Increased carotid artery intima-media thickness in subjects with primary hypoalphalipoproteinemia

The plasma concentration of high-density lipoprotein cholesterol (HDL-C) is inversely correlated with the incidence of atherosclerotic vascular events. In the present study we evaluated preintrusive atherosclerosis in subjects with plasma HDL-C at the extremities of normal distribution. Fifty-five subjects with primary hypoalphalipoproteinemia (HypoALP) or hyperalphalipoproteinemia (HyperALP) were compared with fifty-five control subjects with average HDL-C levels, matched for sex, age and plasma cholesterol. The average and maximal intima-media thickness (Avg-IMT and Max-IMT) of 48 carotid segments for each subject were approximately 40% greater in HypoALP than control subjects (0.94±0.06 vs. 0.69±0.04 mm, p=0.004; and 1.86±0.16 vs. 1.35±0.10 mm, p=0.025). The IMT values in HyperALP subjects (Avg-IMT: 0.71±0.04 and 1.38±0.14 mm) were the same as controls. In a large cohort of hyperlipidemic subjects (n=559), significantly greater Avg-IMT and Max-IMT were found in subjects belonging to the first HDL-C quintile (< 42 mg/dl) than all the others. The measurement of carotid IMT in cases with HypoALP and HyperALP, and in a large series of hyperlipidemic patients, thus indicates that a low HDL-C is associated with significant preintrusive atherosclerosis, while a HDL-C above average values does not lead to a further reduction of arterial wall thickening.