Diabetes mellitus as a risk factor for gastrointestinal cancer among American veterans

AIM: To assess the risk of biliary and pancreatic cancers in a large cohort of patients with type 2 diabetes mellitus (DM). METHODS: Eligibility for this study included patients with type 2 DM (ICD-9 code 250.0) who were discharged from Department of Veteran Affairs hospitals between 1990 and 2000. Non-matched control patients without DM were selected from the same patient treatment files during the same period. Demographic information included age, sex and race. Secondary diagnoses included known risk factors based on their ICD-9 codes. By multivariate logistic regression, the occurrence of biliary and pancreatic cancer was compared between case subjects with DM and controls without DM. RESULTS: A total of 1 172 496 case and control subjects were analyzed. The mean age for study and control subjects was 65.8 ± 11.3 and 64.8 ± 12.6 years, respectively. The frequency of pancreatic cancer in subjects with DM was increased (0.9%) in comparison to control subjects (0.3%) with an OR of 3.22 (95% CI: 3.03-3.42). The incidence of gallbladder and extrahepatic biliary cancers was increased by twofold in diabetic patients when compared to controls. The OR and 95% CI were 2.20 (1.56-3.00) and 2.10 (1.61-2.53), respectively. CONCLUSION: Our study demonstrated that patients with DM have a threefold increased risk for developing pancreatic cancer and a twofold risk for developing biliary cancer.