Association between elevated plasma total homocysteine and increased common carotid artery wall thickness.

Homocysteine is increasingly recognized as a risk factor for atherothrombotic arterial diseases. We investigated the relation between plasma concentrations of total homocysteine (tHcy) and common carotid artery intima-media wall thickness, measured by B-mode ultrasonography, in 513 asymptomatic men and women from eastern Finland aged 45-69 years. The subjects were examined in 1994-95 at the baseline of the Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) study, a randomized double-blind placebo-controlled two by two factorial trial on the effect of vitamin E and C supplementation in the prevention of atherosclerotic progression. The subjects were assigned into two categories according to the plasma tHcy concentration; concentration over 11.5 micromol/L (highest quartile) or concentration below 11.5 micromol/L. In this study population the mean plasma tHcy concentration was 10.0 micromol/L, and the prevalence of plasma tHcy concentration exceeding 11.5 micromol/L was 33% in men and 18% in women. The adjusted mean intima-media thickness of the right and left common carotid arteries was 1.12 mm in men with elevated plasma tHcy concentration and 1.02 mm in men with a plasma tHcy concentration below 11.5 micromol/L (P = 0.029). In women there was no significant difference. We conclude that elevated plasma tHcy concentrations are associated with early atherosclerosis, as manifested by increased common carotid artery intima-media wall thickness, in middle-aged eastern Finnish men.