Jury Still Out on Vitamin D Screening

Vitamin D deficiency screening recommendations were inconclusive due to lack of evidence

(RxWiki News) Knowing which medical screenings and tests are worthwhile can be difficult. The jury is still out on one such screening for a vitamin deficiency.

A new report from a panel of US experts said there was not enough evidence to say whether vitamin D deficiency screening was effective.

Released by the US Preventive Services Task Force (USPSTF), the report compiled current expert opinions and studies about vitamin D screenings and came up inconclusive.

In an editorial about this new report, however, Robert P. Heaney, MD, and Laura A. G. Armas, MD, of Creighton University in Omaha, NE, said screening may serve a purpose — despite the inconclusive USPSTF findings.

"Usually testing improves patient compliance because it provides patient-specific, personally applicable information," Drs. Heaney and Armas wrote. "General assurances that one probably needs extra vitamin D are not as compelling a motivator as knowing one’s number."

According to the Mayo Clinic, vitamin D works in the body to normalize calcium levels. It is thought to improve bone, kidney and thyroid health. Vitamin D can be found in foods like fish and eggs. The body can also produce it through exposure to sunlight.

After reviewing a number of recent studies on the benefits and harms of screening for vitamin D deficiency in adults without symptoms of related health problems, the USPSTF did not find enough evidence to make a recommendation for or against screening.

The task force behind this new report was led by Michael L. LeFevre, MD, of the University of Missouri School of Medicine in Columbia.

These report authors found no evidence in past studies for a direct health benefit tied to vitamin D screenings, nor was there evidence that treating vitamin D deficiency when no symptoms were present reduced cancer, diabetes or death risks.

However, the experts also did not find convincing evidence that tied vitamin D screening to any harm. And treating vitamin D deficiency didn't appear to hurt patients.

Dr. LeFevre and team noted that no agreed-upon definition for the proper level of vitamin D existed at the time of the study. Editorial authors Drs. Heaney and Armas said uncertainties — including those about ideal vitamin levels and how to properly test these levels — were not surprising.

"These problems are not peculiar to vitamin D, but are issues also for many other nutrients (e.g., folate, ascorbate, calcium, and protein)," Drs. Heaney and Armas wrote.

The USPSTF stressed that its inconclusive stance on vitamin D deficiency screenings only applied to adults without any symptoms of vitamin D deficiency. The Mayo Clinic reported that symptoms of a vitamin D deficiency can include bone weakness and muscle pain.

Dr. LeFevre and team said doctors should take each patient's unique health situation into account when considering vitamin D screening. They said more research is needed to better understand the harms and benefits of screening for vitamin D deficiency.

The report and editorial were published Nov. 24 in Annals of Internal Medicine.

One report author received royalties from Cambridge University Press.

Review Date: 
November 22, 2014