Vitamin D deficiency is an unrecognized, emerging cardiovascular risk factor, which should be screened for and treated, a U. S. researcher says.

Dr. James H. O'Keefe, cardiologist and director of Preventive Cardiology at the Mid America Heart Institute in Kansas City, Mo., said it is estimated that up to half of U. S. adults and 30 percent of children and teenagers have vitamin D deficiency.

Vitamin D deficiency also alters hormone levels and immune function, which can increase the risk of diabetes, a major contributor to cardiovascular disease, O'Keefe said.

Recent data from the Framingham Heart Study suggest patients with vitamin D levels below 15 nanograms per milliliter were twice as likely to experience a heart attack, stroke or other cardiovascular event within the next five years compared with those with higher levels.

"Restoring vitamin D levels to normal is important in maintaining good musculoskeletal health, and it may also improve heart health and prognosis," O'Keefe said in a statement. "We need large randomized controlled trials to determine whether or not vitamin D supplementation can actually reduce future heart disease and deaths."

Vitamin D can also be consumed through supplements and food intake. Natural food sources of vitamin D include salmon, sardines, cod liver oil, and vitamin D-fortified foods including milk and some cereals, O'Keefe said.

The findings are published in the Dec. 9 issue of the Journal of the American College of Cardiology. (UPI)