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.

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.

Early countermeasures to COVID-19 at long-term care facilities in Gwangju Metropolitan City, Republic of Korea.

OBJECTIVES: The coronavirus disease 2019 (COVID-19) pandemic has continued since its first detection in the Republic of Korea on January 20, 2020. This study describes the early countermeasures used to minimize the risk of COVID-19 outbreaks during cohort quarantine and compares the epidemiological characteristics of 2 outbreaks in long-term care facilities (LTCFs) in Gwangju Metropolitan City in summer 2020. METHODS: An epidemiological investigation was conducted via direct visits. We investigated epidemiological characteristics, including incidence, morbidity, and mortality rates, for all residents and staff members. Demographic characteristics were analyzed using a statistical program. Additionally, the method of managing infection in LTCFs is described. RESULTS: Residents and caregivers had high incidence rates in LTCF-A and LTCF-B, respectively. LTCF-B had a longer quarantine period than LTCF-A. The attack rate was 20.02% in LTCF-A and 27.9% in LTCF-B. The mortality rate was 2.3% (1/43) in LTCF-B, the only facility in which a COVID-19 death occurred. CONCLUSIONS: Extensive management requires contact minimization, which involves testing all contacts to mitigate further transmission in the early stages of LTCF outbreaks. The findings of this study can help inform and prepare public health authorities for COVID-19 outbreaks, particularly for early control in vulnerable facilities.

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.

Factors Associated with COVID-19 Vaccine Hesitancy in Korea.

COVID-19 vaccine hesitancy will likely increase in the unvaccinated general population because of several vaccine safety issues that arose during priority vaccination. To investigate the potential rate of COVID-19 vaccine hesitancy in the unvaccinated population and evaluate factors that affect the attitude towards vaccine acceptance, a cross-sectional survey was performed. A telephone survey was conducted in 1,357 people older than 18 years; 99 were excluded from the analysis because they had already been vaccinated (n=58) or hesitated (n=41) after an official call. The COVID-19 vaccine hesitancy rate was 21.9% and was highest among those aged under 30 years (33.4%) and lowest among those aged 65 years and over (8.7%). Age, occupation, and perceived confidence in vaccine safety and efficacy were associated with vaccine hesitancy. These findings suggest that public health authorities should strengthen the spread of correct information, especially in the younger population, to increase vaccination rates.

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.

Comparing the nutritional status of children and adolescents from North Korean defector families and South Korean families.

OBJECTIVE: This study aimed to investigate the nutritional status of children and adolescents from North Korean defector (NKD) families who are currently living in South Korea (SK) and compared with the status of those from SK families. DESIGN: A cross-sectional study comparing the prevalence of malnutrition, overweight and obesity between children and adolescents from NKD families and SK families. SETTING: Children and adolescents from NKD families were interviewed face-to-face directly, whereas the data about those from SK families acquired by using 2017 Korea National Health and Nutrition Examination Survey. Their nutritional status were estimated using the 2017 Korean National Growth Charts for children and adolescents. PARTICIPANTS: The total number of children and adolescents was 2136 consisting of 527 subjects from the NKD families and 1609 subjects from the SK families. RESULTS: The overall prevalence of stunting, wasting, underweight, overweight and obesity in NKD group was 8.9%, 10.2%, 10.4%, 11.2% and 12.2% respectively, and 1.9%, 7.1%, 5.9%, 9.2% and 9.3%, respectively, in SK families. The NKD group showed significantly higher prevalence than SK group in stunting (p<0.001), wasting (p=0.014), underweight (p<0.001), obesity (p=0.041) but not in overweight. CONCLUSIONS: The nutritional status of children and adolescents form NKD families was worse than that of those from SK families, and also higher prevalence of obesity.

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.

Low muscle mass is associated with osteoporosis: A nationwide population-based study.

OBJECTIVES: To assess the association between low muscle mass and osteoporosis in the Korean general population. METHODS: We analyzed 14,429 participants (6,261 men and 8,168 women) from the 2009-2011 Korean National Health and Nutrition Examination Survey (KNHANES) aged 20 years or more. MAIN OUTCOME MEASURE: The association of low muscle mass with osteoporosis was investigated using multivariate logistic regression models that included age, marital status, residence, current smoking, monthly drinking, physical activities, strength exercise, comorbidity, and the use of dietary supplements, and in women postmenopausal status and experience of pregnancy. RESULTS: After adjusting for covariates, low muscle mass was significantly associated with osteoporosis in the lumbar spine and femoral neck in both men (lumbar spine: OR 1.73, 95 % CI 1.08-2.76; femoral neck: OR 3.39, 95 % CI 1.69-6.80) and women (lumbar spine: OR 1.52, 95 % CI 1.17-1.97; femoral neck: OR 2.09, 95 % CI 1.56-2.80). Also, the association between low muscle mass and osteoporosis was significant in men and women in every age group except for men aged 50-64 years. CONCLUSION: Low muscle mass was significantly associated with osteoporosis in both men and women for all age groups, except for men aged 50-64 years.

