Korean Population Research Articles

Exploring the diversity of Brachonella: Morphological and molecular analysis with the discovery of a new species, Brachonella tenuicauda nov. spec. (Ciliophora, Armophorea, Metopida).

Exploring the diversity of Brachonella: Morphological and molecular analysis with the discovery of a new species, Brachonella tenuicauda nov. spec. (Ciliophora, Armophorea, Metopida).

Population modeling of pharmacokinetic variability of epinastine, a histamine H1 receptor antagonist, according to cytochrome P450 2D6 phenotypic polymorphisms.

Although epinastine has been actively used in clinical practice for treatment of allergic diseases, attempts to interpret and quantify pharmacokinetic (PK) diversity within population have been very limited. In particular, there have been no studies on population-pharmacokinetic (pop-PK) modeling of epinastine focusing on genetic factors. The primary objective of this study was to quantitatively interpret the PK variability of epinastine according to phenotypic polymorphisms of cytochrome P450 (CYP) 2D6 in Korean population and to construct a new pop-PK model considering such polymorphisms. The bioequivalence PKs, physiologic and biochemical parameter analyses, and CYP2D6 genotyping results performed in 26 healthy Korean males were used in this study. The pop-PKs of epinastine were described by the first-order oral absorption and distribution between central and peripheral compartments, and elimination from the central compartment as the basic model structure. The covariate reflection of physiologic and biochemical parameters was not valid. Conversely, CYP2D6 phenotypic polymorphisms were explored as valid covariates for clearance from the central compartment (CLc/F). Compared to extensive-metabolizers (EMs), the decreases in typical CLc/F values in intermediate-metabolizers (IMs) and poor-metabolizers (PMs) were estimated as 28.06% and 49.48%, respectively. As a result of pop-PK model simulation, the serum concentrations of epinastine at steady-state significantly increased from CYP2D6 EMs to IMs and PMs. The degree of increase was 1.97 (in PMs compared to EMs) and 1.39 (in IMs compared to EMs) based on the corresponding value of 50% of the group. This study provides a new perspective on the quantitative interpretation of PK changes for epinastine according to CYP2D6 genotypic factors and is expected to be an important bridgehead for improving clinical efficacy and safety through precision pharmacotherapy.

Association of Lipoprotein(a) with Progression of Coronary Artery Calcification: Retrospective Longitudinal Study.

Atherosclerotic cardiovascular disease (ASCVD) is a major health concern, and lipoprotein(a) (Lp(a)) is an independent risk factor. However, there is limited evidence regarding Lp(a) and the risk of ASCVD in Asian populations. This study aimed to assess the predictive value of changes in coronary artery calcification (CAC) for ASCVD risk associated with Lp(a) level. Participants (n=2,750) were grouped according to their Lp(a) levels, and the association between Lp(a) and CAC progression was examined. CAC progression was defined as the occurrence of incident CAC or a difference ≥2.5 between the square root (√) of baseline and follow-up coronary artery calcium scores (CACSs) (Δ√transformed CACS). To adjust for differences in follow-up periods, Δ√transformed CACS was divided by the follow- up period (in years). Over an average follow-up of 3.07 years, 18.98% of participants experienced CAC progression. Those with disease progression had notably higher Lp(a) levels. Higher Lp(a) tertiles correlated with increased baseline and follow-up CACS, CAC progression (%), and Δ√transformed CACS. Even after adjustment, higher Lp(a) levels were associated with CAC progression. However, annualized Δ√transformed CACS analysis yielded no significant results. This study demonstrated an association between elevated Lp(a) levels and CAC progression in a general population without ASCVD. However, longer-term follow-up studies are needed to obtain meaningful results regarding CAC progression. Further research is necessary to utilize Lp(a) level as a predictor of cardiovascular disease and to establish clinically relevant thresholds specific to the Korean population.

Measuring functioning and disability in Korea: comparing general and dedicated surveys using the ICF as a reference framework.

