Song Vogue Ahn

Prospective Study of Serum Adiponectin and Incident Metabolic Syndrome: The ARIRANG study

OBJECTIVE Increased adiponectin levels may play a protective role in the development of metabolic abnormalities, but prospective studies of the predictive value of serum adiponectin to identify individuals at high risk of new-onset metabolic syndrome are lacking. We investigated whether serum adiponectin predicts incident cases of the metabolic syndrome in a population-based longitudinal study. RESEARCH DESIGN AND METHODS A prospective cohort study was conducted of 2,044 adults (831 men and 1,213 women) aged 40–70 years without metabolic syndrome examined in 2005–2008 (baseline) and 2008–2011 (follow-up). Baseline serum adiponectin concentrations were measured by radioimmunoassay. RESULTS During an average of 2.6 years of follow-up, 153 men (18.4%) and 199 women (16.4%) developed metabolic syndrome. In multivariable-adjusted models, the odds ratio for incident metabolic syndrome comparing the highest with the lowest quartiles of adiponectin levels was 0.25 (95% CI 0.14–0.47) in men and 0.45 (0.28–0.74) in women. While serum adiponectin did not improve the area under the ROC curve for predicting new-onset metabolic syndrome based on information from metabolic syndrome components, the net reclassification improvement and the integrated discrimination improvement of prediction models including adiponectin were significantly higher compared with those of models not including adiponectin among men, with a significant difference between men and women (P = 0.001). CONCLUSIONS Increased adiponectin is an independent protective factor for incident metabolic syndrome in men and women, and it may have a clinical role in predicting new-onset metabolic syndrome among men.

Prevalence of Dyslipidemia among Korean Adults: Korea National Health and Nutrition Survey 1998-2005.

Background Dyslipidemia is a disorder of lipid metabolism, including elevated total cholesterol, elevated triglyceride, elevated low density lipoprotein cholesterol (LDL-C), and decreased high density lipoprotein cholesterol (HDL-C). The objective of this study was to investigate recent changes in the prevalence of dyslipidemia and also the rates of awareness, treatment, and control of dyslipidemia among Korean adults. Methods Dyslipidemia is defined according to the National Cholesterol Education Program-Adult Treatment Panel III as total cholesterol ≥240 mg/dL, LDL-C ≥160 mg/dL, HDL-C <40 mg/dL, and triglyceride ≥200 mg/dL. The prevalence of dyslipidemia was estimated for adults aged ≥20 years using the Korea National Health and Nutrition Survey (KNHANES) in 1998 (n=6,923), 2001 (n=4,882), and 2005 (n=5,323). Rates of awareness, treatment and control of dyslipidemia were calculated for adults aged ≥30 years using the KNHANES in 2005 (n=4,654). Results The prevalence of dyslipidemia (aged ≥20 years) increased from 32.4% in 1998 to 42.6% in 2001 and 44.1% in 2005. Compared with the KNHANES in 1998, the prevalence of dyslipidemia was 47% (95% confidence interval [CI], 35% to 59%) higher in 2001 and 61% (95% CI, 49% to 75%) higher in 2005. In 2005, only 9.5% of people with dyslipidemia were aware of the disease, 5.2% used lipid-lowering medication, and 33.2% of patients with treatment reached treatment goals. Conclusion The prevalence of dyslipidemia in Korea gradually increased between 1998 and 2005. These findings suggest that more intense efforts for the prevention and treatment of dyslipidemia may lead to further improvement in the management of dyslipidemia.

Six-year survival and causes of death among stroke patients in Korea.

