Mild hyperhomocysteinemia is an independent risk factor of arterial vascular disease.

Evidence of a positive association between mild hyperhomocysteinemia and arterial vascular disease has been accumulating in the last decade. Mild hyperhomocysteinemia acts as an independent vascular risk factor with equal strength as hypercholesterolemia and smoking. If jointly present with hypertension and smoking, its effect seems synergistic. This could make the outcome of homocysteine-lowering intervention beneficial, particularly in cases with concomitance of conventional vascular risk factors. So far, however, data on the clinical outcome of homocysteine-lowering treatment with a simple, safe, and cheap vitamin regimen are lacking. Trials investigating a beneficial clinical effect of homocysteine-lowering treatment using folic acid in a dose ranging from 0.2 to 5 mg daily, alone or in combination with vitamin B12 with or without vitamin B6 versus placebo, are ongoing. Furthermore, exploration of the unifying mechanism by which increased homocysteine levels may lead to both arterial and venous occlusions is warranted. These lines of investigations have to provide the ultimate proof of causality of hyperhomocysteinemia in vascular disease in the near future.