Insulin sensitivity in prepubertal Caucasian normal weight children.

BACKGROUND: Determining whether or not a child is insulin resistant is becoming a matter of fundamental interest even in childhood, as the incidence of metabolic complications of insulin resistance is rising. Thus reference values are needed. AIM: To set percentiles for HOMA-IR and WBISI in Caucasian normal weight prepubertal children. POPULATION: 238 normal weight prepubertal Caucasian children (126 males/112 females). METHODS: After physical examination including anthropometric measurements all children underwent an oral glucose tolerance test from which HOMA-IR and WBISI were calculated. RESULTS: HOMA-IR values above the 95th percentile (2.03) and WBISI values below the 5th percentile (5.67) represent the cut-off values for the determination of insulin resistance. CONCLUSION: These reference values are useful to easily detect insulin resistance within the prepubertal Caucasian population representing a helpful tool for clinicians to target such children in order to improve insulin sensitivity.

Liver steatosis in obese prepubertal children: a possible role of insulin resistance.

OBJECTIVE: To determine whether in obese prepubertal children insulin resistance (IR) is associated with the development of liver steatosis. METHODS AND PROCEDURES: Cross-sectional study evaluating the prevalence of liver steatosis in 100 severely obese prepubertal children and comparing IR indexes between children with (group 1) and without steatosis (group 2). Furthermore, IR indexes were compared to values of 50 normal weight children. Fasting blood samples were collected for the evaluation of liver function tests, lipid profile, plasma glucose, and insulin levels. All children underwent an oral glucose tolerance test and anthropometric measurements. Hepatic ultrasound was performed according to international criteria and by one single operator. Analysis was performed by Mann-Whitney U-test, Pearson correlation, and logistic regression. RESULTS: Liver steatosis was found in 52% obese children and was equally distributed between the two sexes. Obese children were more insulin resistant when compared to controls (homeostasis model assessment of IR (HOMA-IR): P = 0.0001; whole body insulin sensitivity index (WBISI): P = 0.0005; fasting glucose/fasting insulin ratio (G/I): P = 0.0001), and group 1 presented an even higher degree of IR when compared to group 2 (HOMA-IR P = 0.0001; WBISI P = 0.0004; G/I P = 0.0001). The area under the curve (AUC) for insulin was significantly higher in group 1 when compared to group 2, while no difference was found in the AUC for glucose. There was no association between IR and adiposity indexes (P >0.05). The role of IR as a predictor for the development of steatosis was analyzed by multiple logistic regression, which documented that IR indexes were significantly related to steatosis independently of BMI-SDS. DISCUSSION: Liver steatosis is an emerging problem in prepubertal severely obese children, and it appears to be an association between liver steatosis and IR in these subjects.