Vitamin D guidelines advise on dietary intake, screening for deficiency

New guidelines from the Endocrine Society offer recommendations on evaluation, treatment and prevention of vitamin D deficiency.

The guidelines, which were prepared by an expert task force guided by systematic evidence reviews, call for screening for vitamin D deficiency in at-risk individuals (including African-American, Hispanic and obese patients as well as those with conditions, medications or histories that put them at greater than normal risk) but not the population as a whole. The serum circulating 25-hydroxyvitamin D [25(OH)D] assay is recommended as the method of screening over the serum 1,25-dihydroxyvitamin D [1,25(OH)₂D] assay. Deficiency is defined as a 25(OH)D level below 20 ng/mL.

To treat or prevent deficiency, the guidelines recommend vitamin D₂ or D₃. Adults who are deficient can be treated with 50,000 IU of D₂ or D₃ once a week for eight weeks or 6,000 IU daily, to achieve a 25(OH)D level above 30 ng/mL, after which they should receive maintenance therapy of 1,500 to 2,000 IU per day. Patients who are obese, have malabsorption syndromes, or take medications affecting vitamin D metabolism should take a higher dose: at least 6,000 to 10,000 IU per day, followed by maintenance therapy of 3,000 to 6,000 IU per day. For patients with extrarenal production of 1,25(OH)₂D, the guidelines suggest serial monitoring of that level and serum calcium during treatment with vitamin D. They also recommend as-needed treatment and serum calcium monitoring for patients with primary hyperparathyroidism.

Adults up to age 70 should consume at least 600 IU of vitamin D per day, the guidelines say. Those over 70 should get at least 800 IU/day. However, maintaining a 25(OH)D level above the target of 30 ng/mL may require supplementation of vitamin D in the amount of 1,500 to 2,000 IU/day, the guidelines said. They called for two to three times as much vitamin D to be consumed by patients who are obese or take anticonvulsants, glucocorticoids, antifungals or medications for AIDS. The maintenance tolerable upper limit for vitamin D in healthy adults is 4,000 IU per day, although that may be exceeded under medical supervision to correct deficiency, the guidelines noted.

Prescribing vitamin D supplements for fall prevention is recommended, but giving patients more than the recommended daily amounts in order to prevent cardiovascular disease or death or to improve quality of life is not advised by the guidelines. The guidelines were published in the July 2011 Journal of Clinical Endocrinology and Metabolism. More on vitamin D and calcium supplementation is available from ACP Internist.