Assessment of insulin sensitivity from measurements in fasting state and during an oral glucose tolerance test in obese children

BACKGROUND: Few previous studies have examined the validity of the fasting glucose-to-insulin ratio (FGIR), homeostasis model assessment of insulin resistance (HOMA-IR) and quantitative insulin-sensitivity check index (QUICKI) in pediatric populations. OBJECTIVE: To compare simple indices of insulin resistance calculated from fasting glucose and insulin levels with insulin sensitivity indices (area under the response curve [AUCinsulin], insulin sensitivity index [ISI-compositeL) determined by oral glucose tolerance testing (OGTT) in obese children. METHODS: One hundred and forty-eight obese children and adolescents (86 girls and 62 boys, mean age: 10.86 +/- 3.08 years, mean body mass index (BMI): 27.7 +/- 4.2) participated in the study. OGTT was performed in all participants. After glucose and insulin measurements from OGTT, the children were divided into two groups according to the presence or absence of insulin resistance. Insulin sensitivity indices obtained from the OGTT were compared between the groups. The total plasma glucose response and insulin secretion were evaluated from the AUC estimated by the trapezoid rule. Cut-off points, and sensitivity and specificity calculations were based on insulin resistance with receiver operating characteristic curve (ROC) analysis. RESULTS: The prevalence of insulin resistance, glucose intolerance and dyslipidemia was 37.1%, 24.3% and 54% in obese children, respectively. The groups consisted of 93 children without insulin resistance (54 girls and 39 boys; mean age: 10.5 +/- 3.3 years; mean BMI: 27.0 +/- 4.2) and 55 children with insulin resistance (32 girls and 23 boys; mean age: 11.4 +/- 2.5 years; mean BMI: 27.9 +/- 3.9). There were significant differences in mean FGIR (10.0 +/- 7.2 vs 5.6 +/- 2.8, p < 0.001), HOMA-IR (3.2 +/- 2.3 vs 4.9 +/- 2.3, p < 0.001) and QUICKI (0.33 +/- 0.03 vs 0.30 +/- 0.02, p < 0.001) between the groups. The cut-off points for diagnosis of insulin resistance were < 5.6 for FGIR (sensitivity 61.8, specificity 76.3), > 2.7 for HOMA-IR (sensitivity 80, specificity 59.1), and < 0.328 for QUICKI (sensitivity 80, specificity 60.2). CONCLUSIONS: Indices derived from fasting samples for diagnosis of insulin sensitivity are reliable criteria in obese children and adolescents. HOMA-IR and QUICKI appeared to have similar sensitivity and specificity and to have higher sensitivity than FGIR.     

Glucose tolerance status in 510 children and adolescents attending an obesity clinic in Central Italy

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.     

The absence of insulin resistance in metabolic syndrome definition leads to underdiagnosing of metabolic risk in obese patients

This study explores in a group of obese children and adolescents aged 10 to 16 years, the prevalence of metabolic syndrome (MS) according to the criteria of International Diabetes Federation (IDF). In addition, the prevalence of insulin resistance (IR) was investigated to find correlations between MS and IR. IDF definition was compared to a modified WHO definition. A total of 159 obese patients (74 male and 85 female; median age 12.7 years) were included in the study. Anthropometric measurements, blood pressure, and serum fasting lipids were evaluated. An oral glucose tolerance test (OGTT) was performed, and serum glucose and insulin levels were measured at 0, 30, 60, 90, and 120 min. Homeostasis model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), fasting glucose/insulin ratio (FGIR), Matsuda index, and total insulin levels during OGTT were calculated. For the IR diagnosis, we used cutoff values described in previous publications (HOMA-IR of >3.16, QUICKI of <0.357, FGIR of <7, and/or the sum of insulin levels during OGTT of >300 mIU/mL). MS prevalence, defined according to IDF criteria, was 34.6 %. Using the IDF definition, there was no statistically significant difference for the surrogate IR indices between patients with or without MS (QUICKI, 94.5 vs. 83.7 %), FGIR (81.1 vs. 78.8 %), HOMA-IR (70.9 vs. 63.5 %), and total insulin levels during OGTT (61.8 vs. 51.9 %). The Matsuda index values, the prevalence of fasting hyperinsulinemia, and impaired glucose tolerance were also similar in these two groups. In conclusion, IR was prominent in obese patients with and without MS. IDF definition of MS fails to discover individuals with IR, unless it is specifically investigated.     

