Korea Seroprevalence Study of Monitoring of SARS-COV-2 Antibody Retention and Transmission (K-SEROSMART): findings from national representative sample.

OBJECTIVES: We estimated the population prevalence of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including unreported infections, through a Korea Seroprevalence Study of Monitoring of SARS-CoV-2 Antibody Retention and Transmission (K-SEROSMART) in 258 communities throughout Korea. METHODS: In August 2022, a survey was conducted among 10,000 household members aged 5 years and older, in households selected through two stage probability random sampling. During face-to-face household interviews, participants self-reported their health status, COVID-19 diagnosis and vaccination history, and general characteristics. Subsequently, participants visited a community health center or medical clinic for blood sampling. Blood samples were analyzed for the presence of antibodies to spike proteins (anti-S) and antibodies to nucleocapsid proteins (anti-N) SARS-CoV-2 proteins using an electrochemiluminescence immunoassay. To estimate the population prevalence, the PROC SURVEYMEANS statistical procedure was employed, with weighting to reflect demographic data from July 2022. RESULTS: In total, 9,945 individuals from 5,041 households were surveyed across 258 communities, representing all basic local governments in Korea. The overall population-adjusted prevalence rates of anti-S and anti-N were 97.6% and 57.1%, respectively. Since the Korea Disease Control and Prevention Agency has reported a cumulative incidence of confirmed cases of 37.8% through July 31, 2022, the proportion of unreported infections among all COVID-19 infection was suggested to be 33.9%. CONCLUSIONS: The K-SEROSMART represents the first nationwide, community-based seroepidemiologic survey of COVID-19, confirming that most individuals possess antibodies to SARS-CoV-2 and that a significant number of unreported cases existed. Furthermore, this study lays the foundation for a surveillance system to continuously monitor transmission at the community level and the response to COVID-19.

Association Between Plasma Homocysteine Level and Mortality: A Mendelian Randomization Study.

BACKGROUND AND OBJECTIVES: In previous studies, high homocysteine levels were associated with high cardiovascular mortality. However, these results were inconsistent with those of randomized controlled trials. We aimed to evaluate the causal role of homocysteine on all-cause and cardiovascular mortality using Mendelian randomization (MR) analysis. METHODS: This study included the 10,005 participants in the Namwon Study. In conventional observational analysis, age, sex, survey years, lifestyles, body mass index, comorbidities, and serum folate level were adjusted using multivariate Cox proportional regression. MR using 2-stage least squares regression was used to evaluate the association between genetically predicted plasma homocysteine levels and mortality. Age, sex, and survey years were adjusted for each stage. The methylenetetrahydrofolate reductase (MTHFR) polymorphism was used as an instrumental variable for predicting plasma homocysteine levels. RESULTS: Observed homocysteine levels were positively associated with all-cause (hazard ratio [HR], 1.40; 95% confidence interval [CI], 1.26-1.54) and cardiovascular (HR, 1.62; 95% CI, 1.28-2.06) mortality when plasma homocysteine levels doubled. However, these associations were not significant in MR analysis. The HRs of doubling genetically predicted plasma homocysteine levels for all-cause and cardiovascular mortality were 0.99 (95% CI, 0.62-1.57) and 1.76 (95% CI, 0.54-5.77), respectively. CONCLUSIONS: This MR analysis did not support a causal role for elevated plasma homocysteine concentrations in premature deaths.

Effect Modification of Kidney Function on the Non-linear Association Between Serum Calcium Levels and Cardiovascular Mortality in Korean Adults.

