In the subsequent SNP-SNP interaction analysis, after adjustment for sex, age, BMI, smoking and alcohol consumption, interactions were found between GG genotype of rs10830963 and AG genotype of rs780094 from MTNR1B and GCKR (OR = 0.392, 95% CI = 0.157–0.982, p = 0.046), and CC genotype of rs151290 with AA genotype of rs780094 from KCNQ1 and GCKR (OR = 4.883, 95% CI = 1.366–17.464, p = 0.015) in T2DM patients (Table 4). This evidence concerns the gene GCKR and type 2 diabetes mellitus.