Hong-Kyu Kim

Ulsan University Hospital, Urusan, Ulsan, South Korea

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Publications (30)80.19 Total impact

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    ABSTRACT: Purpose To determine whether C-reactive protein is associated with the type of coronary plaque seen at computed tomographic (CT) angiography. Materials and Methods The institutional review board approved this retrospective study, and the need for informed consent was waived. C-reactive protein levels were measured in 2653 asymptomatic subjects (mean age ± standard deviation, 54.7 years ± 9.2; 1811 men) who underwent self-referred coronary CT angiography as part of a general health checkup. The presence of coronary plaque, plaque type (calcified, mixed calcified, or noncalcified), stenosis degree, and number of involved segments were evaluated. Subjects with one type of plaque (calcified plaque, mixed plaque, and noncalcified plaque groups) and two or more types of plaque (multiple lesions group) were analyzed separately. Multivariate logistic regression analysis was used to evaluate the association between increasing C-reactive protein levels and plaque type. Results Coronary plaque was found in 1150 of the 2653 subjects (43.3%): calcified plaque (n = 604, 22.8%), mixed plaque (n = 67, 2.5%), noncalcified plaque (n = 208, 7.8%), and multiple lesions (n = 271, 10.2%). The C-reactive protein cutoff value of the fourth quartile was 1.2 mg/L (11.4 nmol/L), and all types of coronary plaque were increased in the higher quartile of the C-reactive protein levels. Multivariate logistic regression analysis showed that a higher C-reactive protein level was an independent predictor for the presence of noncalcified plaque (fourth vs first quartile group, odds ratio = 1.70, P = .025) and significant (50% and higher) coronary stenosis (odds ratio = 1.76, P = .020) after adjustment for traditional risk factors for coronary artery disease. Conclusion C-reactive protein is associated with noncalcified coronary arterial plaque, as seen at coronary CT angiography in asymptomatic patients after adjustment for traditional risk factors. © RSNA, 2014 Online supplemental material is available for this article.
    Radiology 04/2014; · 6.34 Impact Factor
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    ABSTRACT: Context: Although the prevalence of both metabolic syndrome (MetS) and fractures increases with advancing age, studies on possible associations between these conditions in men are limited and the results are inconsistent. Objective: To clarify the impact of MetS on male risk of incident fractures. Design and Setting: A large, longitudinal study with an average 3-year follow-up period. Participants: Korean men (n=16,078) aged 50 years or older who had undergone comprehensive routine health examinations. Main Outcome Measures: Incident fractures found after baseline examinations were identified using selected ICD-10 codes in the nationwide claims database of the Health Insurance Review and Assessment Service of Korea. Results: In total, 158 (1.0%) men developed incident fractures. The fracture event rates for subjects with and without MetS were 26.2 and 35.7 per 10,000 person-years, respectively. After adjustment for potential confounders, subjects with MetS had a much lower risk of incident fractures than subjects without MetS (HR = 0.662, 95% CI = 0.445-0.986). Furthermore, subjects with 3 and 4 or more MetS components had a 49.4% and 50.4% lower risk, respectively, of incident fractures compared to subjects without any MetS components. Importantly, additional adjustment for body mass index eliminated the statistical significance of these associations. Conclusion: Our current results indicate that the beneficial effects of MetS in reducing fracture risk could be explained by the general obesity that accompanies MetS, although other related factors, such as greater padding effect, peripheral aromatization or adipokine changes, may also contribute.
    The Journal of clinical endocrinology and metabolism 02/2014; · 6.50 Impact Factor
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    ABSTRACT: Background. The presence of common risk factors suggests that there is a relationship between osteoporosis and cardiovascular disease, possibly via dyslipidemia and inflammation. We investigated the relationships among the lipid profile, the inflammation marker high-sensitivity C-reactive protein (hsCRP), bone turnover markers, and bone mineral density (BMD) to assess the correlation between osteoporosis and cardiovascular disease and identify factors predicting osteoporosis. Methods. The study included 759 Korean women older than 20 years of age. The BMD, serum lipid profile, and levels of hsCRP, cross-linked C-terminal peptide (CTX), and osteocalcin were measured. We compared the serum biomarkers between groups with normal and low BMD and assessed the correlations between the levels of bone turnover markers and the lipid profile and hsCRP level. Results. The concentrations of CTX, osteocalcin, and total cholesterol were significantly higher in the low BMD group than in the normal BMD group in premenopausal women group. However, hsCRP was not correlated with these parameters. Multivariate logistic regression analysis revealed that TC (OR, 1.647; 95% CI, 1.190-2.279) and osteocalcin (OR, 1.044; 95% CI, 1.002-1.088) had an increased risk of low BMD in premenopausal women. Conclusions. These results indicate that total cholesterol concentration is correlated with the levels of bone turnover markers, suggesting that it might predict osteoporosis in premenopausal women.
