It has been shown that severe hypercholesterolemia is associated with carotid atherosclerosis but it is unclear whether this is true for moderate hypercholesterolemia. The aim of the study was to determine the prevalence of ultrasound detectable extent and severity of carotid intima-media thicknesses in 143 asymptomatic (79 males, 64 females, age range 45-64 years) primary moderate hypercholesterolemic patients (serum LDL cholesterol range 160-190 mg/dl). This group was compared with 143 asymptomatic normolipidemic subjects (serum LDL cholesterol < or = 130 mg/dl and serum triglycerides < 200 mg/dl) matched for age, sex and other cardiovascular risk factors. The maximum intima-media thickness (IMT) was measured using B-mode ultrasonography at 12 sites on the near and the far wall of the common, bifurcation and internal carotid arteries. The mean-maximum IMT at the 12 sites was compared in cases and controls. Moreover, the prevalence of intima-media thickening (i.e. at least one of the 12 sites with an IMT equal to or greater than 1.0 mm but less than 1.3) and plaques (i.e. at least one of the 12 sites with an IMT equal to or greater than 1.3 mm) was considered in the two groups. The mean-maximum intima-media thickness was 0.97 +/- 0.12 mm in hypercholesterolemic patients and 0.93 +/- 0.05 mm in controls (P < 0.0001). Intima-media thickening and plaques were detected in 76% of hypercholesterolemics vs. 57% of controls (P < 0.0002). Gender did not influence these differences.(ABSTRACT TRUNCATED AT 250 WORDS)