American Association for Clinical Chemistry
Better health through laboratory medicine
May 2011 Clinical Laboratory News: News Brief

IOM Proposes New Thresholds for Vitamin D

A new report released by the Institute of Medicine (IOM) found that the majority of people in the U.S, 67%, are getting sufficient amounts of vitamin D, based on serum 25-hydroxyvitamin D (25OHD) thresholds proposed by the institute. However, the report puts roughly one-quarter of the U.S. population at risk of inadequacy and 8% at risk of deficiency.

The report, “Vitamin D Status: United States, 2001–2006” examined the role age, sex, race, and ethnicity play in determining a person’s risk of vitamin D deficiency and/or inadequacy. The prevalence of vitamin D deficiency was significantly lower in people who were younger or non-Hispanic white. Among women, the prevalence at risk was lower in pregnant women.

According to IOM, males were less likely to be at risk of vitamin D deficiency than females. Data pulled from 1988–1994 showed that only 4% of males age 12 years and over had serum 25OHD values that put them at risk of deficiency. The risk of vitamin D deficiency increased significantly with age until age 30 in males and age 18 in females, after which it did not change considerably with age.

The IOM also recently released new dietary reference intakes for vitamin D that incorporate higher quality studies than were available when the values for this nutrient were first established in 1997 (CLN Dec 2009). The agency defined four categories of vitamin D status based on 25OHD: risk of deficiency; risk of inadequacy; sufficiency; and above recommended levels.

Vitamin D status has been a controversial issue in recent years. The confusion stems from both analytical considerations and clinical interpretation of testing results, making it more difficult for labs to correctly interpret and implement the tests. Today, new technology is available for measuring vitamin D status, including high performance liquid chromatography and tandem mass spectrometry.

The full report is available online.