Symptomatic vitamin D deficiency is known to affect health adversely, as is asymptomatic vitamin D deficiency in certain patient populations. But the evidence that deficiency contributes to adverse health outcomes in asymptomatic adults is inadequate. The evidence that screening for such deficiency and treating “low” vitamin D levels prevents adverse outcomes or simply improves general health also is inadequate, Dr. LeFevre and his associates said.
Similarly, no studies to date have directly examined possible harms of screening for and treating vitamin D deficiency. Although there are concerns that vitamin D supplements may lead to hypercalcemia, kidney stones, or gastrointestinal symptoms, there is no evidence of such effects in the asymptomatic patient population.
The USPSTF concluded that the harms of screening for and treating vitamin D deficiency are likely “small to none,” but it still is not possible to determine whether the benefits outweigh even that small amount of harm.
At present, no national primary care professional organization recommends screening of the general adult population for vitamin D deficiency. The American Academy of Family Physicians, the Endocrine Society, the American College of Obstetricians and Gynecologists, the American Geriatrics Society, and the National Osteoporosis Foundation all recommend screening for patients at risk for fractures or falls only. The Institute of Medicine has no formal guidelines regarding vitamin D screening, Dr. LeFevre and his associates noted.
The USPSTF summary report and the review of the evidence are available at www.uspreventiveservicestaskforce.org.