Vitamin D Deficiency
  • The preferred test for Vitamin D deficiency is a serum 25-hydroxy Vitamin D level
    • In the past, the lower limit of normal for most 25-OH Vitamin D assays was 8-10 ng/ml
    • Currently, the following has become accepted as categories for interpretation of serum 25-OH Vitamin D levels:
    • <20 ng/ml- Vitamin D deficiency; treatment is strongly recommended
    • 20-30 ng/ml- Vitamin D insufficiency, treatment is recommended
    • >30 to 100 ng/ml-optimum Vitamin D level
    • >100 ng/ml-high Vitamin D level, treatment should be adjusted downward
  • Biochemical picture of advanced (severe) Vitamin D deficiency:
    • Low serum calcium (especially ionized calcium)
    • Low phosphorus
    • Elevated PTH
    • Low urinary calcium
    • Elevated alkaline phosphatase
  • Risk factors for Vitamin D deficiency:
    • Increasing age
    • Chronic steroid use 
    • Chronic anticonvulsant drug use
    • Malabsorption syndromes (including particularly Celiac Disease)
    • Little sun exposure (including institutionalized patients)
    • Chronic low intake of calcium (low dairy product intake; especially patients with lactose intolerance)
  • Clinical situations where Vitamin D deficiency should be considered:
    • Anyone found to have reduced BMD (Osteopenia OR Osteoporosis)
    • Hx of risk factors for Vitamin D deficiency
    • Hx of an elevated PTH level with normal or low calcium
    • Hx of elevated alkaline phosphatase level
  • Suggested treatment of Vitamin D deficiency
    • Vitamin D deficiency (25-OH Vitamin D level <20): Vitamin D 50,000 units twice a week for 3 months, repeat 25-OH Vitamin D level
      • If >20 ng/ml, change the Vitamin D supplement to 50,000 units once a week
      • If still <20 ng/ml, continue Vitamin D 50,000 units twice a week   OR consider giving it more frequently (with certain clinical situations, especially with malabsorption syndromes, up to 50,000 units daily may be needed)
    • Vitamin D insufficiency (25-OH Vitamin D level 20-30 ng/ml):Vitamin D 50,000 units once a week for 3 months, repeat 25 OH Vitamin D level
      • If <30 ng/ml, continue Vitamin D 50,000 units once a week
      • If  >30 ng/ml, change to Vitamin D as part of a calcium supplement and/or as multiple vitamin (give at least 800 IU/day)
  • NOTE: Treatment for Vitamin D deficiency should ALWAYS include a calcium supplement(possible exception: a patient with a history of kidney stones)
  • While the RDA for Vitamin D is currently listed as 400-800 IU daily, the GHS Osteoporosis Disease Management Team suggests that the optimum intake for healthy individuals should be 800 IU daily.