An important risk factor for cardiovascular disease (CVD) that can be removed with vitamin B12 and folic acid supplementation is the hypothesis that any major folate-sensitive abnormality in homocysteine metabolism may lead to diminished methylenetetrahydrofolate reductase activity Patients with mild to moderate CKD and higher B12 levels who received folic acid treatment saw a greater decline in their risk of CKD progression. This evidence concerns the gene MTHFR and chronic kidney disease.