    BioMed Research International 01/2014; 2014:398397. · 2.88 Impact Factor
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    ABSTRACT: Oxidative stress has detrimental effects on bone metabolism, and gamma-glutamyl transferase (GGT) is known to play an important role in the generation of free radical species through the extra-cellular hydrolysis of glutathione, the main cellular antioxidant. We performed a large longitudinal study with an average follow-up period of 3 years to investigate the association between baseline serum GGT levels and the development of future osteoporotic fractures (OFs) in men. A total of 16,036 Korean men aged 50 years or older who had undergone comprehensive routine health examinations were enrolled. Incident fractures at osteoporosis-related sites (e.g., hip, spine, distal radius, and proximal humerus) that occurred after baseline examinations were identified from the nationwide claims database of the Health Insurance Review and Assessment Service of Korea using selected ICD-10 codes. Among the study subjects, 156 cases (1.0%) developed incident OFs during the study period. The event rate was 32.7 (95% CI = 28.0-38.3) per 10,000 person-years. Multivariable adjusted Cox proportional hazard analyses adjusted for age, body mass index, lifestyle factors, and medical and drug histories revealed that the hazard ratio per standard deviation increase of the baseline GGT levels for the development of incident fractures was 1.115 (95% CI = 1.011-1.230). These data provide the first epidemiological evidence, in support of previous in vitro and animal studies, of the harmful effects of GGT on bone metabolism, and indicate that the serum GGT level may be a useful biomarker of poor bone health outcomes in men.
    Endocrine Journal 12/2013; · 2.23 Impact Factor
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    ABSTRACT: Backgroud: Low serum vitamin D level has been associated with several autoimmune diseases, but its association with thyroid autoimmunity is unclear. We evaluated the association of serum vitamin D level with the prevalence of autoimmune thyroid disease (AITD). Methods: Our cross-sectional study included subjects who underwent routine health check-ups, which included assays of serum 25-hydroxy vitamin D3 (25(OH)D3) and anti-thyroid peroxidase antibody (TPO-Ab), as well as thyroid ultrasonography (US) between 2008 and 2012 at Asan Medical Center. We defined AITD according to the level of TPO-Ab and US findings. Results: Total 6,685 subjects (Male, 58%; Female, 42%) were enrolled for this study. Overall prevalence of TPO-Ab positivity and both TPO-Ab/US positivity were 10.1% (Male, 6.3%; Female, 15.3%) and 5.4% (Male, 2.3%; Female, 9.7%), respectively. In female subjects, mean serum 25(OH)D3 levels were significantly lower in TPO-Ab(+) (22.0 vs. 23.5 ng/mL, P=0.030), and TPO-Ab(+)/US(+) group (21.6 vs. 23.4 ng/mL, P=0.027) as compared with corresponding control group, respectively. According to the level of serum 25(OH)D3, the prevalence of TPO-Ab positivity (21.2%, 15.5% and 12.6% in deficient, insufficient, and sufficient group, respectively, P=0.001) and both TPO-Ab/US positivity (14.7%, 9.9% and 7.1% in deficient, insufficient, and sufficient group, respectively, P<0.001) was decreased in female subjects. Interestingly, this pattern was significant only in pre-menopausal women (P=0.003 and P<0.001, respectively), but not in post-menopausal women. Multivariate analysis indicated that the adjusted odds ratios (OR) for AITD among those in the 25(OH)D3-deficient (TPO-Ab(+); OR=1.95, P=0.001 and TPO-Ab(+)/US(+); OR=2.36, P<0.001), and -insufficient group (TPO-Ab(+); OR=1.31, P=0.043 and TPO-Ab(+)/US(+); OR=1.50, P=0.017) were significantly increased when compared with -sufficient group. Conclusions: The level of serum vitamin D was significantly lower in pre-menopausal women with AITD. Vitamin D deficiency and insufficiency were significantly associated with AITD in pre-menopausal women.
