Plasma Insulin and Lipoprotein Concentrations: An Atherogenic Association?

Plasma insulin concentrations have been shown to be predictive of future cardiovascular disease in men. Though many clinical studies have documented correlations between plasma insulin and triglyceride concentrations, few epidemiologic studies have reported insulin-lipid correlations. In this report, the authors present correlations obtained from 323 non-diabetic first degree relatives of insulin dependent diabetic patients who underwent 4 hour oral glucose tolerance tests at Children's Hospital, Pittsburgh, Pennsylvania, in February 1980-December 1981 as part of an epidemiologic study of insulin dependent diabetes mellitus. Significant positive correlations were seen between insulin (measured as fasting insulin and the 3 hour area under the insulin curve during the oral glucose tolerance test) and the atherogenic lipids, total and low density lipoprotein cholesterol and triglycerides ranging from r = +0.14 (p less than 0.01) to r = + 0.35 (p less than 0.001). An inverse correlation with high density lipoprotein cholesterol was also noted r = -0.27 (p less than 0.001). A computed score of insulin activity, which the authors call the insulin-glucose sensitivity index, shows equally strong correlations but of reverse sign. In multivariate analyses, these insulin measures and age largely account for the associations of sex and obesity (measured as body mass index) with the atherogenic lipids, though this was only partly true for high density lipoprotein cholesterol. The biologic plausibility of these findings and their relevance to the development of atherosclerosis are discussed.