[Vitamin treatments that lower homocysteine concentration: can they decrease cerebrovascular disease in primary prevention?].

INTRODUCTION

High plasma homocysteine (Hcy) concentration or hyperhomocysteinemia is associated with an increased vascular risk of disease in case-control studies and, to a lesser extent, in prospective studies.

DEVELOPMENT

Several large randomized, double-blind, placebo-controlled trials have been already conducted using specific vitamin therapies with the aim of reducing secondary cardiovascular (HOPE, NORVIT, WAFACS and WENBIT studies) and cerebrovascular (VISP study) disease risk. The results from these major secondary prevention trials and one meta-analysis, that included other smaller studies up to 12 of them, showed that treatment decreased plasma Hcy concentration but failed to reduce cardiovascular risk. It is nevertheless noteworthy that a recent meta-analysis addressing the effects of these vitamin treatments on cerebrovascular risk found a positive effect on primary stroke prevention. These data would be consistent with the fact that increased Hcy is known to be associated more strongly with stroke risk than with cardiovascular risk. Moreover, folic acid supplementation in grain food has recently been shown to be associated with a decreased stroke incidence in USA and Canada.

CONCLUSIONS

Obviously, these data on primary stroke prevention will require extensive confirmation. However, there now appear to be more reasons to expect a positive outcome of Hcy intervention studies.