What Biomarkers Can (or Can’t) Tell Us About Heated Tobacco Product Health Risks

The world’s four largest international tobacco companies, Philip Morris International, British American Tobacco, Japan Tobacco International and Imperial Brands, have a product they’re excited to tell you about. Some of these companies have described this product as a “less risky” alternative and a “much better choice” than cigarettes. Others have labeled it as “reduced-risk” and even an “important milestone” on the company’s “journey to build a healthier future…”

Sound familiar?

These claims echo the industry’s past attempts to convince smokers to switch to its newer, “safer” products, instead of quitting.

These claims aren’t from decades past—they’re all live on these companies’ public websites, and they are all referring to heated tobacco products, or HTPs. Each of these companies has developed HTPs, which they claim heat rather than burn tobacco and are, therefore, lower-risk than cigarettes.

The problem? The evidence to date on the risks of HTPs is inconclusive, and switching to HTPs has not been proven to reduce someone’s risk of disease. Given the industry’s history of manipulating science and pushing products it knew were not actually safer, policymakers, the public health community and the public should be wary of the industry’s claims.

Independent research shows there isn’t enough evidence to prove heated tobacco products are safer

One way both the tobacco industry and independent researchers have tried to determine the health risks of heated tobacco products is through data on biomarkers (short for “biological markers”). Biomarkers are characteristics that researchers can measure, like your blood pressure or white blood cell count, to understand the effects of a tobacco product on the body.

In a recent paper from the Tobacco Control Research Group at the University of Bath, researchers looked at data on biomarkers to assess the risk of lung cancer posed by HTP use. The authors of the paper looked specifically at biomarkers of exposure (which determine whether a person has been exposed to a chemical) and biomarkers of potential harm (which determine whether harm happened to the person’s body as a result of that exposure).

The authors found that 16 biomarkers out of 82 measured in clinical trials studying HTPs could provide indications of lung cancer risk. Of those 16, only three exposure biomarkers improved in smokers who switched to HTPs. The other 13 either showed no improvement, got worse or had inconsistent results. Ultimately, the researchers concluded that the risk of lung cancer associated with HTP use is unknown, and currently there is limited data available that’s appropriate to use in estimating lung cancer risk from HTP use.

The paper points out that the industry has claimed that HTPs are likely to reduce the risk of lung cancer based on simulation models, which use biomarker data alongside other data. But the biomarker data, as the authors note, may not be appropriate for measuring or predicting the risk based on ideal characteristics for markers of tobacco use and lung cancer.

Another study from 2018 examined biomarker data in research published by Philip Morris International. The author concluded that PMI’s biomarker studies showed no statistically detectable difference between American adult IQOS (PMI’s main HTP product) users and cigarette smokers for 23 of 24 biomarkers of potential harm. And in Japan, there were no significant differences between IQOS users and cigarette smokers in 10 of 13 biomarkers of potential harm.

HTPs do, in fact, expose users to lower levels of some chemicals than cigarettes. But these studies, along with other independent research, the U.S. Food and Drug Administration’s assessment and PMI’s own claims, show that this does not mean users are at lower risk of tobacco-related disease when using HTPs. Further, IQOS emissions contain higher levels of certain harmful or potentially harmful chemicals than cigarette smoke. All of these findings raise a warning flag about the seemingly confident claims coming from the tobacco companies.

Despite the lack of conclusive evidence, the industry claims HTPs are a better alternative to cigarettes

Tobacco companies market their HTPs with direct and implied claims of being less harmful than cigarettes. Whether they refer to HTPs as “smoke-free” or “reduced risk,” these claims can carry real weight with people who may not look at the small print, where the tobacco companies disclose that HTPs are addictive and not risk-free. Research suggests that they contribute to consumer uptake of HTPs and that users perceive them as being safer. Indeed, HTP use is increasing around the world, even as their long-term health risks remain unknown.

Given the industry’s history and its profit motivation, we must all be skeptical of its claims

The industry has a history of trying to influence science to “purposefully create misinformation, doubt, or ignorance” around the proven harms of its products, or around the efficacy of tobacco control measures. It did this when the link between smoking and cancer was first established in the 1950s, and again in the ‘80s and ‘90s when the dangers of second-hand smoke became widely known.

History has also shown that whenever its customers become worried about the harms of smoking, the industry doesn’t take meaningful measures to reduce tobacco use—it develops new addictive products and encourages customers to switch to those instead. The industry did this when advertising filtered, “light,” “mild,” and “low-tar” cigarettes, which have proven to be just as harmful. These examples have shown time and again that the industry’s interest in tobacco harm reduction is marketing rhetoric, designed to preserve its profits—not protect health. Is the industry doing the same thing today with HTPs?

Until the long-term health risks of HTPs are known and supported with independent evidence, everyone—including policymakers and the public—should stay vigilant and remain skeptical about HTPs and industry claims that they are “safer” than cigarettes.