Vitamin D Status and Reference Intervals Measured by Liquid Chromatography-Tandem Mass Spectrometry for the Early Adulthood to Geriatric Ages in a South Korean Population during 2017-2022.

This study aimed to describe the latest 25-hydroxyvitamin D (25(OH)D) status of the South Korean population aged ≥ 20 years using 25(OH)D concentrations measured by liquid chromatography-tandem mass spectrometry and to determine the factors associated with total 25(OH)D concentrations. This cross-sectional, retrospective study consecutively selected 119,335 subjects with a median age of 57 (20-101) years who underwent health checkups among 13 Korean cities during 2017-2022. The total 25(OH)D concentration was 54.

Changes in nonalcoholic fatty liver disease and M2BPGi due to lifestyle intervention in primary healthcare.

Background: A healthy lifestyle is the most important method for managing nonalcoholic fatty liver disease (NAFLD). Mac-2-binding protein glycosylated isomer (M2BPGi) has been suggested as a biomarker for NAFLD. This study aimed to determine the efficacy of personalized lifestyle interventions on NAFLD remission.

Reference intervals of cell population data parameters in Sysmex XN-Series and its patterns of changes from early adulthood to geriatric ages in South Korea.

Introduction: Cell population data (CPD) parameters may be putative biomarkers for the screening of various diseases including some infections and myelodysplastic syndrome. This study aimed to establish the age- and sex-specific reference intervals (RIs) for the CPD parameters in the Korean population.

Methods: The reference population for the RIs of CPD parameters comprised 124 856 subjects aged 20-99 years.

SARS-CoV-2 Antibody Response and Sustainability after a Third Dose of BNT162b2 in Healthcare Workers at Health Promotion Centers.

The aim of this study was to determine the antibody response and the sustainability of immunogenicity after a third dose of BNT162b2 (BNT) in homologous [ChAdOx1 (ChAd)/ChAd, BNT/BNT, and mRNA-1273 (Moderna)/Moderna] and heterologous (ChAd/BNT) vaccinations of two primary doses with different schemes. This prospective observational study recruited consenting healthcare workers from 16 health checkup centers in 13 Korean cities. Three-point blood tests were analyzed as the antibody response after the third vaccination: T3-1 (1 month after the third dose), T3-3 (3 months after the third dose), and T3-4-10 (4-10 months after the third dose).

Establishment and validation of reference intervals for tumor markers (AFP, CEA, CA19-9, CA15-3, CA125, PSA, HE4, Cyfra 21-1, and ProGRP) in primary care centers in Korea: A cross-sectional retrospective study.

Background And Aims: The reference interval (RI) for a tumor marker may vary between populations, detection systems, and the methods used to obtain their values. The aims of this study were to establish age- and sex-specific RIs for the following nine common tumor markers and to validate the established RIs in Korean adults: alpha fetoprotein (AFP), carcinoembryonic antigen (CEA), cancer antigen (CA) 19-9, CA15-3, CA125, Human epididymis protein 4 (HE4), total prostate specific antigen, cytokeratin fragment (Cyfra) 21-1, and progastrin-releasing peptide (ProGRP).

Methods: This cross-sectional study consecutively selected 214,159 individuals (aged 18-98 years) who underwent health checkups at 16 health-promotion centers in 13 Korean cities.

Chronic kidney disease in nonalcoholic fatty liver disease at primary healthcare centers in Korea.

Background: The prevalence rates of nonalcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD) are expected to increase with the rising trends in diabetes and obesity associated with aging populations. Considering the impacts of coexistent NAFLD and CKD on morbidity and mortality rates, screening strategies for groups at high-risk of CKD are needed in community-dwelling individuals with NAFLD. The aims of this study were to determine the prevalence and distribution of CKD in NAFLD, as well as the risk factors for CKD and the correlation with liver fibrosis in asymptomatic individuals with NAFLD at primary healthcare centers in Korea.

The usefulness of the estimated average glucose/fasting blood glucose ratio for pancreatic β-cell function assessment in hyperglycemia during health checkups.

Background: Type 2 diabetes (T2DM) is a disease marked by inadequate insulin secretion by pancreatic beta-cell function (BCF) failure and insulin resistance (IR). Assessing and managing the BCF and IR should be started early to prevent or delay the progression of the disease. The aim of this study was to determine the usefulness of the estimated average glucose (eAG)/fasting blood glucose (FBG) ratio for pancreatic BCF in hyperglycemia.

