The role of IQOS risk perceptions on cigarette smoking behaviours: results from a prospective pilot study

Abstract

Background

IQOS is a heated tobacco product marketed as an alternative to combustible cigarette smoking. Little is known about cigarette smokers’ IQOS health risk perceptions and if these risk perceptions impact IQOS use and cigarette smoking behaviour.

Methods

Adult, daily, non-treatment-seeking cigarette smokers (n=27), naïve to IQOS, were recruited from Philadelphia, Pennsylvania, USA. Participants were introduced to IQOS and then completed measures of risk perceptions. Participants were given an IQOS 2.4 holder, charger and HeatSticks, and asked to switch completely from cigarettes to IQOS for 14 days. The effects of risk perceptions on changes in IQOS use, cigarettes per day (CPD), the substitution of IQOS for cigarettes and motivation to quit smoking were evaluated.

Results

Over the 14-day switch period, CPD significantly decreased (B=−0.18, 95% CI=−0.26 to –0.09, p<0.0001), IQOS use significantly increased (B=0.02, 95% CI=0.00 to 0.03, p=0.042), as did the percentage IQOS HeatSticks that replaced CPD (B=0.02, 95% CI=0.01 to 0.03, p=0.005). Participants who perceived IQOS as less risky than cigarettes used fewer IQOS HeatSticks per day. A lower percentage of IQOS HeatStick substitution for cigarettes was observed for participants with higher versus lower risk perceptions (B=−0.14, 95% CI=−0.28 to –0.01, p=0.042). Motivation to quit increased from a mean of 5.53 to 6.79 on the contemplation ladder from baseline to day 14 (B=1.26, 95% CI=0.54 to 1.97, p<0.001).

Conclusions

Smokers reduced their smoking rate and increased motivation to quit smoking while using IQOS. IQOS risk perceptions did not directly account for reductions in smoking, although they may contribute indirectly through increased IQOS use.

INTRODUCTION

IQOS, a heated tobacco product, entered the US market in 2019, receiving Food and Drug Administration authorisation to advertise as a reduced exposure tobacco product in July 2020.^{1 2} While concerns have been raised regarding smokers conflating reduced exposure claims with reduced risk claims,^{3 4} little research has examined IQOS risk perceptions or risk perceptions relative to cigarette smoking.^{5 6} Qualitative research noted that participants perceive IQOS as healthier than combustible cigarettes but maintain uncertainty about potential health harms.⁵ Current and former smokers reported that their perceptions of reduced harm were important in their decision to use IQOS, with most reporting concurrent IQOS and cigarette use.⁵ IQOS marketing asserts that switching completely from cigarettes to IQOS is necessary to obtain reduced toxicant exposure.⁷

Novel tobacco products receiving modified exposure or risk marketing authorisation must be carefully evaluated for how smokers perceive the risks associated with their actual use, the impact on cigarette smoking⁸ and the related policy implications for product adoption and dual-use. In 2021, the import of IQOS products into the USA was banned by the US International Trade Commission until further litigation between Philip Morris International and British American Tobacco is resolved.⁹ This prospective pilot study, conducted prior to the ban, examined whether IQOS risk perceptions influence IQOS use, the substitution of IQOS for cigarettes and motivation to quit smoking.

METHODS

Participant eligibility

Cigarette smokers were eligible to participate in the study if they smoked >5 cigarettes per day, were 18–65 years old, were interested in quitting within the next 6 months but not the next 30 days and had no prior exposure to IQOS. Smokers were ineligible to participate if they currently used other forms of nicotine, were currently being treated for an unstable medical or psychiatric condition (eg, cancer, recent heart attack or psychoses), were pregnant or nursing, or screened positive for an illicit substance.

