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The impact of vitamin D on disease activity in Crohn's disease



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Canada has the highest rate of Inflammatory Bowel Disease (IBD) in the world with approximately 0.67%. One of the primary nutritional health issues faced by Crohn’s disease (CD) patients is vitamin D deficiency, which can subsequently lead to more serious health complications. Vitamin D is shown to act as a modulator for the autoimmune system among CD patients. Phase I study aimed to determine vitamin D concentrations and disease activity among CD cases in Canada and Saudi Arabia, and evaluate the impact of higher doses of vitamin D compared to EAR on disease activity among CD patients. This pilot study was a double blind, randomized, control trial involving approximately 60 recent, active CD patients engaged in induction therapy. The sample size includes patients in Saskatoon, Saskatchewan, Canada (n=30) and Riyadh, Saudi Arabia (n=30). The patients have been divided into three groups to receive different oral doses of vitamin D including: 1: 400 IU/day (Control group, EAR level) 2: 2,000 IU/day 3: 10,000 IU/day. Data were collected at baseline (0), end of 9 weeks (end of intervention), and at 2 months follow-up. Along with anthropometric measurements participants undergo laboratory examinations such as, WBC, HGB, Hct, platelets, ferritin, vitamin D, hsCRP and calprotection, undertake the Health related quality of life (HRQOL), and fill out socio-demographic and physical activity questionnaires. We also assessed their dietary intake at the baseline and Week 9 using two sets of three 24-hour dietary recalls. Due to a small sample size (n=9 cases) we have recruited, we presented Phase I as a case series. Phase II study determined the association between vitamin D concentrations and disease activity among CD cohort in Saskatoon, Canada. In a retrospective cohort design, we studied 201 CD patients; 116 participants had vitamin D data. We extracted data from medical records over three years at IBD clinic, Royal University Hospital, Saskatoon, Canada. I evaluated the association between vitamin D status (serum 25OHD) and indicator of disease activity (hsCRP) as well as Harvey-Bradshaw index (HBI) in CD patients. The analyses conducted in the presence of other potential factors in three-time points (baseline, midpoint, last visit) using generalized estimating equation (GEE). Vitamin D concentrations was improved significantly from baseline to the last visit (p=0.005). At the baseline, mean 25OHD was 58.2±30.0 nmol/L; 26% of patients had optimal, 30% had adequate, 26% had insufficient, and 18% patients had deficient vitamin D levels. At the midpoint, mean serum vitamin D concentrations was 60.1±31.2 nmol/L; 31.3% had optimal level, 31,3% patients had insufficient level, 22.1% patients had adequate level, and 15.2% patients were vitamin D deficient. At final visit, mean vitamin D was 74.5±42.6 nmol/L; 43.9% patients had optimal and 24.2% patients had adequate levels of vitamin D, while 18.1% patients were vitamin D insufficient and 13.6% patients had vitamin D deficiency. Vitamin D concentrations showed significant inverse association with hsCRP level over 15 months. Compared to vitamin D deficient category, patients in other categories (including insufficient, adequate and optimal levels of vitamin) had significantly lower hsCRP level over time (p <0.05). Vitamin D deficiency was associated with higher disease activity in Crohn’s disease patients. Higher vitamin D (25OHD) concentrations was associated with lower D disease activity levels in Crohn’s patients over 15 months.



Crohn's disease, inflammatory bowel disease, vitamin D



Master of Science (M.Sc.)


Pharmacy and Nutrition





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