Leptin levels in patients with Type 1 diabetes receiving intensive insulin therapy compared with those in patients receiving conventional insulin therapy

Several reports suggest that insulin may have a role in the regulation of serum leptin levels, and this is related to the fact that serum leptin levels generally indicate the amount of body fat. Studies show that leptin levels are low in newly diagnosed patients with Type-1 diabetes (T1DM) and increase after institution of insulin therapy. This study was designed to test whether serum leptin levels are higher in patients receiving intensive insulin therapy (IIT) compared to conventional insulin therapy (CIT). Young patients with T1DM were studied, 23 on IIT and 23 on CIT. The patients were matched for age (19±3 and 20±5 yr, respectively), duration of diabetes (8±5 and 10±6 yr, respectively) and BMI (24±4 and 23±3 kg/m2, respectively). Leptin levels were higher in IIT compared to CIT (13±12 vs 7±7 ng/ml, respectively, p<0.05). The results of this study demonstrate that patients on IIT have higher leptin levels than patients on CIT. This increase in leptin level in IIT patients is independent of changes in bw and is probably due to the stimulatory effect of insulin on leptin production.