Five-hour oral glucose tolerance test in obese children.

Concentrations of blood glucose, plasma free fatty acids, and plasma glycerol during a 5-hour oral glucose tolerance test on 46 obese children are reported. Seven children had unequivocally impaired glucose tolerance. However in the group as a whole, there was a delay in return of blood glucose to baseline levels after oral glucose, 27 children (60%) having a blood glucose concentration greater than 110 mg/100 ml at 2 hours. It was concluded that some degree of glucose intolerance is common in childhood obesity. No relation was seen among the following: impairment of glucose tolerance and age, degree or duration of obesity, or family history of diabetes. Fasting plasma free fatty acids and glycerol concentrations were high (mean ± 1SD, 1030 ± 221 μEq/litre FFA and 121 ± 44 μmol/l. glycerol). For all children, concentrations of FFA and glycerol decreased during the first hour after glucose, though minimal levels were not reached until 90-120 minutes (mean ± 1SD, 395 ± 170 μEq/litre FFA, 77 ± 24 μmol/l. glycerol). For those children (27) who had raised blood glucose at 2 hours, there was a positive correlation between fasting plasma glycerol concentration and glucose tolerance sum, suggesting that impaired glucose tolerance was associated with increased basal lipolysis.