In female subgroup, after adjustment for age, body mass index (BMI), smoking status and alcohol use by logistic regression analysis, the TCF7L2 rs290481 CC genotype were associated with an increased risk of T2DM compared with the TCF7L2 rs290481 TT and TC/TT genotypes [CC vs. TT: adjusted OR = 2.05, 95% CI 1.12–3.76, P = 0.020 and CC vs. TC/TT: adjusted OR = 1.83, 95% CI = 1.05–3.21, P = 0.034 (Table 4)]. This evidence concerns the gene TCF7L2 and type 2 diabetes mellitus.