Functioning is the third health indicator besides mortality and morbidity. Although Korea periodically collects functioning information, the functioning indicator has not been generated yet. This study aimed to evaluate how functioning information is currently collected in Korea's health and disability surveys, especially in terms of comparability and comprehensiveness, using the International Classification of Functioning, Disability and Health (ICF) as a reference framework. Data sources included three health and disability surveys in Korea, namely the Population and Housing Census, the Korean National Health and Nutrition Examination Survey, and the Survey on the Living condition of Persons with Disabilities, and two international ICF-based surveys, the International Spinal Cord Injury Survey and the Model Disability Survey. Functioning information was linked by category to the ICF Generic-30 Set utilizing the ICF linking rules. Three ICF categories - d450 walking; d510 washing oneself; d540 dressing ̶ were covered by all the data sources. Excluding the Population and Housing Census, which inherently differs from the other data sources, all the surveys addressed six ICF categories - b152 emotional functions; b280 sensation of pain; d240 handling stress and other psychological demands; d450 walking; d510 washing oneself; d540 dressing. The ICF categories b152 emotional functions and b130 energy and drive functions were the most frequently covered across all the surveys. Despite of the common ICF categories, important differences in the operationalization of questions and response options were found. The overlap of content of health and disability surveys in Korea enables interoperability with other data sources. Available functioning data can be used for estimating the functioning indicator and metric, as recommended by WHO, which can serve as a valuable epidemiological indicator for complementing mortality and morbidity indicators and for estimating and monitoring rehabilitation or long-term care needs of the Korean population.

Association Between Perfluoroalkyl Substance (PFAS) Exposure and Nonalcoholic Fatty Liver Disease in Korean Adults: Results From the KoNEHS 2018-2020: A Cross-Sectional Study.

Nonalcoholic fatty liver disease (NAFLD) is a major public health problem and the most common chronic liver disease today. In Korea, the prevalence and incidence of NAFLD are currently very high, causing a serious social burden. Perfluoroalkyl substances (PFAS) have been consistently implicated as a potential cause of NAFLD, but research in Koreans is limited. Using data from the 4th Korean National Environmental Health Survey (KoNEHS, n = 2859), we investigated the association between PFAS blood levels and NAFLD. Multivariable logistic regression models were used to calculate odds ratios (ORs) for the effects of PFAS. A mediation analysis was also conducted to examine the mediating effect of obesity. Finally, weighted quantile sum (WQS) and G-computation methods were implemented to evaluate the joint effect of PFAS mixtures. Hepatic steatosis index was used as a diagnostic tool for NAFLD. Through multivariable logistic regression, statistically significant associations with NAFLD were observed for perfluorooctanoic acid (PFOA) (OR 1.09-1.39), perfluorooctansulfonate (PFOS) (1.09-1.40), perfluorohexanesulfonic acid (PFHxS) (1.04-1.22), perfluorononanoic acid (PFNA) (1.12-1.42), and total PFAS (1.21-1.81). We also found that obesity was a significant mediator for PFOA, PFNA, and total PFAS. The ORs for NAFLD obtained by WQS and G-computation methods in the multivariable adjusted model were 1.10-1.46 and 1.08-1.32, respectively. This study confirmed a significant association between some PFAS and increased odds of NAFLD. Excessive exposure to PFAS might explain the high prevalence and incidence of chronic liver disease in Koreans. Long-term cohort studies are needed to assess geographic and occupational exposures in the Korean population.

Association between obstructive sleep apnea risk and atherosclerosis: A nationwide cross-sectional study in the Korean population.

Obstructive sleep apnea (OSA) increases the risk of all-cause and cardiovascular mortality. This study aimed to investigate the association between OSA and atherogenic risk in the Koreans. Data from 8,158 participants (mean age, 57.9 ± 11.7; male/female, 1:1.4) obtained from the Korea National Health and Nutrition Examination Survey between 2019 and 2021. OSA risk was screened using the STOP-BANG score, and atherogenic risk was measured using the atherogenic index of plasma (AIP). Logistic regression was used to evaluate the association between the STOP-BANG scores and high AIP and subgroups according to the presence of diabetes. The proportions of individuals with atherogenic risk (AIP > 0.24) were 13.7%, 27.6%, and 34.7% in the low-, intermediate-, and high-OSA risk groups (p < 0.001). After adjustment, individuals with intermediate and high OSA risk had 1.35 (95% confidence interval [CI], 1.16-1.58; p < 0.001) and 1.32 (95% CI, 1.08-1.61; p = 0.006) times higher odds of having atherogenic risk than those with low OSA risk. Among patients without diabetes, high OSA risk was not an independent factor affecting atherogenic risk (hazard ratio [HR], 1.17; 95% CI, 0.93-1.47). However, among patients with diabetes, compared with those with low OSA risk, those with intermediate (HR, 1.51; 95% CI, 1.05-2.19) and high OSA risk (HR, 1.58; 95% CI, 1.02-2.46) had significantly increased atherogenic risk. OSA is linked to increased atherogenic risk in the Koreans, especially in individuals with diabetes, thus highlighting the importance of routine OSA screening to manage and reduce cardiovascular risks.

