Association between Vitamin D Status and Risk of Peripheral Arterial Disease: The Dong-gu Study.

Low levels of vitamin D have been associated with increased cardiovascular disease risk. However, few studies have evaluated the association between vitamin D status and peripheral arterial disease (PAD). We therefore aimed to investigate whether low 25-hydroxyvitamin D (25(OH)D) levels were associated with increased risk of PAD in the Korean population. This cross-sectional study was conducted among 8,960 subjects aged 50 years or older without known myocardial infarction or stroke. PAD was defined by an ankle brachial blood pressure index <0.9. Multivariate logistic regression was used to evaluate the association between serum 25(OH)D levels and risk of PAD. Of the 8,960 subjects, 3.0% had PAD and the age and sex adjusted prevalence of PAD decreased with the increasing 25(OH)D quartile. After adjusting for potential confounders and parathyroid hormones, serum 25(OH)D levels were associated with a significantly decreased risk of PAD (OR for one SD increase, 0.98; 95% CI, 0.95-1.0, P for trend=0.040). Compared with the first 25(OH)D quartile, the odds of PAD were 0.86 (95% CI, 0.62-1.21), 0.67 (95% CI, 0.46-0.97), and 0.71 (95% CI, 0.49-1.04) for the second, third, and fourth quartiles, respectively. In this cross-sectional study, we found that low serum 25(OH)D levels were associated with an increased risk of PAD, independent of traditional cardiovascular risk factors and parathyroid hormone. Our findings suggest that low vitamin D levels may contribute to PAD in the Korean population.

25-Hydroxyvitamin D and Parathyroid Hormone Levels Are Independently Associated with the Hemoglobin A1c Level of Korean Type 2 Diabetic Patients: The Dong-Gu Study.

In type 2 diabetic patients, the relationships between 25-hydroxyvitamin D and parathyroid hormone levels, and glycemic control, remain unclear. We evaluated associations between 25-hydroxyvitamin D, parathyroid hormone, and hemoglobin A1c levels after adjusting for other covariates, including log transformed 25-hydroxyvitamin D levels and log transformed parathyroid hormone levels, in Korean patients with type 2 diabetes. In total, 1,175 patients with type 2 diabetes were selected from 8,857 individuals who completed the baseline survey of the Dong-gu study, conducted in Korea from 2007 to 2010. After adjusting for other covariates, we found that the mean hemoglobin A1c level was inversely associated with the 25-hydroxyvitamin D level (Q1: 7.47% [7.30-7.63], Q2: 7.25% [7.09-7.40], Q3: 7.17% [7.02-7.32], Q4: 7.19% [7.02-7.35]; p for trend = 0.021, p for between groups = 0.050) and the parathyroid hormone level (Q1: 7.35% [7.19-7.51], Q2: 7.34% [7.19-7.50], Q3: 7.28% [7.13-7.43], Q4: 7.09% [6.94-7.24]; p for trend = 0.022, p for between groups = 0.048). However, the mean fasting glucose level was not associated with either the 25-hydroxyvitamin D or parathyroid hormone level. In conclusion, inverse associations were evident between hemoglobin A1c, 25-hydroxyvitamin D and parathyroid hormone levels in Korean patients with type 2 diabetes. The associations remained significant after adjusting for other covariates, including the log transformed 25-hydroxyvitamin D levels and log transformed parathyroid hormone levels.

Effects of combination therapy of statin and N-acetylcysteine for the prevention of contrast-induced nephropathy in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention.

