High prevalence of vitamin B-12 insufficiency in patients with Crohn's disease.

BACKGROUND AND OBJECTIVES In Crohn's disease (CD), belonging to inflammatory bowel disease, the small intestine is involved in most cases. Most frequently affected is the distal ileum, where vitamin B-12 is specifically absorbed. Therefore, malabsorption of vitamin B-12 is quite likely to occur in patients with CD. In this study, we have studied the vitamin B-12 status in CD patients. METHODS AND STUDY DESIGN Forty eight patients with CD were evaluated for their food intake, and circulating concentrations of vitamin B-12, folic acid, and homocysteine (Hcy) as a sensitive marker for the insufficiency of these vitamins and a risk factor of atherosclerosis. RESULTS Plasma Hcy concentration was significantly correlated with serum vitamin B-12 concentration alone, and 60.4 % of the subjects had hyperhomocysteinemia. Receiver Operating Characteristics (ROC) analysis showed that serum concentration of vitamin B-12, but not folic acid, predicted hyperhomocysteinemia. Their intake of vitamin B-12 was much higher than the Japanese RDA, but not correlated with blood concentrations of vitamin B-12 or Hcy, probably due to malabsorption. CONCLUSIONS Vitamin B-12 insufficiency and hyperhomocysteinemia were highly prevalent in CD patients. Recently, the significance of extra-intestinal complications of CD has been increasingly recognized, and our finding is likely to be of clinical importance.