High Prevalence of Vitamin D Deficiency in Pregnant Korean Women: The First Trimester and the Winter Season as Risk Factors for Vitamin D Deficiency

We investigated the vitamin D status of Korean women during pregnancy and assessed the effects of vitamin D deficiency on two pregnancy outcomes; preterm births and the births of small for gestational age. We measured the serum 25-hydroxyvitamin D levels in 220 pregnant Korean women who were recruited prospectively and compared these levels with those of 500 healthy non-pregnant women. We analyzed vitamin D status according to patient demographics, season, and obstetrical characteristics; moreover, we also assessed pregnancy outcomes. The overall prevalence of vitamin D deficiency(<20 ng/mL) in pregnant women and healthy non-pregnant women was 77.3% and 79.2%; respectively; and the prevalence of severe vitamin D deficiency (<10 ng/mL) was 28.6% and 7.2%; respectively (p < 0.05). Vitamin D deficiency was more prevalent in the winter (100%) than in the summer (45.5%) in pregnant Korean women. A higher risk of vitamin D deficiency was observed in the first trimester than in the third trimester (adjusted OR 4.3; p < 0.05). No significant association was observed between vitamin D deficiency and any of the pregnancy outcomes examined. Further research focusing on the long-term consequences of vitamin D deficiency during pregnancy in Korean women is warranted

Serum Concentrations of Trace Elements in Patients with Tuberculosis and Its Association with Treatment Outcome

Deficiencies in essential trace elements are associated with impaired immunity in tuberculosis infection. However, the trace element concentrations in the serum of Korean patients with tuberculosis have not yet been investigated. This study aimed to compare the serum trace element concentrations of Korean adult patients with tuberculosis with noninfected controls and to assess the impact of serum trace element concentration on clinical outcome after antituberculosis treatment. The serum concentrations of four trace elements in 141 consecutively recruited patients with tuberculosis and 79 controls were analyzed by inductively coupled plasma-mass spectrometry. Demographic characteristics were also analyzed. Serum cobalt and copper concentrations were significantly higher in patients with tuberculosis compared with controls, while zinc and selenium concentrations were significantly lower (p < 0.01). Moreover, serum selenium and zinc concentrations were positively correlated (ρ = 0.41, p < 0.05). A high serum copper concentration was associated with a worse clinical outcome, as assessed after one month of antituberculosis therapy. Specifically, culture-positive patients had higher serum copper concentrations than culture-negative patients (p < 0.05). Patients with tuberculosis had altered serum trace element concentrations. Further research is needed to elucidate the roles of individual trace elements and to determine their clinical impact on patients with tuberculosis

Intraindividual Changes in Rheumatoid Factor and Anti-Cyclic Citrullinated Peptide Antibody Tests in Korean Patients Visiting Local Clinics and Hospitals

Limited data are available on test utilization and intraindividual changes in rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (anti-CCP) in Korean patients that visit local clinics and hospitals. We retrospectively reviewed longitudinally measured RF and anti-CCP data in Korean patients to investigate the utilization and changes in test results through a laboratory information system. During the 10-year study period, 256,259 specimens were tested for RF. Among them, 32,567 (12.7%) specimens from 31,110 Korean adults had simultaneously measured anti-CCP results. Among them, 1110 (3.6%) subjects had follow-up test results. Among 351 patients with initial positive RF results, 290 (82.6%) had no qualitative change in RF from positive to negative values during follow-up. About 3.8% (29/759) of patients with initial negative results experienced qualitative changes in RF that were positive on follow-up. Among 182 patients with an anti-CCP-positive result at initial measurement, 174 (95.6%) had no qualitative change in anti-CCP from positive to negative or equivocal results during follow-up. About 0.5% (5/928) of patients with initial negative values experienced qualitative changes in anti-CCP to positive values on follow-up. The agreement of qualitative results between RF and anti-CCP was 80.8% (95% confidence interval 78.4–83.1%) at initial measurement and 80.6% (95% confidence interval 79.0–82.1%) overall. The results of this study can help inform utilization of RF and anti-CCP testing for Korean patients visiting local clinics and hospitals

A Prospective Study on Serum Methylmalonic Acid and Homocysteine in Pregnant Women

This study aimed to investigate serum methylmalonic acid (MMA) and homocysteine levels and to assess their effects on pregnancy and neonatal outcomes. Serum MMA and homocysteine levels in 278 pregnant Korean women, determined by liquid chromatography–tandem mass spectrometry in each trimester, were compared with those of previous studies in other ethnic groups. We investigated the association between MMA and homocysteine status with pregnancy and neonatal events: gestational diabetes, preeclampsia, gestational age at delivery, preterm birth, small for gestational age, neonatal birth weight, and congenital abnormalities. The median (range) MMA level was 0.142 (0.063–0.446) µmol/L and homocysteine level was 10.6 (4.4–38.0) µmol/L in pregnant women. MMA levels were significantly higher in the third trimester than during other trimesters (p < 0.05), while homocysteine levels were not. No significant association was observed between MMA or homocysteine levels and any of the maternal or neonatal outcomes examined. Future studies are needed to assess the associations among maternal serum concentrations of MMA and homocysteine, and maternal and neonatal outcomes

Alterations in Glomerular Filtration Rates Using Different Algorithms in the Korean Population Visiting Local Clinics and Hospitals

