Fasting biochemical parameters and their relationship to anthropometric measurements in childhood obesity.

Fasting plasma immunoreactive insulin, triglyceride, free fatty acid, cholesterol, glycerol, blood glucose, lactate, pyruvate level, and lactate/pyruvate ratio were measured and an intravenous glucose tolerance test was done in obese and control children. The levels of most of the metabolites and the glucose tolerance were similar in the two groups except for the higher immunoreactive insulin and triglyceride levels in the obese group. Further metabolic alterations could be detected when the obese children were divided into subgroups on the basis of fasting insulin and triglyceride levels, and of glucose tolerance. Only three significant correlations were found between metabolic parameters and anthropometric measurements when the obese group was treated as a whole, but numerous other positive and negative correlations were detected in the subgroups. The most striking and unexpected finding was the negative correlation between cholesterol and free fatty acids and some indices of fatness in the whole obese group and in some subgroups. It is concluded that obese children ("exogenous obesity") cannot be regarded as a metabolically homogeneous group and the correlations between anthropometric parameters and plasma metabolites remain to be controversial.