Diabetes mellitus and the incidence and mortality of colorectal cancer: A meta-analysis of twenty four cohort studies
Colorectal Disease, 05/10/2012  Clinical Article

Luo W et al. – The meta–analysis suggests diabetic individuals have a significant increase in risk of developing colorectal cancer.

• MEDLINE and EMBASE were searched for articles published before July 2010.
• Cohort studies that evaluated DM and CRC incidence and mortality were included.
• The initial search identified 1887 titles, of which 24 articles met the inclusion criteria.
• The authors defined the relative risk (RR) as the metric of choice, with 95% confidence intervals (CIs) were calculated with a random-effects model.

• There was an increase in the RR of developing colorectal cancer in persons with diabetes compared with those without diabetes (RR 1.28 [95%CI 1.19 - 1.39]), without heterogeneity between studies (Pheterogeneity = .13).
• The association between duration of DM and CRC incidence was stronger in 11–15 yr group (RR 1.51 [95%CI 1.12 - 2.03]) than in < 10 yr (RR 1.05 [95%CI 0.90 - 1.22]) and >15 yr group (RR 1.25 [95%CI 0.80 - 1.94]), and there was significant heterogeneity among subgroups (Pheterogeneity = .01).
• In studies reporting standardized incidence ratios (SIR), there was an increased incidence of CRC with DM (RR 1.27 [95%CI 1.14 - 1.42] Pheterogeneity = .09); and the association was stronger among males (RR 1.47 [95%CI 1.15 - 1.86]) than females (RR 1.08 [95%CI 1.00 - 1.17]), there was significant heterogeneity among gender (Pheterogeneity = .01).