Objectives: Vitamin B-12 and folate deficiency are common, especially in people aged 55 or over, and accompanied by elevated methylmalonic acid (MMA) and homocysteine concentrations. The aims of the study were to investigate the relationship between serum vitamin B-12, homocysteine, folate, erythrocyte folate and urinary MMA in patients with ischemic stroke, and to develop a simple screening HPLC method for the measurement of urinary MMA.
Design and methods: Twenty-eight patients aged 55 years and over with ischemic stroke and 23 age- and sex- matched healthy controls were included in the study. Serum vitamin B-12 and folate were measured by immunoassay; serum total homocysteine and urinary MMA concentrations by HPLC.
Results: There was no significant difference in vitamin B-12, folate and homocysteine concentrations between the patient and control groups. Urinary MMA concentrations and erythrocyte folate levels were significantly higher in patients than controls. There was a significantly negative correlation between vitamin B-12 and MMA.
Conclusions: Increased urinary MMA excretion is associated with ischemic stroke and it may more robustly reflect vitamin B-12 deficiency in patients with ischemic stroke. The method used in this study is eligible for routine urinary MMA measurements.