The study of 6,000 children said that low vitamin D levels raises their risk of bone and heart disease. The data for the study was collected from the National Health and Nutrition Examination Survey 2001-2004
"Several small studies had found a high prevalence of vitamin D deficiency in specific populations of children, but no one had examined this issue nationwide," said lead researcher Michal L. Melamed, assistant professor of medicine and of epidemiology & population health at Einstein.
The study found that 9% or 7.6 million children were vitamin D deficient, while 61 percent, or 50.8 million children were vitamin D insufficient.
"We expected the prevalence of vitamin D deficiency would be high, but the magnitude of the problem nationwide was shocking," said lead author Juhi Kumar.
The details of the study are published in the online version of U.S. journal Pediatrics.