OBJECTIVES: This study aimed to evaluate the potential interaction between kidney function and the non-linear association between serum calcium levels and cardiovascular disease (CVD) mortality. METHODS: This study included 8927 participants enrolled in the Dong-gu Study. Albumin-corrected calcium levels were used and categorized into 6 percentile categories: <2.5th, 2.5-25.0th, 25.0-50.0th, 50.0-75.0th, 75.0-97.5th, and >97.5th. Restricted cubic spline analysis was used to examine the non-linear association between calcium levels and CVD mortality. Cox proportional hazard regression was used to estimate hazard ratios (HRs) for CVD mortality according to serum calcium categories. All survival analyses were stratified by the estimated glomerular filtration rate. RESULTS: Over a follow-up period of 11.9±2.8 years, 1757 participants died, of whom 219 died from CVD. A U-shaped association between serum calcium and CVD mortality was found, and the association was more evident in the low kidney function group. Compared to the 25.0-50.0th percentile group for serum calcium levels, both low and high serum calcium tended to be associated with CVD mortality (<2.5th: HR, 6.23; 95% confidence interval [CI], 1.16 to 33.56; >97.5th: HR, 2.56; 95% CI, 0.76 to 8.66) in the low kidney function group. In the normal kidney function group, a similar association was found between serum calcium levels and CVD mortality (<2.5th: HR, 1.37; 95% CI, 0.58 to 3.27; >97.5th: HR, 1.65; 95% CI, 0.70 to 3.93). CONCLUSIONS: We found a non-linear association between serum calcium levels and CVD mortality, suggesting that calcium dyshomeostasis may contribute to CVD mortality, and kidney function may modify the association.

Association Between Serum Bilirubin and Atrial Fibrillation: A Mendelian Randomization Study.

BACKGROUND AND OBJECTIVES: The association between bilirubin and atrial fibrillation (AF) has been evaluated previously in observational studies but with contradictory results. This study evaluated the causal association between serum bilirubin level and AF using Mendelian randomization (MR) analysis. METHODS: This cross-sectional study includes 8,977 participants from the Dong-gu Study. In the observational analysis, multivariate logistic regression was performed to evaluate the association between bilirubin and prevalent AF. To evaluate the causal association between bilirubin and AF, MR analysis was conducted by using the UGT1A1 rs11891311 and rs4148323 polymorphisms as instrumental variables. RESULTS: Elevated serum bilirubin levels were associated with an increased risk for AF in observational analysis (total bilirubin: odds ratio [OR], 1.31; 95% confidence interval [95% CI], 1.15-1.48 per 1 standard deviation [SD]; direct bilirubin: OR, 1.31; 95% CI, 1.18-1.46 per 1 SD), whereas the genetically predicted serum bilirubin levels in MR analysis did not show this association (total bilirubin: OR, 1.02; 95% CI, 0.67-1.53 per 1 SD; direct bilirubin: OR, 1.03; 95% CI, 0.61-1.73 per 1 SD). CONCLUSIONS: Genetically predicted bilirubin levels were not associated with prevalent AF. Thus, the observational association between serum bilirubin levels and AF may be non-causal and affected by reverse causality or unmeasured confounding.

Association of liver fibrosis biomarkers with overall and CVD mortality in the Korean population: The Dong-gu study.

This study evaluated the associations of liver fibrosis biomarkers [non-alcoholic fatty liver disease fibrosis score (NFS), fibrosis-4 (FIB-4), aspartate aminotransferase/platelet ratio index (APRI), and BARD score] with mortality in Korean adults aged ≥50 years. We analyzed 7,702 subjects who participated in Dong-gu Study. The associations of liber fibrosis biomarkers with mortality were investigated using Cox proportional hazards models. Overall mortality increased with increasing NFS level [adjusted hazard ratio (aHR) 4.3, 95% confidence interval (CI) 3.3-5.5 for high risk vs. low risk], increasing FIB-4 level (aHR 3.5, 95% CI 2.9-4.4 for high risk vs. low risk), and increasing APRI level (aHR 3.5, 95% CI 2.1-5.8 for high risk vs. low risk) but not with BARD score. The Harrell's concordance index for overall mortality for the NFS and FIB-4 was greater than that for the APRI and BARD score. In conclusion, NFS, FIB-4, and APRI showed a significant relationship with the overall mortality, and NFS and FIB-4 showed a significant relationship with the CVD mortality after adjustment for covariates. In addition, the NFS and FIB-4 were more predictive of overall mortality than the APRI and BARD score in Korean adults aged ≥50 years.

