Childhood obesity is known to be associated with various short- and long-term health risks, including development of metabolic syndrome and subsequently of cardiovascular and Type 2 diabetes. The prevalence of metabolic syndrome in obese children is reported to be approximately close to 25%.

Currently, fasting plasma glucose (FPG) is measured to identify obese children with abnormal glucose homeostasis. But data in adults suggest that the development of metabolic syndrome and Type 2 diabetes could be more closely related to post prandial glucose rather than FPG. This paper examines this relationship in children by comparing glucose concentrations during an oral glucose tolerance test with peripheral insulin resistance and cardiovascular risk factors.

Sabin et al. studied 122 children attending an obesity clinic. Thirteen (10.7%) had impaired glucose tolerance (IGT). There was a reported parental history of Type 2 diabetes in 15.6% of the children. The mean FPG in the whole cohort was 4.6 mmol/L (range 3.7–6.6 mmol/L), and children with IGT had higher FPG concentrations at 4.9 mmol/L compared with the whole cohort (4.6 mmol/L). Gender, age, pubertal status or BMI were unrelated to individual measures of or changes in the glucose through the oral glucose tolerance test (OGTT). There was no relationship between glucose tolerance and individual family history of diabetes.

There was a significant correlation between FPG, glucose at 60 minutes, and total glucose area under the curve (AUC) with fasting insulin. Children with metabolic syndrome (defined using any of three definitions) had comparable FPG levels with those without metabolic syndrome, but they demonstrated significantly elevated glucose concentrations at 60 minutes. On sub-group analysis, obese children with normal carbohydrate metabolism were significantly more likely to have a 1 hour glucose level ≥7.8 mmol/L if they had metabolic syndrome.

This study highlighted the fact that the degree of obesity per se cannot be used to determine the disease risk of metabolic syndrome. It also demonstrated the usefulness of using the 1 hour glucose concentration to identify children with associated cardiovascular risk factors. Finally, the development of risk factors appears to correlate with the post prandial glucose and more information could be gathered from analysis of glucose results during an OGTT in obese children rather than simply using the 120 minutes result to define IGT or Type 2 diabetes.