Prevalence of Insulin Resistance and Impaired Glucose Tolerance among Children and Adolescents with Obesity

Kim, Duk Hee; Choi, In Kyong; Kim, Ho Sung

Abstract

Pupose:Recently childhood obesity is increasing and has been accompanied by an increase in the prevalence of type 2 diabetes mellitus(DM) among children and adolescents. We evaluated insulin resistance and impaired glucose tolerance(IGT) in 48 obese children and adolescents.
METHODS
All subjects underwent a two-hour oral glucose tolerance test(1.75 g of glucose per kg of body weight) and then glucose and insulin levels were measured. Insulin resistance was estimated by homeostatic model assessment, and betacell function was estimated by calculating the ratio between the changes in the insulin level and glucose level during the first 30 minutes after the ingestion of glucose.
RESULTS
IGT was detected in 4.2% of the 24 obese children(4-10 years of age) and 20.8% of the 24 obese adolescents(11 to 18 years of age). Type 2 DM was identified in 8.3% in children and 29.2% in adolescent obesity. Insulin levels were markedly elevated after the glucose tolerance test in subjects with IGT but a little decreased in cases with DM. Those changes of insulin levels were not significant statistically. The insulinogenic index was decreased in IGT and DM group of childhood and adolescent obesity compared to normal glucose tolerance(NGT) but it was not significant statistically. Insulin resistance, which was evaluated with fasting insulin, QUICKI and HOMA-IR, was increased in childhood obesity compared with adolescent obesity and the HOMA-IR of adolescent IGT group was significantly higher compared with NGT group(P<0.05).
CONCLUSION
IGT is highly prevalent among children and adolescents with obesity. IGT was associated with insulin resistance and hyperinsulinemia, while beta-cell function was still relatively preserved. Overt type 2 diabetes was linked to insulin resistance and to beta cell failure.