Homocysteine and cardiovascular disease: evidence on causality from a meta-analysis

The genetic studies and the prospective studies do not share the same potential sources of error, but both yield similar highly significant results-strong evidence that the association between homocysteine and cardiovascular disease is causal. On this basis, lowering homocysteine concentrations by 3 micromol/l from current levels (achievable by increasing folic acid intake) would reduce the risk of ischaemic heart disease by 16% (11% to 20%), deep vein thrombosis by 25% (8% to 38%), and stroke by 24% (15% to 33%).