Smokers do not “switch completely” to e-cigs; e-cigarettes cut quitting by 83% in smokers trying to quit

The evidence is rapidly accumulating that e-cigs are harm enhancing rather than harm reducing. Accepting for the sake of argument, even if one accepts claims that e-cigs are less toxic than conventional cigarettes, for e-cigs to be harm reducing smokers who use them need to stop cigarettes — what the tobacco companies and FDA call “switching completely.”

The new study by Olatokunbo Osibogun and colleagues from Florida International University shows that smokers who want to quit are much less likely to actually quit if they use e-cigarettes than if they don’t use e-cigarettes. As they report in their paper “Longitudinal transition outcomes among adult dual users of e-cigarettes and cigarettes with the intention to quit in the United States: PATH Study (2013-2018),” they followed 3542 smokers forward in time for three years (data collected between 2013 and 2018) and compared quitting behavior among sole-cigarette smokers to smokers who also used e-cigs (so-called “dual users”).

As shown in the graph above (taken from Figure 1 in their paper), after adjusting for a wide range of factors (listed below), smokers who also used e-cigs were 83% and 79% less likely quit (adjusted relative risk ratio, aRRR: 0.17, 95% CI: 0.09–0.32) or drop e-cigarettes (aRRR: 0.21, 95% CI: 0.14–0.32) than smokers who just smoked cigarettes at the beginning of the study. Both groups were interested in quitting.

Most important, there was not a statistically significant increase in “switching completely” to e-cigarettes (what is called mono e-cigarette use in the figure; aRRR=1.31, 95% CI: 0.73-2.35) over three years of follow up among dual users interested in quitting at baseline. On average, people don’t “switch completely.”

The data for this study came from the FDA/NIH PATH study, which is the largest, high quality longitudinal study of tobacco use behavior in the world. And, as noted above. Osibogun and colleagues adjusted for a wide range of potential confounders: age, sex, race/ethnicity, education, income, census region, tobacco dependence, other tobacco use (beyond e-cigs and cigs), and diagnosis of several chronic diseases. Interestingly, and consistent with other studies, accounting for all these factors had little effect on the estimated effects of e-cigs on quitting behavior.

This study is an important complement to the recent UCSD study, also based on PATH, that also concluded that e-cigarettes depressed smoking cessation among smokers who were trying to quit. While the data source was the same, the Florida and UCSD groups used different analytical approaches. The fact that the results were so similar increases the confidence that we — and the FDA — can have in the conclusions in both papers.

These two new papers reach more troubling conclusions than our 2020 meta-analysis, which showed, overall, no significant association between e-cigarette use and stopping cigarettes among people motivated to quit. Our earlier analysis, did find a statistically significant depression in quitting in the longitudinal studies (aOR 0.751, 95% CI 0.591 to 0.954), which is in the same direction, but smaller, than the new studies. This difference is likely due to the fact that the new studies are larger, have longer follow-up and more precisely define “motivated to quit” than the earlier work.

It is long past time for FDA to stop basing regulatory decisions on the unjustified assumption that a substantial number of people will switch completely and accept the reality that e-cigarettes increase harm by making it harder for people to quit smoking.

Here is the abstract:

Many adult dual users of e-cigarettes and cigarettes in the United States report using e-cigarettes with the intention to quit (ITQ) smoking. This study examined transition outcomes among adult dual users of e-cigarettes and cigarettes with the ITQ compared to mono cigarette smokers with ITQ. We conducted a longitudinal analysis of 3,542 adults aged 18 years with data from Waves 1 and 4 of the United States Population Assessment of Tobacco and Health study (2013–2018) between May 2021 and January 2022. Current dual users (e-cigarettes and cigarettes use on 20 days in the past month) with the ITQ were compared to current mono cigarette smokers with the ITQ for transition outcomes (cessation, mono e-cigarette, mono cigarette and dual use) three years later. We conducted multinomial logistic regression modeling adjusting for potential confounders and reported the adjusted relative risk ratios (aRRR) with 95% confidence intervals (CI) for the transition outcomes. Approximately 10.7% (7.8–14.3) of dual users with the ITQ (in 2013) reported cessation (no past-month use of any tobacco) three years later, compared to 16.1% (14.6–17.7) of mono cigarette smokers. Dual users were 83% and 79% less likely to transition to cessation (aRRR: 0.17, 95% CI:0.09–0.32) or mono cigarette use (0.21, 0.14–0.32), respectively, compared to mono cigarette smokers. Our findings show that in a real-world scenario, dual e-cigarette and cigarette use may hinder rather than facilitate smoking cessation among those interested in quitting. This needs consideration when assessing the population impact of e-cigarettes and their role in harm reduction.

The full citation is: Osibogun O, Bursac Z, Maziak W. Longitudinal transition outcomes among adult dual users of e-cigarettes and cigarettes with the intention to quit in the United States: PATH Study (2013-2018). Prev Med Rep. 2022 Feb 28;26:101750. doi: 10.1016/j.pmedr.2022.101750. PMID: 35256929; PMCID: PMC8897625. It is available for free 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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