Monitorización continua de glucosa para cribado de alteraciones hidrocarbonadas en fibrosis quística

BackgroundDiabetes mellitus (DM) is an increasing complication of cystic fibrosis (CF). It is associated with enhance morbidity. Continuous glucose monitoring system (CGMS) could detect glucose disorders earlier than other screening tests usually used.AimsTo compare oral glucose tolerance test (OGTT), HbA_1c and CGMS in patients with CF and recent disorders of glucose homeostasis and to analyse changes in nutritional status and/or pulmonary function.Patients and methodsThirteen patients with CF (11–22 years, 7 males) were studied using OGTT, HbA_1c and CGMS. All of them had newly diagnosed glucose disturbances. They were not receiving steroid therapy or had an underlying illness. In all subjects we compared: HbA_1c levels (%), fasting and 2-hours glucose OGTT (mg/dl) and glucose CGMS values (overall, fasting, 2-hours post mean-meals and excursions >140 mg/dl at any time). Furthermore, body mass index, forced expiratory volume in the first second (%) and forced vital capacity (%) were evaluated in the previous year and at the time of the study. We also analysed exocrine pancreatic function and CF-mutation.ResultsMean age at diagnosis of glucose disturbance was 16.4 years. All patients had insufficient exocrine pancreatic function and 11/13 presented ΔF508 CF-mutation. Only one patient was diagnosed with DM using OGGT and 7/13 (53.8%) with CGMS. A total 77% of patients had poor nutritional status and/or pulmonary function at time of diagnosing the glucose disorder. Only 4 patients had abnormal HbA_1c levels.ConclusionsCGMS allows a better detection of glucose disorders than OGTT. Glucose homeostasis abnormalities are associated with a decrease in nutritional status and/or pulmonary function. HbA_1c does not aid in the early diagnose of glucose disorders.     

Repetitiveness of the oral glucose tolerance test in children and adolescents

BACKGROUNDData regarding the most suitable diagnostic method for the diagnosis of glucose impairment in asymptomatic children and adolescents are inconclusive. Furthermore, limited data are available on the reproducibility of the oral glucose tolerance test (OGTT) in children and adolescents who are obese (OB).AIMTo investigate the usefulness of the OGTT as a screening method for glucose dysregulation in children and adolescents.METHODSEighty-one children and adolescents, 41 females, either overweight (OW), OB or normal weight (NW) but with a strong positive family history of type 2 diabetes mellitus (T2DM), were enrolled in the present observational study from the Outpatient Clinic of Paediatric Endocrinology of the University Hospital of Patras in Greece. One or two 3-h OGTTs were performed and glucose, insulin and C-peptide concentrations were measured at several time points (t = 0 min, t = 15 min, t = 30 min, t = 60 min, t = 90 min, t = 120 min, t = 180 min).RESULTSGood repetitiveness was observed in the OGTT response with regard to T2DM, while low repetitiveness was noted in the OGTT response with regard to impaired glucose tolerance (IGT) and no repetitiveness with regard to impaired fasting glucose (IFG). In addition, no concordance was observed between IFG and IGT. During the 1^st and 2^nd OGTTs, no significant difference was found in the glucose concentrations between NW, OW and OB patients, whereas insulin and C-peptide concentrations were higher in OW and OB compared to NW patients at several time points during the OGTTs. Also, OW and OB patients showed a worsening insulin and C-peptide response during the 2^nd OGTT as compared to the 1^st OGTT.CONCLUSIONIn mild or moderate disorders of glucose metabolism, such as IFG and IGT, a diagnosis may not be reached using only one OGTT, and a second test or additional investigations may be needed. When glucose metabolism is profoundly impaired, as in T2DM, one OGTT is probably more reliable and adequate for establishing the diagnosis. Excessive weight and/or a positive family history of T2DM possibly affect the insulin and C-peptide response in the OGTT from a young age.     

