Sang Youl Rhee

Sarcopenia is independently associated with cardiovascular disease in older Korean adults: the Korea National Health and Nutrition Examination Survey (KNHANES) from 2009.

Background The association between sarcopenia and cardiovascular disease (CVD) in elderly people has not been adequately assessed. The aim of this study was to investigate whether CVD is more prevalent in subjects with sarcopenia independent of other well-established cardiovascular risk factors in older Korean adults. Method This study utilized the representative Korean population data from the Korea National Health and Nutrition Examination Survey (KNHANES) which was conducted in 2009. Subjects older than 65 years of age with appendicular skeletal muscle mass (ASM) determined by dual energy X-ray absorptiometry were selected. The prevalence of sarcopenia in the older Korean adults was investigated, and it was determined whether sarcopenia is associated with CVD independent of other well-known risk factors. Results 1,578 subjects aged 65 years and older with the data for ASM were selected, and the overall prevalence of sarcopenia was 30.3% in men and 29.3% in women. Most of the risk factors for CVD such as age, waist circumference, body mass index, fasting plasma glucose and total cholesterol showed significant negative correlations with the ratio between appendicular skeletal muscle mass and body weight. Multiple logistic regression analysis demonstrated that sarcopenia was associated with CVD independent of other well-documented risk factors, renal function and medications (OR, 1.768; 95% CI, 1.075–2.909, P = 0.025). Conclusions Sarcopenia was associated with the presence of CVD independent of other cardiovascular risk factors after adjusting renal function and medications.

The Prediabetic Period: Review of Clinical Aspects

Hyperglycemia that does not satisfy the diagnostic criteria for diabetes mellitus (DM) is generally called prediabetes (preDM). The global prevalence of preDM has been increasing progressively in the past few decades, and it has been established that preDM status is a strong risk factor for DM and cardiovascular disease. Currently, preDM status is classified into two subtypes: impaired fasting glucose and impaired glucose tolerance. Currently, preDM is not regarded as an independent clinical entity, but only as a risk factor for others. In this article, we review various clinical aspects of preDM in terms of the working definition, changes in criteria over the years, epidemiology, and pathophysiological characteristics, and its clinical significance in current medicine.

Low Serum Vitamin D Is Associated with High Risk of Diabetes in Korean Adults

Vitamin D may play a role in glucose metabolism. A low vitamin D level has been associated with increased risk of diabetes mellitus, but the association has not been confirmed in Asians. Our objective was to examine the association of serum 25-hydroxyvitamin D [25(OH)D] levels with insulin resistance and diabetes mellitus in Korean adults based on a large population-based survey. Cross-sectional analyses were carried out on 5787 Korean adults (2453 men and 3334 women) who were 20 y or older and participated in the Fourth Korea NHANES conducted in 2008. Diabetes mellitus was defined as fasting plasma glucose ≥7 mmol/L or current use of oral hypoglycemic agents or insulin. Insulin resistance was estimated by homeostatic model assessment for insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI). Compared to individuals with a sufficient serum 25(OH)D concentration ≥75 nmol/L, the OR (95% CI) for diabetes mellitus were 1.73 (1.09-2.74), 1.30 (0.91-1.84), and 1.40 (0.99-1.98) for serum 25(OH)D concentrations <25, 25 to <50, and 50 to <75 nmol/L, respectively, after multiple adjustments (P-trend < 0.0001). Furthermore, the serum 25(OH)D level was inversely associated with HOMA-IR (β = -0.061; P = 0.001) and positively associated with QUICKI (β = 0.059; P = 0.001) in overweight or obese participants. In conclusion, a low serum vitamin D concentration is associated with a high risk of diabetes mellitus in Korean adults and the concentration is inversely associated with insulin resistance in those who are overweight or obese.

Prevalence of Chronic Complications in Korean Patients with Type 2 Diabetes Mellitus Based on the Korean National Diabetes Program

Background The Korean National Diabetes Program (KNDP) cohort study is performing an ongoing large-scale prospective multicenter investigation to discover the pathogenesis of type 2 diabetes in Korean patients. This study was performed to examine the prevalence of chronic complications in patients with type 2 diabetes among those registered in the KNDP cohort within the past 4 years. Methods This study was performed between June 2006 and September 2009 at 13 university hospitals and included 4,265 KNDP cohort participants. Among the participants, the crude prevalence of microvascular and macrovascular diseases of those checked for diabetes-related complications was determined, and the adjusted standard prevalence and standardization of the general population prevalence ratio (SPR) was estimated based on the 2005 Korean National Health and Nutrition Examination Survey (KNHANES) population demographics. Results Among the KNDP registrants, 43.2% had hypertension, 34.8% had dyslipidemia, 10.8% had macrovascular disease, and 16.7% had microvascular disease. The SPR of the KNDP registrants was significantly higher than that of the KNHANES subjects after adjusting for demographics in the KNHANES 2005 population. However, with the exception of cardiovascular disease in females, the standardized prevalence for the most complicated items in the survey was significantly higher than that in the KNHANES subjects. Conclusion The prevalence of macrovascular disease and peripheral vascular disease were significantly higher in Korean patients with type 2 diabetes than in the normal population. However, no significant difference was noted in the prevalence of cardiovascular disease in females.

