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Flashcards in Vitamin D Deck (18):

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
-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
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
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:

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:

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.


TX obese adults and those with malabsorption disorders with Vit D deficiency:

Obese adults and patients with malabsorption syndromes or those on medications that enhance vitamin D catabolism

Often require two to three times the dose
6,000–10,000 IU/day of vitamin D to treat
3,000–6,000 IU/day for maintenance


Follow-up with Vit D deficiency:

-Blood is usually redrawn 2 weeks after completion of vitamin D treatment and patient is switched to maintenance if levels therapeutic
-Calcium supplements on maintenance
-Work on long-term secondary prevention: dietary sources and sun exposure (recommend sunscreen)



Though rare, signs of toxicity include
-Abdominal pain
-Polydipsia and polyuria
-Muscle weakness and pain
-Renal damage