BACKGROUND: Acute myocardial infarction (AMI) is a risk factor for contrast-induced nephropathy (CIN). We investigated whether pretreatment with statin, N-acetylcysteine (NAC) and sodium bicarbonate (NaHCO3) reduces the risk of CIN. METHODS: We conducted a prospective trial and enrolled a total of 334 ST-segment elevation myocardial infarction (STEMI) patients. Patients were divided into four groups: Group I (statin 40mg), Group II (statin 80mg), Group III (statin 80mg plus NAC 1200mg) and Group IV (regimen of group III plus NaHCO3 154mEq/L). CIN was defined as ≥25% or ≥0.5mg/dL increase in serum creatinine from the baseline within the 72h after PCI. RESULTS: CIN occurred in 72 (21.6%) patients. The incidence of CIN was the lowest in the group III (14.3%), and multivariate analysis showed the lower incidence of CIN in group III compared to Group I [odds ratio (OR) 0.29, 95% confidence interval (CI) 0.13-0.64, p=0.002]. Admission hyperglycemia [(AHG)>198mg/dL] (OR 2.20, 95% Cl 1.20-3.68, p=0.011) and the use of intra-aortic balloon pump (IABP) (OR 4.20, 95% CI 1.38-12.78, p=0.016) were independent predictors for CIN. The CIN (OR 9.00, 95% CI 1.30-62.06, p=0.026) was an independent predictor for in-hospital mortality. CONCLUSIONS: Combination of high-dose statin plus NAC was associated with lower incidence of CIN in patients with STEMI who underwent primary PCI compared to statin only.

Association of APOE Genotype with Bone Mineral Density in Men and Women: The Dong-gu and Namwon Studies.

Many studies have investigated relationships between APOE genotype and bone mineral density (BMD). However, the results of these studies have been inconsistent. Few studies have been carried out in Asian populations. We studied the relationship of the APOE gene polymorphism and BMD in two large population-based studies. The datasets included the Dong-gu Study (3575 men and 5335 women) and the Namwon Study (2310 men, 3512 women). Lumbar spine and femoral neck BMD were measured by dual-energy X-ray absorptiometry. APOE genotypes were analyzed by polymerase chain reaction-restriction fragment length polymorphism. The APOE genotypes were classified into APOE E2 (E2/E2 and E2/E3), APOE E3 (E3/E3), and APOE E4 (E3/E4 and E4/E4). The genotype distribution of the study population was in Hardy-Weinberg equilibrium. There were no significant differences among APOE genotype groups in lumbar and femoral neck BMD in either cohort. Our data do not support the hypothesis that the APOE genotype is associated with BMD.

HbA1c is significantly associated with arterial stiffness but not with carotid atherosclerosis in a community-based population without type 2 diabetes: The Dong-gu study.

OBJECTIVES: We examined the associations between HbA1c levels and various atherosclerotic vascular parameters among adults without diabetes from the general population. METHODS: A total of 6500 community-dwelling adults, who were free of type 2 diabetes and ≥50 years of age, were included. High-resolution B-mode ultrasound was used to evaluate carotid artery structure, including intima-media thickness (IMT), plaque, and luminal diameter. Brachial-ankle pulse wave velocity (baPWV), which is a useful indicator of systemic arterial stiffness, was determined using an automatic waveform analysis device. RESULTS: No significant associations were observed between HbA1c, carotid IMT, plaque, or luminal diameter in a fully adjusted model. However, the odds ratio (95% confidence interval) for high baPWV (defined as the highest quartile) increased by 1.43 (1.19-1.71) per 1% HbA1c increase after adjusting for conventional risk factors in a multivariate logistic regression analysis. In addition, HbA1c was independently associated with baPWV in a multivariate linear regression analysis. CONCLUSIONS: High-normal HbA1c level was independently associated with arterial stiffness, but not with carotid atherosclerotic parameters, in the general population without diabetes. Our results suggest that the functional atherosclerotic process may already be accelerated according to HbA1c level, even at a level below the diagnostic threshold for diabetes.

The association between vitamin D and parathyroid hormone and bone mineral density: the Dong-gu Study.

The primary objective of the present study was to investigate the relationship between 25-hydroxyvitamin D (25[OH]D) and areal bone mineral density (aBMD) in Korean subjects from the general population aged ≥50 years. This study included 8,857 individuals who completed the baseline survey of the Dong-gu study, which was conducted in Korea from 2007-2010. The participants who fulfilled the detailed inclusion criteria underwent assessment of the femoral neck and lumbar spine aBMD as well as measurement of serum 25(OH)D and parathyroid hormone (PTH) levels. After adjusting for other covariates and log-PTH values, the mean aBMD of the femoral neck exhibited a significant increase with increasing 25(OH)D levels in both males (p < 0.001) and females (p = 0.005). Additionally, the mean aBMD of the lumbar spine exhibited a significant increase with increasing 25(OH)D levels in males (p = 0.011) but not females (p = 0.252). After adjusting for covariates and log-25(OH)D values, the mean aBMD values of the femoral neck and lumbar spine showed significant decreases with increasing PTH levels in both males and females (p < 0.001). The present findings demonstrate that the aBMD of the femoral neck was significantly associated with 25(OH)D levels independent of PTH in both males and females and that the aBMD of the lumbar spine was significantly associated with 25(OH)D levels independent of PTH in males, but not females.

