عنوان مقاله [English]
Background: Considering the controversies regarding the association of vitamin D deficiency and disease activity in patients with systemic lupus erythematosus (SLE) and highly recommendations for investigating the effectiveness of this supplement on disease activity through interventional studies, we aimed to study the effectiveness of vitamin D administration on disease activity in patients with systemic lupus erythematosus and vitamin D deficiency.Methods: In this randomized double-blind placebo-controlled clinical trial, 90 patients with systemic lupus erythematosus were selected and randomly allocated in two groups of intervention (50000 unit vitamin D weekly for 12 weeks and then 50000 unit monthly for 6 months) and placebo. The levels of vitamin D and disease activity using Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) were measured and compared before and after intervention in two studied groups. Findings: There was a relationship between the serum level of vitamin D and disease activity before the study (r = 0.26; P = 0.019). But, after intervention, the correlation between serum level of vitamin D and disease activity was not significant (r = 0.19; P = 0.07).Conclusion: The findings of current study indicated that vitamin D administration have no significant effect on the disease activity in patients with systemic lupus erythematosus and vitamin D deficiency. According to our study, it is suggested that using vitamin D in patients with systemic lupus erythematosus could not have better outcomes in this regard. But, there are many unknown environmental or biological factors which are associated with the disease activity of systemic lupus erythematosus and are not identified yet.