Background: Tissue resistance to insulin has been demonstrated in obese individuals. Pancreatic beta-cells respond to the reduced tissue sensitivity with increased insulin secretion so that glucose homeostasis is maintained.
Objective: The purpose of this prospective study was to investigate the presence of hyperinsulinemia and insulin resistance in obese children and adolescents.
Subjects and methods: Fasting glucose (FG) and insulin (FI) levels and fasting glucose to insulin ratio (FGIR) were measured in 26 obese prepubertal children and 20 obese adolescents, as compared to 20 non-obese prepupertal children and 20 adolescents with normal body weight. Furthermore, obese children and adolescents underwent an oral glucose tolerance test with measurements of glucose and insulin 2 hours post glucose load.
Results: In 14/26 (54%) obese prepubertal children and in 16/20 (80%) obese adolescents FI was >24 microU/ml. FGIR was <6 in 23/26 (88%) prepubertal obese children and in all obese adolescents. All non-obese prepubertal children and adolescents had normal FI. However, FGIR was <6 in 6/20 (30%) non-obese prepubertal children and in 15/20 (75%) non-obese adolescents.
Conclusion: Hyperinsulinemia and insulin resistance are already present in prepubertal obese children. As hyperinsulinemia is a potentially reversible condition and the complications related to it may be prevented, early measurements should be undertaken so that obese children lose body weight before the onset of puberty which may enhance the problem of insulin insensitivity.