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Alternate Title

Synonyms

1,25-DHCC, 1,25-dihydroxy-22-ovavitamin D(3), 1,25-dihydroxycholecalciferol, 1,25-dihydroxyvitamin D3, 1,25-diOHC, 1,25(0H) 2D3, 1-alpha-hydroxycholecalciferol, 1 alpha-hydroxyvitamin D2, 1 alpha (OH) D3, 19-nor-1, 25-dihydroxyvitamin D2, 19-nor-1, 25-dihydroxyvitamin D2, 22-oxacalcitriol (OCT), 25-HCC, 25-hydroxycholecalciferol, 25-hydroxyvitamin D3, 25-OHCC, 25-OHD3, activated 7-dehydrocholesterol, activated ergosterol, alfacalcidol, alphacalcidol, calcifediol, calcipotriene, calcipotriol, calcitriol, cholecalciferol, colecalciferol, dichysterol, dihydrotachysterol, dihydrotachysterol 2, ED-21 (vitamin D analog), ergocalciferol, ergocalciferolum, hexafluoro-1,25dihydroxyvitamin D3, irradiated ergosterol, MC903, paracalcin, paricalcitol, viosterol, vitamin D2, vitamin D3.

Background

Vitamin D is found in numerous dietary sources such as fish, eggs, fortified milk, and cod liver oil. The sun is also a significant contributor to our daily production of vitamin D, and as little as 10 minutes of exposure is thought to be enough to prevent deficiencies. The term "vitamin D" refers to several different forms of this vitamin. Two forms are important in humans: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D2 is synthesized by plants. Vitamin D3 is synthesized by humans in the skin when it is exposed to ultraviolet-B (UVB) rays from sunlight or the diet.

The major biologic function of vitamin D is to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones. Recently, research also suggests vitamin D may provide protection from osteoporosis, hypertension, cancer, and several autoimmune diseases.

Rickets and osteomalacia are classic vitamin D deficiency diseases. In children, vitamin D deficiency causes rickets, which results in skeletal deformities. In adults, vitamin D deficiency can lead to osteomalacia, which results in muscular weakness in addition to weak bones. People who are at a high risk for vitamin D deficiencies are the elderly, dark skinned, obese, exclusively breast-fed infants, and those who cover all exposed skin or use sunscreen whenever outside. Also, those who have fat malabsorption syndromes (e.g., cystic fibrosis) or inflammatory bowel disease (e.g., Crohn's disease) are at risk.

Evidence

Familial hypophosphatemia: Familial hypophosphatemia is a rare inherited disorder characterized by impaired transport of phosphate and diminished vitamin D metabolism in the kidneys Familial hypophosphatemia is a form of rickets. Taking calcitriol or dihydrotachysterol orally in conjunction with phosphate supplements is effective for treating bone disorders in people with familial hypophosphatemia. Management should be under medical supervision.
Grade: A

Fanconi syndrome-related hypophosphatemia: Fanconi syndrome is a defect of the proximal tubules of the kidney, and is associated with renal tubular acidosis. Taking ergocalciferol orally is effective for treating hypophosphatemia associated with Fanconi syndrome.
Grade: A

Hyperparathyroidism due to low vitamin D levels: Some patients may develop secondary hyperparathyroidism due to low levels of vitamin D. The initial treatment for this type of hyperparathyroidism is vitamin D. For patients with primary or refractory hyperparathyroidism, surgical removal of the parathyroid glands is commonly recommended.
Grade: A

Hypocalcemia due to hypoparathyroidism: Hypothyroidism (low blood levels of parathyroid hormone) is rare, and is often due to surgical removal of the parathyroid glands. Oral doses of dihydrotachysterol (DHT), calcitriol, or ergocalciferol at high doses can assist in increasing serum calcium concentrations in people with hypoparathyroidism or pseudohypoparathyroidism.
Grade: A

Osteomalacia: In adults with severe vitamin D deficiency, bone mineral is lost ("hypomineralization") and results in bone pain and osteomalacia (soft bones). Osteomalacia may result from deficiency of vitamin D in elderly patients, decreased absorption of vitamin D, patients with chronic malabsorption syndrome secondary to jejunoileal bypass, patients with partial gastrectomy, aluminum-induced bone disease, chronic liver disease, or kidney disease with renal osteodystrophy. Treatment for osteomalacia depends on the underlying cause of the disease and often includes pain control and orthopedic surgical intervention, as well as vitamin D and phosphate binding agents.
Grade: A

Psoriasis: A number of different approaches are used in the treatment of psoriasis skin plaques. Mild approaches include light therapy, stress reduction, moisturizers, or salicylic acid to remove scaly skin areas. For more severe cases, treatments may include UV-A light, psoralen plus UV-A light (PUVA), retinoids such as isotretinoin (Accutane), corticosteroids, or cyclosporine (Neoral, Sandimmune). The synthetic vitamin D3 analog calcipotriene (Dovonex) appears to control skin cell growth and is used for moderately severe skin plaques, particularly for skin lesions resistant to other therapies or located on the face. Vitamin D3 (tacalcitol) ointment has been reported as being safe and well-tolerated.
Grade: A

Rickets : Rickets used to be common but is rarely seen now that countries have adopted the practice of fortifying milk with vitamin D. Ergocalciferol or cholecalciferol is effective for treating vitamin D deficiency rickets. Calcitriol should be used in patients with renal (kidney) failure. Treatment should be under medical supervision.
Grade: A

