Soo Lim

Sarcopenic Obesity: Prevalence and Association with Metabolic Syndrome in the Korean Longitudinal Study on Health and Aging (KLoSHA)

OBJECTIVE We investigated the prevalence of sarcopenic obesity (SO) and its relationship with metabolic syndrome in a community-based elderly cohort in Korea. RESEARCH DESIGN AND METHODS In this study, 287 men and 278 women aged 65 or older were recruited. Sarcopenia was defined as the appendicular skeletal muscle mass (ASM) divided by height squared (Ht2) (kg/m2) or by weight (Wt) (%) of <1 SD below the sex-specific mean for young adults. Obesity was defined as a visceral fat area ≥100 cm2. RESULTS The prevalence of SO was 16.7% in men and 5.7% in women with sarcopenia defined by ASM/Ht2; however, it was 35.1% in men and 48.1% in women by ASM/Wt. Using ASM/Wt, the homeostasis model assessment of insulin resistance of subjects with SO was higher and they were at higher risk for metabolic syndrome (odds ratio [OR] 8.28 [95% CI 4.45–15.40]) than the obese (5.51 [2.81–10.80]) or sarcopenic group (2.64 [1.08–6.44]). CONCLUSIONS SO defined by ASM/Wt was more closely associated with metabolic syndrome than either sarcopenia or obesity alone.

Chronic Exposure to the Herbicide, Atrazine, Causes Mitochondrial Dysfunction and Insulin Resistance

There is an apparent overlap between areas in the USA where the herbicide, atrazine (ATZ), is heavily used and obesity-prevalence maps of people with a BMI over 30. Given that herbicides act on photosystem II of the thylakoid membrane of chloroplasts, which have a functional structure similar to mitochondria, we investigated whether chronic exposure to low concentrations of ATZ might cause obesity or insulin resistance by damaging mitochondrial function. Sprague-Dawley rats (n = 48) were treated for 5 months with low concentrations (30 or 300 µg kg−1 day−1) of ATZ provided in drinking water. One group of animals was fed a regular diet for the entire period, and another group of animals was fed a high-fat diet (40% fat) for 2 months after 3 months of regular diet. Various parameters of insulin resistance were measured. Morphology and functional activities of mitochondria were evaluated in tissues of ATZ-exposed animals and in isolated mitochondria. Chronic administration of ATZ decreased basal metabolic rate, and increased body weight, intra-abdominal fat and insulin resistance without changing food intake or physical activity level. A high-fat diet further exacerbated insulin resistance and obesity. Mitochondria in skeletal muscle and liver of ATZ-treated rats were swollen with disrupted cristae. ATZ blocked the activities of oxidative phosphorylation complexes I and III, resulting in decreased oxygen consumption. It also suppressed the insulin-mediated phosphorylation of Akt. These results suggest that long-term exposure to the herbicide ATZ might contribute to the development of insulin resistance and obesity, particularly where a high-fat diet is prevalent.

Android Fat Depot Is More Closely Associated with Metabolic Syndrome than Abdominal Visceral Fat in Elderly People

Background Fat accumulation in android compartments may confer increased metabolic risk. The incremental utility of measuring regional fat deposition in association with metabolic syndrome (MS) has not been well described particularly in an elderly population. Methods and Findings As part of the Korean Longitudinal Study on Health and Aging, which is a community-based cohort study of people aged more than 65 years, subjects (287 male, 75.9±8.6 years and 278 female, 76.0±8.8 years) with regional body composition data using Dual energy X-ray absorptiometry for android/gynoid area, computed tomography for visceral/subcutaneous adipose tissue (VAT/SAT), and cardiometabolic markers including adiponectin and high-sensitivity CRP were enrolled. We investigated the relationship between regional body composition and MS in multivariate regression models. Mean VAT and SAT area was 131.4±65.5 cm2 and 126.9±55.2 cm2 in men (P = 0.045) and 120.0±46.7 cm2 and 211.8±65.9 cm2 in women (P<0.01). Mean android and gynoid fat amount was 1.8±0.8 kg and 2.5±0.8 kg in men and 2.0±0.6 kg and 3.3±0.8 kg in women, respectively (both P<0.01). VAT area and android fat amount was strongly correlated with most metabolic risk factors compared to SAT or gynoid fat. Furthermore, android fat amount was significantly associated with clustering of MS components after adjustment for multiple parameters including age, gender, adiponectin, hsCRP, a surrogate marker of insulin resistance, whole body fat mass and VAT area. Conclusions Our findings are consistent with the hypothesized role of android fat as a pathogenic fat depot in the MS. Measurement of android fat may provide a more complete understanding of metabolic risk associated with variations in fat distribution.