Validation of the obstetric comorbidities index for predicting maternal mortality and severe maternal morbidity in South Korea

To validate the Obstetric Comorbidity Index (OB-CMI) and estimate its predictive and discriminative performance for maternal outcomes in the South Korean population. This study used data on births from the National Health Insurance Service Delivery Cohort database in South Korea. The data on pregnant people who gave birth during 2003–2019 were included. The obstetric comorbidities were identified using the Bateman’s OB-CMI. The outcomes were severe maternal morbidity (SMM) as defined by the CDC in the US; severe acute maternal morbidity (SAMM), as defined by EURONET; and maternal death within 30 days postpartum. The predictive and discriminative abilities of the index were calculated using the Brier score and area under the receiver operating characteristic curve (AUC). Of 6,527,810 births, 143,392 (2.2%), 84,994 (1.3%), and 555 (< 0.1%) resulted in SMM, SAMM, and maternal death, respectively. The predictive ability and discriminative performance of the OB-CMI were moderate and good (Brier scores of 0.02, 0.01, and 0.00 and AUC of 0.72, 0.68, and 0.78 for SMM, SAMM, and maternal death, respectively). The OB-CMI demonstrated moderate and good predictive and discriminative performance for SMM, SAMM, and maternal mortality in the South Korean population. These findings align with previous research, supporting OB-CMI as a valuable tool for identifying high-risk pregnancies.

Neuro-ophthalmic findings of Visual Snow Syndrome in Korea.

To investigate the neuro-ophthalmologic characteristics, potential triggers, and treatment responses of visual snow syndrome (VSS) in a Korean population. Retrospective case series. We retrospectively reviewed the data of patients diagnosed with VSS at a tertiary hospital from March 2021 to February 2024. Data on visual and nonvisual symptoms, self-reported events that caused VSS, and medical and psychiatric comorbidities were chart-reviewed. Neuroimaging findings from MRI and 18F-FDG PET were evaluated, along with treatment responses to pharmacological interventions and filter glasses. The sample comprised 27 men and 36 women, with a mean age of 27±11 years (mean±SD) and onset age of 22.4±11 years. Common symptoms included floaters, palinopsia, anxiety, and depression. Fourteen participants attributed VSS onset to specific ophthalmic events (e.g. refractive surgery or ophthalmic examinations with bright-light). 18F-FDG PET scans showed hypermetabolism in the visual cortices (81.8%), with no significant MRI abnormalities. Lamotrigine (18.9%), alprazolam (20%), and filter glasses (32.1%) showed modest efficacy in reducing the intensity of VSS. Korean patients with VSS exhibited clinical features, neuroimaging findings, and treatment responses similar to those reported in Western populations. Ophthalmic procedures, such as refractive surgery and bright-light examinations, may act as potential triggers in susceptible individuals. Although functional imaging, including 18F-FDG PET, may be useful for evaluating VSS, further studies with healthy controls and quantitative analyses are needed to validate its diagnostic value. Given the modest treatment efficacy, a multidisciplinary approach combining pharmacological intervention, filter glasses, and psychological support is essential to optimize outcomes.

Underweight increases the incidence of infective endocarditis in the Korean population: a nation-wide cohort study.

Underweight increases the incidence of infective endocarditis in the Korean population: a nation-wide cohort study.

HLA Association With AQP4-IgG-Positive Neuromyelitis Optica Spectrum Disorder in the Korean Population.