APOE Polymorphism Is Associated with C-reactive Protein Levels but Not with White Blood Cell Count: Dong-gu Study and Namwon Study.

We evaluated the association of the APOE polymorphism with serum C-reactive protein levels and white blood cell count in two large population-based studies in Korean. The datasets included the Dong-gu study (n = 8,893) and the Namwon Study (n = 10,032). APOE genotypes were identified by polymerase chain reaction-restriction fragment length polymorphism. Multivariable linear regression analysis was performed to evaluate the relationship of APOE genotypes with C-reactive protein levels and white blood cell count with adjustments for age, sex, body mass index, smoking, diabetes, hypertension, and serum lipids. In the multivariate model, carriers of E3E4 or E4E4 genotype had significantly lower C-reactive protein levels compared with carriers of E3E3 genotype group (0.50 mg/L vs. 0.67 mg/L; 0.37 mg/L vs. 0.67 mg/L, respectively, for the Dong-gu Study and 0.47 mg/L vs. 0.66 mg/L; 0.45 mg/L vs. 0.66 mg/L, respectively, for the Namwon Study). However, there was no difference in white blood cell count among APOE genotypes. We found that the APOE E4 allele is associated with lower C-reactive protein levels, but not white blood cell count. Our results suggest that APOE genotype may influence C-reactive protein levels through non-inflammatory pathway.

[Students' perception of the educational environment of medical schools in Korea: findings from a nationwide survey].

PURPOSE: The purpose of this study was to examine students' perception of the educational environment of medical schools in Korea. METHODS: A total of 9,096 of 12,035 students (75.6%) responded to our questionnaire. This study was conducted at the end of the 2013 academic year using the Dundee Ready Education Environment Measure (DREEM) at 40 medical schools in Korea. DREEM comprises five domains: students' perceptions of learning (SPL); students' perceptions of teachers (SPT); students' academic self-perceptions; students' perceptions of atmosphere; and students' social self-perception. The data were analyzed using descriptive statistics, independent t-test, and one-way analysis of variance. RESULTS: The overall mean DREEM score was 113.97 (of 200), and the scores for the 40 medical schools ranged from 100.24 to 134.32. The overall mean and domains scores of the DREEM differed significantly between educational systems, grades, genders, and academic achievement levels. Graduate-level medical students had higher scores for the DREEM and its five domains than undergraduate medical students. The scores were lowest in second-year students (mean, 111.80). Male students' perceptions were significantly higher than those of female students except for SPL and SPT. High academic achievers' perceptions were also greater versus low academic achievers. CONCLUSION: Students' perceptions of their educational environment are positive in Korea. The learning environment should be evaluated by curriculum planners and administrators of medical schools to improve its quality.

Estimation of the cutoff value of vitamin D: the Dong-gu study.

BACKGROUND: Vitamin D plays an essential role in bone health and growth, but the optimal serum 25-hydroxyvitamin D (25(OH)D) concentration is not known. This study was performed to investigate the optimal 25(OH)D concentration in regard to parathyroid hormone (PTH) concentration in the Korean general population aged 50 years or older. FINDINGS: The study population consisted of 8,857 subjects (3,545 men and 5,312 women) who participated in the baseline survey of the Dong-gu study, conducted in Korea between 2007 and 2010. Serum 25(OH)D and PTH concentrations were measured by chemiluminescent microparticle immunoassay. The optimal 25(OH)D concentration was estimated by using nonlinear regression model. Our data show that PTH concentration reached a theoretical plateau at 38.2 pg/ml and corresponding 25(OH)D concentration was 21.1 ng/ml in men and PTH concentration at 42.9 pg/ml and 25(OH)D concentration at 13.8 ng/ml in women. CONCLUSIONS: These results indicate that, for Korean general population aged 50 years or older, the optimal 25(OH)D concentration is 21.1 ng/ml in men and 13.8 ng/ml in women.