Glucose metabolism abnormalities among pediatric acute lymphoblastic leukemia survivors: Assessment and relation to body mass index and waist to hip ratio

BackgroundAs survival rates of pediatric acute lymphoblastic leukemia (ALL) improve, attention is turning to side and late effects of therapy including glucose metabolism abnormalities.ObjectiveTo asses the presence of abnormal glucose metabolism in pediatric ALL survivors and its possible relation to body mass index (BMI), waist to hip ratio and treatment related factors.Subjects and methodsRetrospective study with a prospective follow-up of 12 ALL survivors who had been off chemotherapy for >9 months was done. Fifteen healthy sex and age matched children were involved as controls. Body mass index (BMI) waist to hip ratio (WHR), and Oral glucose tolerance test (OGTT) were performed with assessment of glycated hemoglobin (Hb A1C) and insulin sensitivity indices.ResultsAt study time the mean BMI, WHR, all components of the OGTT (except the 2 h post load glucose), all indices of insulin sensitivity and the mean Hb A1C% were significantly higher compared to those of the controls. Two survivors (16.6%) developed transient hyperglycemia during therapy, one (8.3%) had pre-diabetes, seven (58.3%) had a risk level of Hb A1C but no one had diabetes mellitus (DM) or insulin resistance (IR). At study time the two survivors with transient hyperglycemia during therapy had a significantly high WHR compared to the remainders. WHR of the survivors at study time correlated significantly with fasting plasma glucose and area of insulin under the curve (AUC). The 2 h post-prandial plasma glucose correlated with the duration after therapy completion.ConclusionsWHR may play a better role than BMI in the prediction of insulin resistance in those patients. Hb A1C may increase earlier than other indices of glucose tolerance.     

Prevalence of impaired glucose metabolism in β-thalassemic children receiving hypertransfusions with a suboptimal dosage of iron-chelating therapy

A cross-sectional study of impaired glucose metabolism was carried out in 48 beta-thalassemic patients receiving hypertransfusions. An oral glucose tolerance test (OGTT) was performed using the method and criteria of the American Diabetes Association (ADA). Diabetes mellitus was diagnosed in two patients, and impaired glucose tolerance was found in four patients, giving a prevalence of impaired glucose metabolism of 12.5% in our patient population. The significant clinical characteristics associated with the diagnosis of impaired glucose metabolism were wasting (-2.15/-0.86 SDS, p = 0.025), stunting (-2.69/-1.22 SDS, p = 0.03), higher ferritin levels (8679/4710 mug/L, p = 0.005), splenectomy (50/9.5%, p = 0.012), and lower area under curve (AUC) of insulin secretion after OGTT (40.0/77.7, p = 0.002). The significant decrease of AUC insulin in thalassemic patients with an impaired glucose tolerance test suggests that the pathogenesis may originate from pancreatic beta-cell damage rather than from insulin resistance. In conclusion, the prevalence of impaired glucose tolerance in our population of thalassemic patients receiving hypertransfusions with suboptimal iron chelating therapy was 12.5%. The clinical characteristics of thalassemic patients who developed impaired glucose tolerance were wasting, stunting, higher ferritin levels, splenectomy, and lower AUC insulin.     

Oral glucose tolerance testing in cystic fibrosis: Correlations with clinical parameters and glycosylated haemoglobin determinations

In 48 patients (age 2–28 years) with documented cystic fibrosis, glucose tolerance was evaluated by means of an oral glucose tolerance test (OGTT) and repeated glycosylated haemoglobin (HbA1C) measurements. An impaired OGTT was found in 15 patients. Their degree of undernutrition and severity of lung and liver involvement were no different from those with normal glucose tolerance. The mean peak insulin concentration as well as the integrated insulin concentration during the OGTT were comparable with patients with normal glucose tolerance (GT) and those with an impaired tolerance (GI). The mean time to attain peak insulin levels was significantly delayed in the GI group. (117 min vs 86 minP<0.01). On initial testing, elevated HbA1C levels were found in 22 patients. Mean HbA1C levels in the GI group were higher than in the GT group *8.2% vs 7.5%P<0.01). The HbA1C levels at the moment of OGT testing were positively correlated with the glycaemic response during the OGTT. The repeated HbA1C measurements 1 year later were no different from the initial mean HbA1C values in both groups. Two GI patients with initial HbA1C levels of 7.5% and 11% respectively developed diabetes mellitus several months after testing. The need for serial HbA1C determinations in cystic fibrosis is questioned.     

