Homeostatic model assessment of adiponectin (HOMA-Adiponectin) as a surrogate measure of insulin resistance in adolescents: Comparison with the hyperglycaemic clamp and homeostatic model assessment of insulin resistance.

BACKGROUND: Studies on adults have reported inverse association between the homeostatic model assessment (HOMA) of adiponectin (HOMA-Adiponectin) and the insulin resistance assessed by the glucose clamp technique. To our knowledge, in the pediatric population this association has not been previously investigated. OBJECTIVES: To evaluate the association between the HOMA-Adiponectin and the insulin resistance assessed by the glucose clamp technique in adolescents, and to compare the accuracy of HOMA-Adiponectin and HOMA-insulin resistance (HOMA-IR) for identifying insulin resistance. METHODS: This was a cross-sectional study of 56 adolescents (aged 10-18 years). Insulin resistance was assessed using the HOMA-IR, HOMA-Adiponectin and the hyperglycaemic clamp technique. The clamp-derived insulin sensitivity index, HOMA-Adiponectin, and HOMA-IR were log-transformed to get closer to a normal distribution before analysis. RESULTS: In the multivariable linear regression analysis controlling for sex and Tanner stage, HOMA-Adiponectin was inversely associated with the clamp-derived insulin sensitivity index (unstandardized coefficient [B] = -0.441; P < 0.001). After additional adjustment for waist circumference-to-height ratio, this association remained significant (B = -0.349; P = < 0.001). Similar results were observed when HOMA-IR replaced HOMA-Adiponectin in the model (B = -1.049 and B = -0.968 after additional adjustment for waist circumference-to-height ratio); all P < 0.001. The area under the receiver operating characteristic curve for predicting insulin resistance was 0.712 (P = 0.02) for HOMA-Adiponectin and 0.859 (P < 0.0001) HOMA-IR. CONCLUSIONS: The HOMA-Adiponectin was independently associated with insulin resistance and exhibited a good discriminatory power for predicting it. However, it did not show superiority over HOMA-IR in the diagnostic accuracy.

Sagittal abdominal diameter resembles waist circumference as a surrogate marker of insulin resistance in adolescents-Brazilian Metabolic Syndrome Study.

OBJECTIVE: To evaluate the association of the sagittal abdominal diameter (SAD) with insulin resistance (IR) and metabolic syndrome (MetS) components, and to compare SAD with waist circumference (WC). SUBJECTS/METHODS: This was a multicenter, cross-sectional study of 520 adolescents (10- to 18-years old). IR was assessed using the homeostasis model assessment of IR (HOMA-IR) and the hyperglycaemic clamp (n = 76). RESULTS: SAD and WC were positively correlated with HOMA-IR (r = 0.637 and r = 0.653) and inversely correlated with the clamp-derived insulin sensitivity index (ISI) (r = -0.734 and r = -0.731); P < .001. In the multivariable linear regression analysis, SAD was positively associated with HOMA-IR (B = 0.046 ± 0.003) and inversely associated with the clamp-derived ISI (B = -0.084 ± 0.009) after adjusting for sex, age, and Tanner's stages (P < .001). When WC replaced the SAD, it was positively associated with HOMA-IR (B = 0.011 ± 0.001) and inversely associated with the clamp-derived ISI (B = -0.018 ± 0.002); P < .001. The values of the areas under the curves (AUC) were 0.823 and 0.813 for SAD and WC, respectively. In Bland-Altman analysis, there were agreement between both, SAD and WC, with the clamp-derived ISI (mean = 0.00; P > .05). The SAD and WC were positively associated with blood pressure, triglycerides, and uric acid, and inversely associated with high-density lipoprotein (HDL)-cholesterol after adjusting for sex, age, and Tanner's stages. CONCLUSION: The SAD was associated with IR and MetS components, with a good discriminatory power for detecting IR. When compared to WC, SAD showed equivalent results.

Adiposity and family history of type 2 diabetes in an admixed population of adolescents: Associations with insulin sensitivity, beta-cell function, and hepatic insulin extraction in BRAMS study.

