June 7, 2011 (Boston, Massachusetts) — The Endocrine Society today unveiled a Clinical Practice Guideline on the evaluation, treatment, and prevention of vitamin D deficiency, with an emphasis on the care of patients who are at risk for vitamin D deficiency.
Michael F. Holick, MD, PhD, from Boston University Medical Center, Massachusetts, who chaired the 8-member task force that developed the guideline, summarized the recommendations at a press briefing here at ENDO 2011: The Endocrine Society 93rd Annual Meeting.
The guideline also was published online June 6 in the Journal of Clinical Endocrinology & Metabolism.
"Based on all the evidence, at a minimum, we recommend vitamin D levels of 30 ng/mL, and because of the vagaries of some of the assays, to guarantee sufficiency, we recommend between 40 and 60 ng/mL for both children and adults," Dr. Holick said.
The society's clinical practice guideline was developed by "experts in the field who carefully reviewed the current literature and features the latest and most comprehensive recommendations available on the prevention and treatment of vitamin D deficiency," he said.
The guideline recommends that clinicians screen for vitamin D deficiency in people at risk for deficiency, including obese individuals, blacks, pregnant and lactating women, and patients with malabsorption syndromes.
"We do not recommend population screening for vitamin D deficiency in individuals who are not at risk," Dr. Holick said, but added that "vitamin D deficiency is very common in all age groups — essentially everyone is at risk."
Screening should be performed using a "reliable assay" for 25-hydroxy-vitamin D (25[OH]D), not 1,25-dihydroxy-vitamin D (1,25[OH]2D), "which tells you nothing about vitamin D status," Dr. Holick said. Vitamin D deficiency is defined as 25[OH]D levels below 20 ng/mL.
"Considering that vitamin D deficiency is very common in all age groups and that few foods contain vitamin D, the Task Force recommended supplementation at suggested daily intake and tolerable upper limit levels, depending on age and clinical circumstances," the guideline states.
For bone health, infants and children up to 1 year of age require at least 400 IU/day vitamin D, and children 1 year and older need at least 600 IU/day, the guideline states. However, at least 1000 IU/day of vitamin D may be needed to raise the blood level of 25(OH)D consistently above 30 ng/mL, it notes.
Adults aged 19 to 70 years require at least 600 IU/day of vitamin D to maximize bone health and muscle function. However, getting 25(OH)D levels consistently above 30 ng/mL may require at least 1500 to 2000 IU/day of vitamin D.
Adults 70 years and older require at least 800 IU/day of vitamin D for bone health and fall prevention; at least 1500 to 2000 IU/day of supplemental vitamin D may be needed to keep 25(OH)D levels above 30 ng/mL.
Pregnant and lactating women need a minimum of 600 IU/day of vitamin D; 1500 IU/day may be needed to maintain blood levels of 25(OH)D higher than 30 ng/mL.
"Obese children and adults and children and adults on anticonvulsant medications, glucocorticoids, antifungals such as ketoconazole, and medications for AIDS need at least 2 to 3 times more vitamin D for their age group to satisfy their body's vitamin D requirement," Dr. Holick reported.
Tolerable upper limits of vitamin D, which "should not be exceeded without medical supervision," include the following:
1000 IU/day for infants aged up to 6 months,
1500 IU/day for infants aged 6 months to 1 year old,
2500 IU/day for children aged 1 to 3 years,
3000 IU/day for children aged 4 to 8 years, and
4000 IU/day for everyone older than 8 years.
However, the guideline states that for individuals who are vitamin D deficient, higher levels of vitamin D (2000 IU/day for children up to age 1 year; 4000 IU/day for children aged 1 - 18 years, and up to 10,000 IU/day for adults aged 19 years and older) "may be necessary to correct, treat, and prevent vitamin D deficiency," Dr. Holick said.
"Both vitamin D2 and vitamin D3 is equally fine in treating and preventing vitamin D deficiency," he added.
For all age groups, it is unknown whether these age-specific levels of vitamin D are "enough to provide all of the potential nonskeletal health benefits associated with vitamin D," Dr. Holick noted.
He also said that at present, "there is not sufficient evidence to recommend prescribing vitamin D to attain the noncalcemic benefit for cardiovascular protection." However, association studies have suggested that increasing vitamin D levels may help protect against some cancers, including colorectal cancer, as well as infectious disease, diabetes, and high blood pressure.
The upper limits and the dietary intake levels in The Endocrine Society guideline for the most part mirror those of the 2010 Institute of Medicine consensus report, "Dietary Reference Intakes for Calcium and Vitamin D," although The Endocrine Society gives more explicit recommendations for care.
Dr. Holick commented that the Institute of Medicine report used a "population model, not a medical model, and was not intended to direct physicians on care of patients. It was up to professional associations to establish guidelines of care, which is why [The Endocrine Society] became involved."
Christine Stencel, media relations officer of the National Academy of Sciences, said the committee that issued the 2010 report is no longer an entity and would not have a comment on The Endocrine Society guideline.
"At some point down the road, there is the potential that [Institute of Medicine] could convene a new committee to reexamine all the new information and look at changing the [dietary reference intakes], but at this point we wouldn't do any immediate re-look at this," she said.
Development of the clinical practice guideline was supported solely by The Endocrine Society. Dr. Holick has disclosed financial or business/organizational interests with Merck, Novartis, Nichols-Quest Diagnostics, Bayer, Aventis, Warner Chilcott, Amgen, the UV Foundation, DMI, and the Mushroom Council. A complete list of disclosures for the task force are listed with the original article.
ENDO 2011: The Endocrine Society 93rd Annual Meeting. Presented June 6, 2011.
J Clin Endocrinol Metabol. Published online June 6, 2011. Abstract
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