Chemicals used to flavor electronic cigarettes can damage cells that line blood vessels and may pose a risk to a user's heart in the long term, according to a study published Monday.
Why it matters: The study, published in the Journal of the American College of Cardiology, is the latest evidence that vaping may be harmful.
What they're saying: "Until now, we had no data about how these e-liquids affect human endothelial cells," said study co-author and Stanford Cardiovascular Institute director Joseph Wu.
"This study clearly shows that e-cigarettes are not a safe alternative to traditional cigarettes. When we exposed the cells to six different flavors of e-liquid with varying levels of nicotine, we saw significant damage. The cells were less viable in culture, and they began to exhibit multiple symptoms of dysfunction."
Joseph Wu, professor of cardiovascular medicine and radiology
The other side: A January study found e-cigarettes are an effective way for smokers to quit smoking — twice as effective as other nicotine products like gum and patches.
Go deeper: Podcast: The war on vaping
