Hyperhomocysteinemia and venous thrombosis: A meta-analysis

Hyperhomocysteinemia is an established risk factor for atherosclerosis and vascular disease. Until the early nineties the relationship with venous thrombosis was controversial. At this mnoment ten case-control studies on venous thrombosis are published, We performed a meta-analysis of these reports. We performed a MEDLINE-search from 1984 through June 1997 on the keywords 'homocysteine' or 'hyperhomocysteinemia' and 'venous thrombosis', which yielded ten eligible case-control studies. We found a pooled estimate of the odds ratio of 2.5 (95% CI 1.8-3.5) for a fasting plasma homocysteine concentration above the 95th percentile or mean plus two standard deviations calculated from the distribution of the respective control groups. For the post-methionine increase in homocysteine concentration we found a pooled estimate of 2.6 (95% CI 1.6-4.4). These data from case-control studies support hyperhomocysteinemia as a risk factor for venous thrombosis. Further research should focus on the pathophysiology of this relationship and on the clinical effects of reducing homocysteine levels by vitamin supplementation.