Heating Tobacco Sticks Instead of Combusting Conventional Cigarettes and Future Heart Attacks: Still Smoke, and Risk
2021; Lippincott Williams & Wilkins; Volume: 144; Issue: 19 Linguagem: Inglês
10.1161/circulationaha.121.056959
ISSN1524-4539
AutoresReto Auer, Pascal Diethelm, Aurélie Berthet,
Tópico(s)Suicide and Self-Harm Studies
ResumoHomeCirculationVol. 144, No. 19Heating Tobacco Sticks Instead of Combusting Conventional Cigarettes and Future Heart Attacks: Still Smoke, and Risk Free AccessEditorialPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyRedditDiggEmail Jump toFree AccessEditorialPDF/EPUBHeating Tobacco Sticks Instead of Combusting Conventional Cigarettes and Future Heart Attacks: Still Smoke, and Risk Reto Auer, MD, MAS, Pascal Diethelm, MSc and Aurélie Berthet, PhD Reto AuerReto Auer Correspondence to: Reto Auer, MD, MAS, University of Bern, Institute of Primary Health Care (BIHAM), Mittelstrasse 43, Bern, 3012, Switzerland. Email E-mail Address: [email protected] https://orcid.org/0000-0003-4222-4849 Institute of Primary Health Care (BIHAM), University of Bern, Switzerland (R.A.). Centre for Primary Care and Public Health (Unisanté), University of Lausanne, Switzerland (R.A., A.B.). , Pascal DiethelmPascal Diethelm OxySuisse, Geneva, Switzerland (P.D.). and Aurélie BerthetAurélie Berthet https://orcid.org/0000-0002-8625-5156 Centre for Primary Care and Public Health (Unisanté), University of Lausanne, Switzerland (R.A., A.B.). Originally published8 Nov 2021https://doi.org/10.1161/CIRCULATIONAHA.121.056959Circulation. 2021;144:1539–1542This article is a commentary on the followingCombined Associations of Changes in Noncombustible Nicotine or Tobacco Product and Combustible Cigarette Use Habits With Subsequent Short-Term Cardiovascular Disease Risk Among South Korean Men: A Nationwide Cohort Studyis corrected byCorrection to: Heating Tobacco Sticks Instead of Combusting Conventional Cigarettes and Future Heart Attacks: Still Smoke, and RiskOther version(s) of this articleYou are viewing the most recent version of this article. Previous versions: November 8, 2021: Previous Version of Record Article, see p 1528About 5 years ago, tobacco companies launched and heavily marketed a generation of products that heat tobacco and produce an aerosol that users inhale. These battery-powered devices account for a substantial share of the tobacco market in some countries. The tobacco companies argue that heated tobacco products (HTPs) do not produce harmful smoke, and laboratory analyses do indicate that HTP users inhale a lower concentration of toxic substances than smokers of conventional combustible tobacco cigarettes (CC).1–4 But some toxic substances produced by HTPs are unsafe in any quantity, and we don't know whether HTPs will harm smokers who use them heavily and consistently for years.The tobacco companies argue that HTPs produce "aerosol" and not "smoke," because they have redefined smoke as the product of complete combustion; however, the toxicants in CC smoke are mainly produced by incomplete combustion (ie, thermogenic degradation, pyrolysis). In complete combustion, tobacco and oxygen react to produce heat, carbon dioxide, and water—the latter 2 notoriously innocuous for health. With HTPs, an electronic battery produces heat that directly or indirectly releases nicotine from tobacco: pyrolytic processes and thermogenic degradation occur in most HTPs, especially those that heat tobacco to >250 °C.5In both CCs and HTPs, pyrolization, temperature, and the contents of tobacco products combine to produce harmful and potentially harmful constituents like polycyclic aromatic hydrocarbons, tobacco-specific nitrosamines, and carbon monoxide. Despite tobacco companies' new definition of smoke, it is pyrolysis, not combustion, that is the source of many carcinogenic emissions, and we can expect to see health hazards associated with exposure.4,5To make the "smoke without fire" phenomenon of pyrolysis clearer, it is helpful to think about bread toasters. If we set our toaster to between 200° to 250 °C, the surface of the bread closest to the heating wires will first brown nicely and smell delicious but, if forgotten, will char (ie, thermogenically degrade and pyrolyze) and fill the house with stinking smoke that no one would call "bread vapor." Although our noses can easily distinguish between toasted and burned, even tasty, toasted bread may be unhealthy. When smokers switch to HTPs, they may enjoy the distinctive toasted flavor of tobacco which, like toasted bread, may not be as safe as it is delicious. We thus suggest labeling HTPs "tobacco toasting systems" to