There was no evidence of a causal relationship between genetically predicted HCT [OR = 1.069(CI: 0.786–1.456, P = 0.667)], HGB [OR = 0.866(CI: 0.701–1.070, P = 0.183)], and RDW [OR = 1.050(CI: 0.884–1.247, P = 0.576)] with risk of T2D. This evidence concerns the gene CYGB and type 2 diabetes mellitus.