    Thyroid: official journal of the American Thyroid Association 12/2013; · 2.60 Impact Factor
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    ABSTRACT: Aims/IntroductionInsulin has been associated with the risk of colorectal cancer (CRC). However, few studies have evaluated the association between insulin and colorectal adenoma. We investigated the relationship between fasting serum insulin levels or homeostasis model assessment of insulin resistance (HOMA-IR) and colorectal adenoma. Materials and Methods We retrospectively enrolled 15,427 participants who underwent both fasting serum insulin measurement and colonoscopy for a routine health examination at Asan Medical Center from January 2007 to December 2008. Participants with a history of any cancer, previous colectomy or polypectomy, those taking antidiabetic medications, and inflammatory bowel disease, non-specific colitis, non-adenomatous polyps only or CRC on colonoscopic findings were excluded. Finally, 3,606 participants with histologically confirmed colorectal adenoma and 6,019 controls with no abnormal findings on colonoscopy were included. Participants were categorized into quartiles (Q) based on fasting serum insulin levels and HOMA-IR. ResultsFasting serum insulin and HOMA-IR were significantly higher in participants with colorectal adenomas compared with controls. Multivariate regression analysis adjusting for age, sex, smoking habits, drinking habits and family history of CRC showed that participants with higher quartiles of fasting serum insulin levels (odd ratio [OR] 1.17 for 2nd Q, 1.19 for 3rd Q, and 1.42 for 4th Q, P < 0.05) or HOMA-IR (OR 1.18 for 2nd Q and 1.45 for 4th Q, P < 0.05) showed significantly increased ORs of colorectal adenoma compared with the lowest quartiles. Conclusions These findings showed that increased serum insulin levels and insulin resistance were significantly associated with the presence of colorectal adenoma.
    Journal of Diabetes Investigation. 12/2013;
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    ABSTRACT: Bilirubin, a natural product of heme catabolism by heme oxygenase, one of key antioxidant enzymes, has been recognized as a substance with potent antioxidant and cytoprotective properties. Several studies have shown a significant negative relationship between serum bilirubin levels and the risk of metabolic disorders, including type 2 diabetes. However, longitudinal studies investigating the association of elevated serum bilirubin levels and type 2 diabetes are lacking. In the present study, we aimed to investigate the longitudinal effects of baseline serum bilirubin concentrations on the development of type 2 diabetes in healthy Korean men. This 4year retrospective longitudinal observational study was conducted at the Asan Medical Center, Seoul, Republic of Korea. The study population consisted of 5960 men without type 2 diabetes who underwent routine health examinations in 2007 (baseline) and 2011 (follow-up). Baseline serum bilirubin concentrations were determined by the vanadate oxidation method. During a 4year period, 409 incident cases of diabetes (6.9 %) were identified. Incident type 2 diabetes decreased across the baseline bilirubin quartile categories (P for trend <0.001). In multivariable-adjusted model, the relative risk (RR) for the development of type 2 diabetes was significantly lower in the highest (i.e., 1.30-2.00mg/dl) than in the lowest bilirubin quartile category (i.e., ≤0.90mg/dl), even after adjustment for confounding variables (RR=0.69, 95% confidence interval 0.48-0.99, P for trend=0.041). The results indicate that serum total bilirubin level may provide additional information for predicting future development of type 2 diabetes in healthy subjects.
    Metabolism: clinical and experimental 10/2013; · 3.10 Impact Factor
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    ABSTRACT: Despite the noninvasiveness and accuracy of multidetector computed tomography (MDCT), its use as a routine screening tool for occult coronary atherosclerosis is unclear. We investigated whether the ratio of apolipoprotein B (apoB) to apolipoprotein A1 (apoA1), an indicator of the balance between atherogenic and atheroprotective cholesterol transport could predict occult coronary atherosclerosis detected by MDCT. We collected the data of 1,401 subjects (877 men and 524 women) who participated in a routine health screening examination of Asan Medical Center. Significant coronary artery stenosis defined as > 50% stenosis was detected in 114 subjects (8.1%). An increase in apoB/A1 quartiles was associated with increased percentages of subjects with significant coronary stenosis and noncalcified plaques (NCAP). After adjustment for confounding variables, each 0.1 increase in serum apoB/A1 was significantly associated with increased odds ratios (ORs) for coronary stenosis and NCAP of 1.23 and 1.18, respectively. The optimal apoB/A1 ratio cut off value for MDCT detection of significant coronary stenosis was 0.58, which had a sensitivity of 70.2% and a specificity of 48.2% (area under the curve, 0.61; 95% CI, 0.58-0.63, P < 0.001). Our results indicate that apoB/A1 ratio is a good indicator of occult coronary atherosclerosis detected by coronary MDCT.
