Mediciones de adiposidad intraabdominal por ultrasonido y factores asociados con riesgo cardiovascular en niños obesos / Ultrasound measurements of intra-abdominal adiposity and factors associated with cardiovascular risk in obese children

Background: Cardiovascular risk factors are commonly present in obese children. Aim: To evaluate the association among radiological measurements of intra-abdominal adipose tissue, and cardiovascular risk factors, in prepuberal obese children. Patients and Methods: We evaluated 30 obese (body mass index > p95) children aged 6 to 12 years (15 males). Anthropometry and blood pressure were measured. Subcutaneous and intra-abdominal fat thickness and fat area were measured by ultrasound (US) and computed tomography. Serum insulin, glucose and lipid profile were measured in a fasting blood sample. Homeostasis model assessment (HOMA) was calculated as an index of insulin resistance. Results: There was a significant correlation between US intra-abdominal fat thickness and HOMA (r = 0.47, p < 0.01), serum triglycerides (r = 0.46, p < 0.05) and with positive criteria for metabolic syndrome (r = 0.66, p < 0.01). A receiver operating curve (ROC) analysis showed that, above a cut-off of 45 mm for intra-abdominal fat thickness, US was able to identify insulin resistance with a sensibility and specificity of 79 and 69 percent respectively and metabolic syndrome with sensibility and specificity of 100 and 67 percent respectively. US and computed tomography measurements for intra-abdominal fat thickness were significantly correlated (r= 0.62, p < 0.01). Conclusions: US measurements of intra-abdominal fat thickness identify obesity-associated damage in childhood. Age-specific measurements of intra-abdominal adipose tissue may improve the detection power of this approach.

Adiposidad visceral y su asociación con lípidos séricos e insulinemis en adolescentes obesas / Visceral adiposity and its association with serum lipids in female obese teenagers

Background: Increased visceral or abdominal adipose tissue in children and adults is strongly associated with metabolic and a variety of chronic diseases. Aim: To study the association between visceral or external body measurements of adiposity with blood lipids, glucose and insulin levels, in obese female adolescents. Material and methods: In a cross-sectional study, 47 obese female adolescents (body mass index (BMI) >95th percentile) aged 10 to 15 years, were analyzed. Weight, height, BMI, Tanner pubertal stages, skinfold thickness, waist circumference, waist-to-hip ratio, fasting and 120 min post prandial blood glucose, serum insulin, and lipid profile were studied. Visceral fat was assessed by computed tomography at the L4-L5 level, measuring the fat area or the length of a straight drawn line between the spine and the internal border of the rectus abdominus muscle. Results: No association between lipid profile and BMI or external body measurements (skinfold thickness, waist circumference, waist-to-hip ratio) was observed. Total serum cholesterol >170 mg/dL was positively associated with the straight line over 63 mm (a cut-off obtained by ROC analysis (RR 2.64; 1.15-6.08). This association was statistically significant in girls in Tanner I + II (n =21; Fisher, p <0.023), but not with Tanner III + IV (n =26) stages. Increased cholesterol (>170 mg/dL) was also positively associated with a serum insulin >17 uU/mL in the Tanner I + II group (Fisher p<0.05), but not with the homeostasis model assessment of insulin resistance (HOMA). Conclusions: No external body measurement of adiposity was associated to increased serum cholesterol in these obese female adolescents. Increased total cholesterol (>170 mg/dL) was associated with visceral fat (evaluated through the straight line spina-rectus abdominus muscle), and also with a serum insulin >17 uU/ml in those teenagers with Tanner I or II pubertal stages.