Overall, the MTHFR Ala222Val polymorphism was not associated with the development of bladder cancer in all genetic models (Ala/Ala vs. Val/Val--OR = 0.961, 95 % CI = 0.763-1.209; Ala/Ala vs. Ala/Val--OR = 0.918, 95 % CI = 0.795-1.060--Ala/Val vs. Val/Val--OR = 1.022, 95 % CI = 0.852-1.227; dominant model--OR = 0.998, 95 % CI = 0.869-1.145; recessive model--OR = 0.921, 95 % CI = 0.794-1.069; Ala allele vs. Val allele--OR = 0.957, 95 % CI = 0.857-1.067).