Causal Association Between Alcohol Consumption and Atrial Fibrillation: A Mendelian Randomization Study.

BACKGROUND AND OBJECTIVES: Previous observational studies presented a positive association between alcohol and atrial fibrillation (AF). However, previous studies using genetic polymorphisms on the causal relationship between alcohol consumption and AF have reported conflicting results. This study aimed to evaluate the causality between alcohol consumption and AF using the aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism, which is the genetic variant with the most potent effect on drinking behavior. METHODS: A total of 8,964 participants from the Dong-gu Study were included in the present study. The causal association between alcohol consumption and AF was evaluated through a Mendelian randomization (MR) analysis using the ALDH2 rs671 polymorphism as an instrumental variable. RESULTS: No significant relationship between alcohol consumption and AF was found in the observational analysis. However, the genetic analysis using the ALDH2 polymorphism showed a significant association in men. In the MR analysis, genetically predicted daily alcohol consumption was positively related to AF. CONCLUSIONS: MR analysis revealed a significant association between the amount of alcohol consumption and AF, which suggests that the association may be causal.

Association between alcohol and bone mineral density in a Mendelian randomization study: the Dong-gu study.

INTRODUCTION: Many previous studies have reported a positive relationship between alcohol and bone mineral density (BMD). However, the causality between alcohol and BMD has not been fully evaluated. MATERIALS AND METHODS: This study enrolled 8892 participants from the Dong-gu study. Mendelian randomization (MR) using two-stage least-squared regression was used to evaluate the association between the genetically predicted amount of alcohol consumption per day and BMD. The aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism was used as instrumental variables for alcohol consumption. Age, smoking history, and BMI were adjusted in the multivariate model. RESULTS: Self-reported alcohol consumption was positively related to total hip and lumbar spine BMD in both sexes. In multivariate Mendelian randomization analysis, the genetically predicted amount of alcohol consumption was positively associated with both total hip and lumbar spine BMD in men. Total hip BMD and lumbar spine BMD increased by 0.004 g/cm2 (95% confidence interval [CI] 0.002-0.007) and 0.007 g/cm2 (95% CI 0.004-0.011) with doubling of alcohol consumption. However, in women, genetically predicted alcohol consumption was not significantly associated with BMD. CONCLUSION: In our MR study, genetically predicted alcohol consumption was positively associated with BMD in men. This result suggests that the association between alcohol consumption and BMD is causal.

Evaluating the spatial and temporal patterns of the severe fever thrombocytopenia syndrome in Republic of Korea.

Severe fever with thrombocytopenia syndrome (SFTS) is a new infectious disease with a high mortality rate and increased incidence in Republic of Korea since the first case was reported in 2013. The average mortality rate varies by region and year but remains high in Asia. This study aimed to evaluate the spatial and temporal patterns of SFTS cases reported to the national Disease Control and Prevention Agency (KDCA). We analysed the spatial and temporal distribution of SFTS and observed changes in areas vulnerable to the disease. We analysed data concerning 1086 confirmed SFTS patients from 2013 to 2019 categorized according to the 247 district level administrative units. To better understand the epidemiology of SFTS, we carried out spatiotemporal analyses on a yearly basis and also calculated and mapped spatial clusters of domestic SFTS by global (regional) and local Moran's indices. To observe the annual changes in SFTS incidence rate, scan statistics for each city and district were calculated. The incidence rate showed significant clustering in specific regions, which reoccurred annually in some regions. In Republic of Korea, SFTS clusters have been expanding into the southern regions, with annual clusters concentrated between May and October. This pattern allows prediction of SFTS occurrences through spatiotemporal analysis, which makes it possible to guide measures of disease prevention.

Associations of regional-level perceived stress and depression with health-related quality of life in Korean adults: a multilevel analysis of 2017 Korea Community Health Survey data.

