Published online Apr 14, 2017. doi: 10.3748/wjg.v23.i14.2539
Peer-review started: November 13, 2016
First decision: December 19, 2016
Revised: March 7, 2017
Accepted: March 15, 2017
Article in press: March 15, 2017
Published online: April 14, 2017
Processing time: 155 Days and 3.3 Hours
To study the association between vitamin D level and hospitalization rate in Crohn’s disease (CD) patients.
We designed a retrospective cohort study using adult patients (> 19 years) with CD followed for at least one year at our inflammatory bowel disease center. Vitamin D levels were divided into: low mean vitamin D level (< 30 ng/mL) vs appropriate mean vitamin D level (30-100 ng/mL). Generalized Poisson Regression Models (GPR) for Rate Data were used to estimate partially adjusted and fully adjusted incidence rate ratios (IRR) of hospitalization among CD patients. We also examined IRRs for vitamin D level as a continuous variable.
Of the 880 CD patients, 196 patients with vitamin D level during the observation period were included. Partially adjusted model demonstrated that CD patients with a low mean vitamin D level were almost twice more likely to be admitted (IRR = 1.76, 95%CI: 1.38-2.24) compared to those with an appropriate vitamin D level. The fully adjusted model confirmed this association (IRR = 1.44, 95%CI: 1.11-1.87). Partially adjusted model with vitamin D level as a continuous variable demonstrated, higher mean vitamin D level was associated with a 3% lower likelihood of admission with every unit (ng/mL) rise in mean vitamin D level (IRR = 0.97, 95%CI: 0.96-0.98). The fully adjusted model confirmed this association (IRR = 0.98, 95%CI: 0.97-0.99).
Normal or adequate vitamin D stores may be protective in the clinical course of CD. However, this role needs to be further characterized and understood.
Core tip: Growing body of epidemiological evidence supports a key role of vitamin D deficiency not just in inflammatory bowel disease development but also on Crohn’s disease (CD) severity. Our study sought to test the hypothesis that adequate vitamin D levels have a protective role in the clinical course of CD in terms of a decreased likelihood of hospitalization. Our results are clinically important as they suggest potentially worse outcomes in CD patients with low vitamin D levels as reflected by a numerically increased rate of hospitalization in this group.