Household and area income levels are associated with smoking status in the Korean adult population.

BACKGROUND: Some previous studies have suggested that area-level characteristics have effects on smoking. The aim of this study was to evaluate the associations between household income and area income on smoking in Korean adults. METHODS: This study was based on the Korean Community Health Survey (KCHS) performed in South Korea, between September and November 2009. In total, 222,242 subjects (103,124 men and 119,118 women) were included in the analysis. Information on smoking status was collected using a standardized questionnaire. Income status was determined by monthly household income. Household income was categorized as: <1 million won; <2 million won; <3 million won; and ≥3 million won. Area-level income categorized as quartiles. Data were analyzed using multilevel regression models. The analysis was conducted separately urban and rural, by sex. RESULTS: The lowest household income group had a higher risk of smoking than the highest household income group in both urban and rural areas for both men and women after adjusting for individual characteristics (urban men: odds ration [OR], 1.44; 95% confidence interval [CI], 1.36-1.53; rural men: OR, 1.33; 95% CI, 1.25-1.42; urban women: OR, 2.38; 95% CI, 2.06-2.76; rural women: OR, 1.51; 95% CI, 1.25-1.83). In men, the lowest area-level income group had a higher risk for smoking than the highest area-level income group in urban areas after adjusting for individual characteristics and household income (OR, 1.17; 95% CI, 1.02-1.33). In women, the lowest area-level income group had a lower risk for smoking than the highest area-level income group in rural areas after adjusting for individual characteristics and household income (OR, 0.52; 95% CI, 0.39-0.70). However, no association was observed between area-level income and smoking in rural areas for men or in urban areas for women. CONCLUSIONS: The results showed that smoking is strongly associated with household income status in both men and women, and area-level income is partly associated with smoking. Effects of area-level income on smoking differed by sex and region. These findings suggest that area characteristics have contextual effects on health related behavior independent of individual characteristics.

Erratum: correction of prevalence of falls by sex in article 'risk factors for falls in older korean adults: the 2011 community health survey'.

[This corrects the article on p. 1482 in vol. 29, PMID: 25408578.].

Risk factors for falls in older Korean adults: the 2011 Community Health Survey.

Falls are a major health problem for elderly populations worldwide. We analyzed data from the 2011 Korean Community Health Survey to identify potential risk factors for falls in a representative population-based sample of community-dwelling older Korean adults. Risk factors for falls were assessed by multivariate survey logistic regression models. The prevalence of falls was 16.9% in males and 24.3% in females [Corrected]. Age and female sex were associated with a higher risk of falls. Similarly, living alone, living in an urban area, poor self-rated health, and high stress were associated with a high risk of falls. Subjects with diabetes mellitus, stroke, osteoarthritis, osteoporosis, urinary incontinence, cataracts, or depression had a high risk of falls. However, subjects with hypertension were at low risk for falls. In conclusion, age, female sex, marital status, residence location, self-rated health, stress, and several chronic conditions were significantly associated with the risk for falls in the older Korean adults. Our findings suggest that these risk factors should be addressed in public health policies for preventing falls.

Association between Apolipoprotein E Polymorphism and Chronic Kidney Disease in the Korean General Population: Dong-gu Study.

