Should we monitor vitamin B12 and folate levels in Crohn's disease patients?

Objective. Crohn's disease commonly involves the small intestine, which is the site of vitamin B-12 and folate absorption. Our aim was to define the prevalence of vitamin B-12 and folate deficiency in patients with Crohn's disease and to identify predictive factors associated with such abnormalities. Methods. Two years prospective study of 180 consecutive Crohn's disease patients. Vitamin B-12 and folate deficiency was defined as serum levels below 200 pg/ml and 3 ng/ml, respectively. We analysed prevalence of these deficiencies and possible predictive factors including small intestine resection, disease location, activity and duration of disease. Controls were ulcerative colitis patients (n = 70). Results. The prevalence of B-12 deficiency in Crohn's disease was 15.6% (95% CI 9.7-20%) compared with 2.8% (95% CI 0.8-9.8%) in ulcerative colitis (p = 0.007). With regard to folate deficiency, the prevalence in patients with Crohn's disease was 22.2% (95% CI 16-28%) compared with 4.3% (95% CI 1.4-12%) in ulcerative colitis (p = 0.001); 7.8% of Crohn's disease patients had macrocytic anemia. Ileal resection was found to be a risk factor for B-12 deficiency (OR 2.7; 1.2-6.7; p = 0.02), and disease activity a risk factor for folate deficiency (OR 2.4; 1.2-5.1; p = 0.01). Conclusion. A significant proportion of patients with Crohn's disease suffer from vitamin B-12 and/or folate deficiency, suggesting that regular screening should be performed, with closer monitoring in patients with ileal resection or active disease.