Cognitive and clinical outcomes of homocysteine-lowering B-vitamin treatment in mild cognitive impairment: A randomized controlled trial

Background Homocysteine is a risk factor for Alzheimer's disease. In the first report on the VITACOG trial, we showed that homocysteine-lowering treatment with B vitamins slows the rate of brain atrophy in mild cognitive impairment (MCI). Here we report the effect of B vitamins on cognitive and clinical decline (secondary outcomes) in the same study. Methods This was a double-blind, single-centre study, which included participants with MCI, aged ≥70y, randomly assigned to receive a daily dose of 0.8mg folic acid, 0.5mg vitamin B 12 and 20mg vitamin B 6 (133 participants) or placebo (133 participants) for 2y. Changes in cognitive or clinical function were analysed by generalized linear models or mixed-effects models. Results The mean plasma total homocysteine was 30% lower in those treated with B vitamins relative to placebo. B vitamins stabilized executive function (CLOX) relative to placebo (P=0.015). There was significant benefit of B-vitamin treatment among participants with baseline homocysteine above the median (11.3μmol/L) in global cognition (Mini Mental State Examination, P