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Vitamin D deficiency linked to heart, stroke risk

Mon Jan 7, 2008 5:11pm EST

WASHINGTON (Reuters) - People with low vitamin D levels face an elevated risk for heart attack, heart failure and stroke, according to a study published on Monday suggesting that the vitamin may protect against cardiovascular disease.

The elevated risk was particularly acute among those with high blood pressure, the researchers found.

Vitamin D helps the body absorb calcium and is considered important for bone health, but a number of studies have indicated it might provide a number of other benefits. In adults, vitamin D deficiency can lead to osteoporosis, and it can lead to rickets in children.

Researchers led by Dr. Thomas Wang of Harvard Medical School in Boston followed 1,739 people, average age 59, for 5 years, taking blood samples to gauge vitamin D levels.

Those with low vitamin D levels had about a 60 percent higher risk of a cardiovascular event like heart attack, heart failure or stroke compared to those with higher levels, even with well-known cardiovascular risk factors such as diabetes, high cholesterol and high blood pressure taken into account.

The risk for heart attack, heart failure or stroke was double in people with both high blood pressure, also known as hypertension, and vitamin D deficiency, the researchers said.

The findings were published in Circulation, a journal published by the American Heart Association.

Wang called the findings intriguing but said it was too early to say that taking vitamin D supplements would lower one's risk for heart disease or stroke, and premature to recommend that people take such supplements for that purpose.

"Vitamin D deficiency is extremely common, especially in areas of the world that don't get a lot of sunlight during the winter months. It's actually fairly straight forward to correct vitamin D deficiency with changes in the diet or the addition of dietary supplements containing vitamin D," Wang said.

The body makes vitamin D when skin is exposed to sunlight. Not many foods are naturally rich in it. It is found in fatty fish such as salmon. Milk commonly is fortified with it.

Experts say exposure to 10 to 15 minutes of sunshine three times weekly is enough to produce necessary vitamin D levels.

"There is a growing body of experimental literature suggesting that vitamin D may have some actions on the heart and major blood levels. As a corollary, the lack of vitamin D may be associated with the development of cardiac abnormalities," Wang added.

Past studies also have suggested that higher intake of vitamin D may protect against developing certain types of cancer as well as multiple sclerosis.

The people in this study were offspring of original participants in the long-running Framingham Heart Study centered in Massachusetts. They had no prior history of cardiovascular disease. All of them were white.