BACKGROUND: Few studies have investigated the association between Apolipoprotein E (APOE) polymorphisms and chronic kidney disease (CKD) in the general population, and their results are inconsistent. METHODS: The current study population was composed of 9,033 subjects aged ≥ 50 years who participated in the baseline survey of the Dong-gu Study, which was conducted in Korea between 2007 and 2010. APOE polymorphisms were identified by polymerase chain reaction, and the estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease equation. RESULTS: Individuals with the APOE E2 allele had significantly lower total and low density lipoprotein cholesterol levels, those with the APOE E4 allele had lower high density lipoprotein (HDL) cholesterol levels, and those with the APOE E3 allele had lower log-triglyceride levels. Adjusting for covariates (sex, age, body mass index, smoking, systolic blood pressure, hypertension, diabetes, total cholesterol, HDL cholesterol, log-transformed triglycerides, and log-transformed albumin to creatinine ratio), mean eGFR was not significantly different among APOE alleles (E2, 69.4 mL/min/1.73 m(2); E3, 69.5 mL/min/1.73 m(2); E4, 69.4 ml/min/1.73 m(2); P = 0.873). Additionally, the odds ratios (ORs) indicated that APOE polymorphisms were not independent risk factors for CKD (OR, 1.07; 95% confidence interval [CI], 0.91 to 1.26 for the E2 vs. E3 allele; OR, 1.01; 95% CI, 0.88 to 1.16 for the E4 vs. E3 allele). CONCLUSION: APOE polymorphisms were not associated with either eGFR or CKD in the general Korean population.

Sex-related differences in the association between waist circumference and bone mineral density in a Korean population.

BACKGROUND: Large waist circumference is linked to poor health. Investigations of the relationship between waist circumference, as an index of abdominal fat, and bone mineral density (BMD) have yielded inconsistent results. We investigated the association between abdominal obesity measured using waist circumference and BMD in a large-scale population-based study. METHODS: We enrolled 8981 Korean (3592 males and 5389 females) community-dwelling individuals aged ≥50 years from 2007 to 2010. BMD was measured using dual-energy X-ray absorptiometry at lumbar spine and femoral neck skeletal sites. A multiple linear regression analysis was used to evaluate the relationship between waist circumference quartiles and BMD after adjusting for age, height, weight, and regular exercise. RESULTS: The adjustment for age, height, weight, and regular exercise revealed a negative linear association between quartile of waist circumference and BMD at the femoral neck and lumbar spine sites in males and females. Waist circumference was more strongly correlated with BMD in males than in females. Although the correlations were slightly attenuated following further adjustment for percent body fat, they remained statistically significant. CONCLUSIONS: Our results revealed that waist circumference is independently and inversely associated with BMD after adjusting for age, weight, height, regular exercise and percent body fat, suggesting that waist circumference is a potential predictor of osteoporosis in middle-aged and older Korean males and females.

The association of socioeconomic status with three-year clinical outcomes in patients with acute myocardial infarction who underwent percutaneous coronary intervention.

The aim of this study was to evaluate whether the clinical outcomes were associated with socioeconomic status (SES) in patients with acute myocardial infarction (AMI) who underwent percutaneous coronary intervention (PCI). The author analyzed 2,358 patients (64.9 ± 12.3 yr old, 71.5% male) hospitalized with AMI between November 2005 and June 2010. SES was measured by the self-reported education (years of schooling), the residential address (social deprivation index), and the national health insurance status (medical aid beneficiaries). Sequential multivariable modeling assessed the relationship of SES factors with 3-yr major adverse cardiovascular events (MACEs) and mortality after the adjustment for demographic and clinical factors. During the 3-yr follow-up, 630 (26.7%) MACEs and 322 (13.7%) all-cause deaths occurred in 2,358 patients. In multivariate Cox proportional hazards regression modeling, the only lower education of SES variables was associated with MACEs (hazard ratio [HR], 1.41; 95% confidence interval [CI], 1.04-1.91) and mortality (HR, 1.93; 95% CI, 1.16-3.20) in the patients with AMI who underwent PCI. The study results indicate that the lower education is a significant associated factor to increased poor clinical outcomes in patients with AMI who underwent PCI.

APOE polymorphism and carotid atherosclerosis in Korean population: the Dong-gu Study and the Namwon Study.

