. 2010 Mar 5;2(3):299–316. doi: 10.3390/nu2030299

Table 3.

Meta-analyses of studies assessing vitamin B₁₂ and CVD.

Trial Type	Study Details	Main Outcome
Meta-analysis [53]	9 case-control studies. Assessed associations between tHcy and CVD risk.	5µM tHcy increment associated with increased risk of CAD, OR = 1.6 (95% CI:1.4 to 1.7) for males and 1.8 (95% CI:1.3 to 1.9) for females.
Meta-analysis [54]	30 prospective or retrospective studies assessed tHcy and CVD risk.	25% lower tHcy associated with lower risk of IHD & stroke.
Meta-analysis 7 RCTs [55]	B vitamin supplementation and tHcy lowering, assessed effect of vitamin B₁₂(range 0.02–1.0 mg/day)	Vitamin B₁₂ (median dose 0.4 mg/d) - further decrease (-7%) in tHcy
Meta-analysis 12 RCTs [56]	Preexisting CVD or renal disease- included 3 studies of vitamin B₁₂supplementation, with doses 0.4–1.0 mg B₁₂/day.	Reduction in stroke risk in vitamin B₁₂ (1 mg/d) intervention OR = 0.76 (95% CI:0.59, 0.96)
Meta-analysis8 RCTs [57]	4 studies assessed vitamin B₁₂ supplementation (0.018–1 mg) and stroke risk	Reduction in stroke greater in longer trials with more tHcy lowering and no stroke history. No specific effect of vitamin B₁₂.
Meta-analysis 24 RCTs [58]	Assessed CIMT: 3 with vitamin B₁₂: 0.4–0.5 mg/d; endothelial function: 5 with B₁₂: 6 µg–1 mg/day	↓ CIMT, ↑ FMD found in short-term not long term trials

µM = micromolar, tHcy = total homocysteine, CAD = coronary artery disease, OR = odds ratio, CI=confidence intervals, CVD = coronary vascular disease, IHD=ischaemic heart disese, CIMT = carotid intima media thickness, FMD = flow mediated dilation