Vitamin D Flashcards
Vitamin D: what it is, how obtained; prevalence of deficiency
-Deficiency and insufficiency more and more prevalent in all populations
Especially those in the North
=A fat-soluble vitamin naturally found in fish liver oil and fatty fish
-Also found in supplemented dairy products, cereals, and eggs from hens fed vitamin D
-Can by synthesized by the body if skin is exposed to sunlight
Forms of Vit D
Must be converted to active form (from food, supplements, or sun exposure)
Liver: converts to 25-Hydroxyvitamin D (calcidiol)
Kidneys: convert to 1,25-dihydroxyvitamin D (calcitriol)
Screening for Vit D deficiency
When screening for deficiency
- Draw 25(OH)D lab test
- When renal disease or other conditions are present, may draw 1,25(OH)D
Functions of Vit D
=Required for absorption of calcium from the intestinal tract
- As calcitriol, regulates serum calcium and phosphate levels
- Critical in bone growth and remodeling
Signs of Vit D deficiency-
With deficiency -Rickets develops in children -Osteomalacia and osteoporosis in adults -Both groups will have brittle, potentially misshapen bones -Muscle weakness -Chronic pain -Possible associations Cardiovascular disease Cognitive changes Some cancers Autoimmune disease Severe asthma
Women’s Health Initiative (2014) found supplementing -
With supplementation of 1,000 mg of elemental calcium and 400 IU of vitamin D
29% reduction in hip fracture 13% reduction in vertebral fracture 13% reduction in breast cancer in situ 9% in all cancer reduction 9% in all cause mortality No effect on cardiovascular outcomes
TX Vit D deficiency
-First prevent
-Diet
-Supplementation: required vitamin D daily
Age Daily requirement if at risk
0–12 months 400–1,000 IU
1–18 years 600–1,000 IU
19–70+ years 1,500–2,000 IU
Screening for Vit D deficiency:
American Endocrine Society says to screen those at risk.
Who is at risk for Vit D deficiency?
- Hispanic and African American patients
- Those with malabsorption syndromes
- Patients with rickets, osteomalacia, and osteoporosis
- Elderly patients with history of falls or fractures
- Obese patients
- Pregnant or lactating women
- Patients with chronic kidney or liver disease
- Patients on certain medications
Some may need higher dosing:
Special groups who may need higher dosing range if treated: -Obese children and adults -Patients on the following medications Anticonvulsants Glucocorticoids Antifungals HIV medications
Vit D toxicity? Who to monitor:
Review of literature by the Endocrine Council (2011) found that vitamin D toxicity was rare.
However, high doses of vitamin D can potentially induce hypercalcemia.
Monitor those at risk, particularly
Children
Patients with sarcoidosis, tuberculosis, or fungal disorders
Patients with lymphoma
TX Infants and Toddlers with Vit D deficiency:
-May dose 2000 IU per day or 50,000 IU per week for 6 weeks
-May use vitamin D2 or vitamin D3
-Blood draw after completion should be 30 ng per milliliter
-Maintenance therapy should be 400–1000 IU per day
This dose is high and new.
* Many pediatric providers will dose lower given risk of hypercalcemia.
TX peds 1-18 yo with Vit D deficiency:
Treatment 2,000 IU/day of vitamin D2 or D3, or 50,000 IU of vitamin D2 weekly for 6 weeks to achieve a blood level of 30 ng/mL or more Maintenance therapy 600–1,000 IU/day
TX adults with Vit D deficiency:
Treatment 6,000 IU/day of vitamin D2 or D3, or 50,000 IU of vitamin D2 weekly for 8 weeks to achieve a blood level of 30 ng/mL Maintenance therapy 1,500–2,000 IU/day
Nonresponders to Vit D deficiency TX?
- Patients who fail to respond to vitamin D therapy should be screened for celiac disease or occult cystic fibrosis (if compliant).
- Dosing once every other week with 50,000 IU was effective in poor responders in maintaining blood levels without toxicity.