Association of human leukocyte antigen (HLA) with anti-aquaporin-4 immunoglobulin G-positive neuromyelitis optica spectrum disorder (AQP4-IgG NMOSD) has been reported. However, this association in the Korean population has not been previously investigated. We aimed to evaluate whether specific HLA subtypes were associated with Korean patients with AQP4-IgG NMOSD and whether the HLA genotype is associated with specific clinical features. We compared the HLA subtypes of 122 patients with AQP4-IgG NMOSD with those of 485 (HLA-A, HLA-B, HLA-C, HLA-DRB1, and HLA-DQB1) and 173 (HLA-DPB1) healthy controls. In addition, we compared the clinical features of patients with and without specific HLA genotypes. The most significant risk allele for AQP4-IgG NMOSD was HLA-DRB1*03:01 (24 patients [19.67%], odds ratio [OR]: 3.997, pc value = 0.0001). Susceptibility of AQP4-IgG NMOSD was significantly associated with the HLA-DRB1*03:01-DQB1*02:01 (23 patients [18.85%], OR: 3.792, pc value = 0.0002) and DRB1*12:02-DQB1*03:01 (23 patients [18.85%], OR: 3.402, pc value = 0.0009) haplotypes. Patients with the DRB1*12:02-DQB1*03:01 haplotype showed more frequent spinal involvement, a higher Expanded Disability Status Scale score at disease-onset nadir, and a shorter time to second attack than patients without this haplotype. In a Korean cohort of patients withAQP4-IgG NMOSD, the HLA-DRB1*12:02-DQB1*03:01 haplotype was associated with disease severity at onset. HLA-DRB1*03:01, broadly reported as a significant susceptibility allele across diverse ethnic groups, showed a significant risk association in Korean patients with AQP4-IgG NMOSD.

Per- and polyfluoroalkyl substances exposures are associated with non-alcoholic fatty liver disease, particularly fibrosis.

Per- and polyfluoroalkyl substances exposures are associated with non-alcoholic fatty liver disease, particularly fibrosis.

Re: Hwang etal: Ocular Adverse Events Following COVID-19 Infection: A Self-controlled Case Series Study from the Entire Korean Population.

Re: Hwang etal: Ocular Adverse Events Following COVID-19 Infection: A Self-controlled Case Series Study from the Entire Korean Population.

A digital reminiscence intervention program using a time-traveling road map for community-dwelling older adults with subjective cognitive decline.

Subjective cognitive decline (SCD) is a common concern among older adults in the South Korean population. Thus, non-pharmacological interventions are needed to reduce cognition, communication, and mood complaints. This study evaluated the effects of a Roadmap Time-Traveling Intervention program (RMTI), a digital reminiscence therapy intervention, on cognitive measurements, communication, and mood in older adults with SCD. Fifty participants were randomly assigned to the experimental or control group. Cognitive function, communication difficulties, quality of life (QoL), depression, and anxiety were assessed at baseline (T0), immediately after the intervention (T1), and four weeks post-intervention (T2). Generalized estimation equations were utilized to analyze the program's effectiveness over time (T0-T1) between groups. A repeated measures ANOVA and the Friedman/Wilcoxon signed-rank tests examined changes across the three time points (T0-T1-T2) within the experimental group. The study followed the Consolidated Standards of Reporting Trials guidelines. The experimental group exhibited significant improvements in the Korean version of the Mini-Mental State Examination (MMSE-K) scores (p < .001) and QoL (p < .001) compared with the control group: MMSE-K scores (Ⲭ² = 9.55, p = .008), communication difficulties (Ⲭ² = 8.57, p = .014), and QoL (Ⲭ² = 3.35, p = .046) improved significantly across the three time points (T0-T1-T2). The RMTI effectively enhanced MMSE-K scores, reduced communication difficulties, and enhanced the QoL in older adults with SCD. This program shows promise for broader implementation in community settings for older adults with SCD.

Interethnic Validation of an ECG Image Analysis Software for Detecting Left Ventricular Dysfunction in Emergency Department Population.

