Relationship between Body Mass Composition, Bone Mineral Density, Skin Fibrosis and 25(OH) Vitamin D Serum Levels in Systemic Sclerosis

Abstract

A reduced bone mineral density (BMD) is observed in several rheumatic autoimmune diseases, including Systemic Sclerosis (SSc); nevertheless, data concerning the possible determinants of bone loss in this disease are not fully investigated. The aim of this study is to evaluate the relationship between BMD, body mass composition, skin sclerosis and serum Vitamin D levels in two subsets of SSc patients. 64 post-menopausal SSc patients, classified as limited cutaneous (lcSSc) or diffuse cutaneous (dcSSc) SSc, were studied. As control, 35 healthy post-menopausal women were recruited. Clinical parameters were evaluated, including the extent of skin involvement. BMD at lumbar spine, hip, femoral neck and body mass composition were determined by dual-energy X-ray absorptiometry. Serum calcium, phosphorus, alkaline phosphatase, urine pyridinium cross-links, intact parathyroid hormone and 25-hydroxyvitamin D (25OHD) were measured. BMD at spine, femoral neck and total hip was significantly lower in SSc patients compared to controls. In dcSSc subset, BMD at spine, femoral neck and total hip was significantly lower compared to lcSSc. No differences in both fat and lean mass were found in the three study groups even if patients with dcSSc showed a slightly lower total body mass compared to healthy controls. Total mineral content was significantly reduced in dSSc compared to both healthy subjects and lcSSc group. Hypovitaminosis D was observed both in healthy post-menopausal women and in SSc patients, but 25OHD levels were significantly lower in dcSSc compared to lcSSc and inversely correlated with the extent of skin thickness. These results support the hypothesis that the extent of skin involvement in SSc patients could be an important factor in determining low circulating levels of 25OHD, which in turn could play a significant role in the reduction of BMD and total mineral content.

Association between hypovitaminosis D and systemic sclerosis: True or fake?

“…Auto-antibodies profile, including anti-topoisomerase antibody I (Scl 70), anti-nuclear antibodies (ANA) and anti-centromere antibodies (ACA), has been reported to be associated with low hormone levels by Vacca et al, but following reports in the same findings failed [9][10][11]; [13][14][15][16][17]. Lately, Carmel et al reported no correlation between antivitamin D antibodies and some clinical features [18].…”

“…Not surprisingly, the association with pulmonary and gastrointestinal tests have been greatly sought, but inconsistent data have been provided [9,11,13,14,16]; [24][25][26].…”

“…Corrado et al [9] and Arnson et al [10] found an inverse relation between skin fibrosis and low vitamin D serum levels; however, the former failed when seeking an association of Hypovitaminosis D with the extent of skin fibrosis [10]. Immune system dysfunction and extracellular matrix deposition are the main pathogenetic steps underlying the hallmarks of disease.…”

“…Both malabsorption and skin thickening might cause vitamin D deficiency [9]; thereby, it is an intriguing question, still unanswered, whether hypovitaminosis D has a role in the pathogenesis of SSc or it is a consequence of clinical features.…”

“…Manifold data [9][10][11][12][13] have been provided about the association between low Vitamin D serum levels and clinical features of disease, but few evidences were found to be concordant. Since understanding the pathogenesis implies advances in therapeutic strategies, it is a need to draw conclusions about the role, true or fake, of the hormone, in promoting the onset of SSc.…”