidence of NAFLD and to identify genetic differences contributing to NAFLD development between non-HDL cholesterol trajectory groups. METHODS: We analyzed data from 2203 adults (aged 40-69 years) who participated in the Korean Genome and Epidemiology Study. During the 6-year exposure periods, participants were classified into an increasing non-HDL cholesterol trajectory group (n = 934) or a stable group (n = 1269). NAFLD was defined using a NAFLD-liver fat score > -0.640. Multiple Cox proportional hazard regression analysis estimated the hazard ratio (HR) and the 95% confidence interval (CI) for the incidence of NAFLD in the increasing group compared with the stable group. RESULTS: A genome-wide association study identified significant single-nucleotide polymorphisms (SNPs) associated with NAFLD. During the median 7.8-year of event accrual period, 666 (30.2%) newly developed NAFLD cases were collected. Compared with the stable non-HDL group, the adjusted HR (95% CI) for the incidence of NAFLD in the increasing non-HDL cholesterol group was 1.46 (1.25-1.71). Although there were no significant SNPs, the polygenic risk score was highest in the increasing group, followed by the stable and control groups. CONCLUSION: Our study indicates that lifestyle or environmental factors have a greater effect size than genetic factors in NAFLD progression risk. Lifestyle modification could be an effective prevention strategy for NAFLD for people with elevated non-HDL cholesterol.

Comparison of the triglyceride glucose index and modified triglyceride glucose indices in assessing periodontitis in Korean adults.

BACKGROUND: Periodontal diseases are closely connected with insulin resistance (IR) and metabolic syndrome. The Triglyceride Glucose Index (TyG) assesses IR, and recently, a few indices combining TyG and body composition have emerged with higher IR predictive performance than TyG alone. We aimed to examine which TyG-related parameters are most helpful in predicting the risk of periodontal disease. METHODS: From 2013 to 2015, data were collected through the Korean National Health and Nutrition Examination Survey. Periodontitis was defined using the Community Periodontal Index. TyG-body mass index (BMI), TyG-waist circumference (WC), and TyG-waist-to-height ratio (WHtR) were calculated by multiplying TyG index score by BMI, WC, and WHtR, respectively. Multiple logistic regression analysis was used to calculate odds ratio (OR) and 95% confidence intervals (CI). Receiver operating characteristic curves were used to estimate areas under the curve (AUC). RESULTS: Compared to each reference quartile (Q)1, Q4 of the TyG index, TyG-BMI, TyG-WC, and TyG-WHtR were significantly associated with a higher risk of periodontitis after adjusting for confounders (OR, 95% CI; 1.23, 1.01-1.49 for TyG; 1.63, 1.22-2.17 for TyG-BMI; 1.37, 1.04-1.81 for TyG-WC; and 1.53, 1.16-2.02 for TyG-WHtR). The AUC and 95% CIs of TyG, TyG-BMI, TyG-WC, and TyG-WHtR in predicting periodontitis were 0.609 (0.600-0.617), 0.605 (0.596-0.617), 0.629 (0.621-0.637), and 0.636 (0.628-0.644), respectively (all p < .001). CONCLUSIONS: TyG, TyG-BMI, TyG-WC, and TyG-WHtR appear to be significantly associated with the prevalence of periodontitis. Among the TyG and modified TyG indices, TyG-WHtR exhibited the highest predictive performance for periodontitis.

Trends in serum uric acid levels among Korean children and adolescents between 2016 and 2020: a nationwide study.

