[Vitamin D metabolism and osteoporosis in systemic sclerosis]

In the past few years more and more data have become available on the important role of vitamin D in immunological processes and inflammation. The role of vitamin D deficiency in the pathogenesis as well as in disease progression of different autoimmune and inflammatory conditions is suspected. Vitamin D deficiency is prevalent in several autoimmune diseases, including systemic sclerosis. Hypovitaminosis has been found to be associated with low bone mineral density and higher prevalence of osteoporosis in this group of patients. Determinants of low bone density in SSc are poorly understood. Studies have shown the importance of both traditional osteoporotic as well as disease-specific factors (extent of skin involvement, presence of internal organ manifestation, malabsorption, systemic sclerosis subtype, serological profile, medication) in the development of low bone mineral density. The relationship between low bone density in systemic sclerosis patients and the above mentioned risk factors may be more complex and the real role of each factor is unclear. Yet very few studies reported clinically relevant low bone mass outcomes such as fracture risk assessment and fracture associated mortality in scleroderma. This review aims to synthesize data about the essential role of vitamin D in immune homeostasis as well as the prevalence of hypovitaminosis, low bone density, changes in bone turnover markers and presence of osteoporosis in scleroderma patients. Orv Hetil. 2017; 158(32): 1252-1258.