    Journal of Korean medical science 05/2013; 28(5):709-16. · 0.84 Impact Factor
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    ABSTRACT: OBJECTIVE: Obesity is a well known risk factor for many cancers, including those of the esophagus, colon, kidney, breast, and skin. However, there are few reports on the relationship between obesity and thyroid cancer. We conducted this study to determine whether obesity is a risk factor for thyroid cancer by systematically screening a selected population by ultrasonography. DESIGN AND METHODS: We obtained data from 15,068 subjects that underwent a routine health checkup from 2007 to 2008 at the Health Screening and Promotion Center of Asan Medical Center. Thyroid ultrasonography was included in the checkup, and suspicious nodules were examined by ultrasonography-guided aspiration. Those with a prior history of thyroid disease or family history of thyroid cancer were excluded from this study. RESULTS: In total 15,068 subjects, 8,491 men and 6,577 women were screened by thyroid ultrasonography. Fine needle aspiration (FNA) cytology was performed in 1,427 of these patients based on predefined criteria and thyroid cancer was diagnosed in 267 patients. The prevalence of thyroid cancer in women associated with a high body mass index (BMI, per 5kg/m2 increase) (odds ratios [OR]= 1.63, 95% CI 1.24-2.10, p<0.001), after adjustment of age, smoking status, and thyroid-stimulation hormone (TSH) levels. There was no positive correlation between the prevalence of thyroid cancer in men and a high BMI (OR=1.16, 95% CI 0.85-1.57, p=0.336). There was no association between age, fasting serum insulin, or basal TSH levels and thyroid cancer in both genders. CONCLUSIONS: Obesity was associated with a higher prevalence of thyroid cancer in women when evaluated in routine health checkup setting. This association between risk factor and disease was unrelated to serum insulin and TSH levels. Additional studies are needed to understand the mechanism(s) behind the association of obesity with thyroid cancer risk.
    European Journal of Endocrinology 03/2013; · 3.14 Impact Factor
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    ABSTRACT: Bilirubin is known to have a physiologic role as an antioxidant that efficiently scavenges peroxyl radicals and suppresses oxidation, and oxidative stress has detrimental effects on bone metabolism. In the present study, we performed a 3-year longitudinal study of healthy middle-aged men, investigating the association between serum total bilirubin concentrations and annualized changes in bone mineral density (BMD). The study enrolled a total of 917 Korean men aged 40 years or older who had undergone comprehensive routine health examinations with an average follow-up interval of 3 years. BMD at proximal femur sites was measured with dual-energy X-ray absorptiometry using the same equipment at baseline and follow-up. The overall mean annualized rates of bone loss at the total femur, femoral neck, and trochanter were -0.25 %/year, -0.34 %/year, and -0.44 %/year, respectively. After adjustment for potential confounders, the rates of bone loss at all proximal femur sites were significantly attenuated in a dose-response fashion across increasing bilirubin concentrations (P = 0.006-0.046). Moreover, compared to subjects in the lowest bilirubin quartile category, those in the highest bilirubin quartile category showed significantly less bone loss at all proximal femur sites after adjustment for confounding factors (P = 0.010-0.048). This study provides the first clinical evidence that serum total bilirubin could be a protective marker against future bone loss, especially in subjects without liver diseases.
    Calcified Tissue International 02/2013; · 2.50 Impact Factor
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    ABSTRACT: Elevated ferritin concentration has been implicated in the etiology of type 2 diabetes. Accumulating evidence, mostly from studies conducted on western populations, has demonstrated a strong association between the elevated ferritin concentrations and incident type 2 diabetes. In Asian populations, however, the longitudinal studies investigating the association of elevated serum ferritin levels and type 2 diabetes are lacking. In present study, we aimed to determine whether elevated serum ferritin levels are related to the incident type 2 diabetes in healthy Korean men. This 4 year longitudinal observational study was conducted at the Asan Medical Center, Seoul, Republic of Korea. The study population consisted of 2,029 men without type 2 diabetes who underwent routine health examination in 2007 (baseline) and 2011 (follow-up). Baseline serum ferritin concentrations were measured by chemiluminescent two-site sandwich immunoassay. In multiple-adjusted model, the relative risk (RR) for incident type 2 diabetes was significantly higher in highest compared with the lowest ferritin quartile category, even after adjusting for confounding variables including homeostasis model assessment of insulin resistance (RR = 2.17, 95% confidence interval 1.27-3.72, P for trend = 0.013). These results demonstrated that elevated level of serum ferritin at baseline was associated with incident type 2 diabetes in an Asian population.