Influencia de la antropometría neonatal sobre las comorbilidades del paciente obeso

IntroductionSmall for gestational age (SGA) newborns show an increased risk of several diseases such as short stature, childhood obesity, and metabolic comorbidities.Patients and methodsThe study included 883 obese patients (47% females/53% males; mean age: 10.33 ± 3.32 years, BMI: + 3.93 ± 1.42 SD), with prospective follow-up (5 years) of growth, recording adult height when achieved (n = 104). Comparisons at diagnosis, according to their neonatal anthropometry; adequate for gestational age (AGA; n = 810) vs. SGA (n = 73), were performed for the following features: age at their first visit, standardised height for target height (Z-score), bone age, adult height prediction, BMI (Z-score), glycaemia, insulinaemia, HOMA, total cholesterol, HDL, LDL, triglycerides, 25-OH-vitamin D, area under the curve (AUC) for glucose and insulin in the OGTT, LDL/HDL and triglyceride/HDL ratio, insulin-like growth factor (IGF-I) and IGF-binding protein 3 (IGFBP-3) serum levels.ResultsDespite similar BMI-SDS, ethnic, and pubertal distribution in both groups, patients with SGA showed more severe changes in lipid profile (triglyceride and triglyceride/HDL ratio, both P < .05) and carbohydrate metabolism (higher glycaemia, glucose and insulin AUCs, HOMA, HbA1c and lower whole-body insulin sensitivity index (WBISI), all P<.05) and lower 25-OH vitamin D levels (P<.05). They also showed a poorer adult height prediction (adjusted for target height) (P<.01), despite a similar degree of advance in skeletal maturation and similar IGF-I and IGFBP-3 levels than AGA patients.ConclusionsThe background of SGA neonatal anthropometry is associated with a higher prevalence and severity of metabolic comorbidities and to a poorer adult height prediction in obese children and adolescents.     

Alterations of glucoregulation in childhood obesity--association with insulin resistance and hyperinsulinemia

AIM: To study the prevalence of alterations of glucoregulation in childhood obesity. PARTICIPANTS: 250 obese children. Oral glucose tolerance test was performed, serum glucose and insulin were determined, and HOMA-IR was calculated. RESULTS: Impaired fasting glucose (IFG) was found in 1.2% according to World Health Organisation criteria and 4.4% according to the criteria of the International Diabetes Federation. Impaired glucose tolerance (IGT) was found in 13.6%, type 2 diabetes mellitus (DM2) in 2.4%. Frequency of fasting glucose (FG) above 7.0 mmol/l was 1.2%. Basal hyperinsulinemia was increased in 70%, reactive hyperinsulinemia in 88%, frequency of elevated HOMA-IR was 78%. 120' insulin was increased in all cases with abnormal FG, IGT and DM2, HOMA-IR was elevated in 79% of patients with IGT and all patients with abnormal FG and DM2. Significant positive correlations were demonstrated between body mass index and insulin levels. CONCLUSION: Our data show that hyperinsulinemia can successfully compensate for insulin resistance in the majority of the obese children. Since IFG is less frequent than IGT there is a need for performing OGTT to demonstrate abnormality of glucoregulation in obese children.     

Relationship between pediatric adiposity and cardiovascular risk factors in Saudi children and adolescents

BackgroundThe etiology of childhood obesity is growing at alarming rates in developed and developing countries. The aim of the present study was to investigate the prevalence of cardiovascular risk factors (hypertension, dyslipidemia, and hyperglycemia) in a sample of Saudi children and to assess their association with different measures of body adiposity.MethodsA cross-sectional study was conducted of 200 Saudi children, who were randomly selected from the pediatric clinics at King Abdulaziz University Hospital, Jeddah, Saudi Arabia. Anthropometric variables were measured for all study subjects. Fasting blood samples were collected for measurement of blood glucose, insulin, and lipid profile.ResultsAlmost half of the study population was overweight and one tenth was obese according to body mass index levels, irrespective of sex. The prevalence of central obesity was higher using the waist-height ratio as opposed to waist circumference and this was true for both sexes. Significantly higher means levels of glucose, insulin, and lipids (P < 0.0001 in all) were seen among overweight and obese children than their lean counterparts. All obesity measures in children were significantly associated with cardiovascular risk factors.ConclusionThe severity of overall and abdominal obesity in Saudi children is associated with a higher prevalence of cardiovascular risk factors, with the relationship strength varying by sex.     

