Snuff and E-Cigs Are Not Harmless, Say Scientists

New research from the American Heart Association journal Circulation shows that patients who stopped using smokeless tobacco after a heart attack had improved life expectancy—similar to that of people who quit smoking. The finding offers new information about the dangers of smokeless tobacco, the risks of which are not as well understood as cigarettes’.

“That was a big surprise for us,” said Dr. Gabriel Arefalk, lead researcher and a cardiologist at Uppsala University Hospital in Uppsala, Sweden. “For smoking, it has been known for decades now that people benefit from discontinuation, especially after having suffered a heart attack, but for snus we had no idea what to expect.”

The researchers reviewed data on 2,474 heart attack survivors under 75 in Sweden who used snus (oral snuff) from 2005 to 2009. About 675 quit. During the two years of follow-up, 69 of those who continued using snus died, compared with only 14 quitters. Based on this data, researchers determined that those who quit snus had almost half the mortality risk of those who didn’t quit, which is similar to the benefit of smoking cessation, according to a release from the American Heart Association

Dr. Arefalk, who is also a clinician, said the researchers wanted to study the problem because they didn’t know what to tell patients about the risks of using snus after a heart attack. He cautioned that the study was small and far from enough to determine a causal relationship, but added “It’s the best evidence we’ve got so far, so from our perspective at our clinic, [the advice to patients] is probably that you should discontinue all kinds of tobacco,” if you’ve had a heart attack, Dr. Arefalk told TIME.

The study is one more piece of evidence that ads to our understanding that smokeless tobacco carries its own risk. Though the study was about snus, it has implications for other kinds of nicotine delivery systems, including e-cigarettes.

The FDA is currently taking comment from experts over the next few weeks as the agency tries to determine the best rules to regulate the nascent e-cig industry, which is approaching nearly $2 billion in U.S. annual sales. And though there isn’t yet enough information or scientific research to back this up, common sense says that e-cigs, which do not burn and contain fewer chemicals than regular tobacco cigarettes, must be better for a smoker’s health. Yet, some cardiologists, as TIME learned, are reluctant to see electronic cigarettes as harm-reduction tools.

For starters, nicotine is not a benign substance, especially when it comes to cardiovascular health. As Dr. Steven Nissen, Department Chair of Cardiovascular Medicine at the Cleveland Clinic, put it, nicotine has “profound effects on the heart.” The highly addictive drug can lead to surges in heart rate, constriction in the blood vessels, and spikes in blood pressure—the very effects that heart medications are designed to counteract.

“To come up with new diabolically clever way to addict Americans to nicotine is a terrible idea,” says Dr. Nissen. “[E-cigarette companies] are pitching very hard that they can make smoking safer. [But] nicotine is an addictive drug, no matter if you smoke it or ‘aerosolize’ it. Why you would want to addict another generation to nicotine is beyond me. Public health suggests we should fight electronic cigarettes the same way we fought tobacco.”

Another concern, beyond the possible impact of nicotine, are concerns about small, potentially toxic, particles and what they can do to the sensitive cardiovascular system, says Dr. Aruni Bhatnagar, a professor of medicine at the University of Louisville and spokesperson on electronic cigarettes for the American Heart Association.

Dr. Bhatnagar is studying the toxic effects of e-cig vapor on mice. Like all doctors, he is careful to point out that we don’t know enough about these devices. But he says that wishful thinking about harm reduction could be especially problematic when it comes to cardiovascular health. The risk of cardiovascular disease for a person who smokes only 2-3 cigarettes a day is already 80 percent of the risk to a pack-a-day smoke. “Very low levels of smoke are very dangerous for cardiovascular tissues. Cancer is more linear—you have to smoke a large amount for a very long period of time to get lung cancer,” he says. “But reducing harmful levels is not going to mitigate the cardiovascular risk. That is why we are greatly concerned about e-cigarettes when it comes to the high sensitivity of cardiovascular tissues to a low level of these pollutants.”

Electronic cigarette manufacturers and their customers often point to the low levels of particles in electronic cigarette smoke as compared to the appropriate levels of air pollution determined by agencies like OSHA. But, Dr. Bhatnagar says, these claims can be misleading because the thresholds take into account the necessity of polluting the air to some degree—they aren’t an endorsement of a safe level of pollution. From a cardiovascular perspective, he says: “There is no threshold, there is no level of these particles that you can say is safe.”

For now: Smokers—and snuffers, and e-cig smokers—beware.