E-cigarettes can cause just as much damage to a person’s arteries and blood vessels as traditional cigarettes, according to a new study published in the Journal of the American Heart Association.

“Many people believe e-cigarettes are safer than combustible cigarettes,” lead author Jessica L. Fetterman, PhD, an assistant professor of medicine at the Boston University School of Medicine, said in a statement. “In fact, most e-cigarette users say the primary reason they use e-cigarettes is because they think e-cigarettes pose less of a health risk. Meanwhile, the evidence from scientific studies is growing that e-cigarettes might not be the safer alternative to smoking traditional cigarettes when it comes to heart health. Our study adds to that evidence.”

Fetterman’s team assessed data from more than 400 men and women who had not previously been diagnosed with heart disease or any heart disease risk factors. All participants were between the ages of 21 and 45 years old. While 285 participants smoked traditional cigarettes, 36 used e-cigarettes and 52 used both. Another 94 participants were nonsmokers. All e-cigarette users were former smokers.