AIMS: Insulin resistance and beta-cell dysfunction manifest differently across racial/ethnic groups, and there is a lack of knowledge regarding the pathophysiology of type 2 diabetes mellitus (T2DM) for ethnically admixed adolescents. This study aimed to investigate the influence of adiposity and family history (FH) of T2DM on aspects of insulin sensitivity, beta-cell function, and hepatic insulin extraction in Brazilian adolescents. METHODS: A total of 82 normoglycemic adolescents were assessed. The positive FH of T2DM was defined as the presence of at least one known family member with T2DM. The hyperglycemic clamp test consisted of a 120-min protocol. Insulin secretion and beta-cell function were obtained from C-peptide deconvolution. Analysis of covariance considered pubertal stage as a covariate. RESULTS: Both lean and overweight/obese adolescents had similar glycemic profiles and disposition indexes. Overweight/obese adolescents had about 1/3 the insulin sensitivity of lean adolescents (1.1 ±â€¯0.2 vs. 3.4 ±â€¯0.3 mg·kg·min·pmol ∗ 1000), which was compensated by an increase around 2.5 times in basal (130 ±â€¯7 vs. 52 ±â€¯10 pmol·l·min) and total insulin secretion (130,091 ±â€¯12,230 vs. 59,010 ±â€¯17,522 pmol·l·min), and in the first and second phases of insulin secretion; respectively (p < 0.001). This increase was accompanied by a mean reduction in hepatic insulin extraction of 35%, and a 2.7-time increase in beta-cell glucose sensitivity (p < 0.05). The positive FH of T2DM was not associated with derangements in insulin sensitivity, beta-cell function, and hepatic insulin extraction. CONCLUSIONS: In an admixed sample of adolescents, the hyperglycemic clamp test demonstrated that adiposity had a strong influence, and FH of T2DM had no direct influence, in different aspects of glucose metabolism.

Hypertriglyceridemic Waist Phenotype Indicates Insulin Resistance in Adolescents According to the Clamp Technique in the BRAMS Study.

OBJECTIVE: This study aimed to identify cutoff points for detecting hypertriglyceridemic waist phenotype (HTWP) in adolescents and to investigate the association of the HTWP with insulin resistance (IR) and metabolic syndrome components. METHODS: A multicentric cross-sectional study of 861 adolescents (10-19 years of age, 504 girls) was conducted. Pubertal stage, anthropometric, and laboratory parameters were assessed. IR was assessed by Homeostasis Model Assessment for Insulin Resistance (HOMA1-IR) index and hyperglycemic clamp (n = 80). HTWP was defined by the presence of increased plasma triglycerides (TGs) and increased waist circumference (WC) according to cutoff points obtained in ROC curve analysis given the HOMA1-IR index as a reference method. RESULTS: Cutoffs for WC and TGs, with a higher sum of sensitivity (S) and specificity (E), were, respectively: >84 cm (S:65.1%, E:71.9%) and >87 mg/dL (S:65.1%, E:73.4%) in pubertal girls; >88.5 cm (S:80.2%, E:60.2%) and >78 mg/dL (S:60.5%, E:53.2%) in postpubertal girls; >94 cm (S:73.1%, E:83.1%) and >79 mg/dL (S:61.5%, E:60.2%) in pubertal boys; and >99 cm (S:81.3%, E:78.7%) and >86 mg/dL in postpubertal boys (S:68.1%, E:60.7%). HTWP frequency was 27.5%. In the phenotype presence, after adjustment for age and pubertal stage, blood pressure and fasting glucose levels were elevated and high-density lipoprotein cholesterol was lower (p < 0.001). Adolescents with the HTWP showed more IR, evaluated both by the HOMA1-IR and by the clamp test (p < 0.003). CONCLUSION: The findings suggest HTWP as an IR status in adolescents. Cutoff point standardization for gender and pubertal stage, combined with the ease of application of the method, may allow their use for screening adolescents who would most benefit from lifestyle changes.

Association of Sleep Deprivation With Reduction in Insulin Sensitivity as Assessed by the Hyperglycemic Clamp Technique in Adolescents.

