Increased intima-media thickness in familial combined hyperlipidemia associated with apolipoprotein B

The aim of the present study was to quantify intima-media thickness (IMT) in familial combined hyperlipidemia (FCHL) and to evaluate the relationship of IMT in FCHL-affected subjects with lipids and apolipoproteins, blood pressure values, and surrogate markers of insulin resistance. IMT was measured by ultrasound at the left and right common carotid arteries in 46 FCHL-affected subjects who were free of clinical manifestations of atherosclerosis and in 55 age- and sex-matched healthy control subjects. FCHL-affected subjects had significantly increased IMT compared with healthy control subjects, with a difference of 57 microm (age- and sex-corrected P<0.01). In the FCHL group, significantly positive age- and sex-corrected univariate correlations were observed between IMT and total cholesterol, non-high density lipoprotein cholesterol, and apolipoprotein B. Multivariate regression analyses revealed that age, sex, and apolipoprotein B were significant and independent predictors of IMT, whereas body mass index was of borderline significance. Combined, these factors explained almost 50% of the observed IMT variation (P<0.001). The increased IMT observed in FCHL corresponds with approximately 7 years of physiological IMT increase in excess of the average IMT in age- and sex-matched control subjects. These novel findings show the important relationship between lipoprotein particles, marked by increased apolipoprotein B concentrations, and an increased IMT in FCHL. The increased IMT in FCHL-affected subjects is in agreement with the known high risk of cardiovascular disease in FCHL.