Vitamin D treatment for connective tissue diseases: hope beyond the hype?

Abstract

The prevalence of vitamin D deficiency is increased among patients with CTDs. The active form of vitamin D (calcitriol) is a potent regulator of the immune system and may suppress inflammatory responses. This has led to claims that vitamin D may be a safe treatment, or a treatment adjunct, to reduce systemic inflammation in this patient population. It is important to note, however, that there is insufficient evidence from robust clinical trials to support these novel uses for vitamin D. In this review we examine the potential role of vitamin D as a treatment adjunct for CTDs. We will discuss how vitamin D may modulate the immune response and review the current evidence for using vitamin D to treat CTDs and their associated co-morbidities. We conclude that while there is much excitement about vitamin D in this context, further well-designed trials are needed to demonstrate its efficacy in the treatment of patients with CTDs.

Keywords: cardiovascular disease; connective tissue disease; inflammation; systemic lupus erythematosus; vitamin D.

Fig. 1

Summary of the effects of vitamin D on the innate and adaptive immune systems A schematic representation, derived principally from in vitro studies, of the effects of 1,25(OH)₂D on the immune system. The green arrows show an increase in response to 1,25(OH)₂D and the red arrows show a decrease.