(CNN)People using e-cigarettes to quit smoking found them to be less helpful than more traditional smoking cessations aids, a new study found.
The study, published Monday in the journal BMJ, analyzed the latest 2017 to 2019 data from the Population Assessment of Tobacco and Health Study, which follows tobacco use among Americans over time.
"This is the first time we found e-cigarettes to be less popular than FDA-approved pharmaceutical aids, such as medications or the use of patches, gum, or lozenges," said John P. Pierce, the director for population sciences at the Moores Cancer Center at the University of California, San Diego.
"E-cigarettes were also associated with less successful quitting during that time frame," said Pierce, a professor emeritus of family medicine and public health. In fact, nearly 60% of recent former smokers who were daily e-cigarette users had resumed smoking by 2019, the new study found.
"There's no evidence that the use of e-cigarettes is an effective cessation aid," Pierce said.
A three-month randomized trial in the United Kingdom, published in 2019, found e-cigarettes, along with behavioral interventions, did help smokers quit tobacco cigarettes. In guidance published in late 2021, the UK National Institute for Health and Care Excellence decided to recommend that smokers use e-cigarettes to help them quit.
However, observational studies in the United States that study smoking in real-world environments have not found that to be true, Pierce said. A 2021 study by his team found people who quit smoking tobacco cigarettes between 2013 and 2016 by switching to e-cigs or other tobacco products were 8.5% more likely to resume smoking when compared with people who quit all tobacco products.
Uptick in use by teens
Proponents of e-cigarettes as a smoking cessation tool say higher-nicotine versions should assist tobacco cigarette smokers to quit tobacco cigarettes because they would be able to take fewer puffs off a vape than smoking the entire cigarette, Pierce said.
"In 2017, cigarette sales increased by 40%," with a majority of the market share being held by new brands of e-cigarettes with very high nicotine levels, he said.
"We wanted to look at these new high-nicotine versions and see whether there's any evidence that they helped people quit because the previous ones didn't."
Instead of an uptick in use by smokers, the study found use of e-cigarettes as a cessation aid dropped by 25% over the two-year period, Pierce said.
Did the higher-octane e-cigarettes help those who did use them to stop smoking?
"We can't study the effectiveness of these high-nicotine e-cigarettes because no smokers were using them during the majority of the two-year period," Pierce said. There was a small uptick in 2019, he added, which will need to be analyzed when the next PATH data are released.
If smokers weren't driving the uptick in sales during 2017 to 2019, who was?
More teens were using vapes during that period, according to data collected by the US Food and Drug Administration. By September 2018, then-FDA Commissioner Dr. Scott Gottlieb was calling teen use of e-cigarettes "an epidemic."
Prior work by Pierce and his team have found e-cigarettes can function as a gateway drug for many teens. Youth ages 12 to 24 who used e-cigarettes were three times as likely to become daily cigarette smokers in the future, a 2021 study found.
In addition to a connection to later cigarette smoking, vaping by teens has also been linked to psychological issues, headaches, stomachaches and significant addictions to nicotine. In 2019, teens began to die from lung damage that was later connected to chemicals in vape liquids, including vitamin E acetate, according to the American Lung Association.
The FDA told CNN that the agency doesn't comment on specific studies, but "evaluates them as part of the body of evidence to further our understanding about a particular issue and assist in our mission to protect public health."
"The FDA is reviewing the findings of the paper," said FDA press officer Alison Hunt via email.