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Homeostatic Model Assessment (homeostatic + model_assessment)
Selected AbstractsGlucose tolerance status in 510 children and adolescents attending an obesity clinic in Central ItalyPEDIATRIC DIABETES, Issue 1 2010Claudia Brufani Brufani C, Ciampalini P, Grossi A, Fiori R, Fintini D, Tozzi A, Cappa M, Barbetti F. Glucose tolerance status in 510 children and adolescents attending an obesity clinic in Central Italy. Childhood obesity is epidemic in developed countries and is accompanied by an increase in the prevalence of type 2 diabetes (T2DM). Aims: Establish prevalence of glucose metabolism alterations in a large sample of overweight/obese children and adolescents from Central Italy. Methods: The study group included 510 overweight/obese subjects (3,18 yr). Oral glucose tolerance test (OGTT) was performed with glucose and insulin determination. Homeostatic model assessment of insulin resistance (HOMA-IR) and insulin sensitivity index (ISI) were derived from fasting and OGTT measurements. Beta-cell function was estimated by insulinogenic index. Fat mass was measured by dual-energy x-ray absorptiometry. Results: Glucose metabolism alterations were detected in 12.4% of patients. Impaired glucose tolerance (IGT) was the most frequent alteration (11.2%), with a higher prevalence in adolescents than in children (14.8 vs. 4.1%, p < 0.001); silent T2DM was identified in two adolescents (0.4%). HOMA-IR and glucose-stimulated insulin levels were higher in patients with IGT than individuals with normal glucose tolerance (HOMA-IR = 4.4 ± 2.5 vs. 3.4 ± 2.3, p = 0.001). Fat mass percentage and insulinogenic index were not different between the two groups. In multivariate analysis, age, fasting glucose, and insulin resistance influenced independently plasma glucose at 120 min of OGTT. Individuals with combined impaired fasting glucose/IGT (IFG/IGT) and T2DM were older and had reduced plasma insulin values at OGTT when compared to patients with simple IGT. Conclusions: Glucose metabolism alterations are frequently found among children and adolescents with overweight/obesity from Central Italy. Age, fasting glucose, and insulin resistance are main predictors of IGT. We suggest the use of OGTT as a screening tool in obese European adolescents. [source] Rosiglitazone is more effective than metformin in improving fasting indexes of glucose metabolism in severely obese, non-diabetic patientsDIABETES OBESITY & METABOLISM, Issue 6 2008A. Brunani Aim:, In obese patients, the diet-induced weight loss markedly improves glucose tolerance with an increase in insulin sensitivity and a partial reduction of insulin secretion. The association with metformin treatment might potentiate the effect of diet alone. Methods:, From patients admitted to our Nutritional Division for diet programme, we selected obese, non-diabetic, uncomplicated patients with age 18,65 years and body mass index 35,50 kg/m2 and studied the effects of a 6-month pharmacological treatment with either metformin (850 mg twice daily) or rosiglitazone (4 mg twice daily) on possible changes in body weight, fat mass, glucose and lipids metabolism. Results:, A significant weight loss and reduction of fat mass was demonstrated with metformin (,9.7 ± 1.8 kg and ,6.6 ± 1.1 kg) and also with rosiglitazone (,11.0 ± 1.9 kg and ,7.2 ± 1.8 kg), without fluid retention in either treatment group. Rosiglitazone administration induced a significant decrease in glucose concentration (4.7 ± 0.1 vs. 4.4 ± 0.1 mmol/l, p < 0.005) and insulin-circulating level (13.6 ± 1.5 vs. 8.0 ± 0.,7 ,U/ml, p < 0.005), an increase in insulin sensitivity as measured by homeostatic model assessment (HOMA) of insulin sensitivity (68.9 ± 8.8 vs. 109.9 ± 10.3, p < 0.005) with a concomitant decrease in ,-cell function as measured by HOMA of ,-cell function (163.2 ± 16.1 vs. 127.4 ± 8.4, p < 0.005). In contrast, metformin did not produce any significant effect on blood glucose concentration, insulin level and HOMA2 indexes. No adverse events were registered with pharmacological treatments. Conclusion:, Our study shows that in severely obese, non-diabetic, hyperinsulinaemic patients undergoing a nutritional programme, rosiglitazone is more effective than metformin in producing favourable changes in fasting-based indexes of glucose metabolism, with a reduction of both insulin resistance and hyperinsulinaemia. In spite of previous studies reporting rosiglitazone-induced body weight gain, in our study the joint treatment with diet and rosiglitazone was accompanied by weight loss and fat mass reduction. [source] An increase in insulin sensitivity and basal beta-cell function in diabetic subjects treated with pioglitazone in a placebo-controlled randomized studyDIABETIC MEDICINE, Issue 6 2004T. M. Wallace Abstract Aims To investigate the effect of treatment with pioglitazone on beta-cell function and insulin sensitivity in Type 2 diabetes. Methods Thirty subjects with diet-controlled