Vitamin D

Vitamin D Deficiency - NEJM 7/07

Courtesy of Eileen Fingerman, MD

  1. What test to get to diagnose Vitamin D deficiency?

Order a 25-OH vitamin D level (not 1,25-OH). The reason you DO NOT want a 1,25 is because when someone is deficient in Vitamin D the body increases conversion of 25-OH vit D to 1, 25_OH  (the active form, made in the kidneys)..so if you measure 1,25-OH you may be incorrectly reassured that the patient’s level is okay when in fact they are deficient

  1. What is a “normal” level? 

The lab will tell you >25 ng/ml is okay..NOT TRUE.  Below 30ng/ml you are getting stimulation of PTH and therefore getting bone turnover. Optimal level is >60 ng/ml

  1. How much Vitamin D to give to a patient? 

Everyone in the winter in Maine should be on a minimum of 1000 IU QD or  10,00 IU a week or 50,000 IU a month.

Some helpful vitamin D3 supplementation guidelines might be:

Vitamin D levels < 20 ng/ml 5,000–7,000 i.u. per day for 6–8 weeks. Retest. Then 3,000–5,000 i.u.per day for another 6–8 weeks, followed by 2,000 i.u. per day
Vitamin D levels 20–32 ng/ml 5,000 i.u. per day for 6–8 weeks. Retest. Then 2,000–3,000 i.u. for 6–8 weeks, followed by 2,000 i.u. per day
Vitamin D levels 32 ng/ml–40 ng/ml 2,500–5,000 i.u. per day for 4–6 weeks, then 2,000 i.u. per day. Retest every 3 months
Vitamin D levels 50–60 ng/ml (optimal) Maintain at 1,000–2,000 i.u. per day, retest yearly.