Study design

This within-subjects longitudinal pilot study of the effects of IQOS use on cigarette smoking behaviours was conducted between September 2020 and July 2021. Participants were recruited from Philadelphia, Pennsylvania, USA, using print, traditional and social media advertisements. Participants were given safety information and detailed instructions on using and cleaning the IQOS device on two separate occasions before use. The consent form described the study, provided detail on IQOS use and instructions on safe use, and indicated that participants would be asked to switch completely from cigarettes to IQOS during the study. The consent form stated if participants did not switch completely from cigarettes to IQOS, their risks from smoking would remain the same.

Eligible participants completed six laboratory visits across a 21-day protocol (online supplemental figure 1). Baseline cigarette smoking rate was measured over 5 days of ad-libitum smoking. On day 6, participants abstained from smoking overnight before a laboratory session (verified CO <10 ppm). Before IQOS exposure, participants were provided instructions on how to use IQOS with important safety information a second time. Participants completed relative and absolute risk measures before and after two 14-puff IQOS HeatSticks exposures.^{10 11} On day 7, after completing a reinforcement task, participants were provided an IQOS 2.4 holder, charger, and a supply of tobacco and/or menthol Marlboro HeatSticks, based on preference and baseline smoking rate. Participants were instructed to completely switch from cigarette smoking to IQOS for the following 14 days (days 8–21).

To assess daily consumption, all spent cigarette filters and HeatSticks were collected in date-labelled plastic bags and returned to the laboratory on days 11, 14, 17 and 21. At the end of the study, participants received written and oral information on using IQOS as a smoking cessation aid. It was noted that there were no health benefits of concurrently using IQOS and smoking cigarettes and that there may be health risks. Participants were informed that IQOS use could result in less exposure to harmful chemicals than combustible cigarettes, only if smokers switch completely to IQOS. Participants received $500 compensation.

Measures

Outcomes

Over the 14-day switch period, IQOS use and cigarette smoking were measured separately by the respective daily count of spent HeatSticks and cigarette filters returned.^{10 12} Substitution was operationalised as the percentage of baseline cigarettes per day (CPD) (average cigarettes smoked over days 1–5) replaced by HeatSticks during the switch period. Motivation to quit smoking was measured at baseline and study end using the contemplation ladder (range: 0–10).¹³

IQOS risk perceptions

Two IQOS risk perception scales were developed based on items drawn from previous studies.^{4 14–17} For absolute risk, participants were asked to imagine that they began using an IQOS device daily and to rate their risk (0=‘no chance’ to 6=‘very high chance’) for lung cancer, lung disease, heart disease, addiction and premature death if they continued to use IQOS every day. Perceived risk of IQOS relative to cigarette smoking was measured by asking participants to rate how true (1=‘definitely untrue’ to 5=‘definitely true’) eight statements comparing IQOS with their cigarettes (ie, lower in nicotine, lower in tar, less addictive, less likely to cause cancer, has fewer chemicals, is healthier, makes tobacco safer and helps people quit smoking). Both scales demonstrated good psychometric properties (see note in table 1).

Table 1.

IQOS-related risk perceptions predicting change in IQOS use, cigarette smoking and motivation to quit smoking during a 14-day switch period