Background: Stroke is the second leading cause of death in Korea but long-term survival of Korean stroke patients has not been studied. Thus, we examined 6-year survival and causes of death in a nationally representative inpatient sample. Methods: Between January 2000 and March 2000 in 152 sample hospitals, 4,299 first-ever stroke patients were identified and followed-up for vital status until December 2005. Mortality and mortality-related factors were evaluated by the Kaplan-Meier method and Cox proportional hazard regression analysis. Results: Ischemic stroke was the most common subtype (62.9%), followed by intracerebral hemorrhage (ICH, 21.2%), and subarachnoid hemorrhage (SAH, 6.4%). Six-year mortality was estimated at 37.1% for all strokes, 37.2% for ischemic, 41.0% for ICH, and 29.2% for SAH. Common causes of death were stroke (58.2%), malignancies (10.3%), other cardiovascular diseases (7.7%), and diabetes (6.8%). Six-year mortality was associated with old age (hazard ratio 1.70 per 10 years, 95% CI 1.62–1.78), male sex (1.29, 1.16–1.43), subtypes of ICH (1.30, 1.15–1.48) and SAH (1.43, 1.14–1.80), longer hospital admission (1.01 per 10 days, 1.00–1.03), and loss of consciousness (1.32, 1.13–1.55). Conclusions: More than 60% of Korean patients with first-ever stroke survived to 6 years. Major causes of death were stroke, cancer, cardiovascular diseases, and diabetes.

The ratio of serum leptin to adiponectin provides adjunctive information to the risk of metabolic syndrome beyond the homeostasis model assessment insulin resistance: The Korean Genomic Rural Cohort Study

BACKGROUND Leptin and adiponectin are adipokines, shown to have opposing functions for fat metabolism and development of metabolic syndrome. We determined if the ratio of serum leptin to adiponectin (L/A ratio) adjunctively contributes to the risk of metabolic syndrome beyond the homeostasis model assessment of insulin resistance (HOMA-IR). METHODS This study included 1532 men and 1856 women, aged 40-70 y assessed in the Korean Genomic Rural Cohort Study from 2005 to 2008. The serum concentrations of adiponectin and leptin were measured by radioimmunoassay. Area under the receiver operating characteristic curve (AUROC) analyses were used to describe the ability of L/A ratio and HOMA-IR to differentiate between subjects with and without metabolic syndrome. RESULTS There were no significant differences in the ability of L/A ratio and HOMA-IR to predict metabolic syndrome (AUROC of L/A ratio vs. HOMA-IR, 0.771 vs. 0.774, p=0.8006 for men; 0.677 vs. 0.691, p=0.3088 for women). There was a significant adjunctive contribution by the L/A ratio, beyond that of HOMA-IR, to the risk of metabolic syndrome in men (p<0.0001 with 0.028 increased AUROC) and women (p=0.025 with 0.017 increased AUROC). CONCLUSIONS The L/A ratio provides significant adjunctive information to the risk of metabolic syndrome beyond HOMA-IR alone. The L/A ratio could be a good surrogate marker to assess metabolic syndrome.

Association between Blood Pressure and Carotid Intima-Media Thickness

OBJECTIVE To investigate the association between blood pressure and carotid intima-media thickness (IMT) in healthy adolescents. STUDY DESIGN Study participants included 285 first-year high school students (mean age, 15.2 years) at a rural high school in Korea. Systolic and diastolic blood pressure (SBP and DBP) were measured with an oscillometric automated sphygmomanometer. The carotid arteries were evaluated with high-resolution B-mode ultrasound scanning. IMT value was determined with the average of the maximal IMT at each common carotid artery. Increased IMT was defined as sex-specific top quartile. The odds ratio (OR) for increased IMT per 1 SD increase of SBP and DBP was estimated after adjusting for age, sex, body mass index, waist circumference, fasting glucose level, and total/high-density lipoprotein cholesterol ratio. RESULTS Adjusted OR for increased IMT was 1.70 (P = .003) per 12.4 mm Hg SBP and 1.25 (P = .125) per 7.0 mm Hg DBP. When the analyses were performed by sex, increased IMT was associated with both SBP (OR, 2.67; P = .003) and DBP (OR, 1.68; P = .019) in girls, but it was not associated with either SBP (OR, 1.46; P = .093) or DBP (OR, 0.99; P = .972) in boys. CONCLUSION These results suggest that higher blood pressure level may be associated with increased carotid IMT in apparently healthy adolescents.

