Hyperinsulinaemia as predictor of atherosclerotic vascular disease: epidemiological evidence

Three prospective population studies on non-diabetic subjects--the Helsinki Policemen Study, the Busselton Study, and the Paris Prospective Study--have shown that high plasma insulin levels, fasting or after oral glucose load, are associated with an increased risk of coronary heart disease (CHD). The excess of CHD events accumulating in the highest quintiles or deciles for plasma insulin and multivariate analyses suggests that the predictive value of plasma insulin with regard to CHD risk would be independent of blood glucose levels and other major CHD risk factors. Interpretation of the results of multivariate analyses including plasma insulin is, however, complex owing to relatively strong correlations between plasma insulin and several other risk factors. Interaction of the predictive value of plasma insulin with other risk factors, such as obesity, plasma lipids and lipoproteins, and blood pressure also deserves consideration. Analyses of the follow-up data from the Paris Prospective Study have in fact shown that such interaction exists with regard to obesity, high plasma insulin levels being predictive of increased risk of CHD in obese subjects but not in lean subjects. No information is available about the possible relationship between plasma free-insulin levels and atherosclerotic vascular disease (ASVD) in patients with insulin-dependent type diabetes receiving insulin treatment. Information concerning the relationship of plasma insulin to ASVD in subjects with impaired glucose tolerance (IGT) or non-insulin-dependent diabetes (NIDD) is so far fragmentary but suggests that elevated plasma insulin levels would be predictive of increased risk of ASVD in NIDD and its precursor stage, IGT.(ABSTRACT TRUNCATED AT 250 WORDS)