Plasma phospholipid EPA and DHA in relation to atherosclerosis in 61-year-old men

Increased intake of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) has been shown to decrease the risk for cardiovascular death and to reduce CVD risk factors. It has also been suggested that EPA and DHA reduce atherosclerosis progression, but data are inconclusive. Carotid intima-media thickness (IMT) is a well-established surrogate measure for sub-clinical atherosclerosis. Our aim was to examine if plasma phospholipid EPA and DHA are associated with IMT and plaque occurrence and size in the carotid and femoral arteries.

IMT and plaque occurrence in carotid and femoral arteries was measured by ultrasound in 487 sixty-one-year-old men in this cross-sectional study. Plasma phospholipid levels of EPA and DHA, serum lipids, cell adhesion molecules, and blood pressure were measured, and occurrence of diabetes and socioeconomic factors were assessed.

Plasma phospholipid EPA was negatively associated with IMT in carotid and femoral arteries, and with cigarette years and cell adhesion proteins. EPA was positively associated with HDL, total cholesterol, blood pressure, plasma insulin and years of education. The association between EPA and carotid IMT remained after adjustment for blood pressure, but not for other covariates. Plasma phospholipid DHA was negatively associated with cigarette years and several endothelial markers, and positively associated with years of education and systolic blood pressure. In contrast to other studies, EPA content was higher in diabetic patients compared with patients without diabetes.

Plasma phospholipid EPA, but not DHA, was inversely associated with carotid and femoral IMT, as well as several endothelial markers supporting the concept of an effect of EPA on the vascular wall. This association was independent of blood pressure, but not for other covariates. There was no association between plasma phospholipid EPA or DHA and plaque occurrence in the carotid and femoral arteries.