Folic Acid Supplementation May Reduce Colorectal Cancer Risk in Patients With Inflammatory Bowel Disease

GOALS: To evaluate the role of folic acid supplementation in colorectal cancer (CRC) chemoprevention in patients with inflammatory bowel disease (IBD). BACKGROUND: CRC is a serious complication of IBD. Folic acid supplementation has been shown to be chemopreventative in sporadic CRC. Patients with IBD are at risk of folate deficiency though intestinal malabsorption and also competitive inhibition by concurrent sulfasalazine use. To date, there have been several studies reporting on folic acid supplementation in patients with IBD and CRC. STUDY: We searched electronic databases for studies reporting folic acid use and CRC incidence in patients with IBD. We produced a pooled hazard ratio with 95% confidence intervals using a random-effects model. Preplanned subgroup analyses were performed to explore for any potential sources of heterogeneity. RESULTS: Ten studies reporting on 4517 patients were included. We found an overall protective effect for folic acid supplementation on the development of CRC, pooled hazard ratio=0.58 (95% confidence interval, 0.37-0.80). There was low to moderate heterogeneity among studies, I=29.7%. Subgroup analyses suggested that folic acid use was protective in hospital-based studies, studies from North America and those that were performed before folate fortification of foods in 1998. CONCLUSIONS: CRC remains an important complication of IBD. Chemoprevention is an attractive strategy and folic acid as a cheap, safe, and well-tolerated supplement may have a role. Focused prospective studies are required to precisely define any potential effect.