Still Not Enough Evidence To Support Or Reject Screening Adults For Vitamin D Deficiency: USPSTF

There remains insufficient evidence to recommend for or against screening for vitamin D deficiency in asymptomatic adults, according to an update from the U.S. Preventive Services Task Force (USPSTF).

Therefore, the task force issued an "I" (insufficient) statement, which is unchanged from its 2014 recommendation on screening for vitamin D deficiency in asymptomatic adults.

To update its 2014 recommendation, the USPSTF commissioned an evidence review, which was conducted by Dr. Leila Kahwati, with RTI International, Research Triangle Park, North Carolina and colleagues. The updated review included 46 studies with more than 16,000 participants in total.

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"Among asymptomatic, community-dwelling populations with low vitamin D levels, the evidence suggests that treatment with vitamin D (with or without calcium) has no effect on mortality or incidence of fractures, falls, depression, diabetes, cardiovascular disease, cancer, or adverse events. The evidence is inconclusive about the effect of treatment on physical functioning and infection," Dr. Kahwati and colleagues write in their evidence report in JAMA.

In their recommendation statement, the task force notes that no studies directly evaluated the health benefits or harms of screening for vitamin D deficiency. Therefore, the balance of benefits and harms of screening for vitamin D deficiency in asymptomatic adults cannot be determined.

They emphasize that this recommendation applies to community-dwelling, nonpregnant adults who have no signs or symptoms of vitamin D deficiency or conditions for which vitamin D treatment is recommended. It does not apply to people who are hospitalized or living in institutions such as nursing homes.

Currently no organization recommends population-based screening for vitamin D deficiency.

The authors of a linked editorial note that the importance of vitamin D for maintaining musculoskeletal health is well established. Based on 2014 data, 25% of the U.S. population was vitamin D deficient.

In limiting the scope of their review to asymptomatic adults, "the USPSTF recommendation does not provide clinicians with a clear recommendation for the group of 'symptomatic' adults who would potentially benefit from 25(OH)D testing and treatment," write Dr. Sherri-Ann Burnett-Bowie of Massachusetts General Hospital, in Boston, and Dr. Anne Cappola of the University of Pennsylvania, in Philadelphia.

They note that the best measure of vitamin D deficiency is unclear and 25(OH)D levels vary by race/ethnicity. "Given these challenges, how should clinicians decide whom to screen for vitamin D deficiency? One approach might be to not measure vitamin D levels and to ensure that all individuals consume the age-based recommended daily allowance of vitamin D," Drs. Burnett-Bowie and Cappola suggest.

"Individuals at increased risk for vitamin D deficiency (those who have limited sun exposure, increased skin pigmentation, body mass index >30, malabsorption or altered gastrointestinal anatomy, chronic kidney disease, chronic liver disease, or who have rickets, osteomalacia, or osteoporosis) could be empirically prescribed a higher dose of vitamin D (eg, 2000 IU/d) that is still below the upper daily limit," they further suggest.

Looking ahead, they say, "future studies of treating vitamin D deficiency should assess the best vitamin D biomarker, have adequate racial and ethnic diversity, and target enrollment by degree of vitamin D deficiency and likelihood of benefit. Until the target populations who would benefit from treatment with vitamin D are established, it is premature to conduct studies evaluating the role of screening for vitamin D deficiency."

—Reuters Staff

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