Prospective study of serum uric acid levels and incident metabolic syndrome in a Korean rural cohort

OBJECTIVE Recent studies have demonstrated an association between serum uric acid (SUA) levels and metabolic syndrome (MetS). However, paucity of available data regarding the cause and effect relationship between SUA and MetS in healthy adults is still a big challenge which remains to be studied. Therefore, we investigated whether SUA predicts new onset of MetS in a population-based cohort study. METHODS The study included 1590 adults (661 men and 929 women) aged 40-70 years without MetS at baseline (2005-2008) and subjects were prospectively followed for 2.6 years. To evaluate the relationship between SUA and MetS, we divided the aforementioned subjects into quintiles (SUA-I to SUA-V) from the lowest to the highest values of SUA. SUA was measured by the enzymatic colorimetric method. We used category-free net reclassification improvement (NRI) and integrated discrimination improvement (IDI) to characterize the performance of predicted model. RESULTS During a mean of 2.6 years of follow-up, 261(16.4%) adults developed MetS. MetS variables were significantly related to the baseline SUA level. Waist circumference (WC), blood pressure (BP), and serum triglyceride (TG) were significantly higher in the highest quintile of SUA compared to the lowest SUA quintile in men and women. After adjustment for age, total cholesterol and low-density lipoprotein cholesterol (LDL-C) in men and women, subjects in the fifth quintiles of SUA showed significantly higher ORs for incident MetS. The association between hyperuricemia and new onset of MetS were consistently stronger in women than men. Additionally, among women, we found an improvement in the area under the ROC curve in the models that added SUA to core components of MetS. CONCLUSION Our study suggests that SUA is significantly correlated with future risk of WC, BP, TG and may predicted as a risk factor for developing MetS. SUA may have a clinical role in predicting new-onset metabolic syndrome among women. Large prospective study is needed to reveal the clinical significance of SUA in metabolic disease.

A prospective study of total sleep duration and incident metabolic syndrome: the ARIRANG study

BACKGROUND AND OBJECTIVE Chronic sleep deprivation is increasingly common in industrialized societies. Recent data have revealed that chronic sleep deprivation is associated with negative health outcome. While prospective studies lack the predictive value of sleep duration to identify individuals at high risk of new-onset metabolic syndrome, total sleep duration may play a role in the development of metabolic abnormalities. This study investigates the association between total sleep duration and the incidence of metabolic syndrome in a population-based longitudinal study. RESEARCH DESIGN AND METHODS At baseline, a prospective cohort study was conducted with 2579 adults without metabolic syndrome aged between 40 and 70 years. Based on a self-reported questionnaire, the participants in this study were investigated between 2005-2008 (baseline) and 2008-2011 (follow-up) and were categorized according to their total sleep duration (<6 h, 6-7.9 h, 8-9.9 h, ≥10 h). Metabolic syndrome was defined according to the recent harmonized definition. RESULTS During an average of 2.6 years of follow-up, 558 (21.6%) subjects developed metabolic syndrome. In multivariable adjusted models, the odds ratio (95% confidence interval (CI)) for incident metabolic syndrome comparing the 6 to 7.9 h to the <6 h of total sleep duration was 1.41 (1.06-1.88). The corresponding odds ratios (95% CI) for high waist circumference, low high-density lipoprotein (HDL) cholesterol, high triglycerides, high blood pressure, and high blood glucose were 1.30 (0.98-1.69), 0.75 (0.56-0.97), 0.82 (0.60-1.11), 1.56 (1.19-2.03), and 1.31 (0.96-1.79), respectively. CONCLUSION Short sleep duration is an independent risk factor for incident metabolic syndrome in a population-based longitudinal study.

Adiponectin Provides Additional Information to Conventional Cardiovascular Risk Factors for Assessing the Risk of Atherosclerosis in Both Genders

