Serum Folate and Vitamin B12 Levels in Hemodialysis Patients: Is There any Correlation with Plasma Homocysteine Levels?

Deficiencies of water soluble vitamins such as folate and vitamin B12 has been reported as etiologic factors of hyperhomocysteinemia. This study was conducted to find whether there is a correlation between serum levels of these vitamins and plasma total homocysteine (tHcy) levels. 19 hemodialysis subjects were enrolled. The study group comprised 52.6% girls and 47.4% boys aged 80-324 (204.7±78.4) months who were on dialysis from 1.5-153 (42.1±43.3) months ago. All patients were supplemented by folate and 15 cases were received oral vitamin B12.Folate serum levels <1.5 ng/ml were defined as low (deficiency).As for vitamin B12, levels < 120 pg/ml, 120-160 pg/ml were defined as deficient and borderline, respectively. Plasma Hcy levels of 5-15 µmol/L and > 15 µmol/L were defined as normal and hyperhomocysteinemia, respectively. The correlation between the serum levels of vitamins and plasma Hcy levels was checked by the Pearson correlation test and P-values <0.05 and r>0.7 indicated a good (significant) correlation. 13 patients (68.4%) had hyperhomocysteinemia whereas plasma tHcy levels were normal in 6 (31.6%). No patient had folate or vitamin B12 deficiency.There was no correlation between tHcy levels and serum vitamin B12 (P=0.621, r=1) and serum folate levels (P=0.571, r=1). Normal and even high serum levels of folate and vitamin B12 cannot prevent the occurrence of hyperhomocysteinemia in hemodialysis patients.