Furthermore, since homocysteine was correlated with both the MTHFR genotype and vitamin B12 concentration, we then performed a multifactor logistic regression analysis that was adjusted for the three mutually independent element factors, namely, the MTHFR genotype (TT vs. CT and CC), vitamin B12 deficiency and folate deficiency. This evidence concerns the gene MTHFR and vitamin B12 deficiency.