Study: Daily use of e-cigarettes doubles heart attack risk

SAN FRANCISCO — Some smokers switch to e-cigarettes in an attempt to be healthier, but according to new research, daily use of e-cigarettes may nearly double the risk of heart attack. And when combined with daily use of regular cigarettes, the risk of heart attack is five times that for a nonsmoker.

Researchers from the University of California, San Francisco (UCSF) wanted to see how e-cigarettes impact long-term health, specifically cardiovascular health. Most who vape continue to smoke conventional cigarettes, the study of nearly 70,000 people showed, even though the combination of the two is riskier than either one alone.

“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,” says senior author Stanton Glantz, a UCSF professor of medicine and director of the university’s Center for Tobacco Control Research and Education, in a release. “Using both products at the same time is worse than using either one separately. Someone who continues to smoke daily while using e-cigarettes daily increases the odds of a heart attack by a factor of five.”

E-cigarettes, or electronic cigarettes, have been promoted as a healthy alternative to satisfy nicotine cravings. Unlike regular cigarettes that deliver nicotine by burning tobacco, e-cigarettes use heated liquid to deliver nicotine and other flavors. Though e-cigarettes emit lower levels of carcinogens, they are as bad as conventional cigarettes in terms of discharging ultrafine particles and other toxins known to raise the risks of cardiovascular disease and non-cancerous lung diseases.

For the study, participants were interviewed about their use of e-cigarettes and/or regular cigarettes in two National Health Interview Surveys in 2014 and 2016. They were also asked whether they had ever been diagnosed as having had a heart attack.

Of the 69,452 participants surveyed, 9,352 indicated that they were current or former e-cigarette users. Within the group of e-cigarette users, 3.6 percent of participants had experienced a heart attack at some point in their lives. But for those who used e-cigarettes on a daily basis, the percentage of participants having had a heart attack rose to 6.1 percent.

While about one-fourth of e-cigarette users no longer smoke conventional cigarettes, researchers are concerned that about two-thirds of e-cigarette users continue to smoke regular cigarettes as well, putting themselves at higher risk for heart attack.

Overall, researchers say that the odds of having a heart attack are about equal for cigarettes or e-cigarettes when used separately. So, despite assumptions otherwise, switching from cigarettes to e-cigarettes does not lower the risk. But with the most common choice for smokers — daily use of both e-cigarettes and conventional cigarettes — the risk of heart attack is 4.6 times that for a nonsmoker.

Study authors said that it is probably too soon to know whether the “lasting effect” of being a former cigarette smoker will also apply to being a former e-cigarette user. Because e-cigarettes have been available for less than 10 years, researchers caution that results might be different at a later date when more is known about the long-term cardiovascular effects.

The study does confirm that the best scenario is to quit altogether. “The only way to substantially reduce the risk of a heart attack is to stop using tobacco,” Glantz says. “The risk of heart attack starts to drop immediately after you stop smoking. Our results suggest the same is true when they stop using e-cigarettes.”

The study was published in the October 2018 edition of the American Journal of Preventive Medicine.