effect of vitamin d3 supplementation on tnf-? serum level and disease activity index in iranian ibd patients

background and aim: vitamin d has immune-regulatory functions in experimental inflammatory bowel disease (ibd) and vitamin d deficiency is common in ibd patients. the aim of the study was to assess the effectiveness of vitamin d 3 [1,25(oh) 2 d 3 ] treatment in ibd with regard to tumor necrosis factor-alpha (tnf-?) serum level and  clinical disease activity index (cdai). materials and methods: this was a double blind randomized clinical trial on 108 ibd patients with serum 25-ohd level less than 30ng/ml, whom divided into vitamin d and control groups. vitamin d group received 50000 iu vitamin d 3 for 12 weeks. before and after the study, tnf-? and 25-ohd serum levels were measured by elisa method. data were analyzed using paired t test, chi-square test and spearman correlation coefficient. p values ??less than 0.05 were considered statistically significant. results: before the intervention no significant difference was found between baseline characteristics and tnf-? serum level of two groups. after intervention tnf-? serum level reduced but this reduction was not statistically significant (p= 0.07, 95% ci: -0.45 to 8.14). the mean serum 25-ohd level of vitamin d increased from 15.54 to 67.89, which was statistically significant (p= 0.00, 95% ci: -61.40 to -43.30).  tnf-? level was also associated significantly with cdai before (spearman’s rho: 0.3, p<0.0001) and after (spearman’s rho: 0.27, p=0.01) intervention. conclusion: oral supplementation vitamin d 3 significantly increased serum vitamin d levels and insignificantly reduced serum tnf-? level. more studies with larger samples would be beneficial to assess vitamin d 3 supplementation efficient effect in ibd.