Gender disparity in the secular trends for obesity prevalence in Korea: analyses based on the KNHANES 1998-2009

Background/Aims A similar gender-associated trend in obesity is observed worldwide. Nevertheless, systematic analyses of gender-specific characteristics in the general Korean population are rare. Methods We analyzed the prevalence of obesity in Korean adults aged ≥ 19 years based on data collected from the Korea Health and Nutrition Examination Surveys I to IV, and verified the obesity prevalence characteristics by gender. Results The prevalence of obesity in Korean males increased during the past 12 years from 25.1% to 35.7%, and the trend for an increase in obesity was significant in all age groups (p < 0.001). In contrast, no significant trend over the past 12 years was identified for females, but the prevalence of obesity in the 30- to 39-year, 40- to 49-year, and 50- to 59-year subgroups decreased significantly (p < 0.05). However, the obesity prevalence in the 60- to 69-year and > 70-year female subgroups increased significantly (p < 0.05). Conclusions We observed a gradually widening gender disparity due to an increase in the prevalence of male obesity and a decrease in the obesity prevalence among young and middle-aged women.

Blood lead is significantly associated with metabolic syndrome in Korean adults: an analysis based on the Korea National Health and Nutrition Examination Survey (KNHANES), 2008

BackgroundAlthough an association between low-level environmental heavy metal exposure and the incidence of metabolic syndrome (MS) has been hypothesized, little research on this topic has been conducted on a population-wide level.MethodsWe analyzed MS status and whole blood lead, mercury, cadmium, manganese, and creatinine-adjusted urine arsenic concentrations in 1,405 subjects, ≥ 20 years of age, who were registered for the Korea National Health and Nutrition Examination Survey, 2008.ResultsVarious demographic and biochemical parameters were associated with MS and blood heavy metal status. After adjusting for these variables, lead was the only heavy metal that was significantly associated with MS. Lead concentrations in subjects with MS were significantly higher than those in subjects without MS (p = 0.015). The prevalence of MS and a moderate/high risk for cardiovascular disease, as determined by Framingham risk score, also increased significantly according to the logarithmic transformation of the lead quartile (p < 0.001). The odds ratios and 95% confidence intervals for MS were 1.56 (0.90–2.71), 1.63 (0.94–2.83), and 2.57 (1.46–4.51) for the second, third, and fourth quartiles of the log-transformed lead quartile, respectively, as compared with those of the lowest quartile after multiple adjustments for confounding factors. Serum triglyceride level was the only MS diagnostic component significantly associated with lead level in a multiple linear regression analysis (p = 0.006).ConclusionsThese findings suggest that a higher prevalence of MS is associated with higher blood lead levels in the Korean population.

Methylglyoxal induces oxidative stress and mitochondrial dysfunction in osteoblastic MC3T3-E1 cells

Abstract Methylglyoxal is a reactive dicarbonyl compound produced by glycolytic processing and identified as a precursor of advanced glycation end products. The elevated methylglyoxal levels in patients with diabetes are believed to contribute to diabetic complications, including bone defects. The objective of this study was to evaluate the effect of methylglyoxal on the function of osteoblastic MC3T3-E1 cells. The data indicated that methylglyoxal decreased osteoblast differentiation and induced osteoblast cytotoxicity. Pretreatment of MC3T3-E1 cells with aminoguanidine (a carbonyl scavenger), Trolox (an antioxidant), and cyclosporin A (a blocker of the mitochondrial permeability transition pore) prevented methylglyoxal-induced cytotoxicity in MC3T3-E1 cells. However, BAPTA/AM (an intracellular Ca2+ chelator) and dantrolene (an inhibitor of endoplasmic reticulum Ca2+ release) did not reverse the cytotoxic effect of methylglyoxal. Methylglyoxal increased the formation of intracellular reactive oxygen species, mitochondrial superoxide, and cardiolipin peroxidation in osteoblastic MC3T3-E1 cells. Methylglyoxal also decreased the mitochondrial membrane potential and intracellular ATP and nitric oxide levels, suggesting that carbonyl stress-induced loss of mitochondrial integrity contributes to the cytotoxicity of methylglyoxal. Furthermore, the results demonstrated that methylglyoxal induced protein adduct formation, inactivation of glyoxalase I, and activation of glyoxalase II. Aminoguanidine reversed all aforementioned effects of methylglyoxal. Taken together, these data support the notion that high methylglyoxal concentrations have detrimental effects on osteoblasts through a mechanism involving oxidative stress and mitochondrial dysfunction.