    PLoS ONE 01/2013; 8(9):e75250. · 3.73 Impact Factor
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    ABSTRACT: INTRODUCTION: Despite extensive evidence demonstrating the direct, detrimental role of homocysteine on bone metabolism, the effects of serum total homocysteine (tHcy) on bone loss are still equivocal. In the present study, we performed a longitudinal study on healthy participants of various ages of both sexes in order to investigate the association between serum tHcy concentrations and annualized changes in bone mineral density (BMD). METHODS: A total of 460 Koreans≥30years of age received comprehensive, routine health examinations for an average period of 3years. The BMD at proximal femur sites was measured with dual-energy X-ray absorptiometry using the same equipment at baseline and follow-up. RESULTS: After adjusting for potential confounders, the rates of bone loss at the proximal femur sites were significantly accelerated in a dose-response fashion across increasing tHcy concentrations in premenopausal women and men, but not in postmenopausal women. Consistently, compared with subjects in the lowest tHcy quartile, premenopausal women in the third and/or highest tHcy quartile and men in the highest tHcy quartile showed significantly higher rates of bone loss at all proximal femur sites (p=0.015-0.048) and at the total femur and femur neck (p=0.008-0.013), respectively. In contrast, there were no differences in terms of bone loss among the tHcy quartiles for postmenopausal women. CONCLUSION: These data provide the first clinical evidence that increased tHcy levels could be an independent risk factor for the future deterioration of bone mass in premenopausal women and men.
    Bone 09/2012; 52(1):56-62. · 3.82 Impact Factor
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    ABSTRACT: Despite extensive experimental and animal evidence about the detrimental effects of iron and its overload on bone metabolism, there have been no clinical studies relating iron stores to bone loss, especially in nonpathologic conditions. In the present study, we performed a large longitudinal study to evaluate serum ferritin concentrations in relation to annualized changes in bone mineral density (BMD) in healthy Koreans. A total of 1729 subjects (940 postmenopausal women and 789 middle-aged men) aged 40 years or older who had undergone comprehensive routine health examinations with an average 3 years of follow-up were enrolled. BMD in proximal femur sites (ie, the total femur, femur neck, and trochanter) was measured with dual-energy X-ray absorptiometry using the same equipment at baseline and follow-up. The mean age of women and men in this study was 55.8 ± 6.0 years and 55.5 ± 7.8 years, respectively, and serum ferritin levels were significantly higher in men than in women (p < 0.001). The overall mean annualized rates of bone loss in the total femur, femur neck, and trochanter were -1.14%/year, -1.17%/year, and -1.51%/year, respectively, in women, and -0.27%/year, -0.34%/year, and -0.41%/year, respectively, in men. After adjustment for potential confounders, the rates of bone loss in all proximal femur sites in both genders were significantly accelerated in a dose-response fashion across increasing ferritin quartile categories (p for trend = 0.043 to <0.001). Consistently, compared with subjects in the lowest ferritin quartile category, those in the third and/or highest ferritin quartile category showed significantly faster bone loss in the total femur and femur neck in both genders (p = 0.023 to <0.001). In conclusion, these data provide the first clinical evidence that increased total body iron stores could be an independent risk factor for accelerated bone loss, even in healthy populations. © 2012 American Society for Bone and Mineral Research.
