Serum leptin levels in type 1 diabetic and obese children: relation to insulin levels.

Objectives: To compare serum leptin levels in type 1 diabetic and obese children.
Design and Methods: We studied serum leptin levels in 35 type 1 diabetic, 32 obese, and 35 healthy children. Seven of 35 were new-onset diabetics with ketoacidosis. C-peptide (CPE) levels were used for estimating insulin secretion.
Results: Serum leptin levels were lower in diabetics than in controls (p<0.001). Obese children had higher leptin and CPE levels than diabetics and controls. In new-onset diabetics, 1 month insulin treatment did not cause any change in leptin levels (p>0.05). Leptin was correlated positively with body mass index and CPE (p<0.001) and inversely with glucose (p = 0.001) and HbA1c (p<0.05) in the combined group. HbA1c and gender were the independent predictors of leptin in diabetic children (p<0.01).
Conclusions: Low serum leptin levels in type 1 diabetic children may be due to chronic insulin deficiency related with their metabolic control. Leptin and insulin may have complementary roles in maintaining a stable body weight.