Arsenic Exposure and Prevalence of Diabetes Mellitus in Korean Adults

It has been suggested that there is an association between environmental, low-level arsenic exposure and the risk of diabetes mellitus (DM), but little research has been conducted. Here, the glucose tolerance status and urinary creatinine adjusted total arsenic concentrations were analyzed in 3,602 subjects ≥ 20 yr of age who were registered for the Korea National Health and Nutrition Examination Survey, 2008-2009. Various demographic parameters were associated with urinary arsenic concentrations. After adjusting for these variables, urinary arsenic concentrations in subjects with DM were significantly higher than those in subjects with normal glucose tolerance and those with impaired fasting glucose (P < 0.001). Compared with the lowest quartile ( < 70.7 µg/g creatinine), the odds ratios and 95% confidence intervals for DM were 1.11 (0.73-1.68), 1.42 (0.94-2.13), and 1.56 (1.03-2.36) for urinary arsenic concentrations of 70.7 to < 117.7, 117.7 to < 193.4, and ≥ 193.4 µg/g creatinine, respectively, following multivariate adjustment. Furthermore, the urinary total arsenic concentration was inversely associated with the insulin secretion index, HOMA2 %B (β = -0.033, P = 0.032). These findings suggest that arsenic exposure, possibly involving beta cell dysfunction, is associated with an increased risk of DM in the Korean population.

Risks for opportunistic tuberculosis infection in a cohort of 873 patients with inflammatory bowel disease receiving a tumor necrosis factor-α inhibitor.

Abstract Objective. Real-world epidemiological data on tuberculosis (TB) infection in patients with inflammatory bowel disease (IBD) receiving TNF-α inhibitors are scarce. We investigated the risks for and case characteristics of TB in a large cohort of IBD patients treated with TNF-α inhibitors in Korea, where TB is endemic. Materials and methods. We performed an observational study on all TB cases identified in a cohort of 873 IBD subjects treated with TNF-α inhibitors from January 2001 to December 2013. The standardized incidence ratio (SIR) of TB was calculated using data from the matched general population. Results. A total of 25 newly developed TB cases were identified in the cohort (pulmonary TB, 84% [21/25]; extrapulmonary TB, 16% [4/25]). The adjusted SIR of TB was 41.7 (95% confidence interval, 25.3–58.0), compared with that of the matched general population. Nineteen of the 25 patients (76%) developed TB within 2–62 months of initiation of TNF-α inhibitor treatment despite screening negative for latent TB infection (LTBI), whereas three patients with LTBI (12%, 3/25) developed TB 3 months after completion of chemoprophylaxis. The outcomes of TB treatment were mostly favorable, although one death from peritoneal TB was noted. The type of TNF-α inhibitor prescribed (infliximab) was a significant predictor of TB (p = 0.033). Conclusions. TNF-α inhibitor treatment strikingly increases the risk of TB infection in an IBD population from a TB endemic area. Continuous evaluation of the development of de novo TB infection in IBD patients subjected to long-term TNF inhibitor therapy is mandatory.

Patients with Crohn's disease on anti-tumor necrosis factor therapy are at significant risk of inadequate response to the 23-valent pneumococcal polysaccharide vaccine

BACKGROUND/AIMS The effect of immunosuppressants on the efficacy of a variety of vaccines is a controversial issue in patients with inflammatory bowel disease (IBD). In this study we determined whether specific immunosuppressants impair the serological response to the standard 23-valent pneumococcal polysaccharide vaccine (PPSV23) in a large cohort of patients with Crohns disease (CD). METHODS This was a multi-center, prospective observational study of adult patients with CD at 15 academic teaching hospitals in Korea. The study population received one intramuscular injection of PPSV23. Anti-pneumococcal IgG antibody titers were measured by immunoassay prior to and 4weeks after vaccination. All vaccination-related adverse events and the effect of the vaccine on disease activity were also evaluated. RESULTS The overall serological response rate was 67.5% (133/197). The serological response rate was significantly lower in patients on anti-tumor necrosis factor (anti-TNF) therapy (50.0% on anti-TNF alone; 58.0% on anti-TNF combined with an immunomodulator, IM) than patients on 5-aminosalicylate (78.4%; all P-values vs. 5-aminosalicylate<0.05); 45.6% (41/90) of patients on anti-TNF therapy were not protected against PPSV23. IM did not affect the immunologic response to the vaccine. Female gender and anti-TNF therapy were significant predictors of non-response to the vaccine (odds ratio [OR] 2.316, P=0.015; OR 2.582, P=0.048, respectively). Vaccination was generally safe and tolerated by all patients. CONCLUSIONS Patients with CD on anti-TNF therapy are at significant risk of an inadequate response to PPSV23. The pneumococcal vaccination strategy should be optimized for patients with CD on anti-TNF therapy.