Obesity epidemic in children and the emergence of type 2 diabetes

The prevalence of obesity is increasing alarmingly among children and adolescents in the United States. The increase in the prevalence of obesity reported by the most recent National Health and Nutrition Examination Survey survey, 1999 to 2000, occurred primarily among minority adolescents in the United States. Factors contributing to this unabated rise in juvenile obesity are discussed. Many of the metabolic and cardiovascular complications of obesity are already present during childhood and are closely related to the presence of insulin resistance and hyperinsulinemia, the most common metabolic abnormality of obesity. Both prediabetes and type 2 diabetes are becoming highly prevalent among obese adolescents. The best predictor of impaired glucose tolerance or prediabetes is insulin resistance. The insulin resistance in the early phase of type 2 diabetes is severe and is related to an increased accumulation of intramyocellular lipid. In addition, there appears to be an inappropriate β-cell function early in the disease. On the other hand, in overt type 2 diabetes in youth, β-cell failure becomes fully manifested.