The aim of this study was to examine trends in serum uric acid (SUA) levels over a recent 5-year period according to age, sex, obesity, and abdominal obesity among Korean children and adolescents. We conducted a serial cross-sectional analysis using nationally representative data from the Korea National Health and Nutritional Examination Survey from 2016 to 2020. The study outcome was trends in SUA levels. SUA trends were analyzed by survey-weighted linear regression analysis considering the survey year as a continuous variable. SUA trends were also analyzed for subgroups based on age, sex, abdominal obesity, or obesity. This study included 3,554 children and adolescents aged 10-18 years. SUA increased significantly over the study period in boys (p for trend = 0.043), but not in girls (p for trend = 0.300). In age-specific analyses, SUA increased significantly in the 10-12 years group (p for trend = 0.029). After adjusting for age, SUA increased significantly in the obese group of both boys (p for trend = 0.026) and girls (p for trend = 0.023), but not in the overweight, normal, or under-weight groups of either sex. After adjusting for age, SUA increased significantly in the abdominal obesity group of boys (p for trend = 0.017) and girls (p for trend = 0.014), but not in the non-abdominal obesity group of either sex.   Conclusion: In the current study, SUA levels significantly increased in both boys and girls with obesity or abdominal obesity. Further studies of the effect of SUA on health outcomes in boys and girls with obesity or abdominal obesity are needed. What is Known: • High serum uric acid (SUA) is a risk factor for various metabolic diseases, including gout, hypertension, and type 2 diabetes. What is New: • SUA levels increased in boys and the 10-12 years group of Korean children and adolescents. • SUA levels increased significantly in Korean children and adolescents with obesity or central obesity.

Feasibility and Efficacy of Morning Light Therapy for Adults with Insomnia: A Pilot, Randomized, Open-Label, Two-Arm Study.

Background and Objectives: Light therapy (LT) is used as an adjunctive treatment for sleep problems. This study evaluates the impact of LT on sleep quality and sleep-related parameters in patients with sleep disorders. Materials and Methods: We performed a pilot, randomized, open-label clinical trial. Fourteen patients aged 20-60 years with insomnia were randomized into the control and LT groups (1:1 ratio). The LT group was instructed to use a device that provides bright LT (6000 K, 380 lux, wavelength 480 nm) for at least 25 min before 09:00 a.m. for two weeks. A self-reported questionnaire was used to evaluate circadian preference, mood, and sleep-related parameters. We analyzed serum cortisol levels and clock genes' expression. Results: The Epworth Sleepiness Scale (ESS), insomnia severity index(ISI), and Pittsburgh Sleep Quality index(PSQI) were significantly improved within the LT group only after the two-week period. When comparing the two groups, only the change in ESS was significant (mean difference, control: -0.14 vs. LT: -1.43, p = 0.021) after adjusting for the baseline characteristics. There were no significant differences in serum cortisol or clock genes' expression. Conclusions: LT can improve daytime sleepiness in patients with sleep disorders; however, further well-designed studies are warranted to confirm its efficacy.

Low-protein diet is inversely related to the incidence of chronic kidney disease in middle-aged and older adults: results from a community-based prospective cohort study.

PURPOSE: Dietary protein intake can modulate renal health. However, the effect of dietary protein restriction on kidney function in the general population remains unclear. This study aimed to examine the association between total protein intake and new-onset chronic kidney disease (CKD) in Korean adults. METHODS: We included 7339 participants from the Korean Genome and Epidemiology Study. Participants were divided into low-protein diet (LPD, < 0.8 g/kg/day), normal-protein diet (NPD, 0.8-1.3 g/kg/day), and high-protein diet (HPD, > 1.3 g/kg/day) groups. New-onset CKD was defined as two consecutive events of estimated glomerular filtration rate < 60 mL/min/1.73 m2. Multivariable Cox hazard regression analysis was conducted to examine the association of total protein intake with new-onset CKD. Subgroup analyses according to diabetes mellitus (DM) status were performed. We performed the same analyses by dividing participants into total protein, plant protein, and animal protein intake tertiles. RESULTS: During a median follow-up of 13.7 years, 633 (8.7%) participants newly developed CKD. The fully adjusted hazard ratios (HR) with 95% confidence interval (CI) for incident CKD of the LPD and HPD groups compared with the NPD group were 1.49 (1.18-1.87) and 0.63 (0.45-0.87), respectively. The HR (95% CI) of the highest tertile group of plant protein intake for incident CKD was 0.72 (0.54-0.93), compared with that of the lowest tertile group. Similar trends were observed only in the non-DM subgroup, not in the DM subgroup. CONCLUSION: Protein intake, especially plant proteins, was negatively associated with the incidence of new-onset CKD in middle-aged and older Korean adults.

