The effect of folic acid supplementation on the risk for cancer or dysplasia in ulcerative colitis

BACKGROUND & AIMS: Two case-control studies have shown that folate may protect against neoplasia in ulcerative colitis. This historical cohort study was performed to better define this association. METHODS: The records of 98 patients with ulcerative colitis who had disease proximal to the splenic flexure for at least 8 years were reviewed. Documented folate use of at least 6 months was deemed a positive exposure. RESULTS: Of the patients, 29.6% developed neoplasia and 40.2% took folate supplements. The adjusted relative risk (RR) of neoplasia for patients taking folate was 0.72 (95% confidence interval [CI], 0.28- 1.83). The dose of folate varied with the risk of neoplasia (RR, 0.54 for 1.0 mg folate; RR, 0.76 for 0.4 mg folate in a multivitamin compared with patients taking no folate). Folate use also varied with the degree of dysplasia (RR for cancer, 0.45; RR for high-grade dysplasia, 0.52; RR for low-grade dysplasia, 0.75 compared with patients with no dysplasia) (P = 0.08). CONCLUSIONS: Although not statistically significant, the RR for folate supplementation on the risk of neoplasia is > 1 and shows a dose-response effect, consistent with previous studies. Daily folate supplementation may protect against the development of neoplasia in ulcerative colitis. (Gastroenterology 1997 Jan;112(1):29-32)