Insulin-sensitizing effects of exercise on adiponectin and retinol-binding protein-4 concentrations in young and middle-aged women

CONTEXT Exercise training enhances insulin sensitivity. Changes in retinol-binding protein-4 (RBP4) and adiponectin levels are linked to insulin resistance. OBJECTIVE We tested whether the insulin-sensitizing effect of exercise is associated with age-related changes in circulating RBP4 and adiponectin levels in women. DESIGN, SUBJECTS, AND INTERVENTION We studied 36 healthy young (22.4 +/- 2.8 yr) and 38 middle-aged (59.8 +/- 5.9 yr) women. All subjects performed 60 min of aerobic exercise three times per week for 10 wk at about 70% maximal exercise capacity. RESULTS After a 10-wk training program, maximal exercise capacity was significantly increased in both young and middle-aged women, suggesting increased oxidative capacity. Insulin sensitivity was also improved, as indicated by decreases in plasma insulin levels and homeostasis model assessment for insulin resistance index. Serum adiponectin and RBP4 concentrations were increased and decreased more in older than younger women, respectively (P < 0.01). Concurrently, circulating transthyretin levels were also decreased in older subjects in response to exercise training. The older women showed higher correlations between changes in adiponectin or RBP4 levels and obesity indices or metabolic parameters than the younger group. When subjects showing increasing adiponectin or decreasing RBP4 levels were classified as responders, there were higher correlations between these changes in responders than in nonresponders. CONCLUSIONS We conclude that the mechanism for the insulin-sensitizing effects of exercise could involve increased adiponectin and reduced RBP4 levels in exercise-trained women. These data suggest that alterations in circulating RBP4 and adiponectin levels could play an important role in regulating insulin sensitivity.

Abnormal Liver Function Test Predicts Type 2 Diabetes: A community-based prospective study

Increased activities of liver enzymes such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), and γ-glutamyltranspeptidase (GGT) are indicators of hepatocellular injury. Increased activity of these markers is associated with insulin resistance (1), metabolic syndrome, and type 2 diabetes (2–9). However, most of these studies were performed in Western countries (2–5,7,9), and the two studies from Japan and Korea were not community based (6,8). In this prospective community-based study, we evaluated the relationships between markers of liver function and the onset of type 2 diabetes after adjusting for potential risk factors including inflammatory markers. In 2001, the Korean government funded a large community-based epidemiological survey to investigate the trends in diabetes and the associated risk factors (10). For this study, two communities, one from a rural Ansung and the other from an urban Ansan community, were selected. The baseline examination was performed in 2001–2002, and biennial follow-up examinations will continue through 2010. The age range for eligibility was 40–69 years. Of the 7,192 eligible individuals in Ansung, 5,018 were surveyed (70% response rate) using a cluster sampling method. A total of 15,580 individuals were eligible in Ansan, and we successfully recruited 5,020 (32.4%) using a random sampling method of the local telephone directory. The study protocol was approved by the ethics committee of the Korean Health and Genome Study. Anthropometric parameters and blood pressure were measured by standard methods. Fasting plasma glucose, lipid profiles, insulin, high-sensitivity C-reactive …

Ectopic fat and cardiometabolic and vascular risk

Given that the variation in how regional adipose tissue handles and stores excess dietary energy has substantial cardiometabolic implications, ectopic fat distribution might be an important predictor of cardiometabolic and vascular risk, in addition to overall obesity itself. Conceptually, ectopic fat depots may be divided into systemically acting fat depots and locally acting fat depots. Systemically acting fat depots include visceral fat, fat in the liver, muscle, or neck, and subcutaneous fat. Accumulation in the abdominal visceral area, compared with overall obesity, has an equally or more important role in the development of cardiometabolic risk. Fat depots in liver/muscle tissue cause adverse cardiometabolic effects by affecting energy metabolism. Fat depots in lower-body subcutaneous areas may be protective regarding cardiometabolic risk, by trapping remnant energy. Fat accumulation in the neck is a unique type of fat depot that may increase cardiovascular risk by increasing insulin resistance. Locally acting fat depots include pericardial fat, perivascular fat, and renal sinus fat. These fat depots have effects primarily on adjacent anatomic organs, directly via lipotoxicity and indirectly via cytokine secretion. Pericardial fat is associated with coronary atherosclerosis. Perivascular fat may play an independent role in adverse vascular biology, including arterial stiffness. Renal sinus fat is a unique fat depot that may confer additional cardiometabolic risk. Thus, ectopic fat depots may contribute to the understanding of the link between body composition and cardiometabolic risk. In this review, we focus on the role and clinical implications of ectopic fat depots in cardiometabolic and vascular risk.

Effects of Alpha-Lipoic Acid on Body Weight in Obese Subjects

PURPOSE alpha-lipoic acid is an essential cofactor for mitochondrial respiratory enzymes that improves mitochondrial function. We previously reported that alpha-lipoic acid markedly reduced body weight gain in rodents. The purpose of this study was to determine whether alpha-lipoic acid reduces body weight in obese human subjects. METHODS in this randomized, double-blind, placebo-controlled, 20-week trial, 360 obese individuals (body mass index [BMI] ≥ 30 kg/m(2) or BMI 27-30 kg/m(2) plus hypertension, diabetes mellitus, or hypercholesterolemia) were randomized to alpha-lipoic acid 1200 or 1800 mg/d or placebo. The primary end point was body weight change from baseline to end point. RESULTS the 1800 mg alpha-lipoic acid group lost significantly more weight than the placebo group (2.1%; 95% confidence interval, 1.4-2.8; P<.05). Urticaria and itching sensation were the most common adverse events in the alpha-lipoic acid groups, but these were generally mild and transient. CONCLUSION alpha-lipoic acid 1800 mg/d led to a modest weight loss in obese subjects. Alpha-lipoic acid may be considered as adjunctive therapy for obesity.