Low Muscle Mass Is Associated with Lower 25-Hydroxyvitamin D Level in All Age Groups of South Korean Adults: The 2009-2010 Korea National Health and Nutrition Examination Surveys (KNHANES).

Vitamin D plays pivotal role in bone mineral homeostasis. But the association of vitamin D with muscle mass remains obscure, especially among young adults. Therefore, we assessed the association between muscle mass and 25-hydroxyvitamin D (25[OH]D) in South Korean adults using data from the 2009-2010 Korean National Health and Nutrition Examination Survey (KNHANES). This study involved 12,324 (5,375 males and 6,949 females) participants in the 2009-2010 KNHANES aged 20 y or older. Appendicular skeletal muscle mass (ASM) was measured by dual X-ray absorptiometry. Low muscle mass was defined as an ASM divided by body mass index (BMI) (ASM [kg]÷BMI [kg/m2]) value of <0.789 in males and <0.512 in females. The vitamin D status was evaluated by assaying the serum 25(OH)D level. After adjustment for covariates, low muscle mass was significantly associated with lower 25(OH)D level (odds ratio [OR], 0.55; 95% confidence interval [CI], 0.40-0.75 for 10.0-19.9 ng/mL vs. <10.0 ng/mL; OR, 0.47; 95% CI, 0.33-0.68 for 20.0-29.9 ng/mL vs. <10.0 ng/mL; and OR, 0.39; 95% CI, 0.24-0.64 for ≥30.0 ng/mL vs. <10.0 ng/mL). Moreover, low muscle mass was significantly associated with lower 25(OH)D level in all age groups. In conclusion, low muscle mass was significantly associated with lower 25(OH)D level in South Korean adults in all age groups.

Relationship between Socioeconomic Status and Prevalent Prostate Cancer in the South Korea.

BACKGROUND: Prostate cancer prevalence recently has increased among male adults in South Korea. But, few study has evaluated the reason. Therefore, we investigated the relationship between socioeconomic status and prevalent prostate cancer. METHODS: This study enrolled 16,215 males aged 40 years and over who took part in the Korean National Health and Nutrition Examination Survey 2007-2016. In addition, we obtained the 2000-2016 age-standardized incidence rate and age-standardized mortality rate of prostate cancer from the Korean Statistical Information Service. RESULTS: After adjusting for other covariates, prevalent prostate cancer was significantly associated with monthly household income (OR 3.71, 95% confidence interval [CI] 1.48-9.30, for highest vs. lowest) and significantly associated with education level (OR 3.66, 95% CI 1.54-8.70, for ≥ 13 vs. ≤ 6). In the analysis of the age-standardized incidence rate and the age-standardized mortality rate, the age-standardized incidence rate has soared from 2000 to 2011 and then decreased gradually, but the age-standardized mortality rate did not change. CONCLUSION: In our results, prevalent prostate cancer increased significantly with socioeconomic status and the increase in prevalent prostate cancer may be attributable to earlier detection rather than to a real increase in prevalence.

The Relationship of Neutrophil-Lymphocyte Ratio and Platelet-Lymphocyte Ratio with Bone Mineral Density in Korean Postmenopausal Women.

The neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) are known to be markers of the systemic inflammatory response. However, the few studies that have been done on the relationship between the NLR and PLR and osteoporosis have yielded inconsistent results. Therefore, we assessed the relationship between the NLR and PLR and bone mineral density (BMD). This study was conducted with postmenopausal patients admitted to an orthopaedic hospital. Data including BMD, NLR, PLR and covariates were obtained from the subjects' medical records. In total, 407 postmenopausal patients were enrolled in this study. Analysis of covariance was performed to identify significant differences in BMD according to NLR and PLR. After adjusting for other covariates, a quartile of NLR was negatively associated with the mean value of lumbar BMD (p=0.040, p for trend=0.005) but not with the mean value of femur neck BMD. However, there were no significant associations among the PLR, the BMD of the lumbar and the femur neck. In conclusion, the quartile of NLR was negatively associated with the mean value of lumbar BMD in Korean postmenopausal patients.

Association of Sarcopenia with Metabolic Syndrome in Korean Population Using 2009-2010 Korea National Health and Nutrition Examination Survey.

Background: Some studies have investigated the relationship between sarcopenia and metabolic syndrome, and they have focused mainly on older subjects. Therefore, we assessed the association between sarcopenia and metabolic syndrome in South Korean adults 20 years of age or older using data from the 2009-2010 Korean National Health and Nutrition Examination Survey (KNHANES). Methods: This study involved 12,256 (5350 males and 6906 females) participants from the 2009-2010 KNHANES 20 years of age or older. Appendicular skeletal muscle mass (ASM) was measured by dual X-ray absorptiometry. Sarcopenia index (SI) was calculated as ASM/body mass index and sarcopenia was defined as an SI of <0.789 in males and <0.521 in females. Metabolic syndrome was defined by the presence of at least three of the following abnormalities: abdominal obesity, high blood pressure, high blood glucose level, high triglyceride level, and low high-density lipoprotein cholesterol level. Results: After adjustment for covariates, the association between sarcopenia and metabolic syndrome was significant (odds ratio [OR] 2.06, 95% confidence interval [CI] 1.74-2.45). In addition, when stratified by age groups, the significant associations between sarcopenia and metabolic syndrome remained in all age groups (20-39 years: OR 2.13, 95% CI 1.08-4.19; 40-64 years: OR 2.13, 95% CI 1.68-2.71; ≥65 years: OR 1.98, 95% CI 1.54-2.54). Conclusion: The association between sarcopenia and metabolic syndrome was significant in South Korean adults. Moreover, the significant associations were present in every age group evaluated.