Feasibility and efficacy of TouchCare system using application for older adults living alone: a pilot pre-experimental study.

BACKGROUND: With the number of older people living alone continuously rising, health-monitoring systems using information and communication technology (ICT) have been developed to manage their health issues. Life logging and human body communication sensor, types of ICT, have been adapted to manage and monitor health status of the elderly. However, its feasibility and efficacy remain unclear. This study aimed to examine the feasibility of TouchCare system which combined life logging with human body communication technology and its effect on the physical and psychological status of older adults living alone. METHODS: The TouchCare system, which consisted of a wearable watch, touchpad sensors, TouchCare application, and context-aware artificial intelligence, was developed by DNX Co. Ltd and used by the participants for 5 months. Out of the 111 selected participants, 91 replied to the satisfaction survey, and 22 participated in further investigation regarding their physical and psychological status. Finally, health assessment from 14 participants and sensor data from 13 participants (mean age = 77.4; SD = 3.8) were analyzed to compare their health status and health-related behaviors before and after use of the system. RESULTS: Out of the 91 participants who took the survey, 51.6% were satisfied with the system. Nutritional status (pre-intervention (10.6 ± 2.0) vs. post-intervention (11.8 ± 1.9), P = 0.04) and fall efficacy (pre-intervention (89.2 ± 15.3) vs. post-intervention (99.9 ± 0.5), P = 0.001) significantly improved after use of the system. Chronic pain (pre-intervention (4.8 ± 2.5) vs. post-intervention (4.4 ± 3.7), P = 0.78) and depressive symptoms (pre-intervention (5.7 ± 3.9) vs. post-intervention (5.4 ± 3.1), P = 0.60) reduced, while cognitive function (pre-intervention (4.1 ± 1.4) vs. post-intervention (4.6 ± 1.1), P = 0.15) and physical performance related to walking improved (pre-intervention (3.9 ± 0.2) vs. post-intervention (4.0 ± 0), P = 0.35), but were not significant. Behaviors related to physical activity and gait improved after use of the system; touch counts of refrigerator and microwave also increased with a decrease in night touch counts. CONCLUSIONS: The TouchCare system was acceptable to older people living alone, and it efficiently managed their daily living while promoting their health-related behaviors. Further experimental studies are required to verify the effectiveness of the system, and to develop the system which meet the individualized needs of older people living alone.

Differential relationship between dietary fat and cholesterol on total mortality in Korean population cohorts.

BACKGROUND: Associations among dietary fat, cholesterol intake and total mortality remain controversial, and most available data cover Western populations. The aim of this study was to assess associations for dietary fat and cholesterol in relation to total mortality in Koreans. METHODS: This study used data from three prospective Korean Genome and Epidemiology studies (conducted between June 2001 and December 2013). A total of 194,295 middle-aged and older Korean adults were included. Dietary fat intake was classified into quintiles. Dietary cholesterol intake was categorized into three groups based on cholesterol intake as follows: <200 mg, 200-299 mg and ≥300 mg. A multivariable Cox frailty model with random effects was applied to calculate hazard ratios (HR) and 95% confidence intervals (CIs) after adjusting for confounders. RESULTS: We documented 3866 deaths across a mean (min-max) follow-up period of 8.15 years (3-13 years). Higher fat intake was associated with lower total mortality (Q5 vs. Q1, HR 0.82 [95% CI 0.69, 0.98]; p trend < 0.01) after adjusting for age, sex, body mass index, alcohol, smoking, exercise and total calorie and protein (%) intake. Higher dietary cholesterol intake (≥300 mg/day) was associated with a higher risk of total mortality (HR 1.19 [95% CI 1.04, 1.37]) than lower cholesterol intake (<200 mg/day) in the multivariate model. CONCLUSIONS: In Koreans, high dietary fat intake is associated with a lower risk of total mortality, while dietary cholesterol intake above 300 mg/day is associated with a higher risk of total mortality.

