BOSTON—As many as one in five U.S. children have low levels of vitamin D, according to a new study from Harvard Medical School (PED. 2009 Nov;124(1404-1410)).
Data from the 2001–2004 National Health and Nutrition Examination Survey were analyzed to determine the serum levels of 25-hydroxyvitamin D (25[OH]D) in a nationally representative sample of U.S. children aged 1 to 11 years. During the 2001 to 2004 time period, the mean serum 25(OH)D level for US children aged 1 to 11 years was 70 nmol/L. Children aged 6 to 11 years had lower mean levels of 25(OH)D (68 nmol/L) compared with children aged 1 to 5 years (74 nmol/L). Children with levels less than 25 nmol/L was 0.7 percent, those with less than 50 nmol/L was 15 percent and those with less than 75 nmol/L was 65 percent. The prevalence of serum 25(OH)D levels of less than 75 nmol/L was higher among children aged 6 to 11 years (71 percent) compared with children aged 1 to 5 years (56 percent). Girls were more likely to have less than 75 nmol/L (67 percent) compared with boys (62 percent); and non-Hispanic black (89 percent) and Mexican American (77 percent) children were more likely to have less than 75 nmol/L than non-Hispanic white children (54 percent).
The American Academy of Pediatrics recommends children attain blood levels of vitamin D of at least 50 nanomoles per liter (nmol/L). If these data are used to make a national representation, 6.3 million U.S. children – almost one in 5 – are at less than the recommended 50 nmol/L level of vitamin D.