Links Between Ectopic Fat and Vascular Disease in Humans

The average of overweight individual can have differential fat depots in target organs or specific compartments of the body. This ectopic fat distribution may be more of a predictive factor for cardiovascular risk than obesity. Abdominal visceral obesity, a representative ectopic fat, is robustly associated with insulin resistance and cardiovascular risk. Fat depots in the liver and muscle tissue cause adverse cardiometabolic risk by affecting glucose and lipid metabolism. Pericardial fat and perivascular fat affect coronary atherosclerosis, cardiac function, and hemodynamics. Fat around the neck is associated with systemic vascular resistance. Fat around the kidney may increase blood pressure and induce albuminuria. Fat accumulation in or around the pancreas alters glucose metabolism, conferring cardiovascular risk. Ectopic fat may act as an active endocrine and paracrine organ that releases various bioactive mediators that influence insulin resistance, glucose and lipid metabolism, coagulation, and inflammation, which all contribute to cardiovascular risk. Because both obese and apparently lean individuals can have ectopic fat, regional fat distribution may play an important role in the development of cardiovascular diseases in both nonobese and obese people.

Prevalence, awareness, and management of obesity in Korea: data from the Korea national health and nutrition examination survey (1998-2011).

Background Obesity is a risk factor for diabetes and several cardiovascular diseases. This study was to investigate the trends in the prevalence, awareness, and management status of obesity among the Korean population for recent 13 years. Methods The prevalence, subjective awareness, and management of obesity were investigated in adults aged ≥19 years by using the data from the Korea National Health and Nutrition Examination Surveys (KNHANES) 1998 to 2011. Results The number of participants was 8,117, 5,826, 5,500, 3,025, 6,756, 7,506, 6,255, and 6,155 in the KNHANES in years 1998, 2001, 2005, 2007, 2008, 2009, 2010, and 2011, respectively. The prevalence of obesity was 26.9%, 29.2%, 32.9%, 32.5%, 32.0%, 32.6%, 32.0%, and 32.0% in 1998, 2001, 2005, 2007, 2008, 2009, 2010, and 2011, respectively, while the overall prevalence of obesity and abdominal obesity increased by 1.19-fold and 1.24-fold respectively in 2011 compared against 2001. In general, a gradual increase in the prevalence of severe obesity has been observed as years go by. Furthermore, trends of improvements in obesity awareness and management rates were visible over the period of surveys. Conclusion Although the management status of obesity has improved during the recent years, more effective strategy to control obesity is needed.

Prevalence of Diabetes and Prediabetes according to Fasting Plasma Glucose and HbA1c

Background Due to the inconvenience of performing oral glucose tolerance tests and day to day variability in glucose level, glycated hemoglobin (HbA1c) has been recommended by the American Diabetes Association as a method to diagnose diabetes. In addition, the Korean Diabetes Association has also recommended the use of HbA1c as a diagnostic test for diabetes. In this study, we evaluated the prevalence of diabetes according to fasting plasma glucose (FPG) level only or the combination of FPG and HbA1c tests. Methods Data from the 2011 Korea National Health and Nutrition Examination Survey (KNHANES) were analyzed. Among 5,811 subjects aged 30 years or older, 5,020 were selected after excluding the data of fasting time <8 hours, missing values from fasting glucose or HbA1c level, previous diagnosis of diabetes made by physicians, or current use of antidiabetic medications. Diabetes was defined as FPG ≥126 mg/dL, previous diagnosis of diabetes made by a medical doctor, current use of antidiabetic medications, and/or HbA1c ≥6.5%. Prediabetes was defined as FPG of 100 to 125 mg/dL and/or HbA1c of 5.7% to 6.4%. Results When we used FPG only, the prevalence of diabetes and prediabetes were 10.5% (men, 12.6%; women, 8.5%) and 19.3% (men, 23.8%; women, 14.9%), respectively. When HbA1c was included as a diagnostic test, the prevalence of diabetes and prediabetes increased to 12.4% (men, 14.5%; women, 10.4%) and 38.3% (men, 41%; women, 35.7%), respectively. Participants with HbA1c ≥6.5% and fasting glucose level <126 mg/dL were older and had lower estimated glomerular filtration rate. Conclusion We concluded that using fasting glucose level only may result in an underestimation of diabetes and prediabetes. HbA1c is an acceptable complementary diagnostic test for diabetes in Korean patients. However, national standardization is needed to order to use HbA1c as a diagnostic method of diabetes and prediabetes.