Objective: To evaluate the serum concentrations of vitamin D and their relation with inflammatory bowel diseases. Methods: This is a quantitative and descriptive study, with individuals assisted by the interdisciplinary ambulatory of Inflammatory Bowel Disease of the Family and Community Health Unit of Itajaí/SC from September 2015 to October 2016. Socioeconomic data, life habits, and biochemical tests were collected, with the use of clinical indexes of classification of the disease activity: Harvey-Bradshaw Index (Crohn’s Disease) and Partial Mayo Score (Chronic Nonspecific Ulcerative Colitis). Results: Of the 60 patients evaluated, 57% (n = 34) had Crohn’s Disease and 43% (n = 26) had Chronic Nonspecific Ulcerative Colitis. According to disease activity, 75% (n = 45) were in the remission phase, 13% (n = 8) had mild activity, and 9% (n = 5) had moderate activity. Regarding vitamin D, 63% (n = 38) had deficiency of this vitamin and 37% (n = 22) presented sufficiency. With the association of serum vitamin D concentrations and disease activity, we observed statistical significance among the variables (p = 0.005). Regarding biochemical exams, the majority of patients with fecal calprotectin elevation presented vitamin D deficiency (p = 0.025). Statistically significant correlation between HSV and vitamin D (p = 0.0001) was found. Conclusion: According to the findings of this study, vitamin D deficiency is related to the clinical and laboratory activity of inflammatory bowel diseases.

Introduction

Inflammatory bowel diseases (IBD), which are chronic noninfectious, progressive, and autoimmune inflammations, are divided into two forms of presentation: Crohn’s disease (CD), which can affect the entire extent of the gastrointestinal tract, and Chronic Nonspecific Ulcerative Colitis (CNUC), which is restricted to the colon and rectum.1–۳ The etiology ofthese diseases is not definitively clarified, but some studies suggestthat they are related to a genetic predisposition, an interaction with external factors (e.g., environmental factors), autoimmune events associated with abnormalities, and loss of intestinal mucosal balance and immune cell changes.4,5 Vitamin D and its prohormones and antagonists have been the subject of studies, because of their interaction with the immune system and the expression of vitamin D receptor (VDR) in various tissues of the body, such as brain, heart, skin, gonads, breasts, and immunological and intestinal cells, and their relationship with other conditions such as cancer, cardiovascular diseases, and autoimmune diseases.6,7 VDR is widely expressed in immune cells, especially in the activation of T-lymphocytes and dendritic cells and in the expression of antigen-presenting cells, monocytes, macrophages, and natural killer cells, in addition to stimulating the production of interleukins. These immunomodulatory properties of vitamin D may explain the likely association between its serum concentrations and the number of autoimmune disease cases, including IBD.8 It is not uncommon the occurrence of vitamin D deficiency among patients with IBD.6–۱۰ The mechanisms proposed to explain this frequent occurrence would be intestinal malabsorption (mainly in cases of CD, due to ileus involvement, a decreased enterohepatic circulation of the vitamin, and short bowel syndrome), and a low ingestion of vitamin D-rich foods. It should be noted that the modern lifestyle negatively influences vitamin D production, and factors such as sun exposure, season of the year, clothing, sun block products’ use, and smoking should be taken into account.6–۱۰ In view ofthe above, this study aimed to evaluate serum vitamin D levels and its relationship with IBD in outpatients.