Proof Lacking for Routine Vitamin D Screening: US Task Force

Megan Brooks

June 24, 2014

There is not enough evidence to recommend for or against screening healthy adults for vitamin D deficiency, according to a draft recommendation from the US Preventive Services Task Force (USPSTF).

"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," Task Force member Linda Baumann, PhD, RN, of the University of Wisconsin-Madison School of Nursing, said in a statement.

"There is still scientific debate about what level of vitamin D is optimal and what level is considered deficient," she noted.

Depending on what cut point is used (< 20 ng/mL or < 30 ng/mL), some studies have shown that low levels of vitamin D are associated with increased risk for fractures, functional limitations, cancer, diabetes, cardiovascular disease, depression, and mortality, the Task Force notes.

They also point out that "numerous" testing methods are available to measure total serum 25-hydroxy vitamin D levels. However, the accuracy of these tests is "difficult to determine due to the lack of studies using an internationally recognized reference standard and the lack of consensus on the cut point values used to define vitamin D deficiency." There is evidence suggesting variation in results between testing methods and between laboratories using the same testing methods, according to the Task Force.

They say no studies have evaluated the direct benefit of screening for vitamin D deficiency in adults. On the other hand, "adequate" evidence exists that treatment of asymptomatic vitamin D deficiency has no benefit on cancer, type 2 diabetes, mortality in community-dwelling adults, and risk for fractures in persons not selected based on having a high risk for fracture. There is "inadequate" evidence on the benefit of treating asymptomatic vitamin D deficiency on other outcomes, including psychosocial or physical functioning.

No studies were identified that evaluated the direct harms of screening for vitamin D deficiency.

Final Conclusion Pending

The USPSTF concludes that the evidence on screening for vitamin D deficiency to improve health outcomes in asymptomatic adults is insufficient and the balance of benefits and harms of screening and early intervention cannot be determined.

The Task Force has posted their draft recommendation statement and draft evidence review on screening for vitamin D deficiency in adults on their Web site and will accept public comment until July 21.

"All comments will be considered as the Task Force develops its final recommendation and final evidence summary," the statement notes.

The Task Force notes that the draft recommendation is for generally healthy adults, not people who show signs or symptoms of vitamin D deficiency.

"People who are concerned about their vitamin D levels should talk with their doctor about screening or supplementation based on their individual health needs," Task Force co-vice chair Albert L. Siu, MD, MSPH, of the Icahn School of Medicine at Mount Sinai, in New York, said in a statement.


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