Early detection of impaired glucose tolerance in patients with cystic fibrosis and predisposition factors

INTRODUCTION: The number of patients with glucose tolerance alterations associated with cystic fibrosis (CF) has increased, probably due to the greater survival rate among sufferers of this disease. We studied impaired glucose tolerance (IGT) in patients with CF and investigated whether its appearance has any relationship with age, sex, genetic mutation and/or the degree of clinical involvement. We assessed the parameters that might allow early detection. PATIENTS AND METHODS: In 28 patients with CF (14 M, 14 F; aged 22 months to 18 years), sex, genetic mutation, nutritional status and the degree of pancreatic and pulmonary involvement were recorded. The metabolic study included glycosylated hemoglobin (HbA1c) determination, oral glucose tolerance test (OGTT) and intravenous glucose tolerance tests (IVGTT). RESULTS: In the patients with CF, 35.71% showed impaired glucose tolerance (IGT) and 3.57% had diabetes mellitus. The patients with IGT and CF were 3.2 years older than those with normal glucose tolerance (NGT; p<0.05), but no significant differences were found regarding sex, anthropometric measurements, percentage of pulmonary gammagraphic involvement, Shwachman-Kulczycki test or HbA1c. In the OGTT, the patients homozygous for the deltaF508 mutation had higher blood glucose values than the heterozygous group (p=0.03), but these values were not higher than those in patients with other mutations. During the OGTT, blood insulin values at 30' were reduced in patients with IGT compared to patients with NGT (p<0.02) and the insulin peak occurred at 100.9+/-24.3 min compared to 65.3+/-21.8, respectively (p<0.05). In the IVGTT, 82.14% of the patients had reduced insulin levels at 1 and 3 min (I1'+3'). No differences in the blood glucose levels during the OGTT were found between patients with normal I1'+3' values and patients with reduced values. CONCLUSIONS: A high percentage of patients with CF also present with IGT. This increases with age and is more common among patients homozygous for the deltaF508 mutation and is not related to clinical status. Alterations in the kinetics of insulin secretion play an important role in the appearance of IGT and CF. We suggest that the OGTT is a more sensitive method than IVGTT for identifying early alterations in CF-related diabetes mellitus.     

Carbohydrate metabolism changes in cystic fibrosis

AIMS: To assess the prevalence of impaired glucose tolerance (ITG) and diabetes mellitus (DMRCF) in a group of patients with cystic fibrosis (CF). To study clinical status-related variables and to compare age with the evolution of their carbohydrate metabolism (CHM). PATIENTS AND METHODS: Thirty patients with CF (1.5-26 years). Oral glucose tolerance test (OGTT) in 28 patients. RESULTS: Three patients (10%) showed ITG and four DMRCF (13.3%). CF patients with impaired CHM (ICHM) were older (p = 0.006), and had longer times since diagnosis and first sputum colonization (p = 0.001, p < 0.001). Homozygous deltaF508 mutation was significant (p = 0.001). Insulin peak, area under the curve for insulin, insulin resistance, insulin sensitivity, and pancreatic beta-cell function were all significant. CONCLUSIONS: ICHM was present in 23.3%. Age, time since diagnosis of CF, first sputum colonization and homozygous deltaF508 mutation were significantly associated. CHM in patients with CF is similar to that in the population without CF in the early years.     

Type 2 diabetes mellitus in children--an increasing health problem in Mexico

The incidence of type 2 diabetes mellitus (DM2) in children has increased worldwide and is commonly associated with overweight. Forty-four children with DM2 were studied by clinical histories, anthropometric measurements, and biochemical analysis. Homeostasis model assessment (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI) were determined to evaluate insulin resistance. Only five patients presented normal body mass index (BMI); the remainder were overweight, and 76% had acanthosis nigricans. Laboratory results yielded hyperglycemia, elevated glycosylated hemoglobin, insulin and C-peptide. Elevated HOMA-IR and decreased QUICKI values suggest insulin resistance. No significant difference was found between sexes, although overweight in girls had more influence over blood pressure and lipid levels (p <0.05). Time from diagnosis and HOMA-IR yielded relevant values (p = 0.010). Laboratory results, QUICKI, and HOMA-IR values suggested that these patients present DM2 and decreased insulin sensitivity. We recommend prevention of overweight and sedentary life-style.     