Type 2 diabetes were randomized to 3 months treatment with pioglitazone (n = 19) or placebo (n = 11). All subjects underwent basal sampling for homeostatic model assessment (HOMA), followed by an intravenous glucose tolerance test and hyperglycaemic clamp, followed by an euglycaemic hyperinsulinaemic clamp; at baseline and after treatment. Results All results are expressed as mean (sem). Pioglitazone increased basal insulin sensitivity by 24.7% (7.8) HOMA-%S vs. 2.1% (5.9) in the placebo group (P = 0.02). Stimulated insulin sensitivity, M/I, increased in the pioglitazone group compared with placebo: +15.1 (2.8) l kg,1 min,1 vs. +3.2 (2.9) l kg,1 min,1, respectively (P = 0.009). Pioglitazone increased adiponectin by 39.3 (6.3), ng/ml compared with a decrease of 0.8 (1.3) ng/ml with placebo (P = 0.00004). HOMA-%B increased with pioglitazone, +11.5% (4.8) vs. ,2.0% (4.8) with placebo (P = 0.049), but there was no change in stimulated beta-cell function as determined by hyperglycaemic clamps. There was a significant reduction in the proinsulin/insulin ratio in the pioglitazone group, ,0.057 (0.02) compared with placebo, +0.004 (0.02) (P = 0.03). There was a significant reduction in HbA1c of 0.6% (0.1) in the pioglitazone group compared with placebo (P = 0.003). There was no significant weight gain associated with pioglitazone therapy: +0.7 (sem 0.6) kg vs. +1.1 (sem 0.5) kg in placebo group (P = NS). Conclusions Basal beta-cell function and insulin sensitivity improved following pioglitazone therapy. The improvement in proinsulin to insulin ratio suggests that beta-cells are under less stress. [source] The assessment of insulin resistance in manDIABETIC MEDICINE, Issue 7 2002T. M. Wallace Abstract Background Insulin resistance exists when a normal concentration of insulin produces a less than normal biological response. The ability to measure insulin resistance is important in order to understand the aetiopathology of Type 2 diabetes, to examine the epidemiology and to assess the effects of intervention. Methods We assess and compare methods of measurement and have undertaken a literature review from 1966 to 2001. Results Quantitative estimates of insulin resistance can be obtained using model assessments, clamps or insulin infusion sensitivity tests. There is considerable variation in the complexity and labour intensity of the various methods. The most well-established methods are the euglycaemic clamp, minimal model assessment and homeostatic model assessment (HOMA). No single test is appropriate under all circumstances. Conclusions There are a number of well-established tests used to measure insulin resistance: the choice of method depends on the size and type of study to be undertaken. Although the so-called ,gold-standard' test, the euglycaemic clamp, is useful for intensive physiological studies on small numbers of subjects, a simpler tool such as HOMA is more appropriate for large epidemiological studies. It is important to be aware that most techniques measure stimulated insulin resistance whereas HOMA gives an estimate of basal insulin resistance. Caution should be exercised when making comparisons between studies due to variations in infusion protocols, sampling procedures and hormone assays used in different studies. [source] Increased insulin resistance and risk of incident cerebrovascular events in patients with pre-existing atherothrombotic diseaseEUROPEAN JOURNAL OF NEUROLOGY, Issue 11 2009D. Tanne Background and purpose:, Diabetes and the metabolic syndrome are known risk factors for ischaemic stroke. Our aim was to examine whether amongst patients with pre-existing atherothrombotic disease, increased insulin resistance is associated with incident cerebrovascular events. Methods:, Patients with stable coronary heart disease included in a secondary prevention trial were followed up for a mean of 6.2 years. Coronary heart disease was documented by a history of myocardial infarction ,6 months and <5 years before enrollment and/or stable angina pectoris with evidence of ischaemia confirmed by ancillary diagnostic testing. Main exclusion criteria were insulin treated diabetes, hepatic or renal failure, and disabling stroke. Baseline insulin levels were measured in 2938 patients from stored frozen plasma samples and increased insulin resistance assessed using the homeostatic model assessment of insulin resistance (HOMA-IR), categorized into tertiles or quartiles. Results:, Crude rates of incident cerebrovascular events rose from 5.0% for HOMA-IR at the bottom tertile to 5.7% at the middle tertile, and 7.0% at the top tertile (P = 0.07). HOMA-IR at the top versus bottom tertile was associated with an unadjusted hazard ratio (HR) of 1.37 (95%CI, 0.94,1.98) and a 1-unit increase in the ln HOMA-IR was associated with a HR of 1.14 (95%CI, 0.97,1.35). In further analyses adjusting for potential confounders, or categorizing baseline HOMA-IR into quartiles, or excluding diabetic patients, we did not identify an increased