Serum antioxidant status and oxidized LDL in well-controlled young type 1 diabetic patients with and without subclinical complications.

It has been suggested that oxidative stress may play an important role in the pathogenesis of diabetic complications because hyperglycemia may cause increased production of free radicals. However, studies on the antioxidant status of young type 1 diabetic patients are very scarce as well as the relationships of oxidative stress and the presence of subclinical complications. Therefore, it was decided to evaluate autoantibodies against LDL (o-LAB) and antioxidant status in relationship with glycated hemoglobin levels (HbA1c), lipoproteins and subclinical complications (retinopathy, neuropathy and nephropathy). The study included 110 young type 1 diabetic patients, with a median age of 15 years and a median diabetes duration of 5 years. The mean+/-S.E.M. of HbA1c levels was 7.1+/-0.2%. Subclinical complications were detected in 26 patients. Total antioxidant status (TAS), vitamin A or E were not decreased in the patients and no significant differences were noted between the different subgroups of patients classified according to their subclinical complications. HbA1c levels were not related to antioxidants. Autoantibodies against LDL-lipoproteins decreased with age and diabetes duration, as reported in healthy non diabetic subjects. In conclusion, in the diabetic patients with a more or less good diabetic control, increased lipid peroxidation or reduced lipid antioxidant defense could not be demonstrated, even for the patients with subclinical complications.