Effect of homocysteine-lowering treatment with folic acid plus vitamin B₆ on cerebrovascular atherosclerosis and white matter abnormalities as determined by MRA and MRI: A placebo-controlled, randomized trial

Background: A high plasma homocysteine concentration is an independent risk factor for large and possibly small vessel disease. We investigated the effects of homocysteine-lowering treatment with folk acid plus vitamin B₆ on markers of cerebrovascular atherosclerosis and cerebral microangiopathy. Materials and Methods: Using 158 healthy siblings (mean age 46.0 ± 7.6 years) of patients with premature atherosclerotic disease, we performed a randomized, placebo-controlled trial using 5 mg of folic acid plus 250 mg of vitamin B₆ daily (n = 78) or placebo medication (n = 80). Participants were followed for 2 years with magnetic resonance angiography (MRA) (carotid stenosis; carotid and/or vertebral elongation) and magnetic resonance imaging (MRI) (white matter abnormalities; cerebral atrophy). Results: Seventeen (10.8%) subjects refused MRA/MRI owing to claustrophobia and were excluded. From the remaining 141 participants, 68 received vitamin and 73 received placebo medication [42 (61.8%) and 48 (65.8%) had postmethionine hyperhomocysteinaemia, respectively]. Twenty-four participants (15.2%; 10 in the treatment and 14 in the placebo group) did not complete both years of the trial. Vitamin treatment was associated with an increase in plasma folate (13-fold vs. placebo; P < 0.001) and vitamin B₆ (8.8-fold; P < 0.001). Fasting and postmethionine total homocysteine concentrations decreased 38.7% (95% CI, 27.4-50.0) and 29.1% (95% CI, 19.2-39.0) vs. placebo (all P < 0.001). During follow up six individuals in the vitamin-treated and 11 in the placebo-treated group deteriorated in their outcome measurements. Vitamin treatment, as compared with placebo, was associated with nonsignificantly improved outcomes on both MRA and MRI outcome measurements (odds ratio 0.48; 95% CI 0.17-1.41; P = 0.18 and 0.48; CI 0.14-1.60; P = 0.23, respectively). Conclusions: These results could indicate a possible favourable effect of homocysteine-lowering treatment on cerebrovascular atherosclerosis and cerebral microangiopathy among healthy siblings of patients with premature atherosclerotic disease, but larger trials are required to establish this with certainty.