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Switching from cigarettes to IQOS: the relative importance of IQOS-associated reward, reinforcement and abstinence relief
  1. Janet Audrain-McGovern1,
  2. E Paul Wileyto2,
  3. Olivia Klapec1,
  4. Fodie Koita1,
  5. Andrew A Strasser1
  1. 1Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
  2. 2Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
  1. Correspondence to Dr Janet Audrain-McGovern, Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, 19104, USA; audrain{at}


Introduction This study investigated whether IQOS, a heated tobacco product, can fully substitute for combustible cigarettes and the factors that promote substitution.

Methods Adults who smoked cigarettes daily (N=90; 21–65 years) completed a baseline ad-lib smoking period (days 1–5), two laboratory visits (days 6–7) and a 2-week period where they were instructed to switch from smoking cigarettes to using IQOS 3.0 (days 8–21). Mixed-effect modelling estimated the changes in cigarettes per day (CPD) and the percentage of baseline CPD substituted by HeatSticks during the switch period. Predictors included IQOS-associated subjective reward, relative reinforcing value, craving relief and withdrawal relief.

Results Participants reduced their CPD to about 30% of their baseline smoking rate by the end of the 14-day switch period (p<0001). A lower versus higher reinforcing value of smoking relative to IQOS (RRV; break point <5 vs ≥5) predicted greater reductions in CPD (β=−1.31 (95% CI −2.35 to −0.27) p=0.013). Initially, IQOS use was 72% of the baseline smoking rate (β=71.64 (95% CI 42.79 to 100.48) p<0.0001) and climbed by 0.8% per day (β=0.82 (95% CI 0.01 to 1.64) p=0.05), for an average substitution rate of 83%. The subjective reward of IQOS was the only predictor of a higher substitution rate (β=4.26 (95% CI 1.03 to 7.50) p=0.01).

Conclusions IQOS fully substituted for cigarettes in ~20% of people who were not immediately interested in quitting smoking while the remainder significantly reduced their smoking. Positive reinforcing effects of IQOS foster use and the transition away from combustible cigarettes.

Trial registration number NCT05076708.

  • Non-cigarette tobacco products
  • Nicotine
  • Harm Reduction

Data availability statement

All data relevant to the study are included in the article or uploaded as online supplemental information. These data are not publicly available.

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Data availability statement

All data relevant to the study are included in the article or uploaded as online supplemental information. These data are not publicly available.

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  • Contributors JA-M was the principal investigator responsible for the study. JA-M conceptualised the study. JA-M wrote the majority of the manuscript with assistance from OK and FK, including critical review and revision. EPW conducted the analyses, interpreted the results and drafted the results section. AAS critically reviewed and revised the manuscript. JA-M is the guarantor. All authors approved the manuscript.

  • Funding Research reported in this paper was supported by the National Cancer Institute of the National Institutes of Health (NIH) and the US Food and Drug Administration (FDA) Center for Tobacco Products under award number R01CA260448 (JA-M).

  • Disclaimer The content is solely the authors’ responsibility and does not necessarily represent the official views of the NIH or the FDA.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.