We retrospectively reviewed the estimated glomerular filtration rates (eGFR) calculated by three equations: (1) Modification of Diet in Renal Disease Study (MDRD), (2) Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) using serum creatinine in 2009 (CKD-EPI 2009), and (3) CKD-EPI suggested in 2021 (CKD-EPI 2021), in an adult Korean population visiting local clinics and hospitals for health check-ups between 2019 and 2021 to investigate the effect of changes in the prevalence of chronic kidney diseases using those equations. During the study period, serum creatinine tests were performed on 442,566 subjects (205,236 men and 237,330 women). The overall prevalence rates of decreased eGFR (2) at baseline measurement were as follows: 3.4% using MDRD, 2.8% using CKD-EPI 2009, and 2.1% using CKD-EPI 2021. The prevalence of decreased eGFR increased with age. Among 442,566 tests, specimens having simultaneously measured random urine dipstick tests for proteinuria represented 6.0% of the population, and the albumin-creatinine ratio (ACR) was 0.3%. The prevalence of specimens having both decreased eGFR and proteinuria was significantly different among equations (p 30 mg/g creatinine), while those based on CKD-EPI 2021 were about half of those based on MDRD and CKD-EPI 2009. Future studies are needed to clarify the clinical impact of the changes in the calculations for eGFR

Development and Validation of Multiple Equations for Low-Density Lipoprotein and Apolipoprotein B in Korean Patients Visiting Local Clinics and Hospitals

We investigated the utilization of apolipoprotein B (ApoB), an independent risk factor for cardiovascular disease, and developed and validated a translational equation for calculating low-density lipoprotein cholesterol (LDL-C) in the Korean population visiting local clinics and hospitals. Among a total of 469,520 data sets of the lipid profile panel (total cholesterol, triglycerides, and high-density lipoprotein cholesterols), 142,932 lipid test sets with data on LDL-C and/or ApoB were used for statistical analysis. Using linear regression analysis, we created ApoB percentile value-derived LDL-C equations in a creating set and validated them with previously reported equations (a total of 11 equations) in comparison to directly measured LDL-C using two independent validating sets. Among all lipid test sets, the simultaneously measured ApoB test only accounted for 2.0%, indicating its underutilization in Korea. The ApoB-derived equations, which were derived in this study and previous studies, showed an overall agreement of ≥94.3% for NCEP ATP III criteria. However, the accuracy of the equations varied among data sets of populations. Future studies are needed to validate translational equations for ApoB and LDL-C in different populations to clarify the clinical implications of these equations

Intraindividual Changes in Rheumatoid Factor and Anti-Cyclic Citrullinated Peptide Antibody Tests in Korean Patients Visiting Local Clinics and Hospitals

Limited data are available on test utilization and intraindividual changes in rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (anti-CCP) in Korean patients that visit local clinics and hospitals. We retrospectively reviewed longitudinally measured RF and anti-CCP data in Korean patients to investigate the utilization and changes in test results through a laboratory information system. During the 10-year study period, 256,259 specimens were tested for RF. Among them, 32,567 (12.7%) specimens from 31,110 Korean adults had simultaneously measured anti-CCP results. Among them, 1110 (3.6%) subjects had follow-up test results. Among 351 patients with initial positive RF results, 290 (82.6%) had no qualitative change in RF from positive to negative values during follow-up. About 3.8% (29/759) of patients with initial negative results experienced qualitative changes in RF that were positive on follow-up. Among 182 patients with an anti-CCP-positive result at initial measurement, 174 (95.6%) had no qualitative change in anti-CCP from positive to negative or equivocal results during follow-up. About 0.5% (5/928) of patients with initial negative values experienced qualitative changes in anti-CCP to positive values on follow-up. The agreement of qualitative results between RF and anti-CCP was 80.8% (95% confidence interval 78.4–83.1%) at initial measurement and 80.6% (95% confidence interval 79.0–82.1%) overall. The results of this study can help inform utilization of RF and anti-CCP testing for Korean patients visiting local clinics and hospitals

Lipoprotein(a) in the Korean Pediatric Population Visiting Local Clinics and Hospitals

In this paper we investigate serum lipoprotein(a), an independent risk factor for cardiovascular disease in the Korean pediatric population. Visiting local clinics and hospitals, 600 lipoprotein(a) tests were performed on 416 Korean children and adolescents (124 boys and 292 girls), with a median age of 11.1 years (interquartile range, IQR, 9.8–13.9). The median lipoprotein(a) level was 21.5 nmol/L (IQR, 8.2–51.7). Among the 416 patients, the 90th percentile value of the initial lipoprotein(a) measurement was 107.8 nmol/L. The proportion of patients with lipoprotein(a) ≥ 100 nmol/L was 11.3%. The lipoprotein(a) level and the proportion of patients with lipoprotein(a) ≥ 100 nmol/L were not significantly different among sex, or age group. Among the 416 patients, 122 (29.3%, 21 boys and 101 girls) underwent at least two follow-up lipoprotein(a) measurements. The median follow-up period was 6.7 months (IQR, 5.5–11.8). The median lipoprotein(a) level across the 122 patients was 25 nmol/L (IQR 10.0–72.0). Among those patients, seven (5.7%) experienced an increase in serum lipoprotein(a) to ≥100 nmol/L during follow-up measurements. Further studies are needed in the Korean pediatric population in order to clarify the clinical significance of this change long-term