Blood glucose control and diabetic complications.

Two hypotheses have been advanced to explain the appearance of microvascular complications in diabetic patients with glycemic control. The genetic hypothesis suggests that the development of diabetic complications is genetically determined and independent of diabetic control, whereas the metabolic hypothesis suggests that long-term hyperglycemia causes the subsequent development of small-blood-vessel complications. We review data that either support or reject these hypotheses and suggest a third unifying hypothesis.