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 06/2012; 27(11):2279-90. · 6.04 Impact Factor
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    ABSTRACT: Abstract Background: Although obesity and metabolic syndrome have been associated with the risk of type 2 diabetes mellitus (T2DM), it is unclear whether obese or overweight people without metabolic syndrome are at increased risk for T2DM. Methods: Clinical and laboratory data were assessed in 8,748 subjects without diabetes (5,707 men, 3,041 women; age 20-79 years) who underwent voluntary medical check-ups at a 5-year interval. The subjects were categorized by body mass index (BMI) and metabolic syndrome status at baseline, and the incidence of diabetes over 5 years was assessed. Results: Of the 8,748 subjects, 308 (3.5%) developed T2DM over 5 years. Compared with normal weight (BMI <25.0 kg/m(2)) individuals without metabolic syndrome, the adjusted odds ratios (ORs) were 1.61 (1.13-2.29) and 4.93 (1.90-12.79) for overweight (BMI 25.0-29.9 kg/m(2)) and obese (BMI ≥30.0 kg/m(2)) individuals without metabolic syndrome, respectively, and 6.94 (5.08-9.47) and 10.61 (5.59-20.14) for overweight and obese individuals with metabolic syndrome, respectively. Using the lower BMI cutoff points for Asian populations, compared with subjects with BMI <23 kg/m(2) without metabolic syndrome, the adjusted ORs for subjects with BMI 23-27.4 kg/m(2) and BMI ≥27.5 kg/m(2) without metabolic syndrome were 2.64 (1.74-4.00) and 4.31 (2.36-7.86), respectively, and 10.11 (6.53-15.67) and 16.69 (10.40-26.77), respectively, for those with metabolic syndrome. Conclusions: Overweight/obesity and metabolic syndrome both are significant risk factors for development of T2DM in Koreans, and overweight or obesity without metabolic syndrome should not be considered a harmless condition. The lower BMI cutoffs for Asian populations can be useful in predicting risk of T2DM in Koreans.
    Metabolic syndrome and related disorders 05/2012; 10(5):321-5.
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    Hong-Kyu Kim, Sung-Jin Bae, Jaeone Choe
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    ABSTRACT: We performed the study to examine the impact of hemoglobin A1c (HbA1c) criterion on the screening of increased risk for diabetes among health check-up subjects in Korea. We retrospectively analyzed clinical and laboratory data of 37,754 Korean adults (age, 20 to 89 years; 41% women) which were measured during regular health check-ups. After excluding subjects with previously diagnosed diabetes mellitus (n=1,812) and with overt anemia (n=318), 35,624 subjects (21,201 men and 14,423 women) were included in the analysis. Among the 35,624 subjects, 11,316 (31.8%) subjects were categorized as increased risk for diabetes (IRD) by fasting plasma glucose (FPG) criteria, 6,531 (18.1%) subjects by HbA1c criteria, and 13,556 (38.1%) subjects by combined criteria. Therefore, although HbA1c criteria alone identifies 42% [(11,316-6,531)/11,316] fewer subjects with IRD than does FPG criteria, about 20% [(13,556-11,316)/11,316] more subjects could be detected by including new HbA1c criteria in addition to FPG criteria. Among the 13,556 subjects with IRD, 7,025 (51.8%) met FPG criteria only, 2,240 (16.5%) met HbA1c criteria only, and 4,291 (31.7%) met both criteria. Among subjects with impaired fasting glucose, 65% were normal, 32% were IRD, and 3% were diabetes by HbA1c criterion. In receiver operating characteristic curve analysis, cutoff point of HbA1c with optimal sensitivity and specificity for identifying IRD was 5.4%. Although HbA1c criteria alone identifies fewer subjects with IRD than does FPG criteria, about 20% more could be detected by addition of HbA1c criteria. Further studies are needed to define optimal cutoff point of HbA1c and to establish screening and management guidelines for IRD.
    Diabetes & metabolism journal 04/2012; 36(2):151-6.
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    ABSTRACT: Several biological age (BA) prediction models have been suggested with a variety of biomarkers. Valid models should be able to measure BA in a relatively short time period and predict subsequent physiological capability. Physiological and physical fitness variables have been shown to be distinctive markers for predicting BA and morbidity. The practical and noninvasive nature of such variables makes them useful as clinical assessment tools in estimating BA for in-depth diagnosis and corresponding intervention. To identify, develop and evaluate biomarkers and BA prediction models and validate their clinical usefulness for the practical diagnosis of functional aging. Fourteen variables were measured in 3,112 male and 1,233 female participants aged 30 and older between the years 2004 and 2007. Through a series of parsimonious stepwise elimination processes, two sets of 8 gender-specific variables were selected as candidate biomarkers for 1,604 men and 760 women. Principal component analysis, linear regression analysis and adjustment methods were further applied to obtain two sets of true BA (TBA) prediction models. The TBA models were examined for validity by comparing TBA to the corresponding chronological age (CA) with clinical risk factors. TBA prediction models with r(2) values of 0.638 and 0.672 were developed, each unique to men and women, respectively. The overall mean TBA and CA of the participants were 53.9 and 51.8 years, respectively, with a marginal difference of -2.1 and -1.3 years. The regression slopes or rates of TBA as a function of CA were 1.00 and 1.28 for men and women with r values of 0.799 and 0.820 (p < 0.001), respectively. In comparing TBA to CA rates between healthy and clinical risk groups, both sarcopenic and obese groups showed significant increases in TBA. The selected biomarkers encompass various complex physiopathological factors related to intrinsic and extrinsic physiological and functional aging. The BA prediction models based on the selected biomarkers could be practical in assessing BA for Korean adults.
