This is the first study to explore the effects of CYP19A1 and CYP1A2 on T2DM in the population of Chinese Han, and reported that the influence of the genetic polymorphisms of CYP19A1 and CYP1A2 on the risk of T2DM may be related to age, BMI and disease course. This evidence concerns the gene CYP1A2 and type 2 diabetes mellitus.