Extraskeletal effects of vitamin D

In the last years we observed an increasing number of publications about the vitamin D, due to its recognised therapeutic actions and to the widespread hypovitaminosis D. In addition to the well known skeletal benefits, vitamin D can have multiple effects on other tissues. Muscular apparatus: hypovitaminosis D is associated with myopathy, sarcopenia, muscular strength reduction and increased risk of falls. The vitamin D supplementation increases the muscle functionality indexes. Cardiovascular system: low levels of vitamin D are related to increased levels of cardiovascular risk factors, heart failure, stroke, and cardiovascular mortality, while a good vitamin D status is associated with a decreased incidence of cardiovascular diseases. Diabetes and metabolic syndrome: a good vitamin D status is related to a decreased incidence of type 2 diabetes and metabolic syndrome; a vitamin D supplementation in the early childhood reduces (nearly 30%) the risk of having type 1 diabetes. Cancer: vitamin D deficit is associated with breast, colorectal cancer and melanoma relapses. Low and high levels of 25-hydroxy-vitamin D (25(OH)D) are related to a higher neoplastic mortality. Infectious diseases: hypovitaminosis D is associated with higher incidence of upper respiratory tract infections and worse interferon response in chronic hepatitis C. Vitamin D supplementation decreases the risk of having type A influence. Rheumatic diseases: in rheumatoid arthritis low serum levels of vitamin D metabolites are related to a higher disease activity, while a good vitamin D status is associated with a higher probability of remission or response to therapy and a lower degree of disability. Neurologic diseases: associations between vitamin D deficit and risk of multiple sclerosis, depression, cognitive deficits, and Parkinson’s disease have been reported. There is evidence of the extraskeletal effects of vitamin D, but most derive from observational studies: clinical trials are required the better to determine the therapeutic role of vitamin D.