The research, published in the Journal of the American Medical
Association, calls into question whether e-cigarettes can be an
effective cessation aid, said lead study author Adam Leventhal,
director of the University of Southern California’s Emotion and
Addiction Laboratory in Los Angeles.
“Our most recent study is the first to show that teenagers who vape
not only experiment with cigarettes, but are also more likely to
become regular smokers,” Leventhal said by email. “It is also the
first time teenage vaping has been linked to heavier smoking
patterns involving use of multiple cigarettes per day.”
Big tobacco companies are all developing e-cigarettes. The
battery-powered devices feature a glowing tip and a heating element
that turns liquid nicotine and other flavorings into a cloud of
vapor that users inhale.
E-cigarette use has surged among U.S. teens in recent years,
surpassing traditional cigarettes to become the most popular tobacco
product among young people, according to the Centers for Disease
Control and Prevention. An estimated 3 million middle and high
school students used the devices last year.
While tobacco control advocates fear e-cigarettes may give rise to a
new generation of nicotine addicts who eventually transition to
conventional cigarettes, some small studies suggest the devices
might benefit the health of people who already smoke and switch to
e-cigs, which are widely regarded as less dangerous.
“E-cigarettes do not prevent teens from advancing to smoking and may
possibly do the opposite,” Leventhal said.
For the current study, researchers examined data on 3,084 students
at 10 Los Angeles high schools who participated in two surveys – one
in the fall of tenth grade and another in the spring.
Overall, the prevalence of vaping and smoking was low.
At the start of the study, 2,075 students, or 67 percent, said they
had never tried e-cigarettes. Another 730 participants, or 23
percent, had vaped in the past and 133 vaped on two or fewer days in
the previous 30 days. Just 146 teens, or about 5 percent, said they
were frequent e-cigarette users, meaning they vaped three or more
days in the past month.
One in five teens who reported a regular vaping habit at the start
of the study smoked traditional cigarettes at least three times a
month by the end of the study period. Another 12 percent of routine
vapers smoked at least one day a month.
By comparison, less than 1 percent of students who didn't try vaping
reported smoking even one day a month at the end of the study.
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Researchers also looked at how many cigarettes the teens smoked and
found more frequent vaping associated with smoking two or more
cigarettes on the days when teens chose to smoke.
Limitations of the study include its relatively brief follow-up
period and its reliance on teens to accurately recall and report on
their tobacco use, the authors note.
"One interpretation of these findings is that vaping provided a
bridge to smoking - young people who may not have otherwise ended up
smoking started with palatable, flavored e-cigarettes - and then
after they became accustomed to e-cigarette use, many transitioned
to traditional cigarette smoking," said Dr. Brian Primack, a
researcher at the University of Pittsburgh who wasn't involved in
"Another possibility is that the young people who ended up smoking
by the end of the study were destined to ultimately smoke anyway,"
Primack added by email. "As evidence builds, there is more overall
support for the former explanation."
Vaping might increase the odds of smoking by setting e-cigarette
users on a path toward nicotine addiction, said Thomas Wills, a
researcher at the University of Hawaii cancer Center in Honolulu who
wasn't involved in the study.
E-cigarette users might also develop more positive associations with
tobacco use than non-vapers, making them more willing to transition
to traditional cigarettes, Wills said by email.
"There is no evidence that vaping helps protect teenagers from
cigarette smoking; in fact all the evidence is the other way
'round," Wills concluded.
SOURCE: http://bit.ly/2fdjRuR JAMA, online November 8, 2016.
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