Based on the joint tests, we found that the association of diabetes with colorectal cancer risk is modified by loci on chromosomes 8q24.11 (rs3802177, SLC30A8 – ORAA: 1.62, 95% CI: 1.34–1.96; ORAG: 1.41, 95% CI: 1.30–1.54; ORGG: 1.22, 95% CI: 1.13–1.31; p-value3-d.f.: 5.46 × 10−11) and 13q14.13 (rs9526201, LRCH1 – ORGG: 2.11, 95% CI: 1.56–2.83; ORGA: 1.52, 95% CI: 1.38–1.68; ORAA: 1.13, 95% CI: 1.06–1.21; p-value2-d.f.: 7.84 × 10−09). This evidence concerns the gene LRCH1 and diabetes mellitus.