Pandemic Era: Vitamin D Deficiency and Insufficiency

Vitamin D is not only a fat-soluble vitamin, but also a group of hormone and hormone precursor sterols that can be synthesized endogenously in appropriate biological conditions. Its most profound effect is on calcium and phosphorus metabolism, and on bone mineralization. In recent years, it was reported that Vitamin D deficiency and insufficiency are related with many chronic diseases such as widespread cancers, cardiovascular diseases, metabolic syndromes, infectious diseases and autoimmune diseases. Vitamin D deficiency is also a defined risk factor for osteoporosis, falls and fractures. Vitamin D deficiency is now recognized as a global epidemic. 25(OH) Vitamin D levels under 20 ng/mL is accepted as Vitamin D deficiency, levels between 21-29 ng/mL as insufficiency, over 30 ng/mL as sufficient levels (preferred range is between 40-60 ng/mL), and over 150 ng/mL as Vitamin D intoxication. Vitamin D deficiency leads to ricketts clinics in children and osteomalacia clinics in adults. In this review, we aimed to define Vitamin D deficiency and insufficiency which is currently widespread in adults, and to provide a current approach to the treatment methods.