New guideline calls for vitamin D deficiency screening in at-risk populations

ENDO 2011

BOSTON — A group of experts has released a new clinical practice guideline for the evaluation, treatment and prevention of vitamin D deficiency.

“Vitamin D deficiency is very common in all age groups,” Michael F. Holick, MD, PhD, director of the Bone Health Care Clinic at Boston University Medicine Center, said at a press conference. “Everyone is at risk.”

The task force, which was convened by The Endocrine Society, reviewed the current literature to provide evidence-based recommendations.

The experts recommend screening for vitamin D deficiency only in individuals at risk for deficiency, including obese children and adults (BMI ≥30), black and Hispanic children and adults, pregnant and lactating women, and patients taking certain medications such as glucocorticoids and AIDS therapy.

“At the present time, we do not recommend screening for vitamin D deficiency in individuals not at risk,” Holick said.

Measuring vitamin D

Vitamin D deficiency is defined as a 25-hydroxyvitamin D below 20 ng/mL and vitamin D insufficiency as a 25(OH)D level of 21 ng/mL to 29 ng/mL. To diagnose vitamin D deficiency, the task force recommends using the serum circulating 25(OH)D level, measured by a reliable assay, to evaluate vitamin D status. Using the serum 1,25-dihydroxyvitamin D assay is not advised, and its use is only recommended in certain conditions, such as acquired and inherited disorders of vitamin D and phosphate metabolism.

Daily dietary intake recommendations

Dietary intake recommendations are based on age, with a goal of maximizing bone health. Recommendations include:

• Infants and children aged 0 to 1 years require at least 400 IU and children aged 1 to 18 years require at least 600 IU. To raise 25(OH)D levels above 30 ng/mL may require at least 1,000 IU.
• Adults aged 19 to 50 years require at least 600 IU. To raise 25(OH)D levels above 30 ng/mL may at least 1,500 IU to 2,000 IU.
• Adults aged 50 to 70 years require at least 600 IU per day and adults aged older than 70 years require 800 IU. To raise 25(OH)D levels above 30 ng/mL may require 1,500 to 2,000 IU.
• Pregnant and lactating women require at least 600 IU. To raise 25(OH)D levels above 30/ng/mL may require at least 1,500 IU.

Upper tolerable limits

The guidelines also outline tolerable upper limits of vitamin D. The task force stressed that these levels should not be exceeded without medical supervision.

“We suggest that the maintenance tolerable upper limits of vitamin D, which is not to be exceeded without medical supervision, should be 1,000 IU day for infants up to 6 months, 1,500 IU a day for infants from 6 months to 1 year, at least 2,500 IU a day for children aged 1 to 2 years; 3,000 IU a day for children aged 4 to 8 years; and 4,000 IU a day for everyone over age 8 years.

“However, higher levels of 2,000 IU a day for children aged 0 to 1 years; 4,000 IU a day for children aged 1 to 18 years; and 10,000 IU a day for children and adults aged 19 years and older may be needed to correct vitamin D deficiency,” the task force wrote.

Holick said up to 10,000 IU per day has been demonstrated in healthy adults not to cause any toxicity.

Special considerations

The experts recommend treatment with vitamin D₂ or D₃ for vitamin D-deficient patients.

A two- to three-times higher dose of vitamin D is recommended for obese patients, patients with malabsorption syndromes and patients taking medications that may affect vitamin D metabolism. The dose may be 6,000 IU to 10,000 IU per day to maintain a 25(OH)D level above 30 ng/mL, followed by maintenance therapy of 3,000 IU to 6,000 IU.

The guidelines are now published in the July issue of the Journal of Clinical Endocrinology & Metabolism. – by Katie Kalvaitis

Disclosure: Dr. Holick reports financial or business/organizational interests with Amgen, Aventis, Bayer, Merck, Nichols-Quest Diagnostics, Novartis, Warner Chilcott, the UV Foundation, DMI and the Mushroom Council.

For more information:

• Holick MF. J Clin Endocrinol Metab.2011;doi:10.1210/jc.2011-0385.

I am generally against guidelines, mostly because they often are misused and are rarely used properly. The fact that there is divergence in the guidelines for vitamin D supplementation is an indication of the fact that there is a lot that we still don't know.

– Robert D. Blank, MD, PhD
Endocrine Today Editorial Board Member

The good: The popular press, patients and physicians have finally noticed vitamin D as an important health issue. It is now more likely that patients will take vitamin D supplementation and engage in discussions about vitamin Dwith their physicians. The bad: The debate between the IOM and many professional associations has created confusion about the potential for loss of confidence in mainstream medicine. In addition, the proliferation of vitamin D products and supplements may increase the risk for inappropriately high doses.

Steven M. Petak, MD, MACE, JD

My personal perspective: Guidelines directed toward treating populations have been useful, but are becoming less relevant, clinically. Personalized medicine is the future. The fruits from the human genome project are just starting to ripen. Determining what is most appropriate for a given patient based on their genetic profile is being applied in oncolgy and has potential in all fields of medicine. The major limitation is high cost. Making the cost of testing reasonable should be our major goal, and not just for genetic studies. If a 25(OH)D level were inexpensive enough to run on a chemistry profile, we would know who needs supplementation and how much to use. Since the automated chemical analyzer was used in the 1970s, routine calcium testing dramatically increased the number of patients diagnosed with primary hyperparathyroidism.

A 'ballpark' measurement of 25(OH)D is close enough for most patients. A range of 30 ng/mL to 60 ng/mL is a reasonable optimal range since there remains controversy over levels of 20 ng/mL to 30 ng/mL. With a ballpark measurement, a level of 40 ng/mL to 60 ng/mL would be reasonable for decision-making regarding supplementation. Based on current information, a level of 60 ng/mL would be a safe upper limit. Until we are able to obtain inexpensive levels, it would seem that 1,000 IU to 2000 IU of vitamin D daily is quite reasonable for routine use. Certain patients may have vitamin D requirements that are significantly higher based on underlying medical conditions, such as malabsorption, bariatric surgery and so on, and dosing should be determined based on 25(OH)D measurements. Until the cost of 25(OH)D testing can be brought down to 'routine' testing levels, the Endocrine Society guidelines provide helpful tools to assist with clinical decision making.

– Steven M. Petak, MD, MACE, JD
Director
Osteoporosis Center and Bone Densitometry Unit
Texas Institute for Reproductive Medicine and Endocrinology

Disclosure: Dr. Petak reports no relevant financial disclosures.

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