Crohn's disease and small bowel adenocarcinoma: a population-based case-control study.

BACKGROUND Although Crohn's disease (CD) is thought to predispose to adenocarcinomas of the small bowel, the association has not been well studied in an older population. AIMS The objective of our study was to evaluate the association of CD with small bowel cancer in a population-based case-control study. METHODS All cases of small bowel cancer in persons 67 and older in the Surveillance, Epidemiology and End Results catchment area and in the Medicare claims data base were compared with cancer-free controls residing in the same geographic area. We used multivariable logistic regression models adjusted for demographic and other factors. RESULTS We identified 923 cases of small bowel cancer and 142,273 controls. Although we found a strong association between CD and small bowel cancer (OR = 12.07; 95% CI: 6.07-20.80; P < 0.001), the prevalence of CD in patients with small bowel cancer was low (1.6%). CONCLUSIONS Although CD is a significant risk factor for small bowel cancers among individuals older than 67, the absolute risk is small. IMPACT Older individuals with CD can be reassured that although there is an association between CD and small bowel cancer, the absolute risk remains small.