Loyola study finds fewer children at risk of inadequate or deficient vitamin D levels

Loyola University Health SystemMar 26 2014

Under new guidelines from the Institute of Medicine, the estimated number of children who are at risk for having insufficient or deficient levels of vitamin D is drastically reduced from previous estimates, according to a Loyola University Chicago Stritch School of Medicine study.

The study, led by Holly Kramer, MD, MPH and Ramon Durazo-Arvizu, PhD, is published online ahead of print in the Journal of Pediatric Endocrinology and Metabolism.

New Institute of Medicine guidelines say most people get sufficient vitamin D when their blood levels are at or above 20 nanograms per millilitre (ng/mL). The Pediatric Endocrine Society has a similar guideline. However, other guidelines recommend vitamin D levels above 30 ng/mL.

Loyola researchers analysed vitamin D data from a nationally representative sample of 2,877 U.S. children and adolescents ages 6 to 18 who participated in the National Health and Nutrition Examination Survey.

The study found that under the Institute of Medicine guidelines, 10.3 percent of children ages 6 to 18 are at risk of inadequate or deficient vitamin D levels. (This translates to an estimated 5.5 million children.)

By comparison, a 2009 study in the journal Pediatrics, which defined sufficient vitamin D levels as greater than 30 ng/mL, found that an estimated 70 percent of persons ages 1 to 21 had deficient or insufficient vitamin D levels.

Under previous guidelines, millions of children who had vitamin D levels between 20 and 30 ng/mL would have needed supplementation. Under the Institute of Medicine guidelines, children in this range no longer need to take vitamin D supplements.

The new study found that children at risk of vitamin D deficiency under the Institute of Medicine guidelines are more likely to be overweight, female, non-white and between the ages of 14 and 18.

The Institute of Medicine's new vitamin D guidelines are based on nearly 1,000 published studies and testimony from scientists and other experts. The IOM found that vitamin D is essential to avoid poor bone health, such as rickets. But there have been conflicting and mixed results in studies on whether vitamin D can also protect against cancer, heart disease, autoimmune diseases and diabetes. Moreover, excessive vitamin D can damage the kidneys and heart, the IOM found.