OBJECTIVES: We examined the associations of individual and regional-level perceived stress and depression with health-related quality of life (HRQOL) in Korean adults. METHODS: We used data from the 2017 Korea Community Health Survey, which included 216,713 adults living within 254 municipal districts. As individual-level independent variables, perceived stress (higher vs. lower) and depression (Patient Health Questionnaire-9 ≥10) were defined. Regional-level age-adjusted rates of perceived stress (%) and depression (%) were created for 254 municipal districts and categorized into quartiles to generate regional levels of stress and depression. HRQOL was defined as the individual-level EuroQol 5-dimensional index×100. A multilevel analysis was performed to identify the relationship between individual or regional-level independent variables and individual HRQOL. RESULTS: In the null model, the proportions of individual variation in the HRQOL explained by region were 1.7% and 2.7% for men and women, respectively. When adjusted with all individual-level variables, regional stress and depression, as well as individual-level perceived stress and depression, were significantly related to HRQOL for both genders. In the full model including all variables, the decrease in HRQOL from the first to the fourth quartile group of regional stress was greater in women (-1.09; 95% confidence interval [CI], -1.87 to -0.31) than in men (-0.65; 95% CI, -1.04 to -0.26). CONCLUSIONS: Our results suggest that regional-level perceived stress and depression, as well as individual-level perceived stress and depression, are inversely associated with individual HRQOL.

Association between Alcohol Consumption and Serum Cortisol Levels: a Mendelian Randomization Study.

BACKGROUND: Several studies have reported conflicting results regarding the relationship between alcohol consumption and cortisol levels. However, the causality between alcohol consumption and cortisol levels has not been evaluated. METHODS: This study examined 8,922 participants from the Dong-gu Study. The aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism was used as an instrumental variable for alcohol consumption. The association between the genetically predicted alcohol consumption and cortisol level was evaluated with Mendelian randomization (MR) using two-stage least squares regression. RESULTS: Alcohol consumption was positively associated with the serum cortisol level in both sexes in the observational analysis. In the MR analysis, the genetically predicted alcohol consumption was positively related to the cortisol level in men, with cortisol levels increasing by 0.18 µg/dL per drink per day. However, there was no relationship in women in the MR analysis. CONCLUSION: The predicted alcohol consumption according to the ALDH2 rs671 polymorphism was positively related to the cortisol levels, suggesting a causal relationship between alcohol consumption and cortisol levels.

Factors Related to Regional Variation in the High-risk Drinking Rate in Korea: Using Quantile Regression.

OBJECTIVES: This study aimed to identify regional differences in the high-risk drinking rate among yearly alcohol users in Korea and to identify relevant regional factors for each quintile using quantile regression. METHODS: Data from 227 counties surveyed by the 2017 Korean Community Health Survey (KCHS) were analyzed. The analysis dataset included secondary data extracted from the Korean Statistical Information Service and data from the KCHS. To identify regional factors related to the high-risk drinking rate among yearly alcohol users, quantile regression was conducted by dividing the data into 10%, 30%, 50%, 70%, and 90% quantiles, and multiple linear regression was also performed. RESULTS: The current smoking rate, perceived stress rate, crude divorce rate, and financial independence rate, as well as one's social network, were related to the high-risk drinking rate among yearly alcohol users. The quantile regression revealed that the perceived stress rate was related to all quantiles except for the 90% quantile, and the financial independence rate was related to the 50% to 90% quantiles. The crude divorce rate was related to the high-risk drinking rate among yearly alcohol users in all quantiles. CONCLUSIONS: The findings of this study suggest that local health programs for high-risk drinking are needed in areas with high local stress and high crude divorce rates.

Cystatin C-based estimated GFR and albuminuria are independently associated with all-cause and CVD mortality in Korean population: The Dong-gu Study.