不同指标在评价肥胖儿童胰岛素抵抗中的价值

目的探讨单纯性肥胖儿童胰岛素抵抗临床评估的指标。方法对单纯性肥胖和正常对照儿童进行葡萄糖耐量试验和胰岛素释放试验,在试验前及试验后30、60、120、180 min分别测血糖和胰岛素,并计算稳态模型胰岛素抵抗指数(HOMA-IR)、敏感指数(HOMA-IAI)、胰岛素分泌功能(HOMA-IS)、血糖曲线下面积与胰岛素曲线下面积比及空腹血糖和空腹胰岛紊的比值(FBG/FINS)等胰岛素抵抗评价指标。结果肥胖组FINS明显高于对照组,FBG、HOMA-IS与对照组无显著差异。HOMA-IR和HOMA-IAI之间具有显著相关性,r为-1,与FINS的r分别为0.913和-0.913,与FBG/FINS的r分别为-0.889和0.889,与曲线下面积比的r分别为-0.523和-0.523,P均<0.01。结论FINS、HOMA-IR、HOMA-IAI、血糖与胰岛素曲线下面积比、FBG/FINS均适用于肥胖儿童胰岛素抵抗的评估,尤以FINS、HOMA-IR、HOMA-IAI更可取。     

Can the metabolic syndrome identify children with insulin resistance?

OBJECTIVE: The metabolic syndrome is associated with insulin resistance in adults. We defined pediatric metabolic syndrome using criteria analogous to Adult Treatment Panel III. The purpose of this study was to determine whether these criteria are reliable for insulin resistance in children. RESEARCH DESIGN AND METHODS: Out of 167 children (6.7 +/- 3 yr), 73 overweight [body mass index (BMI) > 95 percentile], 41 at risk of overweight (BMI > 85 < 95 percentile), and 53 normal-weight (BMI < 85 percentile) children matched for sex and age were examined. The results for waist circumference, blood pressure, oral glucose tolerance test, C-reactive protein, adiponectin, insulin, and lipids were obtained. RESULTS: There was a comparable prevalence of the metabolic syndrome in both sexes. The prevalence of the metabolic syndrome was 11.3% [95% confidence interval (CI) 6.56-16.19%] among the whole group and 21.9% (95% CI 12.24-31.0%) among overweight children. Waist circumference >75 percentile 53.2% (95% CI 45.73-60.86%) and low high-density lipoprotein 27.5% (95% CI 20.77-34.32%) were common in this sample. Compared with patients without any component of the metabolic syndrome, homeostasis model assessment insulin resistance (HOMA-IR) for patients with one through four components was higher (beta = 0.6, 95% CI 0.4-0.7, p < 0.0001, R(2) = 0.185). A logistic regression analysis using the metabolic syndrome as the dependent variable showed that HOMA-IR (odds ratio 1.52, 95% CI 1.2-2.0, p = 0.007) was the only independent risk factor for the metabolic syndrome, adjusted for age and sex. CONCLUSIONS: The importance of insulin resistance in the metabolic syndrome is supported by the results of logistic regression analysis. Early identification of children may be useful to predict future cardiovascular disease and type 2 diabetes.     

The abnormalities of carbohydrate metabolism in Turner syndrome: analysis of risk factors associated with impaired glucose tolerance

An oral glucose tolerance test (OGTT) was performed in 103 patients with Turner syndrome (TS) who had normal fasting and postprandial glucose levels. The plasma glucose, insulin, C-peptide and proinsulin levels were measured every 30 min during the test. Using a homeostatic model assessment (HOMA) and a quantitative insulin sensitivity check index (QUICKI), the insulin resistance in TS patients was investigated. Diabetes mellitus and impaired glucose tolerance (IGT) were newly diagnosed in two and 18 patients respectively. There was a significant increase in mean plasma glucose, insulin, C-peptide and proinsulin reponse during an OGTT in the IGT group in contrast to the normal glucose tolerance (NGT) group ( P <0.05). There was a significant decrease in the quantitative insulin sensitivity check index (QUICKI) in the IGT group in contrast to the NGT group ( P <0.05). The fasting insulin and triglyceride levels strongly predicted the 2 h glucose level during the OGTT ( P <0.05). Conclusion:The oral glucose tolerance test is superior to the fasting and postprandial plasma glucose test for the early detection of abnormalities of carbohydrate metabolism in patients with Turner syndrome.     

