Adopted by the 66th WMA General Assembly, Moscow, Russia, October 2015
Vitamin D has major role in calcium and bone metabolism. Normal values are 75-100 nmol/L (30-40 ng/ml). Vitamin D deficiency is defined if serum hydroxyvitamin D levels are less than 50nmol/L (20 ng/ml), insufficiency as 50-75 nmol/L (20-30 ng/ml).
Studies demonstrate that vitamin D is essential also for overall health and well-being. In the body vitamin D is produced during exposure to sunlight and in lesser degree by food intake.
Vitamin D exists in two forms: vitamin D3 (cholecalciferol in humans and other mammals) and vitamin D2(ergocalciferol in plants), but both are similarly metabolized. Vitamin D3 is more active than vitamin D2.
The serum concentration of the hepatic metabolite of vitamin D3, the 25-hydroxyvitamin D, is consideredas the best biomarker of vitamin D status.
Vitamin D deficiency is an important health issue globally. About one third of the population is estimated to have lower serum concentration of vitamin D.
Many studies have shown that vitamin D deficiency is linked to impaired growth and development. Because vitamin D receptors are broadly distributed in tissues, vitamin D deficiency is associated with musculoskeletal disorders (osteoporosis), falls, fractures, autoimmune disorders, chronic inflammatory diseases, type 2 diabetes mellitus, and cardiovascular, neurologic and psychiatric disorders. High risk groups are young children, the elderly and pregnant women. Primary factors, contributing to vitamin D deficiency, include reduced sunshine exposure, poor quality diet, availability of fortified foods and supplement use.
Because of widespread occurrence of vitamin D deficiency/insufficiency it is desirable to focus attention on adequate preventive actions in populations at risk. Determining vitamin D levels requires only a blood test, and oral supplementation is a simple treatment method. Sun exposure is not generally recommended because it can increase the risk of skin cancer.
The World Medical Association recommends that national medical associations:
- Support continued research in vitamin D and its metabolites
- Educate physicians about the evolving science of vitamin D and its impact on health (documents, brochures, posters)
- Encourage physicians to consider measuring the serum concentrations of 25-hydroxyvitamin D in the patients at risk of vitamin D deficiency
- Monitor development of dietary recommendations for vitamin D.