We previously developed and validated an AI-based ECG analysis tool (ECG Buddy) in a Korean population. This study aims to validate its performance in a U.S. population, specifically assessing its left ventricular (LV) Dysfunction Score and left ventricular ejection fraction (LVEF)-ECG feature for predicting LVEF <40%, using N-Terminal Pro-B-Type Natriuretic Peptide (NT-ProBNP) as a comparator. We identified emergency department (ED) visits from the MIMIC-IV dataset with information on LVEF <40% or ≥40%, along with matched 12-lead ECG data recorded within 48 hours of the ED visit. The performance of ECG Buddy's LV Dysfunction Score and LVEF-ECG feature was compared with NT-ProBNP using Receiver Operating Characteristic - Area Under the Curve (ROCAUC) analysis. A total of 22,599 ED visits were analyzed. The LV Dysfunction Score had an AUC of 0.905 (95% CI: 0.899 - 0.910), with a sensitivity of 85.4% and specificity of 80.8%. The LVEF-ECG feature had an AUC of 0.908 (95% CI: 0.902 - 0.913), sensitivity 83.5%, and specificity 83.0%. NT-ProBNP had an AUC of 0.740 (95% CI: 0.727 - 0.752), with a sensitivity of 74.8% and specificity of 62.0%. The ECG-based predictors demonstrated superior diagnostic performance compared to NT-ProBNP (all p<0.001). In the Sinus Rhythm subgroup, the LV Dysfunction Score achieved an AUC of 0.913, and LVEF-ECG had an AUC of 0.917, both outperforming NT-ProBNP (0.748, 95% CI: 0.732 - 0.763, all p<0.001). ECG Buddy demonstrated superior accuracy compared to NT-ProBNP in predicting LV systolic dysfunction, validating its utility in a U.S. ED population.

Metabolic Dysfunction-Associated Steatotic Liver Disease in the Korean General Population: Epidemiology, Risk Factors, and Non-Invasive Screening.

Background/Objectives: Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a contemporary classification of liver disease linked to metabolic dysfunction. It is recognized as the main form of chronic liver disease and significantly contributes to liver-related morbidity and mortality rates. The epidemiology of MASLD is affected by ethnic background, sex, age, and environmental factors. South Korea is one of the countries that has experienced rapid urbanization. Geographical differences also play a crucial role in the prevalence and progression of the disease. Consequently, it is essential to investigate the prevalence of MASLD; its associated risk factors, particularly in relation to liver fibrosis; and the effectiveness of non-invasive screening techniques within the Korean population. Methods: This review describes the prevalence of MASLD, the risk factors related to MASLD with liver fibrosis, and the non-invasive screening approaches suitable for the Korean general population. Results: This review underscores the rising incidence and implications of MASLD in South Korea. Notably, among younger demographics, there is a swift increase in both the prevalence of MASLD and its associated risk factors, indicating that MASLD is poised to become a significant public health concern. Non-invasive testing methods are increasingly utilized within at-risk groups to determine the presence of advanced fibrosis. Conclusions: Addressing these complex liver diseases necessitates not only ongoing monitoring of MASLD epidemiological patterns but also a unified approach to care that integrates medical interventions with lifestyle changes.

서울시 가구구조 변화와 노인 돌봄서비스 수요 예측 분석

With rapid population aging, the demand for care services is increasing. This study aims to estimate future care needs of older adults in Seoul and provide baseline data for policy planning. Using panel data from the 2015-2021 Korean Population and Housing Census, this study constructed a transition matrix of household types among older adults and projected future changes in household structures by sex and age. Data from the Korean Longitudinal Study of Aging (KLoSA) were then used to estimate the probabilities of utilizing different types of care services, applying a multinomial logit model based on the sex, age, and household type of individuals aged 65 and older. Finally, future demand for care services was projected using a cell-based approach that combines the projected older population by sex, age, and household type with their corresponding probabilities of care use. Results show that total care demand will nearly double by 2036 compared to 2021, with a particularly sharp increase among men aged 75 and older using formal care. These findings suggest the need to consider both demographic and household structure changes in developing care service policies for older adults in Seoul.

Weight fluctuation and incidence of end-stage renal disease in Korea: a nationwide cohort study

