Objective. To investigate the association between plasma oxidized low-density lipoprotein (OxLDL) and the progress of clinically silent atherosclerosis, as measured by ultrasound in the carotid arteries.
Design. Prospective, observational study with more than 3 years of follow-up.
Setting. One-centre study at university hospital.
Material and methods. The subjects (n = 326) were obtained by stratified sampling from a population sample of men who were 58 years old at baseline. Carotid artery intima-media thickness (IMT) was measured bilaterally by high-resolution B-mode ultrasound at baseline and after follow-up. Plasma OxLDL cholesterol concentrations and conventional cardiovascular risk factors were measured at study entry. Automated measurements of IMT were performed. Plaque occurrence and size were assessed (plaque status). Plasma OxLDL at entry was measured by a specific monoclonal antibody, mAb-4E6.
Results. OxLDL at entry, but not LDL cholesterol, was associated with the number and size of plaques at follow-up (P = 0.008), also after adjustment for plaque status at entry (P = 0.033). The plasma OxLDL concentration at entry was associated with change in carotid artery IMT (r = 0.17; P = 0.002) and in a stepwise multiple regression analysis this association remained after adjustment for other cardiovascular risk factors (P = 0.005).
Conclusions. These results provide new information, supporting the concept that circulating OxLDL was associated with the silent phase of atherosclerosis progression in clinically healthy men independently of conventional risk factors.