OBJECTIVE: To assess the associations among the estimated glomerular filtration rate (eGFR), albumin to creatinine ratio (ACR), and all-cause and CVD mortality rate and to compare the performances of eGFRMDRD, eGFRCKD-EPI, and eGFRcys using receiver operating characteristic (ROC) analysis in Korean adults aged ≥ 50 years. METHODS: Of the 9,260 subjects who participated in the baseline survey of a prospective longitudinal study conducted in Korea, 9,009 (men: 3,574 (39.7%); women: 5,435 (60.3%)) were included in this analysis after the exclusion of 217 subjects with missing eGFR and 34 subjects with missing ACR data. MAIN OUTCOME MEASURE: The associations of eGFR and ACR with all-cause and CVD mortality were investigated using Cox proportional hazards models that included sex, age, waist circumference, smoking, alcohol intake, degree of physical activity, hypertension, diabetes, systolic blood pressure, log-HbA1c, total cholesterol, log-triglyceride, log-HDL and log-ACR or eGFR. RESULTS: After adjustment for covariates, independent associations were found between all-cause mortality and the eGFRcys (mL/min per 1.73 m2) [HR 1.23, 95% confidence interval (CI) 1.05-1.43 for 60-89 vs. ≥ 90; HR 1.87, 95% CI 1.49-2.34 for 45-59 vs. ≥ 90; HR 2.38, 95% CI 1.77-3.20 for 30-44 vs. ≥ 90; HR 2.82, 95% CI 1.89-4.23 for <30 vs. ≥ 90] and ACR (µg/mg creatinine) [HR 1.09, 95% CI 0.88-1.34 for Q2 vs. Q1; HR 1.34, 95% CI 1.10-1.63 for Q3 vs. Q1; HR 1.49, 95% CI 1.22-1.81 for Q4 vs. Q1]. In addition, independent associations of CVD mortality with the eGFRcys and ACR were significant. In the comparison of eGFR performance, the ROC-plot AUC for all-cause mortality was significantly greater for the eGFRcys than for the eGFRMDRD and eGFRCKD-EPI. CONCLUSION: The eGFRcys and ACR were associated independently with all-cause and CVD mortality after adjustment for covariates, including the eGFRcys and ACR. In addition, the ROC-plot AUC for all-cause mortality was greater for the eGFRcys than for the eGFRMDRD and eGFRCKD-EPI in Korean adults aged ≥ 50 years.

Changes in poor self-rated health status among elderly Koreans over 10 years: Community Health Survey 2008-2017.

AIM: This study investigated the change in self-rated health (SRH) status among elderly Koreans and sought influential factors affecting SRH by reference to data collected during the Korean Community Health Survey 2008-2017. METHODS: We obtained raw data from the Korea Community Health Survey for 10 years (2008-2017), which included sociodemographic and health information on Koreans aged ≥65 years (242 552 men and 349 586 women). SRH was measured using the SRH scale and divided into not-poor and poor. Logistic regression analyses of poor SRH were performed using a weighted sampling method and interaction models (year × variables) to represent the entire Korean elderly population and estimate the changes in poor SRH over time. RESULTS: The proportion of elderly subjects in the population increased over 10 years. After adjusting for all confounding variables, the weighted adjusted odds ratios for poor SRH decreased consistently between 2008 and 2017 (men: 0.64, 95% confidence interval 0.50-0.81; women: 0.62, 0.46-0.83). The odds ratios for poor SRH were markedly higher in subjects who reported being stressed (men: 7.02, 5.89-8.38; women 6.14, 5.33-7.08) and those who lacked formal education (men: 2.42, 2.18-2.69; women 3.12, 2.59-3.75) over times. CONCLUSIONS: Despite the increase in the proportion of the elderly, poor SRH among elderly Koreans decreased over the past 10 years. Poor SRH was associated with high-level perceived stress and a lower educational level in both elderly men and women. Geriatr Gerontol Int 2020; 20: 1190-1195.

An unusual case of herpes simplex virus pneumonia with cavitary and necrotic changes.

Ground glass opacities, consolidation, and pleural effusions are observed in herpes simplex virus (HSV) pneumonia. Neither necrosis nor cavitation has been reported in areas of parenchymal disease. We describe a case of HSV pneumonia with unusual multiple cavitary and necrotic changes in an immunocompetent person. To our knowledge, this is the first reported case of HSV pneumonia with multiple cavitary and necrotic changes in areas of consolidation and nodules.

Effect Modification of Acetaldehyde Dehydrogenase 2 rs671 Polymorphism on the Association between Alcohol Intake and Blood Pressure: the Dong-gu Study.

