APOLIPOPROTEIN(A) LEVELS IN PATIENTS WITH TYPE-1 DIABETES-MELLITUS ARE UNRELATED TO METABOLIC CONTROL OR VASCULAR-DISEASE

Increased serum levels of lipoprotein (a) have been found to be an ind ependent risk factor for coronary heart disease. The major protein con stitents of lipoprotein (a) are apolipoprotein B 100 und apolipoprotei n (a) (apo(a)). We determined the serum levels of apo(a) and several l ipid (cholesterol, HDL- and LDL-cholesterol, triglycerides, apolipopro teins A, A 1 and B) and glycaemic (HbA1c, fasting blood glucose) param eters in 40 patients with type 1 diabetes mellitus and in 103 age- and sex-matached control subjects. The median serum levels of apo(a) were significantly increased in the type 1 diabetic patients (142.7 vs. 80 ,0 U/L; P = 0.03), whilst HDL, LDL-cholesterol, and apo-lipoprotein A, A 1 and B levels were lower (P < 0.01). No significant correlation wa s found between parameters of metabolic control and apo(a) levels. Aft er subdivision of the diabetic patients according to different stages of diabetic nephropathy (DN), determined by urinary albumin excretion, significant relationships were found between DN and triglycerides (P = 0.04), LDL (P = 0.03) and apolipoprotein B (P = 0.008, Kruskal-Walli s test) levels. Apo(a) levels were significantly higher than normal va lues in patients without DN (P < 0.05), but unrelated to the degree of DN. Patients with diabetic macroangiopathy had significant higher lev els of cholesterol (P = 0.0001), triglycerides (P = 0.026), LDL (P = 0 .0003), and apo B (P = 0.002) than patients without. Apo(a) levels wer e unrelated to diabetic macroangiopathy. The significantly elevated le vels of apo(a) even in patients without DN or macroangiopathy are note worthy. Although the elevated apo(a) levels might be an additional exp lanation for the elevated cardiovascular risk of type 1 diabetic patie nts, the great variability of this parameter could be explained by gen etic determination.