Vitamin D Deficiency, Osteoporosis and Effect on Autoimmune Diseases and Hematopoiesis: A Review

Abstract

Vitamin D (VD) is essential for bone homeostasis, but it is also involved in pleiotropic effects on various organs and tissues. In adults, VD deficiency can cause or exacerbate osteoporosis and induce osteomalacia. However, every tissue and cell in the body has a VD receptor, including the brain, heart, stomach, pancreas, skin, gonads, and immune cells, and a deficiency may modify the function of these organs. Thus, the wide-ranging actions of VD help to explain why a reduction in VD amount has been correlated with numerous chronic diseases. In fact, VD deficiency increases the risk of osteoporosis and several other diseases and complications characterized by impaired bone metabolisms, such as autoimmune diseases, inflammatory bowel diseases, allergy, endocrinological diseases, hematological malignancies, and bone marrow transplantation. This review aims to investigate the link between VD deficiency, osteoporosis, and its concomitant diseases. Further epidemiological and mechanistic studies are necessary in order to ascertain the real role of hypovitaminosis in causing the reported diseases; however, adequate vitamin supplementation and restoration of metabolic normality could be useful for better management of these pathologies.

Vitamin D Receptor (VDR) Gene Polymorphisms Modify the Response to Vitamin D Supplementation: A Systematic Review and Meta-Analysis

“…Calcitriol signalling is crucial in bone metabolism as it is involved in calcium absorption, parathormone secretion and, therefore, bone resorption and cellular differentiation. Vitamin D deficiency has been associated with bone metabolism alterations [35][36][37]. Therefore, vitamin D intake as a preventive nutritional treatment of osteoporosis plays an important role in improving health status [38,39], but the efficacy of supplementation varies widely between subjects [18][19][20].…”

Physiology and Inflammation Driven Pathophysiology of Iron Homeostasis—Mechanistic Insights into Anemia of Inflammation and Its Treatment

“…Furthermore, also Th2-cells [338] and Treg-cells are induced [339], while Th17-mediated autoimmunity can be ameliorated by 1,25-dihydroxyvitamin D 3 [340]. As chronic diseases often go along with vitamin D deficiency [341] and low vitamin D levels are correlated with higher immune activation markers like neopterin, e.g., in CAD patients [342], vitamin D supplementation of patients might be very effective to downregulate underlying inflammatory processes.…”

An analysis of Albumin and Vitamin D Deficiency in Patients Treated in Palliative Care Centers

“…Patients requiring palliative care are at greater risk for vitamin D deficiency/insufficiency as a result of less exposure to sunlight, lower oral intake and a decreased ability to absorb dietary vitamin D (19,22). In addition, studies mentioned in the literature have found a relationship between vitamin 25(OH)D and extremity functions, muscle strength and physical activity and it has been determined that vitamin D deficiency may increase the risk of falling in the elderly (10,13). In a cross-sectional study conducted on 30 palliative cancer patients in Spain, a statistically significant relationship was found between 25-OHD vitamin levels and the general quality of life (23).…”

“…Its clinical effects have been documented in many studies. VDD has been associated with cardiovascular diseases, increased risk of fractures, dyslipidemia, increased inflammation, glucose metabolism disorders, weight gain, infectious diseases, multiple sclerosis, mood disorders, cognitive dysfunction, impaired physical functions and mortality rates connected to all types of reasons (10).…”