BACKGROUND: Elevated blood pressure is a major preventable cause of cardiovascular diseases. Alcohol consumption is a well-known risk factor of elevated blood pressure. The aldehyde dehydrogenase 2 (ALDH2) polymorphism is common in Eastern Asians, and inactive ALDH2 genotypes are associated with both avoiding alcohol consumption and aldehyde accumulation. Therefore, this study assessed the associations between alcohol consumption and hypertension and blood pressure according to the ALDH2 genotypes. METHODS: This study consists of 8,526 participants in the Dong-gu Study. Multivariate logistic regression was used to calculate the odds ratio (OR) according to alcohol consumption after stratifying by gender and ALDH2 genotypes. Multivariate linear regression was performed to estimate the systolic blood pressure (SBP) and diastolic blood pressure (DBP) according to the amount of alcohol consumed. RESULTS: In men, alcohol consumption was positively associated with both SBP and DBP in active ALDH2 carriers, but not in inactive ALDH2 carriers. In active ALDH2 carriers, compared to non-drinkers, the OR of hypertension was 1.16 (95% confidence interval [CI], 0.91-1.49) for < 1 drink/day, and 1.44 (95% CI, 1.15-1.80) for ≥ 1 drink/day in men. With each 1 drink/day increase, SBP and DBP increased by 3 and 1 mmHg in men, respectively. There was no significant association between ALDH2 genotypes and hypertension and blood pressure in women. CONCLUSION: ALDH2 genotype modified the association between alcohol consumption and blood pressure in men. There was a positive relationship between alcohol consumption and blood pressure in active ALDH2 carriers, but no significant relationship in inactive ALDH2 carriers.

The Association between the Apolipoprotein E Gene Polymorphism and All-cause Mortality in the Korean Population.

BACKGROUND: Apolipoprotein E (APOE) gene polymorphism is associated with neurodegenerative and cardiovascular diseases. Although the effects of the gene differ by ethnic group, few studies have examined Asians. Therefore, the association between APOE polymorphism and mortality in Koreans was evaluated in this study. METHODS: This study population included participants from the Dong-gu and Namwon Studies. APOE genotypes were categorized as E2 (E2/E2 and E2/E3), E3 (E3/E3), and E4 (E3/E4 and E4/E4). Multivariate Cox proportional hazard models were constructed using the E3 allele as a reference. RESULTS: In the model adjusting for study site, age, gender, and lifestyle, the hazard ratio (HR) of mortality for those with the E4 allele was 1.08 (95% confidence interval [CI], 0.97-1.20), while that for those with the E2 allele was 0.84 (95% CI, 0.74-0.96). After adjusting for blood lipids to evaluate their mediating effects, the HRs of mortality for those with E4 and E2 alleles were 1.08 (95% CI, 0.97-1.20) and 0.80 (95% CI, 0.70-0.92), respectively. These associations were more evident in younger groups, with HRs of 0.70 (95% CI, 0.52-0.92) for the E2 allele and 1.25 (95% CI, 1.03-1.53) for the E4 allele. CONCLUSION: In two large population-based cohort studies, the E2 allele was associated with a lower risk of mortality compared with the E3 allele, whereas the E4 genotype was not associated with mortality in Koreans.

Association of Falls and Fear of Falling with Mortality in Korean Adults: The Dong-gu Study.

This study evaluated the association between falls and the fear of falling (FOF) with the risk of all-cause mortality in Korean adults. The study enrolled 4,386 subjects aged 50 years and over who participated in the Dong-gu Study. Falls in the past year were categorized as yes or no. Injurious falls were defined as falls that resulted in fractures, head injuries, sprains or strains, bruising or bleeding, or other unspecified injuries. FOF was classified as low or high. The associations of falls and fall-related characteristics with mortality were assessed using Cox proportional hazards models. The average follow-up was 7.8 years. During this period, 255 men and 146 women died. In a fully adjusted model, falls in the past year were not associated with an increased risk of all-cause mortality (hazard ratio [HR] 1.16, 95% confidence interval [CI] 0.85-1.58), but a history of injurious falls was associated with an increased risk of mortality (HR 1.36, 95% CI 1.04-1.79). Compared with subjects without a FOF, subjects who were moderately or very afraid of falling had a higher mortality rate (HR 1.26, 95% CI 0.97-1.63). In conclusion, injurious falls and a high FOF increased the risk of all-cause mortality in Koreans. This study suggests that injurious falls and FOF can predict mortality in the general population.

