The electrophoresis of plasma lipoproteins frequently showed midbands between β- and pre-β-lipoproteins in survivors of myocardial infarction. There were increases in intermediate-density-lipoprotein (IDL) cholesterol and triglycerides with an increase in IDL cholesterol/triglycerides in the very-low-density-lipoprotein fraction, even if the increase in cholesterol was not so significant. Impaired glucose tolerance (IGT) was also frequently found in these patients. Among the patients with an apparently normal glucose tolerance, the coronary atherosclerosis scores judged by the Americal Heart Association reporting system on coronary angiography increased as the total insulin area by 75 g oral glucose tolerance test increased. The correlation between the atherosclerosis score and the insulin area was still significant even after adjustement for body mass index and plasma triglyceride level. Our data suggest that hypertriglyceridemia, IGT, and hyperinsulinemia may become independent risk factors for atherosclerosis in addition to cholesterol. Another study showed that the morbidity of coronary heart disease increased with an elevation of plasma triglyceride levels among patients with familial hypercholesterolemia.