more clearly evoke the thermodynamic processes at play and remind consumers that toasting is a short step away from burning.The tobacco toasting system label will also help users distinguish nicotine vaping products (or e-cigarettes) from toasting systems. Nicotine vaping products contain no solid tobacco; instead, they vaporize tobacco-free e-liquids containing propylene glycol, vegetal glycerin, aromas, and nicotine. The aerosol does not typically contain carbon monoxide or polycyclic aromatic hydrocarbons found in tobacco cigarettes but, like conventional cigarettes and HTPs, nicotine vaping products release metals, volatile organic compounds, and carbonyls including formaldehyde and acetaldehyde.6 Nicotine vaping products may be associated with health hazards, but studies suggest they pose less risk for users than HTPs.7–10Both thermogenic degradation and pyrolysis are present in CCs and HTPs, and their emissions contain remarkably similar substances (Table).1–3 Based on laboratory analyses, we expect the health effects of long-term HTP use to resemble those of low-intensity CC smoking. If HTP use is comparable to light smoking (1–4 cigarettes per day), heavy and constant HTP use should substantially increase cardiovascular disease (CVD) risk,11 but we need randomized, controlled trials to affirm these conclusions with certainty. HTP manufacturers ran a few small-scale, randomized trials that compared CC smoking to HTP use or smoking cessation. Their results align with the laboratory analyses; HTP use is comparable with light smoking.12,13 These studies were not powered to test the effects of HTPs on CVD outcomes.Table. Product Content, Heating Temperature, and Composition Aerosol Between Nicotine Inhaling DevicesNicotine inhalerNicotine vaping productHeated tobacco productConventional tobacco cigaretteProduct contents Nicotine++++ Tobacco leaves——++ Propylene glycol, glycerol—++? Aromas—+++ Other additives——++Temperature18°–25 °C100°–240 °C≈160°–330 °C640–780 °CComposition aerosol Nicotine++++ Carbon dioxide——++ Water++++ Carbon monoxide——++ Polycyclic aromatic hydrocarbons——++ Tobacco-specific nitrosamines——++ Volatile organic compounds, carbonyls++++— indicates nonapplicable; +, presence; and ?, no information available in the literature.Without randomized trial data on CVD outcomes, we must rely on observational data to assess the effects of HTPs. These data are likely to arrive first from South Korea, Japan, and other countries where HTP use is most common. South Korea was the site of the first large-scale study to explore associations between tobacco heating systems, CVD events, and mortality, by Choi et al.14 In the study, featured in this issue of Circulation, Choi et al used the Korean National Health Insurance Services database to generate a cohort of more than 5 million men whose health was screened and evaluated at 2 points in time (2014–2015 and 2018); their clinical outcomes were followed for 1 to 2 years. Choi et al used data from 2 health examinations to compute exposure to CC smoking, recent ( 5 years) smoking cessation, with and without exposure to daily noncombustible nicotine or tobacco products (NNTPs). Their dataset was exceptionally complete for a range of relevant covariates, and they used it to estimate confounders of the association between exposure to CCs, HTPs, and CVD outcomes. The dataset did not distinguish between HTPs and nicotine vaping product users, but the authors estimated, based on market share, that almost all participants had used HTPs.Choi et al first compared ongoing CC-only smokers with CC and NNTP users in probabilistic models. In models that adjusted for a range of confounders, they found that quitting CC with or without NNTPs was associated with less CVD than ongoing CC-only smoking, but risk reduction was similar across groups. Because association is not evidence of causation even in prospective cohort studies, they fitted alternate statistical models. They applied propensity score methods based on a range of covariates to match smokers who quit CCs and used NNTPs and smokers who quit CC and did not use NNTP. These propensity score analyses are the key findings from Choi et al. They show that men who quit CCs and used NNTPs had a higher rate of CVD than those who quit CCs and did not use NNTP. Propensity score analyses attempt to estimate observed CVD risk if smokers quit with or without NNTPs. A causal interpretation of these results is that CVD risk is higher if smokers quit CCs with NNTPs than if they quit CCs without NNTPs.The analyses from Choi et al do provide means to loosely estimate absolute risk reduction from quitting