Background This study evaluated the relation between adiponectin and atherosclerosis in both genders, and investigated whether adiponectin provides useful additional information for assessing the risk of atherosclerosis. Methods We measured serum adiponectin levels and other cardiovascular risk factors in 1033 subjects (454 men, 579 women) from the Korean Genomic Rural Cohort study. Carotid intima–media-thickness (CIMT) was used as measure of atherosclerosis. Odds ratios (ORs) with 95% confidence intervals (95% CI) were calculated using multiple logistic regression, and receiver operating characteristic curves (ROC), the category-free net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were calculated. Results After adjustment for conventional cardiovascular risk factors, such as age, waist circumference, smoking history, low-density and high-density lipoprotein cholesterol, triglycerides, systolic blood pressure and insulin resistance, the ORs (95%CI) of the third tertile adiponectin group were 0.42 (0.25–0.72) in men and 0.47 (0.29–0.75) in women. The area under the curve (AUC) on the ROC analysis increased significantly by 0.025 in men and 0.022 in women when adiponectin was added to the logistic model of conventional cardiovascular risk factors (AUC in men: 0.655 to 0.680, p = 0.038; AUC in women: 0.654 to 0.676, p = 0.041). The NRI was 0.32 (95%CI: 0.13–0.50, p<0.001), and the IDI was 0.03 (95%CI: 0.01–0.04, p<0.001) for men. For women, the category-free NRI was 0.18 (95%CI: 0.02–0.34, p = 0.031) and the IDI was 0.003 (95%CI: −0.002–0.008, p = 0.189). Conclusion Adiponectin and atherosclerosis were significantly related in both genders, and these relationships were independent of conventional cardiovascular risk factors. Furthermore, adiponectin provided additional information to conventional cardiovascular risk factors regarding the risk of atherosclerosis.

Gender differences in the association between smoking and dyslipidemia: 2005 Korean National Health and Nutrition Examination Survey.

BACKGROUND Smoking has been reported to be associated with abnormal lipid metabolism. However, it remains uncertain whether adverse metabolic effects of smoking on dyslipidemia differ with gender. The objective of this study was to investigate the association between smoking and dyslipidemia in men and women. METHODS We analyzed data from 2166 men and 3003 women aged ≥20 years assessed in the Third Korea National Health and Nutrition Examination Survey (2005). Dyslipidemia was defined according to the National Cholesterol Education Program-Adult Treatment Panel III. RESULTS The prevalence of dyslipidemia was higher in men than in women. The odds ratios (95% confidence interval) of dyslipidemia associated with current smoking were 1.35 (0.98-1.85) in men and 1.92 (1.19-3.10) in women (p for interaction with gender <0.001). After stratification by components of dyslipidemia, women smokers showed higher odds ratios of having high triglyceride and low high-density lipoprotein cholesterol than men smokers. The association between current heavy-smoking (≥20 pack-years) and dyslipidemia was stronger in women than in men. CONCLUSIONS The association between smoking and dyslipidemia was significantly different between men and women. Women smokers might be more susceptible to develop dyslipidemia than men smokers.

A Prospective Study of Fatty Liver Index and Incident Hypertension: The KoGES-ARIRANG Study

Background Although non-alcoholic fatty liver disease is the hepatic manifestation of metabolic syndrome, its influence on hypertension development is poorly understood. We investigated whether fatty liver disease, as assessed by the fatty liver index, could predict the development of hypertension independently of systemic insulin resistance, inflammatory status and adipokine levels. Methods Prospective cohort study of 1,521 adults (484 men and 1037 women) aged 40 to 70 years without baseline hypertension examined. An equation was used to calculate fatty liver index and classify patients as follows: fatty liver index <30, no non-alcoholic fatty liver disease; fatty liver index ≥60, non-alcoholic fatty liver disease; and 30≤ fatty liver index <60, intermediate fatty liver index. Results During an average of 2.6 years of follow-up, 153 subjects (10.06%) developed hypertension. Fatty liver index was positively associated with baseline blood pressure, homeostasis model assessment of insulin resistance, urinary albumin/creatinine excretion, and high sensitivity C-reactive protein. After adjustment for confounding factors, including markers of insulin resistance, systemic inflammation and adiponectin levels, the odds ratio [95% confidence interval] for the incident hypertension increased in a graded manner with fatty liver index (<30 vs. 30–59 vs. ≥60 = 1 vs. 1.83 [1.16~2.88] vs. 2.09 [1.08~4.055], respectively). Conclusions Non-alcoholic fatty liver disease assessed by fatty liver index was an independent risk factor for hypertension. Our findings suggest that fatty liver index, a simple surrogate indicator of fatty liver disease, might be useful for identifying subjects at high risk for incident hypertension in clinical practice.