In ≥65 years subgroup, after adjustment for gender, BMI, smoking status and alcohol use by logistic regression analysis, the TCF7L2 rs290481 TC/CC and TC genotypes increased the risk of T2DM compared with the TCF7L2 rs290481 TT genotype [TC vs. TT: adjusted OR = 1.42, 95% CI 1.01–2.01, P = 0.047 and TC/CC vs. TT: adjusted OR = 1.41, 95% CI = 1.01–1.95, P = 0.042 (Table 4)]. The gene discussed is TCF7L2; the disease is type 2 diabetes mellitus.