CCs with or without HTPs. Based on reported CVD incidence in the propensity score analyses, in a hypothetical cohort of 10 000 CC smokers who quit >5 years ago and were followed for 1 to 2 years, 24 participants who did not use NNTP would develop CVD. This number would nearly double (42) among quitters who used NNTPs daily. Because Choi et al did not compute propensity scores to compare ongoing CC users to CC quitters, we cannot confidently compare risk reduction from quitting CCs with or without NNTPs to risk of ongoing CC smoking. If we conservatively estimate that 62 of 10 000 older ongoing CC smokers in the cohort would develop CVD, switching from CCs to NNTPs would cut CVD risk by 20 of 10 000 (62 of 10 000 minus 42 of 10 000) and quitting CCs without NNTPs by 38 of 10 000 (62 of 10 000 minus 24 of 10 000). This suggests a relative risk reduction of 32% when switching from CCs to NNTPs compared with ongoing CC use, and 61% when quitting CCs without NNTPs.Our ability to draw causal inferences from these analyses is inherently limited. First, concluding that NNTP use alone increased CVD among CC quitters would require we assume that the set of covariates in the propensity score–matching model make it possible to confidently predict NNTP exposure in CC quitters. But even a wide range of covariates cannot reveal why CC smokers could successfully quit CCs with or without NNTPs. Thus, we need data from a large-scale, randomized, controlled trial to better test the effects of smoking cessation with or without HTPs on CVD. Although the attempt of Choi et al to estimate the effect of CC cessation with HTPs on CVD is limited, it is still the best effort to date. Second, we need more than 1 to 2 years of follow-up to accurately determine the differential effect of exposure on CVD outcomes. Third, the analyses from Choi et al were limited to men.Findings from Choi et al have policy implications: Decreased exposure to harmful and potentially harmful constituents (as measured in laboratory analyses) does not seem to proportionately reduce HTP-associated health risks. Switching from CCs to HTPs may achieve some risk reduction with respect to CVD, but that risk remains nevertheless at a high level—a level which regulators may find unacceptable compared with established or other potential risk reduction strategies. Regulators should also prevent tobacco companies from engaging in deceptive advertising (eg, consumers remember and feel safer using HTPs when advertisements suggest that IQOS is "90% healthier").15 More accurate labeling could help consumers better understand the health risks associated with "tobacco toasting systems."Health authorities should make clear to HTP producers that claims about harm reduction should not conflate reduced exposure with reduced risk of serious health effects like CVD. These same authorities should demand data from rigorously conducted randomized, controlled trials that test the effects of HTPs on meaningful clinical outcomes like CVD. Until large-scale pivotal trials provide evidence to the contrary, we expect HTP use to contribute to CVD and other smoking-related illnesses and recommend it be considered the equivalent of low-grade smoking.11Article InformationAcknowledgmentsWe thank Kali Tal, PhD, for her editorial assistance and Julian Jakob, MD, for his critical review of the manuscript.Sources of FundingDrs Auer and Berthet received research support from the Swiss National Scientific Foundation (grant No. IICT 33IC30_173552), Swiss Cancer Research (grant No. KFS4744-02-2019), and the Swiss Tobacco Prevention Funds (grant No. TPF19.017477). Dr Berthet received funding from the Canton of Vaud and Federal Office of Public Health (Switzerland).Disclosures None.Footnoteshttps://www.ahajournals.org/journal/circThe opinions expressed in this article are not necessarily those of the editors or of the American Heart Association.For Sources of Funding and Disclosures, see page 1541.Correspondence to: Reto Auer, MD, MAS, University of Bern, Institute of Primary Health Care (BIHAM), Mittelstrasse 43, Bern, 3012, Switzerland. Email reto.[email protected]unibe.chReferences1. Jankowski M, Brożek GM, Lawson J, Skoczyński S, Majek P, Zejda JE. New ideas, old problems? Heated tobacco products - a systematic review.Int J Occup Med Environ Health. 2019; 32:595–634. doi: 10.13075/ijomeh.1896.01433CrossrefMedlineGoogle Scholar2. Kopa PN, Pawliczak R. IQOS - a heat-not-burn (HnB) tobacco product - chemical composition and possible impact on oxidative stress and inflammatory response. A systematic review.Toxicol Mech Methods. 