By EMILY JOSHU STERNE HEALTH REPORTER FOR DAILYMAIL.COM
Published: 11:44 EDT, 3 April 2025 | Updated: 11:49 EDT, 3 April 2025
Teens who start vaping after high school are more likely to become addicted, a new study suggests.
Researchers in California found one in five young adults who started vaping after graduating from high school picked up the habit regularly within a year.
This was a 40 percent jump compared to teens who began using e-cigarettes around 14 to 15 years old.
Older teens also became addicted to vaping nearly three times faster than teens who had just started high school.
The findings suggested younger teenagers are less ikely to become addicted to e-cigarettes than those just out of high school.
It's unclear why exactly older teenagers were more prone to addiction, but the team suggested it could be due to a higher likelihood of abusing other substances like alcohol.
The experts also added this 'late initiation' group of older teens were three times more likely to first use highly addictive JUUL products as their first e-cigarettes than their younger classmates.
Given the findings, the researchers said policies aiming to reduce vaping rates 'should target early adulthood as well as adolescence.'
The findings come as a growing body of evidence suggests vaping could be more dangerous than smoking, raising the risk of chronic diseases like heart disease.
Researchers at the University of Southern California found teenagers who have already graduated from high school are the most likely group to become addicted to vaping (stock image)
Dr Junhan Cho, lead study author and assistant professor of Research Population and Public Health Sciences at the University of Southern California, said: 'We know from existing research that youth who begin vaping early in their mid-teens are at high risk for developing nicotine dependence and are more likely to continue using nicotine products later in life.
'Our study identified another high-risk group of late initiators who progressed to frequent use much more quickly.
'Not surprisingly, this "late initiation/rapid progression" group showed swift increases in the use of nicotine and other substances and exhibited higher rates of e-cigarette dependence in young adulthood compared with other groups in our study.'
About seven percent of American adults vaped in 2024 compared to 11 percent who smoked cigarettes.
And around 1.6million US middle and high school students - six percent - used e-cigarettes last year.
The study, published Thursday in the journal Addiction, recruited 2,291 teenagers from 10 California high schools in 2013.
Researchers followed them for 10 years, providing students with questionnaires on their vaping habits every six months.
All participants were in ninth grade at the start of the study, meaning they were 14 to 15 years old. After high school, they were surveyed once per year from 2019 until 2023.
Around two-thirds of students said they preferred sweet e-cigarette flavors like fruit, candy and dessert.
Based on the findings, researchers divided participants into four groups: Young Adulthood/Rapid Progression, Early High School/Gradual Progression, Late High School/Gradual Progression, and Low Initiation Risk/No Progression.
About 21 percent of students fell into the Young Adulthood/Rapid Progression class, meaning they did not start vaping until after high school. They progressed to 'frequent use' - using e-cigarettes 20 out of 30 days of the month - within an average of 1.2 years.
Meanwhile, 14 percent of participants were categorized as Early High School/Gradual Progression. This group started vaping at the beginning of their high school careers and progressed to 'frequent' use within three years.
This progression into addiction was 40 percent slower than the older teens.
The above chart shows the ages participants in the most addicted group were when they started using e-cigarettes compared to how quickly they became hooked on the habit
Additionally, four percent of students were in the Late High School/Gradual Progression class, meaning they started vaping later in their high school years and progressed to frequent use within three years after graduating.
The remainder, around 60 percent, were considered Low Initiation Risk/No Progression, which was defined as having a low risk of vaping or starting to vape but not becoming addicted to it.
Young adults who later became addicted to vaping were also three times more likely to use JUUL and other rechargeable vape pods as their first e-cigarette products.
These have about 20 times more nicotine than traditional cigarettes, increasing the risk of them becoming addictive.
The researchers wrote: 'This study represents one of the most comprehensive, long-term characterization of patterns and timings of e-cigarette use initiation and progression among young people to date, spanning 11 assessments across 9 years of follow-up.'
There were several limitations, mainly including the participants all being from southern California and small sample sizes.
Much is still unknown about the long-term risks of vaping, but recent research suggests it could be as likely as traditional cigarettes to cause issues like lung cancer.
The habit has also been linked to dementia, as researchers believe it can damage blood vessels in the brain.
In the US, federal low prohibits anyone under 21 from purchasing e-cigarettes. The FDA has also proposed limits on marketing flavored vapes to children.