Serum Lipids and Lipoproteins in Insulin-treated Diabetes: Demonstration of Increased High Density Lipoprotein Concentrations

Abstract

In view of the high incidence of coronary heart disease in insulin-dependent diabetes, we determined cholesterol and triglyceride concentrations in serum and in three major lipoprotein fractions of 170 nonuremic middle-aged diabetic patients who had been treated with insulin for a minimum of 10 years. In addition, postheparin plasma lipoprotein lipase activity was measured in a subsample of the diabetic subjects. The diabetics had serum cholesterol and triglyceride concentrations similar to those of nondiabetic control subjects of the same age and sex. However, the concentration of high density lipoprotein (HDL)-cholesterol was significantly higher in both male and female diabetic patients than in respective controls (P < 0.001). Male patients with poor diabetic control or with overweight had elevated triglyceride and very low density lipoprotein (VLDL)-triglyceride concentrations, whereas the patients with good diabetic control had significantly lower triglyceride and VLDL-triglyceride concentrations than did nondiabetic subjects. Overweight diabetic patients also had elevated serum cholesterol and LDL-cholesterol concentrations. The HDL-cholesterol of diabetic subjects, on the other hand, was not dependent on the degree of diabetic control or on the relative body weight. Diabetic patients had higher lipoprotein lipase activity in postheparin plasma than did normal subjects of corresponding age and sex. The HDL-cholesterol concentration showed a significant positive correlation with postheparin plasma lipoprotein lipase activity. We conclude that the average serum lipid and lipoprotein pattern of insulin-treated chronic diabetic patients is not more. atherogenic than that of nondiabetic subjects of similar age and sex. On the contrary, the increase of HDL-cholesterol observed in the diabetic subjects should make them less liable to develop coronary heart disease. Thus, the excess cardiovascular disease that is associated with insulin-dependent diabetes must be accounted for by other factors.