Evaluation, Treatment, and Prevention of Vitamin D Deficiency: An Endocrine Society Clinical Practice Guideline
The Endocrine Society published these guidelines on vitamin D deficiency in July 2011. This summary of those guidelines will focus on the screening and treatment recommendations.
Screening for Vitamin D Deficiency
Population-wide screening for vitamin D deficiency is not warranted. However, screening is warranted in individuals at risk for vitamin D deficiency. This includes people with (list is not exhaustive):
- chronic kidney disease
- malabsorption syndromes (eg, cystic fibrosis)
The serum circulating 25-hydroxyvitamin D (25[OH]D)level, as measured by a reliable assay, is recommended to assess vitamin D status. The guidelines recommend against serum 1,25(OH)2D assay.
The 25(OH)D level is the preferred screening level because it is the major circulating form of vitamin D; its half-life is 2 to 3 weeks.
In comparison, the circulating half-life of 1,25 (OH)2D is about 4 hours; serum 1,25(OH)2D also does not include vitamin D reserves. For those 2 reasons, it is not a useful method for monitoring vitamin D status.
In using the 25(OH)D levels, the following definitions should be used:
- Vitamin D deficiency: 25(OH)D below 20 ng/mL (50 nmol/liter)
- Vitamin D insufficiency: 21-29 ng/mL (52.5-72.5 nmol/liter)
- Vitamin D sufficiency: 30-100 ng/mL
Treatment of Vitamin D Deficiency
Either vitamin D2 or vitamin D3 should be used for treatment and prevention of vitamin D deficiency. The following doses are recommended:
- Infants and toddlers 0-1 year: 2,000 IU/day (vitamin D2 pr vitamin D3) or 50,000 IU once weekly (vitamin D2 or vitamin D3)for 6 weeks (followed by maintenance therapy of 400-1,000 IU/day after the serum 25(OH)D level is above 30 ng/mL)
- Children 1-18 years: 2,000 IU/day (vitamin D2 or vitamin D3)for at least 6 weeks or 50,000 IU once weekly (vitamin D2) for at least 6 weeks (followed by maintenance therapy of 600-1,000 IU/d after the serum 25(OH)D level is above 30 ng/mL)
- Adults: 50,000 IU once weekly (vitamin D2 or vitamin D3) for 8 weeks or 6,000 IU/day (vitamin D2 or vitamin D3) (followed by maintenance therapy of 1,500-2,000 IU/d after the serum 25(OH)D level is above 30 ng/mL)
- Obese patients, patients with malabsorption syndromes, patients using medications that affect vitamin D metabolism: at least 6,000-10,000 IU/day of vitamin D (followed by maintenance therapy of 3,000-6,000 IU/d after the serum 25(OH)D level is above 30 ng/mL)
- Patients with extrarenal 1,25(OH)2D production: Serial monitoring of 25(OH)D levels and serum calcium levels should be done in order to prevent hypercalcemia during vitamin D treatment.
- Patients with primary hyperparathyroidism: Treat as needed for vitamin D deficiency, but monitor serum calcium levels during vitamin D treatment.
The threshold which defines vitamin D sufficiency continues to be a controversial topic. The Institute of Medicine recommended a level of 20 ng/ml. This comprehensive guideline from the Endocrine Society recommends a 25(OH)D level of 30 ng/ml to definite sufficiency. Recommendations on screening and therapy for various clinical scenarios are clearly outlined in this clinical guideline. You can access a full copy of the guidelines on the Endocrine Society website.