Role of Vitamin D in Systemic Sclerosis: A Systematic Literature Review

Background. Systemic sclerosis (SSc) is a chronic multisystem autoimmune condition defined by a complex pathobiology, comprising excessive fibrosis of skin and internal organs, peripheral vasculopathy with endothelial cell dysfunction, inadequate vascular repair and neovascularization, and aberrant immunity. Vitamin D is a steroid hormone with pleiotropic effects beyond its traditional role in calcium and bone homeostasis. Since vitamin D has immunomodulatory, cardioprotective, and antifibrotic properties, it could potentially interfere with SSc pathogenesis. Suboptimal vitamin D levels are classically recognized in scleroderma, irrespective of clinical and serological phenotype. Aim. This systematic review is aimed at investigating and clarifying the role of vitamin D in SSc and emphasizing the association of vitamin D status with different clinical settings. Methods and Results. A systematic online search was performed, using PubMed databases to collect articles on the topic of vitamin D in SSc. The final analysis included 40 eligible articles. Conclusions. Hypovitaminosis D is common in SSc patients and could be associated with clinical and serologic patterns of the disease. Intervention for low serum vitamin D levels in SSc pathogenesis remains controversial, as well as the significance of vitamin D supplementation in such patients.