Sources of variability of plasma HDL-cholesterol levels.

Epidemiological data from the Framingham and other prospective studies suggests an inverse correlation between the plasma concentration of HDL-cholesterol (HDL-C) and the incidence of cardiovascular disease. The relationship between HDL-C and its vascular- protective effects is particularly due to the heterogeneity of these particles and their important role in reverse cholesterol transport. It is well-known that many different factors are involved in metabolic regulation of HDL and can affect their plasma concentration. Apolipoprotein A-I, the principal apolipoprotein of HDL, is synthesized and secreted in the intestine and liver, where several enzymatic processes contribute to the biogenesis and the catabolism of HDLs. In this review we report and analyze the main clinical, genetic and environmental determinants of plasma HDL-C concentration; moreover we underline how different laboratory methods of HDL-C dosage can influence the correct assessment of these plasma values. We present a comparison of HDL-C levels variation among populations and groups of subjects with different and particular characteristics or pathological conditions, considering the genetic and environmental factors that can affect synthesis and metabolism of these lipoproteins