IMPORTANCE: The association between short sleep duration and decreased insulin sensitivity in adolescents has been described. However, to our knowledge, no studies have investigated this association measuring insulin sensitivity by the hyperglycemic clamp technique. OBJECTIVES: To compare the distributions of parameters of insulin resistance in adolescents with sleep deprivation vs adequate sleep, and to investigate the association between sleep deprivation and insulin sensitivity. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional multicenter study using data from the Brazilian Metabolic Syndrome Study conducted from June 29, 2011, to December 3, 2014, at an obesity outpatient clinic at the University of Campinas and public schools, with a convenience sample of 615 adolescents aged 10 to 19.9 years with a body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) for age and sex at the fifth percentile or higher. A subsample of 81 adolescents underwent the hyperglycemic clamp technique. MAIN OUTCOMES AND MEASURES: The self-reported sleep duration was used to classify the population into 2 groups: adolescents with sleep deprivation (<8 hours/night) and adolescents with adequate sleep (≥8 hours/night). Insulin sensitivity was assessed using the hyperglycemic clamp technique. RESULTS: Among the 615 adolescents (56.3% female; median age, 15.9 years [interquartile range, 12.9-17.8 years]) included in the sample, the mean (SD) sleep duration was 7.9 (1.7) hours/night. The adolescents with sleep deprivation (n = 257) compared with those with adequate sleep (n = 358) had a higher median (interquartile range) age (17.0 [15.4-18.3] vs 14.1 [11.8-16.9] years), BMI (25.0 [21.2-29.3] vs 23.1 [19.5-27.6]), waist circumference (83.0 [73.5-95.4] vs 79.0 [68.5-91.0] cm), sagittal abdominal diameter (17.9 [15.8-20.8] vs 17.0 [15.0-19.8] cm), neck circumference (35.2 [33.0-38.0] vs 33.0 [30.0-35.5] cm), uric acid level (4.9 [4.0-5.8] vs 4.5 [3.7-5.5] mg/dL), and white blood cell count (7000 [5900-8200] vs 6600 [5600-7800] cells/µL) (all P < .05). Moreover, the adolescents with sleep deprivation had a lower median (interquartile range) insulin sensitivity index compared with those with adequate sleep (0.10 [0.05-0.21] vs 0.21 [0.09-0.33] mg · kgfat-free mass-1 · min-1 · mU/L × 100, respectively; difference, -0.01; 95% CI, -0.01 to -0.00; P = .02). After controlling for age and sex in the multivariate regression model, sleep deprivation remained an independent predictor for those variables. In the sleep deprivation group, BMI and central distribution of fat were higher in all categories of adiposity. CONCLUSIONS AND RELEVANCE: Sleep deprivation (<8 hours of sleep per night) is associated with centripetal distribution of fat and decreased insulin sensitivity in adolescents. Therefore, investigations of sleep duration and sleep quality in adolescents should be included in clinical practice to promote, through health education, the eradication of the health risks associated with sleep restriction.

Neck circumference as a new anthropometric indicator for prediction of insulin resistance and components of metabolic syndrome in adolescents: Brazilian Metabolic Syndrome Study.

OBJECTIVE: To evaluate the correlation between neck circumference and insulin resistance and components of metabolic syndrome in adolescents with different adiposity levels and pubertal stages, as well as to determine the usefulness of neck circumference to predict insulin resistance in adolescents. METHODS: Cross-sectional study with 388 adolescents of both genders from ten to 19 years old. The adolescents underwent anthropometric and body composition assessment, including neck and waist circumferences, and biochemical evaluation. The pubertal stage was obtained by self-assessment, and the blood pressure, by auscultation. Insulin resistance was evaluated by the Homeostasis Model Assessment-Insulin Resistance. The correlation between two variables was evaluated by partial correlation coefficient adjusted for the percentage of body fat and pubertal stage. The performance of neck circumference to identify insulin resistance was tested by Receiver Operating Characteristic Curve. RESULTS: After the adjustment for percentage body fat and pubertal stage, neck circumference correlated with waist circumference, blood pressure, triglycerides and markers of insulin resistance in both genders. CONCLUSIONS: The results showed that the neck circumference is a useful tool for the detection of insulin resistance and changes in the indicators of metabolic syndrome in adolescents. The easiness of application and low cost of this measure may allow its use in Public Health services.