People who puff electronic cigarettes every day have twice the risk of heart attack, and the odds increase almost fivefold for those who use them along with traditional cigarettes, a new study suggests.
"Using both products at the same time is worse than using either one separately," said senior study author Stanton Glantz. He's director of the Center for Tobacco Control Research and Education at the University of California, San Francisco.
Most adults who vape continue to smoke tobacco cigarettes, he added. About 66 percent of the nearly 2,300 current e-cigarette users in the study also smoked tobacco cigarettes.
For the study, researchers analyzed data from nearly 70,000 Americans who took part in national health surveys in 2014 and 2016. Of the more than 9,300 current and former e-cigarette users, 3.6 percent had suffered a heart attack at some point. The rate was highest among those who vaped every day (6 percent).
People who used both e-cigarettes and tobacco cigarettes daily were 4.6 times more likely to have had a heart attack than those who had never used either, the findings showed.
The researchers said their study is the first to examine the relationship between e-cigarette use and heart attacks.
"While people may think they are reducing their health risks, we found that the heart attack risk of e-cigarettes adds to the risk of smoking cigarettes," Glantz said. "Someone who continues to smoke daily while using e-cigarettes daily increases the odds of a heart attack by a factor of five."
Here's the good news: The risk of heart attack starts to drop immediately after smokers quit. And this new research suggests the same is true when people stop vaping, he added.
E-cigarettes deliver lower levels of cancer-causing chemicals than regular cigarettes. But both deliver ultrafine particles and other toxins that increase the risk of heart and lung disease, the study authors pointed out.
"The only way to substantially reduce the risk of a heart attack is to stop using tobacco," Glantz said.
The researchers said that it wasn't known whether the heart attacks were related to e-cig use, so the findings could not prove a cause-and-effect relationship. In addition, some of the heart attacks reported in the study probably occurred before e-cigarettes became available in the United States (around 2009).
The report was published Aug. 22 in the American Journal of Preventive Medicine.