Cecília Noronha de Miranda Carvalho

Ponto de corte do índice Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) avaliado pela curva Receiver Operating Characteristic (ROC) na detecção de síndrome metabólica em crianças pré-púberes com excesso de peso

OBJECTIVE: To establish, among the cut-off values for the homeostatic model assessment for insulin resistance index (HOMA-IR) cited in the literature, the best in identifying metabolic syndrome (MS) in obese and overweight children. METHODS: A total of 106 pre-pubertal children were studied. The definition of MS was adapted from that of the International Diabetes Federation. For each cut-off values for HOMA-IR, it was estimated sensibility and specificity for MS. A receiver operating characteristic (ROC) curve was generated using these values. RESULTS: The study included 106 obese (37 girls and 69 boys) and 34 overweight (19 girls and 15 boys) children aged 6,5 ± 2,3 years. The accuracy of the ROC curve was 72%, and the best cut-off value for HOMAIR was 2,5, with sensitivity of 61% and specificity of 74%. CONCLUSIONS: HOMA-IR may be useful to detect MS and the cut-off 2,5 seems to be the best in obese and overweight pre-pubertal children.

Impact of obesity on metabolic syndrome components and adipokines in prepubertal children

OBJECTIVES To verify the impact of obesity on metabolic syndrome components and adipokine levels in prepubertal children. METHODS This cross-sectional study compared 30 obese, 31 overweight and 33 eutrophic children attending a university hospital-based outpatient pediatric clinic. Parameters assessed included glucose, serum lipids, insulin, homeostasis model assessment-insulin resistance (HOMA-IR), glucose/insulin relation, adiponectin, and leptin. We compared the frequency of acanthosis nigricans and changes in waist, blood pressure, glucose, serum lipids, and insulin. The correlation between body mass index (BMI) z score and adipokines was evaluated. RESULTS Among obese children, there was a difference in the mean values of HDL cholesterol and adiponectin, whereas among the eutrophic children, there was a difference in the mean values of insulin, HOMA-IR, glucose/insulin relation, and leptin (p < 0.001). A difference was also observed regarding the frequency of acanthosis nigricans and alteration in waist and HDL cholesterol (p < 0.005) in the obese group. The BMI z score showed a positive correlation with leptin (p < 0.001) and a negative correlation with adiponectin (p = 0.001). In multiple linear regression, this correlation was maintained only for leptin; HDL-cholesterol correlated with adiponectin (p = 0.007) and HOMA-IR correlated with both variables (p < 0.05). CONCLUSIONS These findings provide evidence of the influence of obesity on metabolic syndrome components and on adipokine levels in prepubertal children, indicating that these components may contribute to the beginning of cardiovascular diseases.

Doença celíaca em tratamento: avaliação da densidade mineral óssea

OBJETIVO: comparar a densidade mineral ossea de criancas e adolescentes com doenca celiaca em tratamento com controles sadios, e avaliar exames laboratoriais relacionados com o metabolismo do calcio. METODOS: foram estudados 30 pacientes com doenca celiaca em dieta isenta de gluten, 17 criancas e 13 adolescentes, e 23 individuos saudaveis. Todos os pacientes e controles realizaram a densidade mineral ossea (DEXA, Lunar). Os pacientes realizaram dosagem serica de calcio total, calcio ionizado, fosforo, magnesio, fosfatase alcalina e paratormonio. RESULTADOS: a media de peso, estatura e densidade mineral ossea dos adolescentes com doenca celiaca foi menor do que dos controles (p<0,05), enquanto que nao se observaram diferencas estatisticamente significantes destes parâmetros, comparando as criancas com doenca celiaca com os controles. A proporcao de adolescentes que iniciou dieta isenta de gluten apos os dois anos de idade foi maior do que a de criancas (p<0,05). Os pacientes apresentaram niveis sericos normais de calcio ionizado, calcio total e paratormonio. CONCLUSOES: a densidade mineral ossea dos adolescentes com doenca celiaca em dieta isenta de gluten foi menor do que dos controles. Por outro lado, nao houve diferenca entre a densidade mineral ossea de criancas com doenca celiaca e controles.

The role of metabolic syndrome components and adipokines in insulin resistance in prepubertal children

Abstract Objective: Insulin resistance has a central role in the pathophysiology of cardiovascular atherosclerotic disease. Adipose tissue is of capital importance in view of its production of adipokines. The present study aims to determine the association of metabolic syndrome components, which constitute risk factors for cardiovascular atherosclerotic disease, and leptin and adiponectin with insulin resistance in prepubertal children. Methods: We conducted a cross-sectional study involving 197 children. Of these, 112 children were obese, 36 were overweight and 49 had normal weight. The association of sex, waist circumference, Acanthosis nigricans, age, BMI Z-score, serum lipids, leptin and adipocytokines with insulin resistance [defined as the homeostatic model assessment for insulin resistance (HOMA-IR) index higher than or equal to 2.5] was investigated using logistic regression. Results: There was positive association of sex (female), age, BMI Z-score, triglycerides and leptin with insulin resistance (p<0.05). Conclusion: Among the conventional components of metabolic syndrome, the role of BMI Z-score and triglycerides stands out in insulin resistance of prepubertal children. Sex (female), age and leptin also showed to be of major importance.

