Vitamin D Insufficiency

  • Levels of serum 25(OH)D (1 ng/mL = 2.496 nmol/L)
    • Sufficient: controverisal, may be30 ng/mL, optimal level is ~40 ng/mL (~100 nmol/L), some recommend levels up to 60 ng/mL
    • Insufficient: 10-29 ng/mL
    • Deficient: <10 ng/mL
    • Excess (?): >50-60 ng/mL, some evidence links potential adverse effects to high levels

  • Risk factors
    • Winter at higher latitudes (November through March)
    • Breast-fed infants
    • Darker skin
    • Malabsorption
    • Obesity
    • Lifestyle-related low UVB exposure
      • Sunscreen use
      • Newborns with exclusive breastfeeding
      • >50 years old due to time spent indoors, decreased skin conversion

  • Low 25(OH)D levels are associated with:
    • Respiratory infections, wheezing, asthma exacerbations
      • No association with incidence childhood asthma
    • Decreased corticosteroid responsiveness
    • Winter-related AD
    • Possible increased risk of food allergy (vitamin D sufficiency may be an important protective factor against food allergy in the first year of life)
    • Emerging data support benefit for infection




Vitamin D Supplementation


Dietary

  • Dietary intakes has modest effect on level
Daily intake
Effect on serum 25(OH)D level (ng/mL)-------
Glass of vitamin D milk (100 IU)-------
+1
200 IU
+2
400 IU
+4
1000 IU
+10

Note:
  • Cod liver may contain 400-1360 IU/tablespoon
  • Salmon (3 oz) 447-794 IU, fortified orange juice (8 oz) 137 IU, egg (1) 41 IU, vitamin D milk (8 oz) 120 IU
  • Skin can create thousands of IUs after 15-20 min of UVB exposure

Treatment

Holick

Cause of deficiency
Preventive and Maintenance Measures to Avoid Deficiency
Treatment of Deficiency
  • Inadequate sun exposure or supplementation
  • Dark skin (up to 18 yo)
  • Decreased 7-dehydrocholesterol in skin because of aging (over 50 yo)
Children
  • 400–1000 IU vitamin D3/day (1000–2000 IU of vitamin D3/ day is safe)
  • Maintenance dose is 400–1000 IU of vitamin D/day
  • Sensible sun exposure

Adults
  • 800–1000 IU of vitamin D3/day
  • 50,000 IU of vitamin D2 every 2 wk or every mo
  • Sensible sun exposure or use of tanning bed or other UVB radiation device (e.g., portable Sperti lamp)
  • Up to 10,000 IU of vitamin D3/day is safe for 5 mo
  • Maintenance dose is 50,000 IU every 2 wk or every mo
Children
  • 50,000 IU of vitamin D2 every wk for 8 wk

Adults
  • 50,000 IU of vitamin D2 every wk for 8 weeks; repeat for another 8 wk if 25-hydroxyvitamin D <30 ng/ml

Misra

  • Infants and children who are vitamin D insufficient or deficient:
    • Replacement
      • 1000 IU/day of vitamin D for infants <1 month old
      • 1000-5000 IU/day for children 1-12 months old
      • >5000 IU/day for children >12 months old
      • For patients who demonstrate poor compliance, a high dose of vitamin D may be given as a single dose or repeated intermittently
    • Maintenance: 400 IU of vitamin D/day
    • Simultaneous calcium supplementation is necessary because of the risk of hypocalcemia from decreased demineralization of bone and increased remineralization as PTH levels normalize
  • Blaiss: as far as dosing, I agree with the Pediatric 2008 article by Misra et al. Usually it will take up to 2-3 months in children deficient to get a therapeutic level so watch serum levels.


IOM Recommendations (2010)


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References