    Gerontology 03/2012; 58(4):344-53. · 2.68 Impact Factor
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    ABSTRACT: Objective  The ratio of apolipoprotein B (apoB) to apolipoprotein A1 (apoA1) has been reported to be associated with the metabolic syndrome (MetS). However, the optimal cut-off value of apoB/A1 ratio for detecting subjects with MetS has remained undetermined. In the present study, we aimed to investigate whether apoB/A1 ratio can be an indicator of MetS and to determine the optimal cut-off value of apoB/A1 ratio in detecting subjects with MetS in a Korean population. Design  This cross-sectional study was conducted at the Asan Medical Center, Seoul, Republic of Korea. Subjects and measurements  We collected the data of 10 940 subjects who participated in a routine health screening examination regarding conventional risk factors and serum levels of apoB and apoA1. Results  The odds for MetS were significantly higher in the highest compared with the lowest apoB/A1 ratio quartiles, after adjustment for confounding variables, in both men [odds ratio (OR) = 4·07, 95% CI = 3·42-4·84] and women (OR = 8·41, 95% CI = 5·85-12·08). The optimal apoB/A1 ratio cut-off value for the detection of MetS was 0·65, which had a sensitivity of 63·5% and a specificity of 61·3% (area under the curve = 0·67, 95% CI = 0·66-0·68, P < 0·001) in men and 0·62, which had a sensitivity of 67·9% and a specificity of 61·9% (area under the curve = 0·70, 95% CI = 0·69-0·71, P < 0·001) in women. Conclusions  These results suggest that apoB/A1 ratio is independently associated with MetS and that an apoB/A1 ratio >0·65 in men and 0·62 in women is a marker of MetS independent from conventional risk factors.
    Clinical Endocrinology 01/2012; 77(5):699-706. · 3.40 Impact Factor
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    ABSTRACT: To explore the utility of the HbA1c criterion in the definition of metabolic syndrome (MS) in Koreans, we cross-sectionally analyzed clinical and laboratory data on 11,293 non-diabetic Korean adults (aged 20-89 years, 34% women) collected during regular health checkups. Dysglycemia was defined as either fasting plasma glucose (FPG) ≥ 5.6 mmol/l or HbA1c ≥ 5.7%. The prevalence of MS as judged by the HbA1c criterion alone (17.8%) was significantly less than that determined by FPG level alone (24.5%). Use of a combination of both criteria slightly increased the prevalence of MS (26.0%). Among the 2953 subjects categorized as having MS using the combined criteria, 929 (31%) were diagnosed by the FPG criterion alone, 177 (6%) by the HbA1c criterion alone, and 1847 (63%) using both criteria. The group diagnosed using FPG values alone had significantly higher BMI, waist circumference, blood pressure, fasting plasma insulin levels, and insulin resistance index compared with those in the group diagnosed using HbA1c levels alone. In men, the brachial-ankle pulse wave velocity was significantly higher and the HDL-cholesterol level was lower in the HbA1c-alone group. Therefore, employment of the HbA1c criterion may be useful to define MS in subjects at increased risk for atherosclerosis.
    Diabetes research and clinical practice 11/2011; 95(3):333-9. · 2.74 Impact Factor
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    ABSTRACT: Gamma-glutamyltransferase (GGT) has been reported to be useful in predicting cardiovascular disease. Arterial stiffness measured by brachial-ankle pulse wave velocity (baPWV) is not only a marker of vascular damage but a significant predictor of cardiovascular events. Gender difference has been reported in the association between GGT and baPWV. We assessed, therefore, the association between GGT and baPWV in a large population and determined whether there was gender difference. This cross-sectional study was conducted at the Asan Medical Centre, Seoul, Republic of Korea. Serum GGT, baPWV and conventional risk factors were measured in 10 988 apparently healthy subjects (7248 men, 3740 women) who participated in a routine health screening examination. In both men and women, we observed positive linearity between GGT quartiles and body mass index, waist circumference, systolic blood pressure, diastolic blood pressure, fasting plasma glucose, total cholesterol, LDL cholesterol, triglycerides, uric acid, high-sensitive C-reactive protein (hsCRP) and homeostatic model assessment of insulin resistance (HOMA-IR) score (P for trends < 0·001). The proportion of individuals with diabetes, hypertension increased as the GGT quartile increased (P for trends < 0·001). Age-adjusted mean baPWV increased gradually in both males and females according to GGT quartiles (P for trends < 0·001 in both genders). The odds for higher baPWV (i.e. >75th percentile in each sex) were significantly higher in the highest compared with the lowest GGT quartiles, after adjustment for confounding variables, in both men [odds ratio (OR) = 1·63, 95% CI = 1·21-2·20] and women (OR = 1·56, 95% CI = 1·08-2·27). These results suggest that GGT is independently associated with the increased level of arterial stiffness both in men and in women and the association between them appears to be stronger in men compared to women.
