RELATION OF ANGIOGRAPHICALLY DEFINED CORONARY-ARTERY DISEASE AND PLASMA-CONCENTRATIONS OF INSULIN, LIPID, AND APOLIPROTEIN IN NORMOLIPIDEMIC SUBJECTS WITH VARYING DEGREES OF GLUCOSE-TOLERANCE

We investigated the association between hyperinsulinemia and changes i n lipid, lipoprotein, and apolipoprotein that would increase the risk of coronary artery disease (CAD) independent of glucose tolerance. A c oronary angiogram was recorded in 127 male subjects, including 41 with normal glucose tolerance, 41 glucose tolerance, and 45 with nondiabet es mellitus (NIDDM). Subjects were divided into 2 groups according to results: the group with CAD (n = 94) and the group with normal coronar y arteries (n = 33), All subjects were normolipidemic (total cholester ol <230 mg/dl and triglycerides <150 mg/dl). The CAD group had a signi ficantly lower plasma level of high-densi)ty lipoprotein (HDL) cholest erol and apolipoprotein A-I (ape A-I) and a higher level of apolipopro tein B (ape B) than the normal group with normal glucose tolerance. In considering subjects with impaired glucose tolerance or NIDDM, the CA D group had a significantly lower plasma level of HDL cholesterol and apo A-I and a significantly higher plasma level of total cholesterol, triglycerides, and apo normal and impaired glucose tolerance, and NIDD M, the elevation of plasma insulin concentration during both the compl ete test period and the early phase of an oral glucose challenge was s ignificantly higher in the CAD than in the normal group. In all subjec ts, graded reductions in HDL cholesterol and apo A-I and graded increa ses in plasma total cholesterol, triglycerides, and apo B were observe d with increasing tertiles of the postglucose challenge measurements o f insulinemia. Multivariate analysis of the data confirmed the indepen dent effect of plasma levels of apo A-I and apo B on the severity of C AD. Thus, hyperinsulinemia appeared to be associated with changes In l ipid and apolipoprotein that predisposed toward coronary atheroscleros is not only in nondiabetic subjects, but also in those with impaired g lucose tolerance and NIDDM. The plasma levels of both apo A-I and apo B, both nontraditional risk factors, were better predictors of CAD tha n were plasma levels of lipids in normolipidemic men.