OBJECTIVE: We evaluated the association between APOE polymorphism and carotid atherosclerosis in two large independent cohorts from South Korea. METHODS: The datasets were from the Dong-gu Study (N = 9056) and the Namwon Study (N = 10,158). Carotid ultrasonography was performed to measure carotid intima-media thickness (IMT) and the presence of carotid plaques. The APOE polymorphism was determined by PCR-RFLP. We performed combined and separate analyses for the two datasets. RESULTS: In the combined analysis, individuals with E2E2 or E2E3 genotype had a lower common carotid IMT compared with individuals with E3E3 genotype (0.684 mm vs. 0.736 mm, p = 0.007; 0.718 mm vs. 0.736 mm, p < 0.001, respectively). This association was very slightly attenuated but remained statistically significant after adjustment for blood lipids (0.690 mm vs. 0.736 mm, p = 0.033; 0.725 mm vs. 0.736 mm, p = 0.005, respectively). Compared with individuals with E3E3 genotype, individuals with E2E3 genotype had lower risk for carotid plaque (odds ratio (OR) = 0.83, 95% confidence interval (CI) = 0.75-0.93), while individuals with E3E4 genotype had a higher risk for carotid plaque (OR = 1.09, 95% CI = 1.00-1.20). After adjustment for blood lipids, ORs of E2E3 genotype for carotid plaque was slightly attenuated but remained significant (OR = 0.87 95% CI = 0.78-0.97), while OR of E3E4 genotype were slightly attenuated and not significant (OR = 1.08, 95% CI, 0.99-1.18). CONCLUSIONS: We found that APOE polymorphism is associated with carotid atherosclerosis and this association was partly mediated through blood lipid. Our results suggest that APOE polymorphism may influence atherosclerosis through non-lipid pathways.

High prevalence of vitamin D deficiency in adults aged 50 years and older in Gwangju, Korea: the Dong-gu Study.

Vitamin D plays an important role in bone metabolism and maintaining bone health. Recently, new evidence has revealed that vitamin D affects chronic diseases such as autoimmune diseases, cardiovascular diseases and certain cancers. The aim of this study was to evaluate the vitamin D status and the prevalence of vitamin D deficiency in an urban Korean population. This study included 8,976 participants (3,587 men and 5,389 women) aged 50 yr and older. Serum 25(OH)D level was measured by chemiluminescent microparticle immunoassay. The prevalence of vitamin D deficiency [25(OH)D < 20 ng/mL] was 59.7% and 86.5% in men and women, respectively. The prevalence of vitamin D deficiency increased significantly with age in men, but not in women and it decreased from April to July, more prominently in men than in women. These results suggest that sun exposure, intake of vitamin D supplement, and regular physical activities is recommended in an urban Koreans, especially in women.

The perceptual differences in learning outcomes between education and achievement levels between faculty and students in medical schools.

PURPOSE: The purpose of this study was to compare the perception of learning outcomes between faculty and students in medical schools. METHODS: A total of 1,766 medical students and 436 faculty members participated in the survey. They responded to the perception of four learning outcomes: medical knowledge and problem solving, clinical skills, medical ethics, and clinical communication. The participants responded to the education and achievement levels of the learning outcomes. RESULTS: In all four learning outcomes, the student's perception of education level differed by educational system, and the students in mixed systems had the highest scores. Students differed significantly in achievement level of medical ethics between genders, wherein male students perceived their achievement level to be higher than females. Students perceived their achievement level to be lower than the education level. The students' clinical skills were the highest in the education and achievement levels. The faculty perceived the education level to be higher than the student's achievement level. In particular, the faculty's perception of education level of medical knowledge and problem solving was the highest, whereas the students' achievement level of it was lower. The faculty assessed the education level to be higher than students. The students showed higher perception of achievement level than faculty. CONCLUSION: There were perceptual differences in learning outcomes between students and faculty. The results of this study are expected to be used to design outcome-based learning methods.

Cohort Profile: The Namwon Study and the Dong-gu Study.

These two cohorts were designed to examine the increasing burden of chronic diseases among Korean populations. The studies investigated determinants for stroke, osteoporosis, dementia and cancer among middle-aged and elderly Korean populations. The Namwon Study baseline survey was performed between 2004 and 2007 (n = 10 667), and followed up 4 years later (n = 8157, follow-up rate = 76.5%). The baseline survey of the Dong-gu Study was administered over 2007-2010 (n = 9260), and will be followed up between 2014 and 2015. Questionnaires included assessment of cognitive function, psychiatric health and lifestyle factors. Clinical examinations, biochemical tests and genotyping focused on evaluating the determinants of target diseases and their intermediate phenotypes. Potential collaborators will be invited to contact the chief investigators.