Antibody response after two doses of homologous or heterologous SARS-CoV-2 vaccines in healthcare workers at health promotion centers: A prospective observational study.

Assaying of anti-spike-protein receptor-binding domain (S-RBD) antibodies are used to aid evaluations of the immune statuses of individuals. The aim of this study was to determine the antibody response after two doses of homologous or heterologous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines and to identify the factors affecting this response among healthcare workers (HCWs) at health promotion centers. In this prospective observational study, 1095 consenting HCWs were recruited from 16 health checkup centers and were tested at T0 (day of first dose), T1-1 (1 month after first dose), T2-0 (day of second dose), T2-1 (1 month after second dose), and T2-3 (3 months after second dose).

The Reproducibility and Usefulness of Estimated Average Glucose for Hyperglycemia Management during Health Checkups: A Retrospective Cross-Sectional Study.

HbA1c reflects average glucose levels over 3 months, but it does not measure glycemic variability. This study aimed to determine the reproducibility and usefulness of HbA1c-derived estimated average glucose (eAG) and to analyze the factors associated with eAG during health checkups. This cross-sectional retrospective study consecutively selected subjects who had undergone health checkups at 16 health-promotion centers in 13 Korean cities in 2020.

Associations of complete blood count parameters with pancreatic beta-cell function and insulin resistance in prediabetes and type 2 diabetes mellitus.

Introduction: Previous studies found controversial associations of CBC parameters with pancreatic beta-cell function (BCF) and insulin resistance (IR). The aim of this was to determine the independent associations of CBC parameters with BCF and IR in prediabetes and type 2 diabetes mellitus (T2DM).

Methods: This study selected subjects who underwent health checkups at 16 health-promotion centers in 13 Korean cities during 2021.

Subclinical steatohepatitis and advanced liver fibrosis in health examinees with nonalcoholic fatty liver disease (NAFLD) in 10 South Korean cities: A retrospective cross-sectional study.

Background: Nonalcoholic steatohepatitis (NASH) has a risk of progressing to cirrhosis. The prevalence of NASH and its associated risk factors in community populations are relatively unknown. This study aimed to determine the prevalence of NASH and advanced liver fibrosis using magnetic resonance elastography (MRE), and determine those risk factors in health examinees with asymptomatic fatty liver.

Nationwide seroprevalence of antibodies to SARS-CoV-2 in asymptomatic population in South Korea: a cross-sectional study.

Objective: Asymptomatic active infection might be an important contributor to the COVID-19 outbreak. Serological tests can assess the extent of exposure and herd immunity to COVID-19 in general populations. This study aimed to estimate the nationwide seroprevalence of SARS-CoV-2 antibodies according to age, sex and clinical status in South Korea.

Prevalence of liver fibrosis and associated risk factors in the Korean general population: a retrospective cross-sectional study.

Objectives: The health burden of chronic liver disease is increasing worldwide. Its main histological consequence is liver fibrosis, and eventually cirrhosis. This process is rarely diagnosed at the pre-cirrhotic stage due to it being asymptomatic.

Reference interval and the role of soluble suppression of tumorigenicity 2 (sST2) in subclinical cardiac dysfunction at health checkups.

Background: Soluble ST2 (sST2) is known to predict adverse outcomes and death in individuals with established heart failure. However, the role of sST2 testing in the general population has not been established. The aims of this study were to determine the reference interval (RI) and the clinical utility of sST2 in subclinical cardiac dysfunction in general population.

Diagnostic performance of Mac-2 binding protein glycosylation isomer (M2BPGi) in screening liver fibrosis in health checkups.

Background: Mild-to-moderate fibrosis is rarely diagnosed because the disease is asymptomatic in the early stage. The serum level of Mac-2 binding protein glycosylation isomer (M2BPGi) has been found to increase with the severity of liver fibrosis. The aim of this study was to determine the diagnostic performance of M2BPGi in screening liver fibrosis using magnetic resonance elastography (MRE) as a reference standard and to compare it with using the aspartate aminotransferase-to-platelet ratio (APRI) and the Fibrosis-4 index (FIB-4) in health checkups.

Distribution of hemoglobin levels and prevalence of anemia according to sex, age group, and region in 13 Korean cities.

Introduction: The distribution of hemoglobin (Hb) levels and the prevalence of anemia are significant public health indicators. The aims of this study were to determine the distribution of Hb levels and the prevalence of anemia according to sex, age group, and region throughout Korea.

