Vitamin D Deficiency Associated with Disease Activity in Patients with Inflammatory Bowel Diseases

Evidence exists on the association between vitamin D deficiency and inflammatory bowel diseases (IBD).

To investigate whether vitamin D level is associated with disease activity and quality of life in IBD patients.

This cross-sectional study was conducted on known adult IBD patients referred to an outpatient clinic of gastroenterology in Isfahan city, Iran. Disease activity was evaluated using the Simplified Crohn's Disease Activity Index and Simple Clinical Colitis Activity Index. Quality of life was assessed with the Short-Inflammatory Bowel Disease Questionnaire. Serum 25[OH]D was measured using the radioimmunoassay method. Vitamin D deficiency and insufficiency were defined as concentration of <50 and 50-75 nmol/L, respectively.

Studied subjects were 85 ulcerative colitis and 48 Crohn's disease patients (54.1% females) with mean age of 42.0 ± 14.0 years. Vitamin D deficiency and insufficiency were present in 52 (39.0%) and 24 (18.0%) patients, respectively. Thirty patients (22.5%) had active disease who, compared with patients in remission, had more frequent low vitamin D levels (80 vs. 50.4%, P = 0.005). Quality of life was not different between patients with low and those with normal vitamin D levels (P = 0.693). In the logistic regression model, low vitamin D was independently associated with active disease status, OR (95% CI) = 5.959 (1.695-20.952).

We found an association between vitamin D deficiency/insufficiency and disease activity in IBD patients. Prospective cohorts and clinical trials are required to clarify the role of vitamin D deficiency and its treatment in clinical course of IBD.