Variable	Cigarettes per day (CPD)*		% IQOS to baseline CPD†		IQOS HeatSticks per day*		Contemplation ladder‡§
	B (95% CI)	P value	B (95% CI)	P value	B (95% CI)	P value	B (95% CI)	P value
Time (in days)¶	−0.18 (−0.26 to 0.09)	0.0001	0.02 (0.01 to 0.03)	0.005	0.02 (0.00 to 0.03)	0.042	1.26 (0.54 to 1.97)	0.001
Sex
Female	Reference		Reference		Reference		Reference
Male	−0.69 (−1.48 to 0.10)	0.09	0.07 (−0.20 to 0.34)	0.58	0.05 (−0.43 to 0.53)	0.83	−0.70 (−1.64 to 0.23)	0.13
Race
White	Reference		Reference		Reference		Reference
African American	0.01 (−1.26 to 1.28)	0.98	−0.22 (−0.54 to 0.10)	0.18	−0.19 (−0.94 to 0.57)	0.63	−0.36 (−1.50 to 0.79)	0.52
Cigarette flavour
Tobacco	Reference		Reference		Reference		—
Menthol	0.71 (−0.27 to 1.68)	0.16	0.26 (−0.07 to 0.58)	0.12	0.39 (−0.19 to 0.97)	0.19	—
FTND	0.18 (−0.03 to 0.39)	0.10	−0.05 (−0.11 to 0.02)	0.18	−0.06 (−0.19 to 0.08)	0.42	0.07 (−0.17 to 0.31)	0.56
Baseline CPD	−0.02 (−0.09 to 0.06)	0.63	—		0.05 (0.02 to 0.09)	0.006	0.03 (−0.04 to 0.10)	0.34
Relative risk**††	0.04 (−0.43 to 0.50)	0.88	−0.14 (−0.28 to −0.01)	0.042	−0.35 (−0.59 to −0.11)	0.005	0.02 (−0.53 to 0.56)	0.94
Absolute risk**‡‡	−0.17 (−0.52 to 0.18)	0.34	0.06 (−0.05 to 0.17)	0.30	0.13 (−0.06 to 0.32)	0.18	0.17 (−0.23 to 0.57)	0.39

Sample size (n=27).

FTND (α=0.61; range: 0–9).

^*Parameter estimates from random intercept, random slope and Poisson mixed-effects models.

^†Parameter estimates from random intercept, random slope and Gaussian mixed-effects models.

^‡Parameter estimates from random intercept Gaussian mixed-effects models.

^§Motivation to quit as measured by the contemplation ladder (range: 0=‘not having thought of quitting’ and 10=‘taking action to quit’).

^¶Time (days 1–14) was treated continuously for the use behaviour outcomes. Time (baseline and end of study) was treated categorically for the contemplation ladder outcome.

^**Parameter estimates from separate mixed-effects models including the respective each risk perception scale and examined set of covariates.

^††Perceived IQOS risk relative to cigarettes (range: 1=‘definitely untrue’ to 5=‘definitely true’; α=0.92; exploratory factor loadings range=0.90–0.92, coefficient H scalability=0.64).

^‡‡Perceived absolute IQOS risk (range: 0=‘no chance’ to 6=‘very high chance’; α=0.95; exploratory factor loadings range=0.93–0.96, coefficient H scalability=0.84).

FTND, Fagerström Test of Nicotine Dependence.

Statistical analysis

To examine within-subject change in daily cigarette and IQOS use over the 14-day switch period, random intercept, random slope and conditional mixed-effects models were fit using the ‘lme4’¹⁸ and ‘lmerTest’¹⁹ packages in R.²⁰ Factors known to influence risk perceptions and cessation motivations were included as covariates (sex, race, menthol status^{21 22} and nicotine dependence²³). Likelihood ratio testing confirmed a Poisson distribution best fit the count outcomes while a Gaussian distribution best fit the per cent substitution outcome.²⁴ Change in motivation to quit smoking was modelled using intercept-only Gaussian mixed-effects models. Time, relative risk and absolute risk were the predictors for each outcome. Separate models were run for each risk scale due to construct collinearity. Estimated marginal means were computed using the ‘effects’ package.²⁵

RESULTS

Twenty-seven participants completed the study and provided data on all study measures. Participants were, on average, 51.15 years old, predominately male (70%), with 59% identifying as white and 41% African American. Participants reported moderate levels of nicotine dependence (Fagerström Test of Nicotine Dependence mean=5.04), preferred menthol (63%) to tobacco (37%) cigarettes, and smoked an average of 16.83 CPD across the 5-day ad-lib smoking period. Table 1 summarises the mixed-effects models’ results.

Change in CPD and HeatSticks per day

On the first day of the switch period, participants smoked an average of 3.34 CPD, which significantly declined to an average of 0.33 CPD by day 14. During this same period, participants used an average of 7.97 IQOS HeatSticks per day (SPD), which significantly increased to an average of 10.04 SPD. On day 1 of switching, participants substituted 59% of their baseline cigarettes with HeatSticks, which significantly increased to 83% by day 14.

