The results based on individuals with body mass index (BMI) over 24 kg/m2 suggested that CYP1A2 rs762551 served as a protective factor of T2DM under the allelic model (OR = 0.70, 95% CI = 0.49–1.00, P = 0.047), co-dominant model with CC genotype (OR = 0.32, 95% CI = 0.14–0.74, P = 0.006), recessive model (OR = 0.31, 95% CI = 0.14–0.66, P = 0.002) and additive model (OR = 0.67, 95% CI = 0.46–0.96, P = 0.031). This evidence concerns the gene CYP1A2 and type 2 diabetes mellitus.