P018  Vitamin D and Related Parameters: A Prospective IBD Patient Cohort With Active Versus Remission State And A Healthy Control Group

P018  Vitamin D and Related Parameters: A Prospective IBD Patient Cohort With Active Versus Remission State And A Healthy Control Group

Akin Hakan1, Kurt Ramazon1, Imeryuz Nese1
1 Marmara University, Istanbul, Turkey

BACKGROUND: Vitamin D deficiency is associated with Inflammatory Bowel Disease (IBD) but the relationship with IBD disease activity with Vitamin D is controversial. The aim of our study is to investigate the relationship between Vitamin D related parameters and disease activity in a prospective IBD cohort by comparing patients' active versus remission period values. The study also looks at data from a healthy control group.

METHODS: The study included a cohort of 88 patients diagnosed with active IBD until they achieved disease remission phase. A group of 87 healthy controls with similar age, gender characteristics were enrolled to the study. Active and remission period was determined by using Crohn's Disease Activity Index and Harvey-Bradshaw Index for Crohn's disease and Mayo Clinic Score for Ulcerative Colitis patients. Active and remission period serum samples from the patient group and samples from the control group were stored at -80Celsius. 25 (OH) D, calcium, phosphorus, parathyroid hormone, albumin, Vitamin D Binding Protein levels were measured by using ELISA method and colorimetric method, then bioavailable vitamin D level was calculated. All demographic, clinical and laboratory results were analyzed using SPSS 20:00. In the patient group each patient's own parameters were used for the comparison of remission and relapse phases of the IBD at statistical analysis. Additionally, patient's data was compared with healthy control group's data separately.

RESULTS: 25(OH)D is significantly higher in the healthy control group (25,86 ng/ml) according to IBD group active period (15,45 ng/ml) and remission period (15,13 ng/ml) (for both p=0,000). Results of the active period and remission period were similar (p = 0.570). Bioavailable vitamin D is significantly higher in control group (4,28 pg/ml) compared with IBD active period (2,56 pg/ml) and remission period (2,52 pg/ml) (for both p = 0,000). The active and remission period results were similar (p = 0,608). Vitamin D Binding Protein (DBP) was significantly lower in control group (206,72 ng/ml) compared with IBD active period (321,86 ng/ml) and remission period (332,68ng/ml) (for both p=0,000). The active and remission periods results were similar (p = 0.595). Parathyroid hormone is significantly higher in control group (40,12 pg/ml) compared with IBD group active period (13,85 pg/ml) and remission period (14,86 g/ml) (for both p=0,000). The active and remission period results were similar (p=0,280).

CONCLUSION(S): The strongest aspect of this study is that it is a prospective cohort study that enabled us to compare the very same patient's own Vitamin D related parameters at active and remission and by excluding most other patient-related confounding factors. 
Our results showed that Vitamin D deficiency is common in IBD but 25(OH)D levels in active and remission periods of the same patient were similar. This shows that vitamin D has no effect on IBD disease activity. Looking at the bioavailable vitamin D in IBD had no additional benefit, because statistical data was similar as data of 25(OH)D. DBP levels were significantly higher in IBD indicate that DBP may be a marker of inflammation.  Further studies are needed.