Cholesterol and triglyceride concentrations in lipoproteins as related to carotid intima-media thickness

Since distinct cholesterol and triglyceride concentrations in major lipoproteins and their subclasses may be related to atherosclerosis, we investigated the relationship of cholesterol and triglyceride concentrations in lipoprotein subclasses and the severity of carotid intima-media thickness (IMT), a surrogate marker of subclinical atherosclerosis. We studied 116 apparently healthy Japanese men (53 ± 9 years) without a history of cardiovascular diseases who were not taking any medication. Carotid IMT was measured by means of high-resolution vascular ultrasound. Plasma cholesterol and triglyceride concentrations in major lipoproteins and their subclasses were determined by HPLC with gel permeation columns. By univariate analyses, carotid IMT was the most closely related to age (r = 0.528, P < 0.001), followed by smoking habit expressed as pack-year cigarette consumption (r = 0.409, P < 0.001). In addition to total cholesterol and LDL cholesterol, carotid IMT was significantly associated with cholesterol and triglyceride concentrations in several LDL and VLDL subclasses. Stepwise multiple linear regression analysis revealed that age (β = 0.436, P < 0.001), smoking (pack-years) (β = 0.225, P = 0.007), and large LDL cholesterol (β = 0.175, P = 0.023) were independent predictors of determining carotid IMT (adjusted R(2) = 0.347, P < 0.001). These results indicate that large LDL cholesterol is an important, independent determinant of carotid IMT in healthy men.