risk for incident cerebrovascular events conferred by the top category. Conclusions:, Increased insulin resistance did not predict incident cerebrovascular events amongst patients with pre-existing atherothrombotic disease. [source] Nonobese population in a developing country has a high prevalence of nonalcoholic fatty liver and significant liver disease,,HEPATOLOGY, Issue 5 2010Kausik Das There is a paucity of community-based epidemiological data on nonalcoholic fatty liver (NAFL) among nonaffluent populations in developing countries. Available studies are radiological and/or biochemical and lack histological assessment, limiting their strength. We conducted a prospective epidemiological study comprising a 1:3 subsample of all adult (>18 years) inhabitants of a rural administrative unit of West Bengal, India. Subjects positive for hepatitis B virus and/or hepatitis C virus infection and consuming any amount of alcohol were excluded. Diagnosis of NAFL was by dual radiological screening protocol consisting of ultrasonographic and computed tomographic examination of the liver. Transient elastographic examination and liver biopsy were performed in a subset to identify significant liver disease. The risk factors of having NAFL were analyzed. A total of 1,911 individuals were analyzed, 7% of whom were overweight and 11% of whom had abdominal obesity. The prevalence of NAFL, NAFL with elevated alanine aminotransferase, and cryptogenic cirrhosis was 8.7%, 2.3%, and 0.2%, respectively. Seventy-five percent of NAFL subjects had a body mass index (BMI) <25 kg/m2, and 54% were neither overweight nor had abdominal obesity. The subjects with the highest risk of having NAFL were those with a BMI >25 kg/m2 (odds ratio 4.3, 95% confidence interval 1.6-11.5). Abdominal obesity, dysglycemia (fasting plasma glucose >100 mg/dL or elevated homeostatic model assessment of insulin resistance), and higher income were the other risk factors. Even having a normal BMI (18.5-24.9 kg/m2) was associated with a 2-fold increased risk of NAFL versus those with a BMI <18.5 kg/m2. Conclusion: There is a significant prevalence of NAFL and potentially significant liver disease, including cryptogenic cirrhosis, in this predominantly nonobese, nonaffluent population in a developing country. NAFL will be a major determinant of future liver disease burden in countries of the developing world. (HEPATOLOGY 2010) [source] Evaluation of Insulin Sensitivity in Clinical Practice and in Research SettingsNUTRITION REVIEWS, Issue 12 2003Lais U. Monzillo MD Insulin resistance is the core metabolic abnormality in type 2 diabetes. Its high prevalence and its association with dyslipidemia, hypertension, hyperinsulinemia, and high coronary and cerebrovascular mortality put it in the forefront as the plausible target for aggressive intervention. Measurements of insulin sensitivity provide clinicians and clinical researchers with invaluable instruments to objectively evaluate the efficiency of both current and potentially useful interventional tools. Although several methods had been developed and validated to evaluate insulin sensitivity, none of these methods can be universally used in all patients. Nonetheless, a method suitable for use in clinical or basic research may not necessarily be a practical method for use in clinical practice or for epidemiologic research. We reviewed the currently used methods for assessment of insulin sensitivity. For each method, we summarized its procedure, normal value, cut-off value for defining insulin resistance, advantages and limitations, validity, accuracy for each patient population, and suitability for use in clinical practice and in research settings. The methods reviewed include fasting plasma insulin, homeostatic model assessment, quantitative insulin sensitivity check index, glucose-to-insulin ratio, continuous infusion of glucose with model assessment, indices based on oral glucose tolerance test, insulin tolerance test, and the so called "gold standard" methods, the hyperinsulinemic euglycemic clamp and the frequently sampled-intravenous glucose tolerance test. [source] The effect of low-carbohydrate diet on left ventricular diastolic function in obese childrenPEDIATRICS INTERNATIONAL, Issue 2 2010Cenap Zeybek Abstract Background:, This study was conducted to evaluate left ventricle (LV) functions using conventional and tissue Doppler imaging in childhood obesity and to identify the effects of diet on LV diastolic functions. Methods:, Conventional and tissue Doppler echocardiographic measurements were compared in 34 obese children and 24 age- and gender-matched lean controls. Fasting plasma glucose, insulin and homeostatic model assessment of insulin resistance levels were also obtained. Thirty-one of the obese children were subjected to a low-carbohydrate diet and their follow-up measurements were obtained after 6 months. Results:, Left atrial diameter, LV mass and LV mass index were higher in obese children than in lean