Boston -- October 26, 2009 -- Millions of children in the United States between the ages of 1 and 11 may suffer from suboptimal levels of vitamin D, according to a large, nationally representative study published in the November issue of Pediatrics.
The study, led by Jonathan Mansbach, MD, Children's Hospital Boston, Boston, Massachusetts, is the most up-to-date analysis of vitamin D levels in US children. It builds on the growing evidence that levels have fallen below what is considered healthy, and that black and Hispanic children are at particularly high risk.
Both the optimal amount of vitamin D supplementation and the healthy blood level of vitamin D are under heated debate in the medical community. Currently, the American Academy of Pediatrics (AAP) recommends children should have vitamin D levels of at least 50 nmol/L. However, other studies in adults suggest that vitamin D levels should be at least 75 nmol/L, and possibly 100 nmol/L, to lower the risk of heart disease and specific cancers.
"If 75 nmol/L or higher is eventually demonstrated to be the healthy normal level of vitamin D, then there is much more vitamin D deficiency in the US than people realise," Dr. Mansbach said.
Dr. Mansbach and collaborators from the University of Colorado, Denver, Denver, Colorado, and Massachusetts General Hospital, Boston, Massachusetts, used data from the National Health and Nutrition Examination Survey (NHANES) to look at vitamin D levels in a nationally representative sample of roughly 5,000 children from 2001 to 2006. Extrapolating to the entire US population, their analysis suggests that roughly 20% of all children fell below the recommended 50 nmol/L. Moreover, more than two-thirds of all children had levels below 75 nmol/L, including 80% of Hispanic children and 92% of non-Hispanic black children.
Dr. Mansbach and his coauthors suggest that all children take vitamin D supplements, because of the generally low levels that they found and the potential health benefits of boosting vitamin D to normal levels. Recent studies suggest that vitamin D may prevent a host of common childhood illnesses, including respiratory infections, childhood wheezing, and winter-related eczema.
In the study, children taking multivitamins that included vitamin D had higher levels overall, but this accounted for less than half of all children. Dr. Mansbach recommends that all children take vitamin D supplements, especially those living in high latitudes, where the sun is scarce in the wintertime.
"We need to perform randomised controlled trials to understand if vitamin D actually improves these wide-ranging health outcomes," Dr. Mansbach says. "At present, however, there are a lot of studies demonstrating associations between low levels of vitamin D and poor health. Therefore, we believe many US children would likely benefit from more vitamin D."
SOURCE: Children's Hospital Boston
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