Objective: The worldwide increase in the prevalence of childhood obesity is reaching epidemic proportions and is associated with a dramatic rise in cases of type 2 diabetes. The prevalence of glucose intolerance and its determinants and the relation of cardiovascular risk factors with levels of glycemia and degree of obesity were studied in grossly obese children of European origin.
Research design and methods: A total of 710 grossly obese Italian children (SD score [SDS] of BMI 3.8 +/- 0.7) aged 6-18 years, including 345 male subjects, underwent an oral glucose tolerance test. Insulin resistance and insulin secretion were estimated using the homeostasis model assessment for insulin resistance and the insulinogenic index, respectively. Fibrinogen, C-reactive protein, lipids, and uric acid were measured. The 2-h postload glucose and degree of obesity, calculated as the SDS of weight/height(2), were used as dependent variables.
Results: The prevalence of glucose intolerance was 4.5%. Insulin resistance (P < 0.0001), impaired insulin secretion (P < 0.0001), and diastolic blood pressure (BP) (P < 0.05) were significantly and independently related to 2-h postload glucose values. The degree of obesity did not relate to insulin resistance but was independently correlated with inflammatory proteins, uric acid, and systolic BP, variables that were often abnormal in this population.
Conclusions: In these grossly obese children, both insulin resistance and impaired insulin secretion contribute to the elevation of glycemia, and the degree of obesity is related to cardiovascular risk factors independently of insulin resistance.