Plasma insulin levels and coronary risk factors in nondiabetic men with ''premature'' ischemic heart disease

Abnormal resistance of peripheral tissues to insulin with compensatory hyperinsulinemia has been suggested to play key role in development of atherosclerosis and coronary heart disease (Reaven). This role could be even greater in pathogenesis of premature (i.e. before 55 years in men) coronary heart disease culminating with myocardial infarction. The aim of the study was to relate fasting and stimulated plasma insulin levels to main coronary risk factors and some parameters of hemostasis in men with ''premature'' ischemic heart disease. Thirty five nondiabetic men aged 32 - 55 years with plasma triglycerides below 400 mg/dl were studied in more that 3 months after definite myocardial infarction. Plasma levels of apoproteins B, A-1, Lp (a), fibrinogen, protein C, plasminogen, antithrombin 3 and activity of plasminogen activator inhibitor were determined in addition to assessment of common risk factors. Hyperinsulinemia (>12,5 mu U/ml) was found in 3/35 patients (8,7%) at rest and (>28 mu U/ml) in 9/23 patients (39%) after standard glucose load. Dyslipidemia was the most frequent metabolic disorder in this group of patients (observed in 97% of cases). Plasma insulin at rest correlated positively with diastolic blood pressure (r=0,331; p=0,026), body mass (r=0,285; p=0,049) and body mass index (r=0,308; p=0,038), hips circumference (r=0,386; p=0,012). Plasma insulin after glucose load correlated with body mass index (r=0,527; p=0,006). At multifactorial analysis presence of arterial hypertension and hips circumference were independent predictors of insulin level at rest and body mass index - of insulin level after glucose load. No relationship was found between plasma insulin levels and plasma lipids, lipo-and apoproteins and characteristics of hemostasis. Thus plasma insulin in men with premature myocardial infarction is related to various characteristics of body mass and hypertension status but not to lipids or parameters of hemostasis.