Vascular Reactivity during the First Year of Diabetes in Children

Functional vascular response to hypoxia was studied in 24 children followed up prospectively for one year after diagnosis of type 1 diabetes mellitus. Postocclusive reactive hyperaemia was detected non-invasively in the skin using a transcutaneous PO2 method at 37 degrees C. Repeated experiments under standardized conditions were performed before institution of insulin treatment and 3, 7, 21, 30, 180 and 360 days after diagnosis. Impaired vascular reactivity was noted at the first experiment as compared with control children and slight but significant improvement was then noted up to the experiment at 180 days (p less than 0.01). At 30 and 180 days no significant difference between diabetic and control children was found. A small decrease in mean postocclusive reactive hyperaemia was observed at the experiment performed after 360 days. Fast normalization of urine glucose excretion, blood glucose and haemoglobin A1 occurred during the first three weeks of treatment but these variables showed no significant correlation to vascular reactivity, either at diagnosis or later. Impaired vascular reactivity can thus be diagnosed even before the institution of insulin treatment and improves during the first months of treatment, reaching the range of controls. Other factors than indicators of carbohydrate control have to be studied in the search for explanations of the abnormal vascular function in newly diagnosed diabetic children.