Evaluation of glucose intolerance in adolescents relative to adults with type 2 diabetes mellitus

AIM: There is an increasing trend in the prevalence of type 2 diabetes mellitus (DM2) in childhood and adolescence, while positive family history of DM2 and obesity are the most important risk factors. To study the influence of family history and obesity on glucose intolerance in our country was the aim of this study. STUDY DESIGN AND METHODS: A total of 105 children and adolescents aged 10-18 years (mean 13.3 +/- 2.5 years) were included in the study. All children and adolescents were divided into three groups according to positive family history of DM2 and obesity, and an oral glucose tolerance test (OGTT) was performed for all. Prediabetes was defined as impaired glucose tolerance (IGT) and/or impaired fasting glucose (IFG). Insulin secretion and insulin resistance were estimated using the insulinogenic index; and the homeostatic model assessment for insulin resistance (HOMA-IR) and Matsuda index, respectively. RESULTS: The prevalence of prediabetes was 15.2% in the whole group, while it was 25.5% in obese children who also had a positive family history of DM2. The frequency of hyperinsulinism was 57.1% in all groups. Prediabetic children had significant insulin resistance (HOMA-IR 11.5 +/- 7.1 and 4.1 +/- 6.4, respectively, p = 0.034). CONCLUSIONS: Obesity and glucose intolerance are also a problem in developing countries. The risk of prediabetes in children is highest in obese children who also have a positive family history of DM2. There is a need for a lifelong preventive program starting in childhood to avoid DM2 and decrease cardiovascular risk factors     

Relationship between different fasting-based insulin sensitivity indices in obese children and adolescents

OBJECTIVES: To evaluate insulin sensitivity from data obtained from baseline values and from an oral glucose tolerance test (OGTT) in normal and obese children and adolescents. STUDY DESIGN: We recruited 89 children 4-10 years old and 82 adolescents 11-18 years old divided into moderately obese (Mod OB), severely obese (Severe OB), and non-obese (Non-OB) controls. We evaluated the relationship between four simple measures of insulin sensitivity: homeostatic model assessment (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), fasting glucose to insulin ratio (FGIR), and fasting insulin resistance index (FIRI), with an insulin sensitivity measure derived from the standard 2-hour OGTT, the composite whole body insulin sensitivity index (ISI Comp). RESULTS: The strongest correlation was between QUICKI and ISI Comp and between FGIR and ISI Comp, (correlations [r] 0.81-0.85 in the Mod OB and 0.63-0.67 in the Severe OB). The relationship between HOMA-IR and ISI Comp and between FIRI and ISI Comp did not appear to be as strong (correlations [r] -0.36 and -0.53 in Mod OB and Severe OB, respectively). Moderately obese and severely obese children had fasting and 2-hour insulin levels 2-3 fold higher than the control group. CONCLUSIONS: QUICKI and FGIR, are strongly correlated with OGTT measures of insulin sensitivity in children and adolescents with different degrees of obesity. These simple fasting-based indices may help the pediatrician identify patients at risk of developing insulin resistance.     

rhGH替代治疗对生长激素缺乏儿童糖代谢的影响

目的探讨重组人生长激素(rhGH)替代治疗对生长激素缺乏症(GHD)儿童糖和胰岛素代谢的影响以及 GH 与糖代谢平衡之间的关系。方法对44例(男28例,女16例)4.5～16.5(10.4±2.6)岁 GHD 患儿在接受 rhGH 治疗前及治疗后每3个月检测体重指数、胰岛素样生长因子-1(IGF-1)、行口服葡萄糖耐量试验,计算稳态模型胰岛素抵抗指数。结果 (1)空腹血糖和 IGF-1在治疗3个月时即显著提高,一直持续较高水平,每个随访时间点与治疗前比较,差异均有统计学意义(F=6.81,7.31,P 均<0.01);稳态模型胰岛素抵抗指数和空腹胰岛素分别在治疗3和9个月时提高(P<0.01和 P<0.05),1年后下降,治疗1年半时与治疗前比较,差异已无统计学意义(均 P>0.05)。(2)相关分析发现,稳态模型胰岛素抵抗指数与体重指数、IGF-1和治疗持续时间显著相关(r=0.251,0.437,0.281,P 均<0.001)。二次方程曲线回归分析发现,稳态模型胰岛素抵抗指数与治疗持续时间呈近似抛物线量变关系。(3)发现2例暂时性高血糖,分别在停用 rhGH 治疗后1个月和5d 血糖恢复正常,再注射 rh GH 后,行口服葡萄糖耐量试验正常。结论 GHD 儿童接受 rhGH 治疗(尤第1年内)可增加胰岛素抵抗,极少数引起短暂糖代谢紊乱。循环 IGF-1可能参与控制胰岛素的敏感性,在 GH 与胰岛素平衡间起重要作用。有必要对所有接受 rhGH 治疗者定期监测糖代谢指标和 IGF-1水平。