Relationship Between Vitamin D Deficiency and Disease Activity in Patients with Inflammatory Bowel Disease in Ahvaz, Iran

Background and Aims: Previous studies have shown that vitamin D plays an important role in inflammatory bowel disease (IBD). This study was designed to investigate the relationship between vitamin D levels and disease activity in IBD patients in Ahvaz, Iran. Methods: This cross-sectional study was conducted on adult IBD patients referring to the outpatient clinic of gastroenterology at Imam Khomeini Hospital in Ahvaz city, in the southwest of Iran. Each patient's disease activity defined according to Crohn's disease activity index (CDAI) in Crohn's disease (CD) and Truelove score in ulcerative colitis (UC) patients, serum 25[OH]D was measured using the radioimmunoassay method. Vitamin D deficiency was defined as concentration of <20 nmol/L. Results: Studied subjects were 130 UC and 23 CD patients (62.1% females) with a mean age of 37.5 +/- 12.35 years. Vitamin D deficiency was present in 99 (64.7%) IBD patients. Fifty-three patients (34.6%) had active disease who, compared with patients in remission, had more frequent low vitamin D levels (80 vs 56.7%, P = 0.017). In UC patients, disease activity was significantly associated with vitamin D deficiency (P = 0.035), but no such relationship was observed in CD patients (P = 0.74). Conclusion: Vitamin D deficiency was significantly associated with disease activity in IBD, especially in UC patients. Therefore, careful monitoring of vitamin D deficiency in these patients is highly recommended. Prospective cohort studies are also needed to determine the role of vitamin D deficiency and its treatment in the clinical course of IBD.