[Insulin sensitivity in children aged 6 to 16 years: association with nutritional status and pubertal development]

There is a high prevalence of obesity and hyperinsulinism among Chilean prepuberal children.

To evaluate insulin sensitivity (IS) using fasting insulin, the Homeostasis Model Assessment (HOMA) and quantitative insulin-sensitivity check index (QUICKI) in Chilean children.

Body mass index (BMI), total body fat percentage (%TBF) using the sum of 4 skin folds, abdominal obesity determined through waist circumference (WC), pubertal maturation using five Tanner stages, fasting glucose (Glu) and insulin (Ins), were measured in 354 children aged 6 to 15 years (173 males). IS was evaluated using HOMA and QUICKI.

IS was strongly associated with %TBF and WC. Ins, HOMA and QUICKI were significantly correlated with BMI (r =0.412; 0.405 y -0.442, respectively), %TBF (r =0.370; 0.367 y -0.394, respectively), and WC (r =0.452; 0.446 y -0.481, respectively). Ins and HOMA increased and QUICKI decreased significantly (p <0.0001) with age. Children in a similar Tanner stage did not have differences in Ins, HOMA and QUICKI. No differences in Ins, HOMA and QUICKI were observed between children in Tanner stages 1 and 2. However, children in Tanner stages 1 and 2, had significantly lower Ins and HOMA and higher QUICKI than those in Tanner 3 to 5 stages. The highest Ins quartile for Tanner stages 1 and 2 was 10.0 micro UI/dl; for Tanner stages 3 to five, the figure was 15.6 microUI/dl.

These results confirm the relationship of IS with BMI, %TBF, WC and pubertal maturation. IS decreases significantly and fasting Ins levels increase approximately 50% with puberty. This fact must be considered for the diagnosis of hyperinsulinism and insulin resistance in children.