Effect of methylenetetrahydrofolate reductase C677T polymorphism on serum folate but not vitamin B12 levels in patients with H-type hypertension

Background Hyperhomocysteinemia (HHcy) is a common complication in Chinese hypertensive patients and associated with methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism, folate, and vitamin B12 (Vit B12) status. This study evaluated the associations of MTHFR C677T polymorphism, folate, and Vit B12 with H-type hypertension. Methods and results 887 eligible patients with essential hypertension were included. Patients were divided into two groups according to the Hcy level, the H-type hypertension group and the normal hypertension group. Related risk factors such as MTHFR polymorphism, folate and Vit B12 status were analyzed in the two groups. Age, gender, SBP, DBP, MTHFR C677T genotype, folate and Vit B12 differed significantly between H-type hypertension and normal hypertension groups (P < 0.05). MTHFR 677TT variant, gender, folate, and Vit B12 were independent risk factors for the occurrence of H-type hypertension. The risk for TT carriers was 8 times higher than that of CC and CT carriers [OR (95% CI) 8.248 (5.274-12.899)]. Male patients had almost fivefold higher odds than female patients [OR (95% CI) 4.923 (2.741-8.842)]. Folate level of patients with H-type hypertension decreased with the C to T substitution of MTFHR C677T gene (P < 0.05), while Vit B12 level was not associated with the gene (P > 0.05). Conclusions MTHFR 677TT variant, gender, folate, and Vit B12 were risk factors for the occurrence of H-type hypertension. Folate but not Vit B12 was associated with MTFHR C677T polymorphism in patients with H-type hypertension. Accordingly, the above factors may be considered in the prevention and treatment of hypertension.