Identification of susceptibility loci for cardiovascular disease in adults with hypertension, diabetes, and dyslipidemia.

BACKGROUND: Hypertension (HTN), diabetes mellitus (DM), and dyslipidemia (DL) are well-known risk factors of cardiovascular disease (CVD), but not all patients develop CVDs. Studies have been limited investigating genetic risk of CVDs specific to individuals with metabolic diseases. This study aimed to identify disease-specific and/or common genetic loci associated with CVD susceptibility in chronic metabolic disease patients. METHODS: We conducted a genome-wide association study (GWAS) of a multiple case-control design with data from the City Cohort within Health EXAminees subcohort of the Korean Genome and Epidemiology Study (KoGES_HEXA). KoGES_HEXA is a population-based prospective cohort of 173,357 urban Korean adults that had health examinations at medical centers. 42,393 participants (16,309 HTN; 5,314 DM; 20,770 DL) were analyzed, and each metabolic disease group was divided into three CVD case-controls: coronary artery disease (CAD), ischemic stroke (IS), and cardio-cerebrovascular disease (CCD). GWASs were conducted for each case-control group with 7,975,321 imputed single nucleotide polymorphisms using the Phase 3 Asian panel from 1000 Genomes Project, by logistic regression and controlled for confounding variables. Genome-wide significant levels were implemented to identify important susceptibility loci. RESULTS: Totaling 42,393 individuals, this study included 16,309 HTN (mean age [SD], 57.28 [7.45]; 816 CAD, 398 IS, and 1,185 CCD cases), 5,314 DM (57.79 [7.39]; 361 CAD, 153 IS, and 497 CCD cases), and 20,770 DL patients (55.34 [7.63]; 768 CAD, 295 IS, and 1,039 CCD cases). Six genome-wide significant CVD risk loci were identified, with relatively large effect sizes: 1 locus in HTN (HTN-CAD: 17q25.3/CBX8-CBX4 [OR, 2.607; P = 6.37 × 10-9]), 2 in DM (DM-IS: 4q32.3/MARCH1-LINC01207 [OR, 5.587; P = 1.34 × 10-8], and DM-CCD: 17q25.3/RPTOR [OR, 3.511; P = 1.99 × 10-8]), and 3 in DL (DL-CAD: 9q22.2/UNQ6494-LOC101927847 [OR, 2.282; P = 7.78 × 10-9], DL-IS: 3p22.1/ULK4 [OR, 2.162; P = 2.97 × 10-8], and DL-CCD: 2p22.2/CYP1B1-CYP1B1-AS1 [OR, 2.027; P = 4.24 × 10-8]). CONCLUSIONS: This study identified 6 susceptibility loci and positional candidate genes for CVDs in HTN, DM, and DL patients using an unprecedented study design. 1 locus (17q25.3) was commonly associated with CAD. These associations warrant validation in additional studies for potential therapeutic applications.

Comparison of bacterial community profiles from large intestine specimens, rectal swabs, and stool samples.

