Philip Morris has aggressively promoted its heated tobacco product (HTP) IQOS all over the world as a safer alternative to smoking cigarettes based on the fact that IQOS delivers lower levels of some combustion products than cigarettes. IQOS is the most populat HTP in Japan, and other tobacco companies make similar claims for their HTP. Satomi Odani and colleagues make an important contribution to the actual effects of HTP on actual disease in people in their new paper “Association between heated tobacco product use and airway obstruction: a single-centre observational study, Japan.”
They measured airway obstruction (lung function) as part of the pre-operative examination in 2850 people who were having surgery to treat their cancer. After controlling for past smoking, demographic variables and kind of cancer, they didn’t find significant differences between HTP users, cigarette only smokers, and dual (both product) users. In other words, contrary to industry claims, HTP use was no better than smoking.
Among former cigarette smokers (>30-day cigarette quitters), current HTP users had 1.42 times the increased prevalence of airway obstruction than never-HTP users after adjusting for pat smoking; an even stronger association was observed when the analysis was restricted to ≥5-year cigarette quitters (adjusted prevalence ratio [APR]=1.96, vs never HTP users). In other words, HTP are a form of harm enhancement for long-time former smokers who relapsed to nicotine addiction with HTP.
And, not surprisingly, airway obstruction was worse among HTP users than people who had never smokers or used HTP.
Odani and colleagues’ new paper is consistent with my analysis of the data PMI submitted to FDA, “PMI’s own in vivo clinical data on biomarkers of potential harm in Americans show that IQOS is not detectably different from conventional cigarettes,” that revealed that the 9 measures of pulmonary function PMI reported showed no significant differences between IQOS and cigarettes.
As with e-cigarettes, these results reinforce that it is important for regulators and clinicians to move beyond a limited number of biomarkers of exposure (like combustion products) top focus on actual health effects when assessing these “new” products.
This paper, together with “Heated tobacco products do not help smokers quit or prevent relapse: a longitudinal study in Japan” by the same group, adds to the case that HTP are harm enhancing rather than harm reducing. As the authors conclude, “In any case, our study’s results do not support PMI’s claim that switching from cigarettes to HTPs is beneficial to health.“
Here is the abstract:
Background: While heated tobacco products (HTPs) may affect pulmonary function, the evidence supporting the utility of screening for HTP use in clinical settings is insufficient. We examined the association between HTP use and airway obstruction after switching from cigarettes.
Method: The study subjects were patients aged ≥20 years undergoing surgery from December 2021 to September 2022 who completed spirometry and reported tobacco (cigarette and HTP) use status during the preoperative assessment. Airway obstruction was defined as forced expiratory volume in 1 s to forced vital capacity ratio below the lower limit of normal. Current tobacco use was defined as past-30-day use. Multivariable Poisson regression analysis was performed to examine the associations between HTP use and airway obstruction by adjusting for demographic characteristics, lifetime cigarette smoking (pack-year) and duration of smoking cessation.
Results: Overall (N=2850, 55.4% women, mean age 62.4), 4.6% and 10.7% reported current HTP use and cigarette smoking, respectively. 16.8% had airway obstruction. Airway obstruction was more common among current HTP-only users (adjusted prevalence ratio (APR)=2.32), current cigarette-only smokers (APR=2.57) and current dual users (APR=2.82) than never-tobacco users. Among current tobacco users (N=398), the prevalence of airway obstruction was not significantly different between HTP-only users and cigarette-only smokers. Among former cigarette smokers (>30-day cigarette quitters) (N=1077), current HTP users had 1.42 times the increased prevalence of airway obstruction than never-HTP users after adjusting for cigarette pack-year; a stronger association was observed when the analysis was restricted to ≥5-year cigarette quitters (N=772) (APR=1.96, vs never HTP users).
Conclusion: Current HTP use was associated with airway obstruction among patients with cancer who had completely switched from cigarettes even after quitting smoking for a long period. Patients should be routinely screened for HTP use and advised to quit any tobacco.
The full citation is: Odani S, Koyama S, Miyashiro I, Tanigami H, Ohashi Y, Tabuchi T. Association between heated tobacco product use and airway obstruction: a single-centre observational study, Japan. BMJ Open Respir Res. 2024 Mar 9;11(1):e001793. doi: 10.1136/bmjresp-2023-001793. PMID: 38460973; PMCID: PMC10928730. It is available here.
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