P0160 Vitamin D and FGF-19 in patients with Inflammatory Bowel Disease
Authors: Topalova-Dimitrova A , Dimitrov I , Nikolov R , Spasova Z 
Published: January 2025

Abstract

Background
Vitamin D (vit. D) has pleiotropic effects, and in recent years, its role in regulating the immune response has been widely discussed. Patients with IBD tend to have lower vit. D levels, and this may be associated with more frequent relapses, increased need for surgical interventions, and a slower response to antibody treatments.

Methods
An observational study was conducted at the Gastroenterology Department of UH "Saint Ivan Rilski," Sofia, Bulgaria, involving 47 patients with ulcerative colitis (UC) and 55 with Crohn’s disease (CD). We evaluated serum vit. D, laboratory markers, Fibroblast growth factor-19 (FGF-19) levels.

Results
Patients with IBD were equally distributed between females (49%) and males (51%). Subnormal vit. D levels were observed in 94% of patients with CD and in 98% of those with UC. This contrasts with the general Bulgarian population, where 76% have lower levels [1]. The mean serum value in patients with IBD was 40 nmol/L, which is insufficient. Vit. D was found to vary depending on treatment. IBD receiving corticosteroids or immunosuppressants had lower levels compared to those treated with biologic agents. The difference was a 13% decrease in CD and 10% in UC. This may be attributed to the inhibitory effects of corticosteroids on vit. D metabolism or the restricted sun exposure when taking azathioprine. The evaluated data revealed that vit. D had a statistically significant inverse correlation with laboratory markers such as C-reactive protein (CRP) (P = 0.0018, r = -0.351), leukocytes (P = 0.0069, r = -0.2661), erythrocyte sedimentation rate (P = 0.0022, r = -0.2992), thrombocytes (P = 0.0083, r = -0.2600), and the neutrophil-to-lymphocyte ratio (NLR) (P = 0.0011, r = -0.3175) and in UC fecal calprotectin (P= 0.0025, r= -0.4025) [2]. Serum FGF-19 levels were evaluated in all IBD and were lower in 8 patients with CD, with a mean level of 20 pg/mL. Six of them had ileocolitis and two had terminal ileitis, which is associated with probable bile acid malabsorption. In other studies was found that patients have bile acid diarrhea with levels of 60pg/mL [3,4]. Statistically significant correlation was observed between FGF-19 and vit. D levels (P = 0.232, r = 0.2836).

Conclusion
Patients with IBD tend to have insufficient levels of vit. D, due to corticosteroid treatment, reduced sun exposure while taking azathioprine. The role of vit. D in inflammation is worth discussing, as it may have a potential effect on inflammatory markers. In CD is a higher risk of bile acid diarrhea in terminal ileitis or ileocolitis. Serum FGF-19 concentrations in CD may be dependent on vit. D. It is also possible that bile acid diarrhea could be affected by vit. D status.

References
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[3]Battat R, Duijvestein M, Vande Casteele N, et al. Serum Concentrations of 7α-hydroxy-4-cholesten-3-one Are Associated With Bile Acid Diarrhea in Patients With Crohn’s Disease. Clin Gastroenterol Hepatol. 2019;17(13):2722-2730.e4. doi:10.1016/j.cgh.2018.11.012
[4]Łukawska A, Mulak A. Serum fibroblast growth factor 19 level correlates inversely with clinical and endoscopic activity of inflammatory bowel disease. Adv Clin Exp Med. 2024 Mar 26. doi: 10.17219/acem/184132. Epub ahead of print. PMID: 38530319.