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.

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.

Higher breast cancer prevalence associated with higher socioeconomic status in the South Korean population; Has it resulted from overdiagnosis?

Recently, breast cancer prevalence has increased in South Korea. In this study, we investigated the correlation between breast cancer prevalence and socioeconomic status. This study enrolled 27,331 people who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) IV-VI (2007-2015). In addition, we obtained data from the Korean Statistical Information Service (KSIS) on the breast cancer age-standardized incidence rate (AIR), the age-standardized mortality rate (AMR), the number of women screened, and the number of newly diagnosed patients. The KHANES data showed that breast cancer prevalence was significantly associated with educational level (odds ratio [OR], 2.02; 95% confidence interval [CI], 1.08-3.77 for 10-12 vs. ≤ 6 years of education, and OR, 2.36; 95% CI, 1.10-5.06 for ≥ 13 vs. ≤ 6 years of education). However, there was no significant association of breast cancer prevalence with monthly household income. In a separate analysis of the AIR, AMR, and number of women screened for breast cancer, the AIR increased with the number of women screened, whereas the AMR did not. Furthermore, the number of newly diagnosed patients in all age groups increased over time. The present results demonstrate that the recently increased breast cancer prevalence documented in South Korea may be attributable to earlier detection rather than to a real increase in prevalence, and that breast cancer may be overdiagnosed.

Parathyroid Hormone Levels Are Independently Associated with eGFR and Albuminuria: The Dong-gu Study.

Increased parathyroid hormone (PTH) was associated with cardiovascular mortality and morbidity in CKD patients. Our aim was to investigate the associations among estimated glomerular filtration rate (eGFR), albumin/creatinine ratio (ACR) and PTH independent of 25-hydroxyvitamin D (25(OH)D). This study included 9,162 individuals who completed the baseline survey of the Dong-gu Study, which was conducted in Korea from 2007 to 2010. The eGFR, ACR, PTH and 25(OH)D were measured in participants who met the detailed inclusion criteria. After being adjusting for covariates (sex, age, waist circumference, smoking, alcohol intake, physical activity, hypertension medications, diabetes medication, total cholesterol, triglyceride, HDL cholesterol) and log-ACR, the PTH value stratified by 25(OH)D level significantly decreased with increasing eGFR levels in each 25(OH)D stratum. Moreover, after adjustment for the same covariates and log-eGFR, the PTH value stratified by 25(OH)D level significantly increased with increasing ACR levels in each 25(OH)D stratum. In conclusion, the PTH values significantly decreased with increasing eGFR levels and increased with increasing ACR levels independently of 25(OH)D in an adult Korean population ≥50 y of age.

25-Hydroxyvitamin D Is Associated with Kidney Function: The Dong-gu Study.

Although the kidneys play a leading part in the biosynthesis of vitamin D, there is no consensus regarding the relationship of the vitamin D concentration with kidney function. Thus, we aimed to estimate the correlation among 25-hydroxyvitamin D (25(OH)D), estimated glomerular filtration rate (eGFR), and albumin/creatinine ratio (ACR) in participants aged ≥50 y in Korea. This study consisted of 9,166 people who participated in a basic survey of the Dong-gu Study. Following an overnight fast, the blood and urine sample were assessed. The serum 25(OH)D, eGFR, ACR of each subject were measured. When adjusting for covariates and log-transformed ACR (Model III), the lower eGFR value was significantly associated with increasing 25(OH)D levels (<10.0: 71.5[70.5-72.4]; 10.0-14.9: 70.0 [69.5-70.4]; 15.0-19.9: 68.7 [68.3-69.2]; ≥20.0: 67.4 [66.8-67.9] mL/min/1.73 m2, p<0.001). When adjusted for the same covariates and log-transformed eGFR (Model III), the lower ACR value was significantly associated with increasing 25(OH)D levels (<10.0: 57.4 [48.0-66.9]; 10.0-14.9: 40.8 [36.5-45.2]; 15.0-19.9: 34.0 [29.5-38.5]; ≥20.0: 34.3 [28.8-39.8] µg/mg creatinine, p<0.001). In conclusion, the mean values of eGFR were significantly decreased with increasing 25(OH)D levels independent of ACR. In additon, the mean values of ACR were significantly decreased with increasing 25(OH)D levels independent of eGFR in participants aged ≥50 y in Korea.