Smoking daily e-cigarettes doubles risk of heart attacks: Study

New US research has revealed that e-cigarettes may be more dangerous than previously thought, finding that daily use could nearly double the risk of heart attack.

Led by UC San Francisco along with researchers from George Washington University, the large-scale study looked at data from National Health Interview Surveys of 69,725 people between 2014 and 2016.

After considering risk factors such as high blood pressure, diabetes and high cholesterol, researchers found that daily e-cigarette use was associated with significantly increased odds of having had a heart attack -- nearly double the risk -- while smoking conventional cigarettes daily was associated with nearly three times the risk.

Using both together everyday leads to five times the risk of heart attack compared to non-smokers.

In addition, although it was thought that former and occasional use of e-cigarettes was not associated with a significant increase in the risk of heart attack, researchers found that such reduced use did in fact pose a small risk.

The team commented that the findings are the first piece of evidence to suggest that e-cigarettes can have a substantial impact on human health since the devices were first introduced around a decade ago.

Since their release, some have believed that e-cigarettes can be a useful tool in helping smokers quit the habit, however studies are increasingly showing that instead of encouraging smokers to switch from tobacco cigarettes to e-cigarettes, or quit altogether, they are actually reducing the likelihood that people will quit smoking, and also encouraging more teens and young people to start.

"E-cigarettes are widely promoted as a smoking cessation aid, but for most people, they actually make it harder to quit smoking, so most people end up as so-called 'dual users' who keep smoking while using e-cigarettes," said senior author Stanton Glantz. "The new study shows that the risks compound. Someone who continues to smoke daily while using e-cigarettes daily has an increased risk of a heart attack by a factor of five."

"The good news is that the risk of heart attack starts to drop immediately after you stop smoking," he added. "Our study also shows little risk associated with being a former e-cigarette user."

The research was presented on February 24 at the 2018 annual meeting of the Society for Research on Nicotine and Tobacco in Baltimore.