    Clinical Endocrinology 03/2011; 75(3):328-34. · 3.40 Impact Factor
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    ABSTRACT: Increased serum ferritin concentrations in nonpathologic conditions, reflecting subclinical iron overload, have been reported to be associated with insulin resistance and an increased risk of type 2 diabetes mellitus (DM). However, serum ferritin concentrations differ significantly according to sex and ethnicity; and data concerning the relationship between serum ferritin concentrations and glucose metabolism abnormalities in Asian men and women are conflicting. This cross-sectional study investigated the association of serum ferritin concentrations with insulin resistance and impaired glucose metabolism in a large number of subjects with normal fasting glucose (NFG) level, impaired fasting glucose (IFG) level, or type 2 DM. We analyzed clinical and laboratory data from 12 090 subjects (6378 men and 5712 women; age, 20-89 years) who underwent general medical checkups. The study population included 1054 subjects with type 2 DM, 3783 subjects with IFG level, and 7253 subjects with NFG level. Serum ferritin, hemoglobin A(1c), fasting glucose, lipid, and insulin levels were measured. Insulin resistance and β-cell function indices were derived from a homeostasis model assessment. Serum ferritin concentrations were highest in the DM group, followed by the IFG group and the NFG group, in both men and women (186 ± 127, 176 ± 108, and 156 ± 92 ng/mL, respectively, in men; 85 ± 62, 75 ± 55, and 59 ± 47 ng/mL, respectively, in women). After adjustment for other variables using multiple regression analysis, homeostasis model assessment of insulin resistance was independently associated with serum ferritin concentration in men, but not in women. When the fourth quartile of ferritin was compared with the first quartile, the age-adjusted odds ratio (OR) for type 2 DM was 1.71 (95% confidence interval, 1.38-2.12) in men and 1.50 (1.05-2.13) in women. The OR in men was attenuated to 1.27 (1.01-1.60) but remained significant after adjustment for body mass index (BMI), waist circumference, blood pressure, serum lipids, liver enzymes, and high-sensitivity C-reactive protein (hsCRP). In nondiabetic subjects, the age-adjusted OR for IFG in the fourth quartile of ferritin was 1.82 (1.56-2.13) in men and 1.68 (1.40-2.02) in women. The OR was attenuated to 1.31 (1.11-1.55) in men and 1.45 (1.19-1.78) in women after adjustment for BMI, waist circumference, blood pressure, serum lipids, liver enzymes, and hsCRP. In NFG subjects, the age-adjusted OR for metabolic syndrome in the fourth quartile of ferritin concentration was 2.85 (1.99-4.07) in men and 1.21 (0.82-1.79) in women. In men, the OR was attenuated to 1.58 (1.06-2.37) after adjustment for BMI, liver enzymes, and hsCRP. Increased serum concentrations of ferritin are associated with insulin resistance, type 2 DM, IFG, and metabolic syndrome in men, but only with IFG in women. These results suggest that iron overload is associated with insulin resistance in men, but not in women.
    Metabolism: clinical and experimental 03/2011; 60(3):414-20. · 3.10 Impact Factor

Publication Stats

183 Citations
80.19 Total Impact Points

Institutions

  • 2009–2013
    • Ulsan University Hospital
      Urusan, Ulsan, South Korea
  • 2004–2013
    • Asan Medical Center
      • • Health Promotion Center
      • • Department of Endocrinology/Metabolism
      Sŏul, Seoul, South Korea
  • 2009–2011
    • Soonchunhyang University
      Onyang, South Chungcheong, South Korea
  • 2008
    • University of Ulsan
      • College of Medicine
      Ulsan, Ulsan, South Korea