By AMERICAN HEART ASSOCIATION NEWS

An up-and-coming smokeless cigarette currently under review by the Food and Drug Administration for sale in the U.S. may not be as harmless as the tobacco industry claims, according to a new study in rats.

The cigarette, a heat-not-burn device called IQOS, works by heating tobacco rather than burning it. This process of heating the tobacco means combustion is avoided.

“The idea here is that without burning the material, you’re supposed to be able to avoid the harmful compounds from smoke,” explains Matthew Springer, Ph.D., senior investigator of the new federally funded study and a researcher at the University of California, San Francisco.

In traditional tobacco-burning cigarettes, combustion is blamed for many of the toxic chemicals that cause heart disease, lung cancer and other serious illnesses.

Springer, however, recently presented research showing that IQOS vapor reduces blood vessel function in rats nearly as much as cigarette smoke. Blood vessel function is the ability of a vessel to react and expand when parts of the body need more blood; studies have consistently shown this ability is impaired after smoking tobacco.

“If your blood vessel function goes down, that means that your heart and other tissues don’t always get enough blood when you need it,” said Springer, who presented the findings in November at the American Heart Association’s Scientific Sessions. “This can actually lead to an increased risk of heart attack, stroke and atherosclerosis later in life.”

In the study, researchers found that exposing rats to IQOS vapor reduced blood vessel function comparable to cigarette smoke.

Ten five-second exposures over five minutes reduced blood vessel diameter by 60 percent for rats exposed to IQOS vapor and by 62 percent for those exposed to cigarette smoke.

Springer said, “The bottom line is that even though combustion isn’t happening, stuff is coming out of the IQOS that is still causing this problem to occur.”

Konstantinos Farsalinos, M.D., a cardiologist and e-cigarette researcher at the Onassis Cardiac Surgery Center in Athens, Greece, whose research has been supported by e-cigarette interest groups, said because the study only looked at the short-term effects of heat-not-burn cigarettes, the impact on long-term cardiovascular health is unclear.

“Acute exposure to a stimulant such as nicotine has no long-term prognostic value,” Farsalinos said.

Even so, Springer said that IQOS’ short-term effect on blood vessel flow proves the product isn’t harmless — they just don’t yet know what’s causing the damage.

“Studies have shown that repeated reductions in blood vessel function due to smoke exposure can have long-term effects, leading to chronic dysfunction of the lining of the blood vessels,” he said.

“A harmful effect is occurring and we really don’t know what chemicals in the IQOS aerosol are causing it. Even if the IQOS is not as bad as for you as regular cigarettes, you could still be doing yourself some harm,” Springer said.

IQOS is currently not sold in the U.S., but is available in other countries such as Canada, Russia and Japan. Users purchase HeatSticks — mini-cigarettes that contain engineered strips of tobacco — and an IQOS holder. The mini-cigarette is inserted into the IQOS holder and heated up to 662 degrees Fahrenheit.

Top row, from left: A HeatStick compared to a Marlboro cigarette; an IQOS charger and an IQOS device; an IQOS loaded with a HeatStick; and a close-up of a HeatStick. Bottom row, from left: The interior of a HeatStick; the HeatStick’s filter; and processed tobacco strips inside the HeatStick. (Image courtesy of Matthew Springer, Ph.D.)

Top row, from left: A HeatStick compared to a Marlboro cigarette; an IQOS charger and an IQOS device; an IQOS loaded with a HeatStick; and a close-up of a HeatStick. Bottom row, from left: The interior of a HeatStick; the HeatStick’s filter; and processed tobacco strips inside the HeatStick. (Image courtesy of Matthew Springer, Ph.D.)

More than 3.7 million smokers outside the U.S. have switched from cigarettes to IQOS, according to the product’s manufacturer Philip Morris International. If approved for sale in the U.S., it could be marketed as a safer alternative to cigarettes.

Philip Morris is still reviewing Springer’s findings, but the company reaffirms that its own research shows IQOS is less harmful than cigarette smoking.

Tobacco control researcher Stanton Glantz, Ph.D., is publicly urging the FDA to deny Philip Morris’s application. He said a close reading of the company’s FDA application shows no detectable difference between the health effects of IQOS and regular cigarettes.

Glantz, a professor who works alongside Springer at UCSF but was not involved in the new study, said, “Philip Morris International’s human studies are consistent with what Dr. Springer found in rats: IQOS [is] just as bad as cigarettes.”

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