UC San Diego Study: E-cigarettes Don’t Help Smokers Stay Off Cigarettes

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The United States Centers for Disease Control and Prevention have suggested that smokers who are unable to quit smoking may benefit by switching from smoking cigarettes to vaping e-cigarettes if they switch completely and are able to avoid relapsing to cigarette smoking.

However, there have been few studies on whether smokers are able to transition to e-cigarettes—battery-operated devices that heat a liquid made of nicotine, flavorings and other chemicals to make an aerosol that users inhale into their lungs—without relapsing back to cigarette smoking.

Published in the Oct. 19, 2021 online issue of JAMA Network Open, an analysis by the Herbert Wertheim School of Public Health and Human Longevity Science at University of California San Diego and UC San Diego Moores Cancer Center reports that e-cigarette use—even on a daily basis—did not help smokers successfully stay off cigarettes.

John P. Pierce, Ph.D., Distinguished Professor at the Herbert Wertheim School of Public Health and UC San Diego Moores Cancer Center

“Our findings suggest that individuals who quit smoking and switched to e-cigarettes or other tobacco products actually increased their risk of a relapse back to smoking over the next year by 8.5 percentage points compared to those who quit using all tobacco products,” said first author John P. Pierce, Ph.D., Distinguished Professor at the Herbert Wertheim School of Public Health and UC San Diego Moores Cancer Center.

“Quitting is the most important thing a smoker can do to improve their health, but the evidence indicates that switching to e-cigarettes made it less likely, not more likely, to stay off of cigarettes.”

Researchers used data from the nationally representative Population Assessment of Tobacco and Health (PATH) longitudinal study, undertaken by the National Institute on Drug Abuse (NIDA) and the FDA Center for Tobacco Products under contract with Westat. The team identified 13,604 smokers between in 2013 and 2015 who were followed over two sequential annual surveys to explore changes in use of 12 tobacco products.

At the first annual follow up, 9.4% of these established smokers had quit. Now considered “former smokers,” 62.9% of these individuals remained tobacco free, while 37.1% had switched to another form of tobacco use. Of these recent smokers who switched to another product, 22.8% used e-cigarettes, with 17.6% of switchers using e-cigarettes daily.

Recent former smokers who switched to e-cigarettes were more likely to be non-Hispanic white, have higher incomes, have higher tobacco dependence scores and view e-cigarettes as less harmful than traditional cigarettes.

Karen Messer, Ph.D., professor and chief of the Division of Biostatistics at the Herbert Wertheim School of Public Health

“Our goal in this study was to assess whether recent former smokers who had switched to e-cigarettes or another tobacco product were less likely to relapse to cigarette smoking compared to those who remained tobacco free,” said senior author Karen Messer, Ph.D., professor and chief of the Division of Biostatistics at the Herbert Wertheim School of Public Health.

At the second annual follow up, the authors compared the former smokers who were tobacco free to those who had switched to e-cigarettes or other tobacco products. Individuals who switched to any other form of tobacco use, including e-cigarettes, were more likely to relapse compared to former smokers who had quit all tobacco, by a total of 8.5 percentage points.

Among recent former smokers who abstained from all tobacco products, 50% were 12 or more months off cigarettes at the second follow up and were considered to have successfully quit smoking; this compared to 41.5% of recent former smokers who switched to any other form of tobacco use, including e-cigarettes.

While individuals who switched were more likely to relapse to smoking, they were also more likely to attempt to quit again and be off cigarettes for at least three months at the second follow up. A further follow-up survey is needed to identify whether this is evidence of a pattern of chronic quitting and relapsing to cigarette smoking, or whether it is part of progress toward successful quitting, said the researchers.

“This is the first study to take a deep look at whether switching to a less harmful nicotine source can be maintained over time without relapsing to cigarette smoking,” said Pierce. “If switching to e-cigarettes was a viable way to quit cigarette smoking, then those who switched to e-cigarettes should have much lower relapse rates to cigarette smoking. We found no evidence of this.”

Co-authors include: Ruifeng Chen, Sheila Kealey, Eric C. Leas, Martha M. White, Matthew D. Stone, Sara B. McMenamin, Dennis R. Trinidad, David R. Strong and Tarik Benmarhnia, all of UC San Diego.

This research was funded, in part, by the National Institutes of Health (1R01CA234539) and the Tobacco-Related Disease Research Program of the University of California Office of the President (28IR-0066).