Lower vitamin D levels are associated with the pathogenesis of inflammatory bowel diseases

Abstract

Vitamin D plays a role in regulating immune homeostasis, inflammation and has an impact on the pathogenesis of inflammatory bowel diseases (IBD). IBD has a multifactorial pathogenesis primarily associated with immune dysregulation, dysbiosis, structurally altered intestinal mucosa, and genetic factors. The immunomodulatory function of this vitamin is linked to its control over innate and adaptive immunity, facilitated through its nuclear vitamin D receptor, leading to the inhibition of nuclear factor kappa-B. This study aimed to investigate serum vitamin D levels in patients with IBD compared to healthy individuals and to evaluate the relationship between vitamin D and inflammatory markers. Cross-sectional study. The study included 106 participants divided into 2 groups: patients with IBD (92), and healthy controls (14). The diagnosis of IBD was based on clinical, laboratory, fecal, endoscopic, and histological findings, following the European guidelines for diagnosis and follow-up ECCO-ESGAR guidelines for diagnostic assessment of IBD from 2019. Serum vitamin D levels were measured along with laboratory tests, imaging, and endoscopic examinations. IBD activity was evaluated using the Montreal classification and clinical and endoscopic indices. Data analysis involved calculating the mean, minimum, and maximum values, standard deviation, and Pearson coefficient. The level of statistical significance for this study was set at P < .05. The study found a prevalence of vitamin D deficiency in 32.6% of patients with IBD, while 66.3% had insufficiency, as compared with healthy individuals. The mean levels of vitamin D in UC and CD were 16 ± 8.6 ng/mL, whereas in the control healthy group, they were 26 ± 9.73 ng/mL. A statistically significant reverse correlation was observed between lower vitamin D levels and higher levels of the inflammatory markers. The study concluded that IBD patients exhibit lower levels of vitamin D, which is associated with inflammation and may contribute to the pathogenesis of the disease.

Figure 1.

Percentage distribution of included patients with Crohn disease according to the Montreal classification. Based on age they were 60% between 17 and 40 years old (A2) and 40% were above 40 years old (A3). The disease behavior was 65% nonstructuring/penetrating (B1), 25% stricturing (B2), and 10% penetrating (B3). The location of the disease was 50% ileocolonic (L3), 43% with colon involvement (L2) and 7% in the terminal ileum (L1). Values are presented as n (%); CD = Crohn disease; yr = years; age: A1 < 16; A2 17 to 40 yr; A3 < 40 yr; behavior: B1 = nonstricturing/nonpenetrating; B2 = stricturing; B3 = penetrating; p = perianal disease; location: L1 = terminal ileum; L2 = Colon; L3 = ileocolon; L4 = isolated upper disease.

Figure 2.

Percentage distribution of individuals with ulcerative colitis according to the Montreal classification who participated in the study. The extent of the disease was 65% left-sided colitis (E2), 25% pancolitis (E3), and 10% proctitis (E1). Based on the severity of the disease 65% are with moderate (S2), 15% severe (S3), 10 % were in remission (S0), and 10% had mild (S1) severity. Values are presented as n (%); UC = ulcerative colitis; extent: E1 = proctitis; E2 = left-side colitis; E3 = pancolitis; severity: S0 = remission; S1 = mild UC; S2 = moderate UC; S3 = severe UC.