Homocysteine and stroke

Epidemiological studies have demonstrated associations between elevated homocysteine and increased risk of cardiovascular diseases including stroke. A meta-analysis of prospective studies demonstrated that after accountingfor known cardiovascular disease risk factors, a 25% lower homocysteine was associated with a 19% lower risk of stroke. A number of recently completed randomised trials on B vitamin homocysteine lowering and risk of stroke do not provide clear evidence ofany beneficial effect, although in one trial fewer patients assigned to active treatment than to placebo had a stroke. There are many ongoing prospective, controlled intervention trials using folate, vitamin B ₁₂ and vitamin B₆ as homocysteine-lowering agents, the results of which (plus future meta analyses) may provide important information as to whether these vitamins can be protective against cardiovascular diseases including stroke. However, even if homocysteine-lowering therapies prove to be effective it still does not clear up whether the beneficial effect can be ascribed to a reduction in homocysteine or to an independent effect of the B-vitamins themselves