Muscle weakness/pain: Vitamin D deficiency has been associated with muscle weakness and pain in both adults and children. Limited research has reported vitamin D deficiency in patients with low-back pain, and supplementation may lead to pain reduction in many patients.
Grade: B

Osteoporosis : Without sufficient vitamin D, calcium absorption cannot be maximized and the resulting elevation in parathyroid (PTH) secretion by the parathyroid glands results in increased bone resorption, which may weaken bones and increase the risk of fracture. Vitamin D supplementation has been demonstrated to slow bone loss and reduce fracture, particularly when taken with calcium.
Grade: B

Renal osteodystrophy: Renal osteodystrophy is a term that refers to all of the bone problems that occur in patients with chronic kidney failure. Oral calcifediol or ergocalciferol may help manage hypocalcemia and prevent renal osteodystrophy in people with chronic renal failure undergoing dialysis.
Grade: B

Anticonvulsant-induced osteomalacia: Supplementation with vitamin D2 has been reported to reduce seizure frequency in initial research. Further study is needed to confirm these results.
Grade: C

Anti-inflammatory (immunomodulator): Preliminary human evidence suggests that vitamin D and its analogues, such as alfacalcidol, may act as immunomodulatory agents. More studies are needed to confirm these results.
Grade: C

Cancer prevention: Limited research suggests that synthetic vitamin D analogs may play a role in the treatment of human cancers. However, it remains unclear if vitamin D deficiency raises cancer risk, or if an increased intake of vitamin D is protective against some cancers. Until additional trials are conducted, it is premature to advise the use of regular vitamin D supplementation to prevent cancer.
Grade: C

Corticosteroid-induced osteoporosis: Some evidence implies that steroids may impair vitamin D metabolism, further contributing to the loss of bone and development of osteoporosis associated with steroid medications. There is limited evidence that vitamin D may be beneficial to bone strength in patients taking long-term steroids.
Grade: C

Diabetes (Type 1/Type 2): Type 1 diabetes: It has been reported that infants given calcitriol during the first year of life are less likely to develop type 1 diabetes than infants fed lesser amounts of vitamin D. Other related studies have suggested using cod liver oil as a source of vitamin D to reduce the incidence of type 1 diabetes. There is currently insufficient evidence to form a clear conclusion in this area. Type 2 diabetes: In recent studies, adults given vitamin D supplementation were shown to improve insulin sensitivity. Further research is needed to confirm these results.
Grade: C

Fall prevention: There is unclear evidence in this area.
Grade: C

Hepatic osteodystrophy: Metabolic bone disease is common among patients with chronic liver disease, and osteoporosis accounts for the majority of cases. Varying degrees of calcium malabsorption may occur in patients with chronic liver disease due to malnutrition and vitamin D deficiency. Oral or injected vitamin D may play a role in the management of this condition.
Grade: C

High blood pressure (hypertension): Low levels of vitamin D may play a role in the development of high blood pressure. It has been noted that blood pressure is often elevated during the winter season, further distance from the equator, and dark skin pigmentation (all of which are associated with lower exposure to vitamin D via sunlight). However, evidence is not definitive, and a clear comparison with more proven methods to reduce blood pressure has not been conducted. Patients with elevated blood pressure should be managed by a licensed healthcare professional.
Grade: C

Hypertriglyceridemia: There is insufficient evidence in this area.
Grade: C

Multiple sclerosis (MS): Scientists have detected MS rates to be lower in areas with greater sunlight and higher consumption of vitamin D rich fish. Preliminary research suggests that long-term vitamin D supplementation decreases the risk of MS, however, additional research is necessary before a firm conclusion can be reached.
Grade: C

Myelodysplastic syndrome: There is insufficient evidence in this area.
Grade: C

Osteogenesis imperfecta (OI): OI is a genetic disease characterized by unusually fragile bones that break easily, often under loads that normal bones bear daily due to a malfunction in the body's production of collagen. Proper calcium and vitamin D intake is essential to maintaining strong bones.
Grade: C

Osteoporosis in cystic fibrosis: Osteoporosis is common in patients with cystic fibrosis (due to fat malabsorption, which leads to a deficiency of fat-soluble vitamins such as vitamin D. Oral calcitriol administration appears to increase absorption of calcium and lower parathyroid concentrations.
Grade: C

Prostate cancer: There is preliminary evidence based on laboratory and limited human studies that high-dose vitamin D may be beneficial in the treatment of prostate cancer. This area is under active investigation, but clear evidence of benefits is not yet available.
Grade: C

Proximal myopathy: There is insufficient evidence in this area.
Grade: C

Seasonal affective disorder (SAD): Seasonal affective disorder (SAD) is a form of depression that occurs during the winter months, possibly due to reduced exposure to sunlight. In one study, vitamin D was found to be superior to light therapy in the treatment of SAD. Further studies are necessary to confirm these findings.
Grade: C

Senile warts: In early study, senile warts have been treated with topical vitamin D3.
Grade: C

Tooth retention: Oral bone and tooth loss are correlated with bone loss at non-oral sites. Research suggests that intake levels of calcium and vitamin D aimed at preventing osteoporosis may have a beneficial effect on tooth retention.
Grade: C

Muscle strength: Oral cholecalciferol does not appear to increase muscle strength or improve physical performance in healthy older men who are not vitamin D deficient.
Grade: D