Background: The impact of weight or weight changes on kidney function remains a matter of debate. This study aimed to investigate the association between weight fluctuation and the incidence of end-stage renal disease (ESRD) using data from the Korean National Health Insurance Corporation health checkups (2009–2015).Methods: The study included 2,310,667 participants (1,546,749 men and 763,918 women), aged ≥40 years. Weight fluctuation was assessed using the average real variability (ARV) of weight and categorized into quartiles (Q1–Q4). Hazard ratios (HRs) and 95% confidence intervals for ESRD incidence were calculated using multivariable Cox proportional hazards models.Results: After adjustment for comorbidities, increased body mass index was associated with a decreased HR for ESRD. The highest quartile of weight variability (ARV Q4) demonstrated a higher probability and HR for ESRD compared to the lower variability quartiles (Q1–Q3). Among men, individuals with sustained weight, and those with weight gain, the ARV Q4 group showed significantly increased HRs for ESRD (HR of 1.372, 1.222, and 1.49, respectively). Furthermore, irrespective of changes in creatinine levels, all ARV Q4 groups exhibited increased HRs for ESRD (HR of 1.342, 1.472, and 1.299, respectively).Conclusions: High weight fluctuation (ARV Q4) was associated with an increased incidence of ESRD in the general Korean population, with notable significance in men and in groups with sustained or increased weight. Clinically, individuals in the ARV Q4 category should be considered at risk for ESRD, and early interventions should be pursued for this population.

Coronary vasomotor response incidence to intracoronary acetylcholine provocation test according to the severity of insignificant coronary artery stenosis in Korean population.

Coronary artery spasm (CAS) is a cause of variant angina. However, the understanding of CAS patterns in the presence of mild-to-moderate coronary artery stenosis is limited. This study aimed to evaluate the incidence and patterns of CAS in patients with insignificant coronary artery stenosis using intracoronary acetylcholine (ACH) provocation test. In this study, 6513 patients without significant coronary artery stenosis who underwent intracoronary ACH provocation test were enrolled. Patients were divided into three groups, based on the severity of coronary artery stenosis: the non group (stenosis <30%, n = 2833), the mild group (30-49%, n = 3278) and the moderate group (50-69%, n = 402). Vasomotor responses were observed among three different groups. The baseline characteristics of the patients in the mild and moderate groups were worse than in the non group. They were older, had higher prevalence of hypertension, diabetes, dyslipidemia, and smoking habit. During the ACH test, CAS was observed in 58.1% of the overall population. The mild group (60.1%) and the moderate group (60.9%) showed a higher incidence than the non group (55.3%, P < 0.001). In addition, among cases of CAS, the mild group (3.2%) and the moderate group (8.5%) responded more at a lowest dose of ACH than the non group (3.1%, P < 0.001). In patients with chest pain without significant coronary artery stenosis, CAS was observed in over half of the cases. Furthermore, CAS was found to be more frequent and more susceptible in patients with mild-to-moderate coronary artery stenosis compared with those without fixed stenosis.

Single-Nucleotide Polymorphisms of BRCA1 and BRCA2 and Risk of Papillary Thyroid Carcinoma.

Background/Objectives: We sought to evaluate the association between the risk of papillary thyroid carcinoma (PTC) and single-nucleotide polymorphisms (SNPs) of breast cancer genes 1 (BRCA1) and 2 (BRCA2). Methods: We prospectively recruited 515 cases with PTC and 296 controls without cancer. The genotypes of five BRCA1 SNPs (rs8176318, rs1799966, rs799917, rs16940, rs1799949) and three BRCA2 SNPs (rs15869, rs1799943, rs1799955) were determined using the TaqMan assay. We evaluated the association of haplotypes with the risk of PTC due to linkage disequilibrium (LD). Results: The five BRCA1 SNPs were significantly associated with the risk of PTC. The AC genotype of rs8176318 (OR = 0.69, p = 0.02) and the CT and CC genotypes of rs1799966 (OR = 0.70, p = 0.02 and OR = 0.67, p = 0.01, respectively) were associated with a decreased risk of PTC. The AG genotype of rs16940 (OR = 0.67, p = 0.01) and the AG genotypes of rs799917 and rs1799949 (both OR = 0.70, p = 0.02) decreased the risk of PTC. Haplotype 1 [rs8176318(C)-rs1799966(T)-rs799917(G)-rs16940(A)-rs1799949(G)] ± (OR = 0.69, p = 0.02) and haplotype 2 [rs8176318(A)-rs1799966(C)-rs799917(A)-rs16940(G)-rs1799949(A)] ± (OR = 0.71, p = 0.03) of BRCA1 reduced the risk of PTC. Conclusions: Our findings suggest that the polymorphisms of BRCA1 may contribute to the susceptibility to PTC in the Korean population.

Longitudinal association between kidney and lung function in the Korean general population.

Longitudinal association between kidney and lung function in the Korean general population.