The human gastrointestinal tract contains a complex and dynamic population of microorganisms, known as the gut microbiota. Although interest in the role of the gut microbiota in human health has increased in recent years, there remains no standard sampling protocol for analyzing these organisms. Here, we aimed to characterize the microbial composition of distinct segments of the large intestine and to determine whether rectal swabs are suitable for identifying colon microbiota. A total of 100 participants who underwent screening colonoscopy from October 2019 to October 2020 were included in this study. Large intestinal samples (ascending colon, descending colon, sigmoid colon, and rectum) were aspirated by colonoscopy. Rectal swabs were collected before colonoscopy, and stool samples were collected before patients began colonoscopy preparation. All samples were subjected to 16S ribosomal RNA gene sequencing. We identified differences in the number of phylum-level operational taxonomic units among large intestinal samples, rectal swabs, and stool. Five major phyla were detected in all samples (Firmicutes, Bacteroides, Proteobacteria, Actinobacteria, Fusobacteria), although their relative abundances varied. Notably, we found that the microbial compositions of rectal swabs were most similar to those of the sigmoid colon and rectum, whereas the microbiota in stool were relatively different than those from the large intestine and rectal swabs. Our results reveal the existence of microbial heterogeneity within different large intestinal compartments and further suggest that rectal swabs are an acceptable and practical tool for gut microbiota analysis. KEY POINTS: • Our findings highlight local microbiome variations within different regions of the large intestine. • Stool samples do not appear to fully recapitulate the gut microbiome. • Our data from a large population-based cohort indicate that rectal swabs can be used to study the gut microbiome.

Association between nutrition education, dietary habits, and body image misperception in adolescents.

BACKGROUND AND OBJECTIVES: In adolescents, adequate nutrition education is essential for making decisions regarding healthy eating habits. We aimed to investigate differences in dietary habits and body image misperception according to nutrition education status. METHODS AND STUDY DESIGN: We analyzed 60,389 adolescents aged 12-18 years old, using the 2017 Korea Youth Risk Behavior Web-based Survey data. Participants were divided into nutrition-educated (EDU) and uneducated (non-EDU) groups, according to nutrition education status within the past year. Skipping breakfast was defined as skipping breakfast ≥5 times/week. Desirable dietary behaviors were divided into the frequency of consumption of 3 items: vegetables ≥1 time/day, milk ≥1 time/day, and fruits ≥1 time/day. Participants with normal weight who reported being slightly fat or very fat were defined as having body image misperception. RESULTS: Compared to the non-EDU group, the odds ratio (OR) and 95% confidence interval (CI) for desirable dietary behaviors in the EDU group were 1.08 (1.04-1.13), 1.14 (1.09-1.19), and 1.16 (1.12-1.20) for the intake of fruits, milk, and vegetables, respectively. The EDU group was less associated with skipping breakfast than the non-EDU group (OR=0.91, 95% CI: 0.87-0.95, p<0.001). The OR and 95% CI of body image misperception in the EDU group were lower than in the non-EDU group (OR=0.92, 95% CI: 0.87- 0.97, p<0.001). CONCLUSIONS: Nutrition education have positive effects on healthy dietary behaviors. It also shows a negative association with body image misperception, confirming the importance of nutrition education at school.

High triglyceride to HDL cholesterol ratio is associated with low testosterone and sex hormone-binding globulin levels in Middle-aged and elderly men.

Objective: We investigated the association between the triglycerides to high-density lipoprotein cholesterol (TG/HDL) ratio and low testosterone and sex hormone-binding globulin (SHBG) levels in middle-aged and elderly men.Methods: This cross-sectional study included 1055 men aged ≥45 years who underwent a medical examination. The cutoff points for low testosterone and SHBG levels were determined as 12.2 and 29.4 nmol/L, which corresponded to the 25th percentile of the current sample. The odds ratios (ORs) and 95% confidence intervals (95% CIs) for low testosterone and SHBG levels were calculated after adjusting for confounding variables across TG/HDL ratio quartiles (Q1: ≤ 1.70, Q2: 1.71-2.54, Q3: 2.55-3.77, Q4: ≥3.78) using multiple logistic regression analysis.Results: The proportion of subjects with low testosterone and SHBG levels significantly increased in accordance with TG/HDL ratio quartile. The ORs (95% CIs) of the lowest TG/HDL ratio quartile compared to the highest TG/HDL ratio quartile for low levels of testosterone and SHBG were 1.96 (1.13-2.75) and 3.90 (2.38-6.38), respectively, after adjusting for age, body mass index, smoking status, alcohol drinking, regular exercise, diastolic blood pressure, fasting plasma glucose, and total cholesterol level.Conclusions: The TG/HDL ratio was inversely associated with testosterone and SHBG levels in middle-aged and elderly Korean men.