Methods: The study analyzed data on 1 159 298 subjects who received health checkups at 16 health-promotion centers in 13 Korean cities during 2018.

Subclinical Iron Deficiency in Non-Anemic Individuals: A Retrospective Analysis of Korean Health Examinees.

Objectives: Non-anemic individuals may have undetected subclinical iron deficiency (SID). The aims of this study were to determine the prevalence of SID and identify the associated factors for SID. In addition, the screening performance of red blood cell (RBC) indices for SID in health check-ups was assessed.

Plasma NT-proBNP levels associated with cardiac structural abnormalities in asymptomatic health examinees with preserved ejection fraction: a retrospective cross-sectional study.

Objectives: Stage B heart failure (HF) is defined as an asymptomatic abnormality of the heart structure or function. The circulating level of N-terminal pro-B-type natriuretic peptide (NT-proBNP) is elevated in symptomatic patients with left ventricular (LV) dysfunction caused by a structural or functional abnormality. This study investigated the association of the NT-proBNP level with echocardiography-detected cardiac structural or diastolic abnormalities in asymptomatic subjects with preserved LV systolic function (ejection fraction >50%).

Complete Blood Count Reference Intervals and Patterns of Changes Across Pediatric, Adult, and Geriatric Ages in Korea.

Background: Sampling a healthy reference population to generate reference intervals (RIs) for complete blood count (CBC) parameters is not common for pediatric and geriatric ages. We established age- and sex-specific RIs for CBC parameters across pediatric, adult, and geriatric ages using secondary data, evaluating patterns of changes in CBC parameters.

Methods: The reference population comprised 804,623 health examinees (66,611 aged 3-17 years; 564,280 aged 18-59 years; 173,732 aged 60-99 years), and, we excluded 22,766 examinees after outlier testing.

Evaluation of the LC-1000 Flow Cytometry Screening System for Cervical Cancer Screening in Routine Health Checkups.

Objective: This study evaluated the performance of a flow cytometry system (LC-1000) in screening cervical precancerous lesions at routine health checkups.

Study Design: In total, 928 health examinees were enrolled at 16 health promotion centers in 13 Korean cities between 2016 and 2017. All participants underwent liquid-based cervical cytology and flow cytometry testing to determine the cell proliferation index (CPIx).

Comparison of Traditional and Reverse Syphilis Screening Algorithms in Medical Health Checkups.

Background: The syphilis diagnostic algorithms applied in different countries vary significantly depending on the local syphilis epidemiology and other considerations, including the expected workload, the need for automation in the laboratory and budget factors. This study was performed to investigate the efficacy of traditional and reverse syphilis diagnostic algorithms during general health checkups.

Methods: In total, 1,000 blood specimens were obtained from 908 men and 92 women during their regular health checkups.

Human Papillomavirus Genotype Distribution Among 18,815 Women in 13 Korean Cities and Relationship With Cervical Cytology Findings.

Background: The prevalence and genotype distribution of Human papillomavirus (HPV) infection vary depending on geographical region and the immunity provided by vaccines. This study aimed to clarify the recent prevalence and genotype distribution of HPV according to age and cervical cytology findings in Korea.

Methods: This study included 18,815 health examinees that underwent cervical cytology and HPV genotyping tests at 16 centers of Korean Association of Health Promotion in 13 cities in Korea, between January 2014 and October 2015.

Comparison of Urine Albumin-to-Creatinine Ratio (ACR) Between ACR Strip Test and Quantitative Test in Prediabetes and Diabetes.

Background: Albuminuria is generally known as a sensitive marker of renal and cardiovascular dysfunction. It can be used to help predict the occurrence of nephropathy and cardiovascular disorders in diabetes. Individuals with prediabetes have a tendency to develop macrovascular and microvascular pathology, resulting in an increased risk of retinopathy, cardiovascular diseases, and chronic renal diseases.

Comparing Results of Five Glomerular Filtration Rate-Estimating Equations in the Korean General Population: MDRD Study, Revised Lund-Malmö, and Three CKD-EPI Equations.

Background: Estimated glomerular filtration rate (eGFR) is a widely used index of kidney function. Recently, new formulas such as the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations or the Lund-Malmö equation were introduced for assessing eGFR. We compared them with the Modification of Diet in Renal Disease (MDRD) Study equation in the Korean adult population.