Role of Vitamin D and Significance of It’s Assessment
Valerija Jablonskienė, Rūta Žilinskaitė, Dalius Vitkus
Summary
Vitamin D insufficiency has achieved pandemic level. Industrialization, air pollution, sedentary lifestyle, other factors that limit vitamin D production in the skin as well as obesity, inadequate alimentary intake - are major causative factors of vitamin D deficiency. Significance of vitamin D for whole human organism has been described by many studies. Their results have shown difterent actions of vit. D - from influence to bone metabolism to “non-classical” role of vit. D. Vit. D acts as steroid hormone via cytosolic vitamin D receptor (VDR), then - nucleus receptor, therefore actively influence on DNA (long time action). Most cells express the VDR: bone, bone marrow, osteoblasts, cartilage, skin, kidney, adrenal, stomach, intestine, liver, pancreas (cells), uterus, placenta, ovarian, breast, prostate, testicle, retina, lung, heart, brain, body fat, tumor cells, hypophysis, thyroid, parathyroid, thymus cells, T and B lymphocyte, macrophages and other. Some cells have membrane vit. D receptors: then activate tyrosine-kinase and rapidly increase concentration of intracellular calcium (fast time action).
Main circulating vitamin D metabolite - 25(OH)D - as indicator of vitamin D status has many advantages to 1,25(OH)2D, because serum 25(OH)D levels retlect the body’s storage of vita - min D, has longer half-life (3-4 weeks) and correlate with the clinical symptoms.
Importance of vitamin D insufficiency has been shown for the genesis of different diseases: cardiovascular, cancer (especially colorectal, breast, prostate and lung), in a number auto-immune pathologies, type 1 diabetes, rheumatoid arthritis, multiple sclerosis and other. Therefore laboratory assessment of serum 25(OH)D level has to be important as well as estimation of reference values of different population.
Keywords: vitamin D, 25-hydroxy- vitamin D, assessment.