Association of milk consumption frequency on muscle mass and strength: an analysis of three representative Korean population studies.

PURPOSE: Sarcopenia is an involuntary loss of muscle mass, strength, and physical performance associated with aging. Sarcopenia contributes to adverse health outcomes. Milk contains essential amino acids important for maintaining muscle. We investigated the relationships among milk consumption frequency (MCF), muscle mass, and strength in Korean adults. METHODS: We analyzed the data from 16,173 adults in the 2008-2011 Korean National Health and Nutrition Examination Survey (KNHANES), 13,537 adults in the 2014-2016 KNHANES, and 8254 adults in the Korean Genome and Epidemiology Study (KoGES). MCF was divided into two groups: (1) MCF less than once per day (MCF < 1 group) and (2) MCF greater than or equal to once per day (MCF ≥ 1 group). Low skeletal muscle mass index (LSMI) was defined using the Foundation for the National Institutes of Health sarcopenia project criteria for low muscle mass. Muscle strength was measured using the hand-grip strength test. RESULTS: The odds ratio (95% confidence interval) for LSMI in the MCF < 1 group was 1.250 (1.013-1.543) after adjusting for confounding factors, compared with the MCF ≥ 1 group (2008-2011 KNHANES). The adjusted mean for hand-grip strength was higher in the MCF ≥ 1 group (2014-2016 KNHANES). After a mean follow-up of 9 years, fat-free mass/body mass index was higher in the MCF ≥ 1 group than the MCF < 1 group (KoGES). CONCLUSION: We found that MCF ≥ 1 was significantly associated with higher skeletal muscle index and muscle strength than lower MCF. Milk consumption could help prevent sarcopenia in adults.

Association of dietary lipid intake with low-density lipoprotein cholesterol levels: analysis of two independent population-based studies.

PURPOSE: Serum low-density lipoprotein cholesterol (LDL-C) concentration is associated with the risk of cardiovascular disease. However, whether cholesterol and fat intake independently affect serum LDL-C levels remains controversial. We aimed to explore the differential effects of dietary cholesterol and fats on blood lipid profiles according to the presence of dyslipidemia. METHODS: A cross-sectional study was conducted based on data from the sixth Korean National Health and Nutrition Examination Survey (2013-2015), and a prospective cohort study was conducted using data from the Korean Genome Epidemiology Study. The analyses used data from 10,068 adults and from 9652 adults, respectively. Adjusted mean values of blood lipids were calculated according to cholesterol and fat intake using analysis of covariance. A repeated-measures covariance pattern linear mixed model with unstructured covariance within participants was used to examine longitudinal associations between cholesterol intake and serum concentrations of total cholesterol and LDL-C. Substitutional analysis was conducted to estimate carbohydrate substitution with saturated fat or unsaturated fat. RESULTS: Serum LDL-C level was significantly higher in dyslipidemic subjects who consumed more than 300 mg cholesterol per day than in those who consumed less than 300 mg cholesterol per day. At a mean 9-year follow-up, levels of total cholesterol and LDL-C were significantly higher in dyslipidemic individuals with higher baseline cholesterol intake after adjustment for potential confounders. In regard to dietary fats, replacing carbohydrate with unsaturated fat was associated with lower level of LDL-C in subjects with dyslipidemia. CONCLUSIONS: Serum LDL-C is associated with the intake of dietary cholesterol, especially in individuals with dyslipidemia.

Oxidative balance score and serum γ-glutamyltransferase level among Korean adults: a nationwide population-based study.

