Alternatives to universal screening. Screening for vitamin D deficiency might benefit some patients, although there is no evidence to support it. Universal screening will likely lead to overdiagnosis and overtreatment based on what is essentially a poorly understood blood test. This was the concern expressed by the NAM.4,16 An editorial accompanying publication of the recent USPSTF recommendation suggested not measuring vitamin D levels but instead advising patients to consume the age-based RDA of vitamin D.3 For those at increased risk for vitamin D deficiency, advise a higher dose of vitamin D (eg, 2000 IU/d, which is still lower than the upper daily limit).3
Other options are to screen for vitamin D deficiency only in those at high risk for low vitamin D levels, and to test for vitamin D deficiency in those with symptoms associated with deficiency such as bone pain and muscle weakness. These options would be consistent with recommendations from the Endocrine Society.5 Some have recommended that if testing is ordered, it should be performed by a laboratory that uses liquid chromatography-mass spectrometry because it is the criterion standard.2
Treatment options. Vitamin D deficiency can be treated with either ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3). These treatments can also be recommended for those whose diets may not provide the RDA for vitamin D. Both are readily available over the counter and by prescription. The Task Force found that the harms of treating vitamin D deficiency with vitamin D at recommended doses are small to none.1 There is possibly a small increase in kidney stones with the combined use of 1000 mg/d calcium and 10 mcg (400 IU)/d vitamin D.17 Large doses of vitamin D can cause toxicity including marked hypercalcemia, nausea, vomiting, muscle weakness, neuropsychiatric disturbances, pain, loss of appetite, dehydration, polyuria, excessive thirst, and kidney stones.15A cautious evidence-based approach would be to selectively screen for vitamin D deficiency, conduct diagnostic testing when indicated, and advise vitamin D supplementation as needed.