Leptin as a predictor of metabolic syndrome in prepubertal children

Objective Leptin has been suggested as a potential biomarker of cardiovascular risk. This paper aims to ascertain, based on a sample of prepubertal children, which serum leptin value best suited to identify metabolic syndrome (MS). Subjects and methods This observational, cross-sectional study recruited children from the outpatient pediatrics clinic, with the purpose of validating serum leptin level cutoffs to identify MS. All obese and overweight children who met eligibility criteria were included in the study, as was a sample of normal-weight children. The sample underwent clinical assessment and blood fasting glucose, lipid profile, insulin, and leptin were measured. Sensitivity and specificity were estimated for each leptin measurement, using MS as the outcome. These values were used to construct a receiver operating characteristic (ROC) curve. The association between MS and leptin was assessed using logistic models to predict MS. Results A total of 65 normal weight, 46 overweight, and 164 obese children were analyzed (160 boys, 115 girls; age: 93.7 ± 17.8 months). The most appropriate leptin cutoff was 13.4 ng/mL (sensitivity 67.6%; specificity 68.9%; accuracy 72.1%). The logistic model indicated that leptin levels above 13.4 ng/dL were significantly associated with MS and that, for every 1 ng/dL increase in leptin levels, the odds of MS increase by 3% (p = 0.002; OR 1.03; 95% CI 1.01-1.05). Conclusions Leptin may be a useful biomarker of cardiovascular risk in prepubertal children, with an optimal cutoff of 13.4 ng/mL. Identification of potential new risk markers for cardiovascular disease in children could contribute to the development of preventive strategies.

Association between cardiovascular risk factors and carotid intima-media thickness in prepubertal Brazilian children

Abstract Background: Early exposure to cardiovascular risk factors creates a chronic inflammatory state that could damage the endothelium followed by thickening of the carotid intima-media. Objective: To investigate the association of cardiovascular risk factors and thickening of the carotid intima. Subjects/Methods: Media in prepubertal children. In this cross-sectional study, carotid intima-media thickness (cIMT) and cardiovascular risk factors were assessed in 129 prepubertal children aged from 5 to 10 year. Association was assessed by simple and multivariate logistic regression analyses. Results: In simple logistic regression analyses, body mass index (BMI) z-score, waist circumference, and systolic blood pressure (SBP) were positively associated with increased left, right, and average cIMT, whereas diastolic blood pressure was positively associated only with increased left and average cIMT (p<0.05). In multivariate logistic regression analyses increased left cIMT was positively associated to BMI z-score and SBP, and increased average cIMT was only positively associated to SBP (p<0.05). Conclusions: BMI z-score and SBP were the strongest risk factors for increased cIMT.

Ultrasound as a method to evaluate the distribution of abdominal fat in obese prepubertal children and the relationship between abdominal fat and metabolic alterations

Abstract. Objective To evaluate, using ultrasound, the distribution of abdominal fat in obese prepubertal children, as well as its possible correlation with metabolic changes due to obesity. Materials and Methods This was a cross-sectional study of prepubescent children: 77 obese children (33 girls and 44 boys), with a mean age of 7.31 years; and 31 normal-weight children (17 girls and 14 boys), with a mean age of 7.32 years. In all of the children, abdominal wall thickness (AWT) and abdominal fat thickness (AFT) were measured by ultrasound. For the evaluation of the associated metabolic alterations, serum levels of glycemia, HDL cholesterol, triglycerides, and insulin were determined. Results The obese children presented with greater abdominal fat, predominantly greater AWT, without a significant gender-related difference in AWT or AFT. The homeostasis model assessment of insulin resistance (HOMA-IR) showed a significant direct correlation with AWT and AFT. Conclusion In obese prepubertal children, the AWT, as measured by ultrasound, was shown to be more closely related to the HOMA-IR than to the lipid metabolism or glycemia.

Physical fitness and activity, metabolic profile, adipokines and endothelial function in children

OBJECTIVES The prevalence of obesity is increasing. The aim of this study was to investigate if there is endothelial dysfunction in children with normal or excess weight, and whether the metabolic profile, adipokines, and endothelial dysfunction would be more strongly associated with physical fitness or with physical activity levels. METHOD Cross-sectional study involving children aged 5-12 years. The evaluation included venous occlusion plethysmography, serum levels of adiponectin, leptin and insulin, lipid profile, physical activity score (PAQ-C questionnaire), and physical fitness evaluation (Yo-Yo test). RESULTS A total of 62 children participated in this study. Based on the body mass index, 27 were eutrophic, 10 overweight and 25 obese. Triglycerides, LDL cholesterol, HOMA-IR, and leptin were higher in the obese and excess-weight groups compared to the eutrophic group (p<0.01). HDL cholesterol and adiponectin levels were higher in the eutrophic group compared to the obese and excess-weight groups (p<0.01). Flow-mediated vasodilation after hyperemia was higher in the eutrophic group in comparison to obese and excess-weight subjects (p<0.05). There was no difference in the physical activity levels among groups measured by PAQ-C. The Yo-Yo test was significantly associated with HDL cholesterol (rho=-0.41; p=0.01), and this association remained after adjusting for body mass index z-score (rho=0.28; p=0.03). CONCLUSION This study showed that endothelial dysfunction is already present in obese children, suggesting a predisposition to atherosclerotic disease. Moreover, HDL cholesterol levels were correlated with physical fitness, regardless of body mass index.