Hyperglycemia and plasma lipid levels: a prospective study of young insulin-dependent diabetic patients.

We explored the relation of plasma lipid levels to the degree of blood glucose control in young, insulin-dependent diabetic patients. Levels of total plasma cholesterol and triglyceride, of their lipoprotein subfractions, and of hemoglobin A, and fasting blood glucose were measured repeatedly over a one-year period in 105 patients. Lipid levels were also measured in 74 nondiabetic siblings. Increasingly poor control of diabetes, reflected by levels of hemoglobin A1 or of fasting blood glucose, was associated with statistically significant increases in total cholesterol (P less than or equal to 0.01), total triglyceride (P less than or equal to 0.007), and lipoprotein subfractions except for high-density lipoprotein cholesterol. Diabetic patients in best control had lipid levels similar to those in their nondiabetic siblings. These data on the relation of plasma lipid levels to diabetic control lend credence to the hypothesis that poor control of blood glucose is conducive to accelerated atherosclerosis in diabetes mellitus.