A Harvard Medical School team studied the link by monitoring vitamin D levels of 1,700 people over a seven-year period. They found that those who had low levels of vitamin D were more likely to suffer a heart attack, heart failure or stroke than those with higher levels.
Researchers believe it's a factor in heart health because receptors for vitamin D are found in the heart muscle and blood vessel lining. However, they say more studies need to be done to figure out why it's important.
The study is published in the journal Circulation.