2020; 30:81–87. doi: 10.1080/15376516.2019.1669245CrossrefMedlineGoogle Scholar3. Mallock N, Pieper E, Hutzler C, Henkler-Stephani F, Luch A. Heated tobacco products: a review of current knowledge and initial assessments.Front Public Health. 2019; 7:287. doi: 10.3389/fpubh.2019.00287CrossrefMedlineGoogle Scholar4. Auer R, Concha-Lozano N, Jacot-Sadowski I, Cornuz J, Berthet A. Heat-not-burn tobacco cigarettes: smoke by any other name.JAMA Intern Med. 2017; 177:1050–1052. doi: 10.1001/jamainternmed.2017.1419CrossrefMedlineGoogle Scholar5. Davis B, Williams MTalbot P. iQOS: evidence of pyrolysis and release of a toxicant from plastic. Tob Control. 2018.MedlineGoogle Scholar6. Farsalinos KE, Yannovits N, Sarri T, Voudris V, Poulas K, Leischow SJ. Carbonyl emissions from a novel heated tobacco product (IQOS): comparison with an e-cigarette and a tobacco cigarette.Addiction. 2018; 113:2099–2106. doi: 10.1111/add.14365CrossrefMedlineGoogle Scholar7. Shahab L, Goniewicz ML, Blount BC, Brown J, McNeill A, Alwis KU, Feng J, Wang L, West R. Nicotine, carcinogen, and toxin exposure in long-term e-cigarette and nicotine replacement therapy users: a cross-sectional study.Ann Intern Med. 2017; 166:390–400. doi: 10.7326/M16-1107CrossrefMedlineGoogle Scholar8. Hartmann-Boyce J, McRobbie H, Lindson N, Bullen C, Begh R, Theodoulou A, Notley C, Rigotti NA, Turner T, Butler AR, et al.. Electronic cigarettes for smoking cessation.Cochrane Database Syst Rev. 2020; 10:CD010216. doi: 10.1002/14651858.CD010216.pub4MedlineGoogle Scholar9. Dusautoir R, Zarcone G, Verriele M, Garçon G, Fronval I, Beauval N, Allorge D, Riffault V, Locoge N, Lo-Guidice JM, et al.. Comparison of the chemical composition of aerosols from heated tobacco products, electronic cigarettes and tobacco cigarettes and their toxic impacts on the human bronchial epithelial BEAS-2B cells.J Hazard Mater. 2021; 401:123417. doi: 10.1016/j.jhazmat.2020.123417CrossrefMedlineGoogle Scholar10. Critcher CR, Siegel M. Re-examining the association between e-cigarette use and myocardial infarction: a cautionary tale.Am J Prev Med. 2021; 61:474–482. doi: 10.1016/j.amepre.2021.05.003CrossrefMedlineGoogle Scholar11. Hackshaw A, Morris JK, Boniface S, Tang JL, Milenković D. Low cigarette consumption and risk of coronary heart disease and stroke: meta-analysis of 141 cohort studies in 55 study reports.BMJ. 2018; 360:j5855. doi: 10.1136/bmj.j5855CrossrefMedlineGoogle Scholar12. Ludicke F, Picavet P, Baker G, Haziza C, Poux V, Lama N, Weitkunat R. Effects of switching to the tobacco heating system 2.2 menthol, smoking abstinence, or continued cigarette smoking on biomarkers of exposure: a randomized, controlled, open-label, multicenter study in sequential confinement and ambulatory settings (part 1). Nicotine Tob Res. 2017. doi: 10.1093/ntr/ntw287MedlineGoogle Scholar13. Haziza C, de La Bourdonnaye G, Donelli A, Poux V, Skiada D, Weitkunat R, Baker G, Picavet P, Lüdicke F. Reduction in exposure to selected harmful and potentially harmful constituents approaching those observed upon smoking abstinence in smokers switching to the menthol tobacco heating system 2.2 for 3 months (part 1).Nicotine Tob Res. 2020; 22:539–548. doi: 10.1093/ntr/ntz013CrossrefMedlineGoogle Scholar14. Choi S, Lee K, Park SM. Combined associations of changes in noncombustible nicotine or tobacco product and combustible cigarette use habits with subsequent short-term cardiovascular disease risk among South Korean men: a nationwide cohort study.Circulation. 2021; 144:1528–1538. doi: 10.1161/CIRCULATIONAHA.121.054967LinkGoogle Scholar15. East KA, Tompkins CNE, McNeill A, Hitchman SC. 'I perceive it to be less harmful, I have no idea if it is or not:' a qualitative exploration of the harm perceptions of IQOS among adult users.Harm Reduct J. 2021; 18:42. doi: 10.1186/s12954-021-00490-8CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetailsRelated articlesCombined Associations of Changes in Noncombustible Nicotine or Tobacco Product and Combustible Cigarette Use Habits With Subsequent Short-Term Cardiovascular Disease Risk Among South Korean Men: A Nationwide Cohort StudySeulggie Choi, et al. Circulation. 2021;144:1528-1538Correction to: Heating Tobacco Sticks Instead of Combusting Conventional Cigarettes and Future Heart Attacks: Still Smoke, and RiskCirculation. 2021;144:e550-e550 November 9, 2021Vol 144, Issue 19Article InformationMetrics © 2021 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.121.056959PMID: 34748392 Originally publishedNovember 8, 2021 Keywordselectronic nicotine delivery systemssmokingtobaccoEditorialsnicotinecardiovascular diseasesheated tobacco productPDF download Advertisement
Referência(s)