Plasma homocysteine and malondialdehyde are correlated in an age- and gender-specific manner.

Homocysteine is an independent risk factor for peripheral vascular and coronary artery disease. The exact mechanism by which homocysteine promotes vascular dysfunction is unclear, but it is speculated to involve oxidative stress. Several studies have investigated the role of homocysteine in promoting oxidative stress and have obtained conflicting results. The age and gender of the subject populations in these studies may have influenced the outcome. Therefore, we investigated whether plasma homocysteine concentrations were correlated with plasma malondialdehyde (MDA, a marker of oxidative stress), and if the subject's age and gender affected this correlation. Plasma homocysteine and MDA were measured in 35 premenopausal women, 14 young men, 38 postmenopausal women, and 18 older men. Homocysteine was significantly higher in men than women (P <.01) and in older subjects versus younger. However, MDA was significantly greater only in the young men (P <.01). Furthermore, there was a significant correlation between homocysteine and MDA only in these young men (R(2) = 0.50, P <.01). Lastly, subjects undergoing a methionine load did not exhibit increased MDA despite significant increases in homocysteine. Since oxidative stress correlates with basal homocysteine only in young men and does not increase with acutely increased homocysteine, it is unlikely to be the result of a direct effect of homocysteine. Copyright 2002, Elsevier Science (USA). All rights reserved.