ESPE Abstracts

Background: Obesity is a global epidemic and major health concern. Studies on insulin resistance and glucose abnormalities in European overweight/obese adolescents are rare.

Aim: To study prevalence of insulin resistance, impaired glucose tolerance and type 2 diabetes mellitus in a cohort of overweight/obese adolescents. To determine correlations between patient characteristics and biochemical parameters of glucose homeostasis.

Method: An oral glucose tolerance tests (OGTT) was performed in 156 overweight or obese adolescents (82 girls/ 74 boys, age 12 to 17 years) as part of the initial medical evaluation in our obesity clinic during a period of 4 years. The mean body mass index (BMI) was 28,9 kg/m². According to the International Obesity Task Force (IOTF) BMI cut-offs, 10 % of patients were classified 'overweight', 49 % 'class I', 31 % 'class II' and 10 % 'class III obesity'. Acanthosis nigricans was present in 19% of patients and a familial history of diabetes was reported in 58%. Fasting blood glucose, fasting insulinemia, peak insulinemia and blood glucose level 120 minutes after ingestion of glucose were determined during OGTT. The HOMA-IR score was calculated. Statistical analysis was performed to determine correlations between patient characteristics and the above-mentioned biochemical parameters of glucose homeostasis.

Results: Most of the patients (86%) had a peak insulinemia during OGTT higher than 800 pmol/L. Even more patients (90%) had an HOMA-IR score above 2.9. The 4 patients with HOMA-IR score under 1.4, had a peak insulinemia of 730 pmol/L or higher and one of these (with HOMA-IR score of 0.5) had a peak insulinemia of 6900 pmol/L.

Only 1 patient (0.6 %) had blood glucose level above 200 mg/dL 120 minutes after administration of glucose (type 2 diabetes mellitus), while 21 patients (13%) had blood glucose level above 140 mg/dL (impaired glucose tolerance). Impaired fasting glucose was detected in 19 patients (12%).

A significant correlation was found between BMI and fasting insulinemia and between BMI and peak insulinemia. We also found correlations between BMI and age, BMI and familial history of diabetes mellitus, fasting insulinemia and peak insulinemia, and finally between peak insulinemia and blood glucose level after 120 minutes.

Conclusion: Although a very high percentage of overweight/obese adolescents has insulin resistance, only a minority of adolescents has glucose intolerance of impaired fasting glucose. Type 2 diabetes mellitus is rarely observed in the overweight/obese adolescents we see. Further studies are necessary to explore this.