Background: Evidence is accumulating for an important role of vitamin D in aetiopathogenesis and outcomes in Crohn's disease (CD) . Vitamin D monitoring and supplementation is now recommended for the general population in the UK: however, there is no recent European guidance on this in CD . We undertook an audit to assess awareness of vitamin D monitoring in our regional CD outpatients.
Methods: We randomly selected 146 patients from the South Birmingham University CD cohort, covering a total population of around 750,000. Using clinical and informatics databases, we retrospectively collected data concerning patient demographics, concomitant steroids and smoking status. We determined whether vitamin D level had been measured within past 2 years. In those vitamin D deficient patients, we assessed whether parameters of bone metabolism (calcium, phosphate and parathyroid hormone) had been measured and if vitamin D supplementation had been provided or recommended.
Results: The mean age of our sample was 41 years and 85/146 (58%) were female. Around 20% (29/146) patients were current smokers and 71% (103/146) had some/variable degree of diagnosed small bowel CD. Vitamin D levels were checked in 46% (68/146) patients, of which 47% (32/68) patients had vitamin D deficiency (<50 nmol/L) and 21/32 patients had severe vitamin D deficiency (<30 nmol/L). Among these deficient patients, there were no clear gender or ethnic differences, but current smokers were more common (37% (12/32)). 63% (20/32) of the deficient patients had some/variable degree of small bowel disease. All had normal calcium: none had parathyroid hormone checked whilst only 22% (7/32) patients had phosphate checked (all normal). Four patients (13%) were taking concomitant steroids. Supplementary treatment or request to GP to prescribe vitamin D supplement was undertaken in 56% (18/32) of vitamin D deficient patients.
Conclusions: In this single-center random UK sample, vitamin D levels were checked in less than half of the sampled population. Of those checked, around half were vitamin D deficient, and around one third were severely deficient, with smokers. Whilst about half of them did receive required supplements following their tests, many did not, highlighting that increased awareness of the role of vitamin D in CD is required.
 Ananthakrishnan et al. Higher predicted vitamin D status is associated with reduced risk of CD. Gastroenterology 2012 Mar;142(3):482–9. doi: 10.1053
 BSG Guidelines for osteoporosis in inflammatory bowel disease and coeliac disease, June 2007.