Table 1.
Summary of representative association studies between type 2 diabetes mellitus (T2DM) and CRC.
| Influence of T2DM on CRC | Ref. | Study design | Main findings |
|---|---|---|---|
| Increased incidence of CRC | Pang et al. [4] | Cohort study (n = 512713) | Diabetic patients showed an increased risk of CRC (HR: 1.18; 95% CI: 1.04–1.39). |
| Ma et al. [5] | Cohort study (n = 134763) | Diabetic patients showed an increased risk of CRC (HR: 1.42; 95% CI: 1.12–1.81). | |
| Guraya et al. [6] | Meta-analysis (n = 924632) | Diabetic patients showed an increased risk of CRC (HR: 1.21; 95% CI: 1.02-1.42). | |
| Larsson et al. [7] | Cohort study (n = 48850) | Diabetic male patients showed an increased risk of CRC (HR: 1.49; 95% CI: 1.14–1.96). | |
| Campbell et al. [8] | Cohort study (n = 154975) | Diabetic male patients showed an increased risk of CRC (RR: 1.22; 95% CI: 1.08-1.44), whereas diabetic female patients failed to show increased risk of CRC (RR: 1.01; 95% CI: 0.82-1.23). | |
| Jiang et al. [9] | Meta-analysis (n = 11692232) | Diabetic patients showed an increased risk of CRC (summary relative risks: 1.27; 95% CI: 1.21-1.34). | |
| Worse prognosis of CRC | Mills et al. [10] | Meta-analysis (n = 212888) | CRC patients with T2DM had higher all-cause mortality (RR: 1.17; 95% CI: 1.09-1.25) and cancer-specific mortality (RR: 1.12; 95% CI: 1.01-1.24). |
| Dehal et al. [11] | Cohort study (n = 393) | CRC patients with T2DM had higher overall mortality (RR: 1.53; 95% CI: 1.28–1.83). | |
| Huang et al. [12] | Cohort study (n = 469) | CRC patients with T2DM had higher overall mortality (RR: 1.21; 95% CI: 1.04–1.41) and CRC-specific mortality (RR: 1.21; 95% CI: 1.02–1.43). | |
| Barone et al. [13] | Meta-analysis (n = 54,740) | CRC patients with T2DM had higher overall mortality (RR: 1.32; 95% CI: 1.24–1.41). | |
| Stein et al. [14] | Meta-analysis (n = 8984) | CRC patients with T2DM had higher overall mortality (RR: 1.32; 95% CI: 1.24–1.41). | |
| Jeon et al. [15] | Cohort study (n = 4131) | Colon cancer patients with T2DM had worse disease-free survival (HR: 1.46; 95% CI: 1.11-1.92) and DFS (HR: 1.45; 95% CI: 1.15-1.84), but such effects were not observed in rectal cancer patients with T2DM. |