controls. Lateral mitral myocardial early diastolic (Em) and peak Em/myocardial late diastolic (Am) were lower, and mitral E/Em and lateral mitral myocardial isovolumetric relaxation time were higher in obese subjects than in lean controls. Insulin and homeostatic model assessment of insulin resistance levels were higher in obese patients and decreased significantly after diet. After diet therapy, lateral mitral Em and peak Em/Am, were increased, mitral E/Em and myocardial isovolumetric relaxation time were decreased. Conclusions:, Obesity predisposes children to increased preload reserve, left ventricular subclinical diastolic dysfunction and deterioration in diastolic filling. Weight reduction with a low-carbohydrate diet seems to be associated with significant improvement in LV diastolic function and a decrease in diastolic filling, as well as causing reversal in insulin resistance seen in obese children. [source] Adipocytokines, insulin resistance, and coronary atherosclerosis in rheumatoid arthritisARTHRITIS & RHEUMATISM, Issue 5 2010Young Hee Rho Objective The prevalence of subclinical coronary atherosclerosis is increased in patients with rheumatoid arthritis (RA), and the increased risk is associated with insulin resistance. Adipocytokines have been linked to obesity, insulin resistance, inflammation, and coronary heart disease in the general population. This study was undertaken to examine the hypothesis that adipocytokines affect insulin resistance and coronary atherosclerosis among patients with RA. Methods The coronary calcium score, homeostatic model assessment for insulin resistance (HOMA-IR) index, and serum adipocytokine (leptin, adiponectin, resistin, and visfatin) concentrations were determined in 169 patients with RA. The independent effect of each adipocytokine on insulin resistance according to the HOMA-IR index and on coronary artery calcification determined by electron beam computed tomography was assessed in models adjusted for age, race, sex, body mass index (BMI), traditional cardiovascular risk factors, and inflammation mediators. In addition, an interaction analysis was performed to evaluate whether the effect of the HOMA-IR index on the coronary calcium score is moderated by adipocytokines. Results Increased concentrations of leptin were associated with a higher HOMA-IR index, even after adjustment for age, race, sex, BMI, traditional cardiovascular risk factors, and inflammation mediators (P < 0.001), but concentrations of visfatin (P = 0.06), adiponectin (P = 0.55), and resistin (P = 0.98) showed no association with the HOMA-IR index. None of the adipocytokines was independently associated with the coronary calcium score (all P > 0.05). Serum leptin concentrations showed a significant interaction with the HOMA-IR index (P for multivariate interaction = 0.02). Increasing leptin concentrations attenuated the increased risk of coronary calcification related to insulin resistance. Serum concentrations of the other adipocytokines showed no significant interactions with the HOMA-IR index (each P > 0.05). Conclusion Leptin is associated with insulin resistance in patients with RA but, paradoxically, attenuates the effects of insulin resistance on coronary calcification. [source] Insulin resistance and the metabolic syndrome in obese French childrenCLINICAL ENDOCRINOLOGY, Issue 6 2006Céline Druet Summary Objective, To estimate the frequency of the metabolic syndrome (MS) and of the insulin resistance syndrome (IRS) in overweight or obese French children and to determine the risk factors. Design, patients and methods, A total of 308 overweight and obese children [166 girls, 142 boys, aged 7,17 years; median body mass index (BMI) 4·7 standard deviation (SD) (Q1,Q3: 3·9,5·8) adjusted for age and sex] were included. The frequency of the MS was assessed with the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) criteria and the frequency of the IRS with World Health Organization (WHO) criteria. Results, The overall frequency of MS and IRS was 15·9% and 42·5%, respectively. The most common component, after abdominal obesity (95·8%) and IR (71·8%), was elevated systolic blood pressure (28·6%). The frequency of glucose tolerance disorders was low (3·6%). The frequency of MS was independently influenced by homeostatic model assessment (HOMA) (P = 0·06) and waist-to-hip ratio (P = 0·09), whereas the frequency of IRS was influenced by adiposity (degree of obesity: P = 0·02; waist-to-hip ratio: P = 0·05), puberty (P = 0·05) and mother's BMI (P = 0·01). Ethnicity had no effect on either MS or IRS. Conclusions, Metabolic complications and IR are frequent in overweight and obese children whereas the frequency of glucose tolerance disorders is very low. IRS is more prevalent than MS, indicating a major role of IR, which could precede the other metabolic complications in obese children. IRS is a relevant marker for the risk of type 2 diabetes (T2D) and cardiovascular complications in obese European children. [source] |