Heated tobacco products have grown in popularity in recent years as a “smoke-free” alternative to cigarettes, but a peer-reviewed report suggested their emissions could be considered smoke — a claim strongly denied by the tobacco industry.
Heated tobacco products, or HTPs, are often confused with e-cigarettes, which heat liquids that may contain nicotine but do not involve tobacco leaves.
HTPs instead use a high heat to decompose the tobacco, through a process called pyrolysis, which does not ignite or burn it, therefore avoiding the production of smoke.
The most popular and widely available HTP, Philip Morris International’s IQOS, is an electronic device that heats a tobacco-filled, paper-wrapped, cigarette-like stick to 350 degrees Celsius (662 degrees Fahrenheit).
A review of research made available last month by experts in pyrolysis at the University of Nottingham in Britain found “chemical evidence that IQOS emissions fit the definition of both an aerosol and a smoke.”
The paper, published in the Omega Journal of the American Chemical Society, was funded by the Stop Anti-Tobacco Initiative.
Its lead author Clement Uguna said that IQOS emissions contain chemical compounds that are “common in tobacco smoke, bush burning and wood smoke”.
“So smoke is only produced by heating organic matter and does not necessarily involve fire,” he told AFP.
The paper also found that previous research on IQOS – much of which has been funded by the tobacco industry – compared a stick to a normal cigarette.
But IQOS sticks are much smaller, containing about 200 milligrams of tobacco compared to 645 milligrams for a standard cigarette, it said.
Because the Philip Morris International (PMI) study did not use a “like versus like” comparison, it “underestimated” the levels of harmful and potentially harmful components (HPHCs) from IQOS, the review added.
PMI said the levels of HPHCs in IQOS emissions — per stick — “are reduced by an average of 90-95 percent compared to cigarette smoke”.
But this level dropped to 68 percent when comparing the tobacco content of the two products, with experts from the University of Nottingham calling for more research.
PMI told AFP that the paper “misleadingly uses parts of the scientific assessment to the exclusion of other important evidence”.
“Numerous international combustion experts and several government agencies have reviewed the same evidence package and concluded that the IQOS aerosol produced is not smoke,” it said.
Reto Auer, a doctor at the University of Bern in Germany who has previously researched heated tobacco, praised the Omega paper, telling AFP it was “a rare report to dare to tackle the question of smoking so deeply”.
Jamie Hartman-Boyce of Oxford University’s Center for Evidence-Based Medicine, author of a highly regarded review on the science of HTP published earlier this year, said the “important” paper “made some very good points”.
“I think there’s a lot of reason to suspect that mechanically HTPs may be more harmful than e-cigarettes and possibly less harmful than conventional cigarettes — but we really need more data,” he told AFP.
IQOS is available in more than 60 countries under widely varying regulations, and the sticks are available in flavors such as menthol, cherry and grape, which critics say help attract younger users.
Last month the European Commission proposed banning flavored HTP varieties after sales of the sticks in the European Union rose more than 2,000 percent — from 934 million to nearly 20 billion — between 2018 and 2020.
PMI told AFP that “the Commission’s proposal is not underpinned by evidence”.
“It fails to demonstrate, for example, that flavors pose any additional health risks or that they attract a significant proportion of non-nicotine users,” it said.
“There is every reason to be concerned about the extent to which the tobacco industry is manipulating the science and messages surrounding new tobacco products,” Hartman-Boyce said.
But he warned that communicating the risks of such products was a “difficult balance” given the overwhelming harm of cigarettes. According to the World Health Organization, tobacco kills half of its users.
“If we say something is safer than a cigarette, it’s not safer — it’s like saying this knife is safer than a loaded gun,” Hartman-Boyce said.