Youth who use heated tobacco products have a much harder time quitting cigarettes

Philip Morris won FDA authorization for its heated tobacco product (HTP) IQOS without addressing the effects it would have on youth. FDA also allowed PM to promote IQOS’ “reduced exposure” claim based on the assumption that people would “switch completely” from combusted cigarettes to IQOS.

An important new study from Hong Kong draws both assumptions into serious question.

The paper, “The association between heated tobacco product use and cigarette cessation outcomes among youth smokers: A prospective cohort study,” reports that young smokers (25 years old and younger) who called the Hong Kong Youth Quitline who also used HTPs successfully quit half as often as young smokers who did not use HTP.

Specifically, at the end of 6 months on 19.0% of HTP users had quit compared to 34.2% or youth who did not use HTP (adjusted relative risk 0.47, 95% CI 0.24-0.91). In addition to measuring smoking cessation at 6 months (the primary outcome), Wei Xia and her colleagues also measured cessation at 1 week, 1 and 3 months. They found that youth who had successfully stopped smoking cigarettes at these intermediate times were nearly five times as likely to relapse if they used HTP (aRR 4.56, 95% CI 1.17-17.79).

In addition, rather than being a general population sample, this is a study of people who were actively trying to quit smoking. Nevertheless, most of the smokers using HTP had done so because of curiosity and peer influences rather than as cessation devices. Indeed, consistent with earlier research, the authors found that “youth smokers were not using them as substitutes for cigarettes but as an alternative in situations where conventional cigarette smoking was not allowed, such as smoke-free areas or schools.”

Philip Morris’ promotion of IQOS as “smoke-free” is almost certainly fueling this behavior.

These results are particularly striking because HTP have not been formally released in Hong Kong. Even so, 18% of the youth and young adults who called the Quitline were using HTP.

Far from “switching,” these youth are simply adding HTP to their cigarettes with the effect that doing so is making it harder for motivated smokers to quit.

This finding — that people are not “switching” to HTP — is consistent with surveys from other countries (USA, Korea-1, Korea-2, Japan) that found that 68%-100% of HTP users also smoked cigarettes.

The authors note that they cannot draw “causal” conclusions about the effects of HTP on cessation because this is an observational study not a randominzed controlled trial (an experiment). That is true if one was assessing HTP as a smoking cessation therapy. But the study is particularly relevant to the FDA is assessing whether IQOS and other HTP are “appropriate for the protection of public health” because the results reported in this longitudinal cohort study are reflecting the effects of HTP as actually used in the real world, which is what the FDA Center for Tobacco Products is supposed to consider.

These results should lead FDA to reconsider its authorization of the sale of IQOS in the United States because the FDA’s fundamental assumption of “switching completely” is not what is actually happening. Even worse than that, HTP are making it harder for these young people to quit smoking.

Here is the abstract:

Introduction: The U.S. Food and Drug Administration authorized the marketing of heated tobacco products (HTPs) with modified-risk information for adults on July 7, 2020. However, the effects of HTP use on cigarette cessation among youth smokers remain unclear. This study aimed to explore the association of HTP use with cigarette abstinence and cessation outcomes among youth smokers in Hong Kong who were willing to receive telephone counseling for smoking cessation.

Methods: This prospective cohort study included youth smokers aged ≤25 years who were enrolled in the Hong Kong Youth Quitline service. From December 1, 2016, to September 30, 2019, this study identified as HTP users 106 youth cigarette smokers who reported using HTPs on at least 1 of the past 30 days at enrollment, and identified as non-HTP users 473 smokers who reported smoking at least one conventional cigarette in the past 30 days and never using HTPs. The participants received follow-ups at 1 week and 1-, 3-, and 6-months postenrollment. The primary outcome was self-reported 7-day point prevalence of cigarette abstinence (PPA) at the 6-month follow-up. Secondary outcomes included reduction in cigarette smoking (excluding quitters), the number of cessation attempts, and the level of readiness to quit.

Results: The self-reported 7-day PPA was statistically significantly lower among HTP users than among non-HTP users after 6 months (19.0% vs. 34.2%; p = 0.009), with an adjusted relative risk of 0.47 (95% confidence interval: 0.24-0.91; p = 0.03). The study identified no significant differences in secondary outcomes between the two groups.

Conclusions: Youth HTP users were less likely to abstain from tobacco use than their non-HTP-using counterparts. These results suggest that HTPs should not be promoted as smoking cessation or reduction aids among the youth population.

The full citation is: Xia W, Li WHC, Luo YH, Liang TN, Ho LLK, Cheung AT, Song P. The association between heated tobacco product use and cigarette cessation outcomes among youth smokers: A prospective cohort study. J Subst Abuse Treat. 2021 Aug 15:108599. doi: 10.1016/j.jsat.2021.108599. Epub ahead of print. PMID: 34419325. It is available here.

Published by Stanton Glantz

Stanton Glantz is a retired Professor of Medicine who served on the University of California San Francisco faculty for 45 years. He conducts research on tobacco and cannabis control and cardiovascular disease/

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