It's difficult to pinpoint the proportion of the U.S. population at risk for vitamin D deficiency, especially given the variance in how deficiency is defined across studies. Suffice it to say that estimates range from about 19 percent to as high as 77 percent of the population.
Against that background of uncertainty, the U.S. Preventive Services Task Force (USPSTF) set about exploring the available evidence(www.uspreventiveservicestaskforce.org) pertaining to screening adults for the condition. Based on that evidence, the USPSTF recently issued a draft recommendation(www.uspreventiveservicestaskforce.org) stating that there is not enough evidence to assess the balance of benefits and harms of screening adults for vitamin D deficiency and the task force cannot, therefore, recommend for or against screening.
"While there is a lot of interest in how vitamin D impacts health, we don't have enough evidence at this time to know whether screening the general adult population for vitamin D deficiency improves health," said USPSTF member Linda Baumann, Ph.D., R.N., in a news bulletin provided by the task force. "There is still scientific debate about what level of vitamin D is optimal and what level is considered deficient."
Foundation for Recommendation
- On June 24, the U.S. Preventive Services Task Force issued a draft recommendation stating that evidence is insufficient to recommend for or against screening adults for vitamin D deficiency.
- According to the draft recommendation, no consensus definition of vitamin D deficiency exists, and the optimal level of total serum 25-hydroxy vitamin D also has been debated.
- The USPSTF has opened the discussion on this draft recommendation and draft evidence review for public comment until July 21.
According to the draft recommendation, there is no consensus definition of vitamin D deficiency, and an optimal level of total serum 25-hydroxy vitamin D (the major circulating form of vitamin D) also remains elusive. For the purposes of the recommendation statement, "vitamin D deficiency" reflects evidence from study populations representing levels of 30 ng/mL or less or subpopulations of studies with levels of less than 20 ng/mL.
The draft recommendation applies to nonpregnant adults ages 18 or older who are seen in the primary care setting and who have no signs or symptoms of vitamin D deficiency or any condition for which vitamin D treatment is recommended. The focus of this just-released draft statement is solely on screening and is distinct from previous USPSTF recommendations on vitamin D and calcium supplementation(www.uspreventiveservicestaskforce.org) to prevent fracture.
"People who are concerned about their vitamin D levels should talk with their doctor about screening or supplementation based on their individual health needs," said task force Co-vice Chair Albert L. Siu, M.D., M.S.P.H., in the USPSTF bulletin.
Although routine screening for vitamin D deficiency in healthy adults is not being recommended by the USPSTF, targeted screening for those at highest risk might be family physicians' best course of action, said Jennifer Frost, M.D., medical director for the AAFP Health of the Public and Science Division. "This frequently includes older home-bound patients, patients with malabsorption disorders and patients with osteoporosis," she added.
Treatment of a patient who is vitamin D-deficient varies based on the level of deficiency. Most sources recommend supplementing vitamin D deficient patients with a high weekly dose of vitamin D2 (50,000 IU) for six to eight weeks, then with a daily dose of 800-1,000 IU, Frost said.
Comment Period Is Open
The USPSTF is seeking public comments(www.uspreventiveservicestaskforce.org) on this draft recommendation and draft evidence review until July 21. All comments will be considered as the task force develops its final recommendation and final evidence summary.