PURPOSE: The oxidative balance score (OBS) comprises dietary and non-dietary lifestyle pro-oxidants and antioxidants. Elevated serum γ-glutamyltransferase (GGT) level has currently emerged as a biomarker of oxidative stress. In this study, we examined whether OBS was inversely associated with serum GGT level and whether OBS could be a useful marker to predict GGT among Korean adults. METHODS: This cross-sectional study was based on data obtained from the 2010 and 2011 Korea National Health and Nutrition Examination Survey. 2087 men and 2071 women were included in final analysis. The OBS was divided into five equal interval categories, and GGT was dichotomized into low and high using its sex-specific median value. Multiple logistic regression analysis was conducted to assess the association between OBS categories and high GGT. RESULTS: Compared with the lowest OBS category as reference, the multivariable adjusted ORs (95% CIs) for the highest OBS category of men and women were 0.05 (0.01-0.19) and 0.27 (0.09-0.78), respectively (p for trend <0.01). CONCLUSION: A higher OBS that indicates a predominance of antioxidant over pro-oxidant exposure was strongly inversely associated with GGT level among Korean adults.

Serum carcinoembryonic antigen is positively associated with leukocyte count in Korean adults.

BACKGROUND: Emerging evidence shows that serum carcinoembryonic antigen (CEA) levels may modestly be increased in non-neoplastic conditions such as cardiometabolic diseases, which are increasingly being seen as inflammatory diseases. Leukocyte count is widely evaluated marker of inflammation in clinical practice and a useful predictor of cardiometabolic disease. In this study, we aimed to determine the relationship between serum CEA levels and leukocyte counts in Korean adults. METHODS: This cross-sectional study included a total of 19 834 individuals enrolled from a health promotion center between November 2006 and July 2010. Multiple linear regression analysis was performed to investigate the association between serum CEA levels and leukocyte counts after adjusting for confounding variables. RESULTS: According to both stepwise-method and enter-method multiple linear regression analyses, serum CEA levels were positively and independently associated with leukocyte counts (P<.001) after adjusting for age, sex, body mass index, systolic blood pressure, diastolic blood pressure, total cholesterol, triglyceride, HDL-cholesterol, cigarette smoking, alcohol ingestion, physical activity, diabetes mellitus, and anti-inflammatory drugs. CONCLUSIONS: We demonstrate a positive relationship between serum CEA levels and leukocyte counts in Korean adults. Our results suggested that an elevated serum CEA level may reflect chronic inflammation state.

Triglyceride to high density lipoprotein cholesterol ratio and its association with periodontal disease in Korean adults: findings based on the 2012-2014 Korean national health and nutrition examination survey.

OBJECTIVES: The aim of this study is to evaluate whether the triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio is associated with periodontal disease in Korean adults. MATERIALS AND METHODS: This cross-sectional study included 12,249 individuals (4,941 men and 7,308 women) who took part in the 2012-2014 Korean National Health and Nutrition Examination Survey. We categorized the TG/HDL-C ratio into three groups. Periodontal disease was defined as a community pocket index score ≥3 with at least one affected site. Multiple logistic analyses were used to analyze the association between TG/HDL-C ratio and periodontal disease. RESULTS: In the study population, prevalence of periodontal disease was 31.6% in men and 21% in women. Compared to the lowest tertile group, OR (95% CI) of the highest tertile group for periodontal disease was 1.474 (1.220-1.780) in men and 1.259 (1.041-1.522) in women after adjusting for age, waist circumference, systolic blood pressure, fasting glucose, current smoking, alcohol drinking, physical activity, household income, oral health behavior, and use of anti-dyslipidemia medication. CONCLUSION: Our study suggests that the TG/HDL-C ratio is associated with periodontal disease in Korean adults. CLINICAL RELEVANCE: TG/HDL-C ratio is a simple and useful marker to reflect insulin resistance. And periodontal disease is also known to be related with insulin resistance. This study indicates that TG/HDL-C ratio was associated with periodontal disease in Korean adults.