Plasma homocysteine and its association with carotid intimal-medial wall thickness and prevalent coronary heart disease: NHLBI Family Heart Study

Mildly elevated plasma total homocysteine (tHcy) levels have been associate d with increased risk of coronary heart disease (CHD). Carotid artery intim al-medial wall thickening is a predictor of cardiovascular disease and has been previously shown to be positively associated with plasma tHcy in studi es of asymptomatic subjects. In the current study we examined 1467 subjects with regard to their fasting plasma tHcy levels and intimal-medial wall th ickness as measured by B-mode ultrasound and early onset CHD. The results s howed that there is a significant positive association between plasma tHcy levels and carotid-artery wall thickness in participants 55 years or older even after the tHcy levels are adjusted for age, smoking and anti-hypertens ive medication. The direction and magnitude of the relationship is similar although the result was not statistically significant in younger participan ts (< 55 years). Early onset CHD at any age was not significantly different across the tHcy quintiles. The lack of an association of tHcy and CHD in t he presence of a positive association with intimal-medial wall thickening m ay be a reflection of increased statistical power of quantitative versus qu alitative traits. We conclude that the present finding of a positive associ ation between tHcy and intimal-medial wall thickness strengthens the in vit ro finding of the stimulating effect of homocysteine on vascular smooth mus cle cell growth. Vascular smooth muscle cell proliferation may be an import ant mechanism through which mildly elevated plasma tHcy promotes atheroscle rosis. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.