FRIDAY, June 5, 2020 (HealthDay News) -- Far from helping them avoid cigarettes, longtime ex-smokers who try vaping are taking a big risk that they'll relapse, a new study finds.
People who've spent a year off smokes are nearly four times more likely to start lighting up again if they experiment with vaping, compared with those who don't, according to findings published June 5 in JAMA Network Open.
"Even sampling nicotine can prime the brain for wanting more," said lead researcher Dr. Wilson Compton, deputy director of the U.S. National Institute on Drug Abuse in Bethesda, Md. "Once you're off of nicotine completely, the safest approach is to stay off of it 100%."
But another study using the same source of data found that flavored e-cigarettes might actually make it easier for adult smokers to kick the habit.
Adult smokers using e-cigs with candy or fruit flavors were more than twice as likely to quit compared to smokers vaping tobacco flavors, researchers report.
"It's possible that the taste of the e-cigarette will have a stronger link to smoking if people are tasting the same tobacco-like flavor," said lead researcher Abigail Friedman, offering one possible explanation for her findings. Friedman is an assistant professor of health policy at the Yale School of Public Health.
Together, the studies "suggest that vaping is probably a mixed bag" for current and former smokers, said Timothy Baker, a professor at the University of Wisconsin School of Medicine and Public Health in Madison. Baker co-authored an editorial that accompanied the two studies.
For the first, Compton's team analyzed data on nearly 2,300 former smokers collected between 2013 and 2018 by the Population Assessment of Tobacco and Health (PATH), an ongoing study of tobacco use in the United States.
Successful quitters were all found to be at risk of relapse if they sampled an e-cigarette, researchers found.
The risk was greatest for long-term ex-smokers, who were 3.8 times as likely to relapse if they experimented with an e-cigarette. Smokers who quit within the last year were 63% more likely to pick up the habit if they tried vaping.
Use of other tobacco products produced similar relapse risks, researchers added.
The data appear to show that smokers' brains are "primed" to respond to any future exposure to nicotine, Compton and Baker said.
"You can almost think of addiction as having a memory trace that can be reactivated if you give a person the drug they were addicted to," Baker said. "If you have a human who hasn't used an addictive drug like nicotine for a long period of time, then you give them a dose of that drug, it primes their addiction. It rekindles the memory and thrusts them back into the state where they want to use again."
The second study also relied on the PATH data, using it to analyze whether flavored e-cigarettes contribute to smoking initiation or cessation among teens or young adults.
Researchers compared nearly 12,000 young nonsmokers to nearly 6,000 teens and young adult smokers, to see how flavored e-cigarettes affected their smoking behavior.
Vaping increased the odds of smoking by 6.7 times among teens and 3.2 times among young adults.
But the results found that non-tobacco flavors were no more strongly associated with the start of youth smoking than tobacco flavors, researchers said.
The study also found that adults who began vaping flavored e-cigarettes were nearly 2.3 times more likely to quit smoking than those who used e-cigs flavored like traditional tobacco.
One possible reason might be that tobacco-flavored e-cigarettes "cue" a person's nicotine addiction, Friedman said.
"What we know about substance abuse generally is if people who are trying to quit go back to a context or person or situation that they associate with that drug, it's much harder to quit. You see more relapse," she said.
Friedman said it's possible that flavored e-cigarettes don't cue conventional smoking as much as tobacco cigarettes. "In that case, the habits are less intertwined, and it may be easier for smokers to quit," she added.
Other potential explanations could be that people who are more motivated to quit will try flavored e-cigarettes, or young adults experimenting with both may simply decide that they prefer flavored vaping and toss away their smokes, Friedman added.
Her team concluded that efforts to ban flavored e-cigarettes could increase smoking, since flavors might help adults quit but don't appear to be associated with smoking uptake among teens.
The authors of both papers stressed that their results were based on observation, and cannot prove a cause-and-effect relationship between e-cigarettes and smoking behavior.
More research is needed to show whether e-cigarettes can serve as a reliable smoking-cessation tool, Baker said.
In the meantime, he recommends federally approved nicotine replacement therapy -- some combination of patch, gum and lozenge, along with supportive counseling.
"Those we know double or triple a smoker's chances of quitting successfully," Baker said. "That should be the first strategy a smoker should try."
The U.S. Surgeon General has more about e-cigarettes and young people.