E-cigarettes may be more harmful for heart than tobacco: Study

Electronic nicotine delivery systems, including devices such as e-cigarettes, may be just as harmful to the heart, if not more, than traditional cigarettes, according to a study.

The findings come at a crucial time, as reports of lung-related e-cigarette injuries are increasing, even while many distributors continue to claim that using e-cigarettes are safe, and can help tobacco cigarette smokers kick the habit, the researchers said.

"What makes e-cigarettes so harmful to the heart and lungs is not just nicotine," said senior author Florian Rader, from Smidt Heart Institute at Cedars-Sinai in the US.

"It's the completely unknown bucket of manufactured products used to form vapours that is likely causing the most harm. This is what we believe is underlying the current public health problem," Rader said in a statement.

The researchers compared healthy, young-adult smokers aged 18 to 38 who were regular users of e-cigarettes or tobacco cigarettes.

They then measured participants' blood flow to the heart muscle-focusing on a measure of coronary vascular function-before and after sessions of either e-cigarette use or cigarette smoking, while participants were at rest and also after they performed a handgrip exercise which simulates physiologic stress.

In smokers who used traditional cigarettes, blood flow increased modestly after traditional cigarette inhalation and then decreased with subsequent stress, the researchers found.

However, in smokers who used e-cigarettes, blood flow decreased after both inhalation at rest and also after handgrip stress, they said.

"Our results suggest that e-cigarette use is associated with coronary vascular dysfunction at rest, even in the absence of physiologic stress," said Susan Cheng, director of Public Health Research at the Smidt Heart Institute.

"These findings indicate the opposite of what e-cigarette and vaping marketing is saying about their safety profile," Cheng said.