Effect of risk perceptions on use behaviour

Participants had moderate levels of absolute (mean=3.35, SD=1.30) and relative (mean=3.00, SD=0.73) IQOS risk perceptions before IQOS exposure, which did not change for either measure after exposure. Neither risk measure predicted change in CPD over the 14-day switch period. Smokers with relative risk perceptions within the lowest quintile smoked an average of 14.6 CPD at baseline, while those in the highest smoked 21 CPD. Those who perceived IQOS as less risky than cigarettes used fewer IQOS SPD. These smokers (upper quintile score=3.69) used an average of 7.34 SPD (95% CI=5.64 to 9.54), whereas those who perceived IQOS to be closer in risk to their cigarettes (lower quintile score=2.38) used an average of 11.31 SPD per day (95% CI=8.56 to 14.94). Similarly, smokers with risk perceptions in the upper quintile had a lower percentage of substitution than smokers in the lower quintile (63% vs 81%, respectively).

Change in motivation to quit

Motivation to quit smoking cigarettes was moderate at baseline (mean=5.53, 95% CI=5.02 to 6.05), increasing to 22.8% (mean=6.79, 95% CI=6.25 to 7.32) after 14 days of IQOS use. Neither risk perceptions nor covariates were predictive of changes in motivation.

DISCUSSION

The present study is among the first studies to assess the impact of IQOS risk perceptions on actual IQOS use, cigarette smoking and intentions to quit smoking. Smokers substantially reduced their daily smoking rate while using IQOS and reported an increase in motivation to quit smoking after 14 days of use. IQOS risk perceptions do not appear to influence reductions in smoking directly, although they may contribute indirectly through increases in IQOS use.

Smokers who perceived IQOS closer in risk to their cigarettes used more SPD, whereas those who perceived IQOS to be less risky than their cigarettes used fewer. This finding appears inconsistent with the literature on tobacco use risk perceptions, where high risk is associated with lower odds of use.²⁶ As novel products enter the market, smokers may have little information to base their perceptions beyond marketing²⁷ and may base risk perceptions on similarities between the novel product and their cigarettes.²⁸ A recent study of IQOS risk claims found that language features (perceived chance of disease, explanation of switching completely and language certainty) differentially affected smokers’ risk perceptions but not intentions to switch to IQOS.²⁷ As such, risk perceptions did not align with intended behaviour.

Motivation to quit smoking cigarettes increased after 14 days of IQOS use. Smokers may have been encouraged by observing a significant reduction in their smoking rate, coupled with nicotine replacement via IQOS. Despite the increased motivation to quit, most smokers did not completely switch to IQOS after 14 days of use. The high rate of dual use observed in one cross-sectional study (96%) led the authors to conclude that IQOS may be a complement rather than a substitute for cigarettes.²⁹

While this pilot study offers an initial glimpse into how IQOS use may impact smoking behaviour, the sample was small. Risk perceptions and other variables that may explain behaviour should be examined within a larger sample of smokers to inform regulatory efforts around IQOS risk communication.

CONCLUSION

Risk perceptions predicted IQOS use among smokers asked to switch completely from cigarettes to IQOS but were not directly associated with cigarette smoking. Smokers who perceive IQOS to be comparable in risk with their cigarettes tend to use IQOS more.

WHAT IS ALREADY KNOWN ON THIS TOPIC

• Sales data show that IQOS use, a heated tobacco product, has increased worldwide.

• Existing data suggest that most smokers may dual use IQOS and combustible cigarettes.

WHAT THIS STUDY ADDS

• Our findings indicate that risk perceptions do not directly affect cigarette smoking or motivation to quit smoking.

• The substitution of cigarettes for IQOS HeatSticks increased over the study’s 2-week switch period.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY

• Further research is necessary to understand the factors that affect partial and complete switching from cigarettes to IQOS.