Case of both rivaroxaban- and dabigatran-induced leukocytoclastic vasculitis, during management of pulmonary thromboembolism.

Leukocytoclastic vasculitis is a disorder characterized by neutrophilic inflammation that is predominantly limited to the superficial cutaneous postcapillary venules. This condition may be idiopathic or may have a defined cause. Rivaroxaban and dabigatran have been widely used as warfarin alternatives, because of their efficacy and safety. In this case report, we describe a case of leukocytoclastic vasculitis induced by both rivaroxaban- and dabigatran-, which developed during the management of pulmonary thromboembolism.

Serum level vitamin D and parathyroid hormone, and mortality, with or without chronic kidney disease.

Levels of vitamin D and parathyroid hormone (PTH) are closely associated with renal function. We evaluated the associations among 25-hydroxyvitamin D (25OHD) levels, PTH levels, and mortality, and whether these associations varied by renal function. We used data from the Dong-gu Study, a population-based cohort in Korean adults. We analyzed the associations among intact PTH, 25OHD levels and mortality in 8580 participants. Hazard ratios (HRs) for mortality were calculated using Cox proportional hazards regression after adjusting for age, sex, month of sampling, lifestyle, and comorbidities. We also evaluated the effects of chronic kidney disease (CKD). A total of 860 deaths occurred during the follow-up period of 7.6 years. Compared to the first 25OHD quartile, the HRs of the second, third, and fourth quartiles were 0.96 [95% confidence interval (CI) 0.79-1.16], 0.84 (95% CI 0.68-1.02), and 0.71 (95% CI 0.57-0.89), respectively. The association between intact PTH levels and mortality varied by renal function, and was both nonlinear and significant only in subjects with CKD. Compared to the second intact PTH quartile in such subjects, the HRs for the first, third, and fourth quartiles were 1.61 (95% CI 0.92-2.81), 1.97 (95% CI 1.17-3.31), and 2.19 (95% CI 1.33-3.59), respectively. In conclusion, we demonstrated that low serum levels of 25OHD are associated with an increased risk of mortality. Serum levels of intact PTH are nonlinearly associated with mortality only in subjects with CKD, with the lowest risk for mortality being evident in the second quartile.

Asymptomatic Middle East Respiratory Syndrome coronavirus infection using a serologic survey in Korea.

OBJECTIVES: The rates of asymptomatic infection with Middle East Respiratory Syndrome (MERS) coronavirus vary. A serologic study was conducted to determine the asymptomatic MERS infection rate in healthcare workers and non-healthcare workers by exposure status. METHODS: Study participants were selected from contacts of MERS patients based on a priority system in 4 regions strongly affected by the 2015 MERS outbreak. A sero-epidemiological survey was performed in 1,610 contacts (average duration from exposure to test, 4.8 months), and the collected sera were tested using an enzyme-linked immunespecific assay (ELISA), immunofluorescence assay (IFA), and plaque reduction neutralization antibody test (PRNT). Among the 1,610 contacts, there were 7 ELISA-positive cases, of which 1 exhibited positive IFA and PRNT results. RESULTS: The asymptomatic infection rate was 0.060% (95% confidence interval, 0.002 to 0.346). The asymptomatic MERS case was a patient who had been hospitalized with patient zero on the same floor of the hospital at the same time. The case was quarantined at home for 2 weeks after discharge, and had underlying diseases, including hypertension, angina, and degenerative arthritis. CONCLUSIONS: The asymptomatic infection was acquired via healthcare-associated transmission. Thus, it is necessary to extend serologic studies to include inpatient contacts who have no symptoms.