Background: Pain and vitamin D deficiency are common in inflammatory bowel disease (IBD). Disease activity, fatigue, frequent relapses, prior surgery and psychological factors all seem to influence the experience of pain in IBD. Vitamin D deficiency has been associated with muscle and skeletal pain. This study aimed to determine whether there is an association between vitamin D deficiency and severity of pain in patients with IBD, and to investigate the influence of other socio-demographic and psychological variables on the experience of pain. Methods: Patients with IBD were recruited from nine hospitals in Norway in a multicenter cross-sectional study. The Brief Pain Inventory (BPI) questionnaire was used to measure pain. Disease activity was assessed using clinical disease activity indices, C-reactive protein (CRP) and fecal calprotectin. Regression models were fitted to explore a possible association between 25-hydroxyvitamin D and pain severity. Results: Of 407 patients included in the analyses, 229 (56%) had Crohn's disease (CD) and 178 (44%) had ulcerative colitis (UC). Vitamin D deficiency was present in half (203/407) of patients. Presence of pain was reported by 76% (309/407). More severe pain was associated with female gender and increased disease activity scores, but not with increased CRP or fecal calprotectin. In CD, patients without prior intra-abdominal surgery reported more severe pain. In multivariate analyses, there was no association between 25-hydroxyvitamin D and pain severity. Conclusions: In this study, no significant association between pain severity and vitamin D deficiency was revealed in patients with IBD.
Keywords: pain severity; patient reported outcomes; vitamin D deficiency.