Teens who smoke sweet or fruit-flavoured e-cigarettes are more likely to stick with the habit and vape more heavily, a new study has found.
And researchers at the University of Southern California have recommended that flavoured vapes should be banned to teens to prevent them taking up the habit.
Professor Adam Leventhal, director of the USC Institute for Addiction Science, said: "While many children try e-cigarettes, not all become regular users.
"Teens who use e-cigarettes may be more inclined to continue vaping rather than just temporarily experiment with e-cigs.
"Whether or not children continue with vaping is important - the longer and more frequently you vape, the more you're exposing yourself to toxins in e-cigarette aerosol and put yourself at risk for nicotine addiction."
The researchers tracked nearly 500 teens from Los Angeles who vaped, surveying them every six months from the spring of 2015 through to 2017.
They found that roughly nine-in-ten teens in the study vaped fruit, candy or other non-traditional flavours.
Of those using non-traditional flavours, 64.3% were still vaping six months later - compared to 42.9% who only used flavours like tobacco or menthol.
The teens vaping with sweeter flavours also vaped more heavily six months later, admitting to taking more puffs each time they smoked.
Professor Leventhal added: "Regulations that reduce youth exposure to flavoured e-cigarettes may aid in preventing young people who try e-cigarettes from becoming long-term e-cig users, and also from inhaling more aerosol into their lungs.
"Regulations like these could also encourage the millions of US adolescents who already use e-cigarettes to quite vaping, especially if they can no longer access e-cigs in the flavours they like."
The research comes amid a backlash against flavoured vapes, less than a month after the Trump administration announced it plans to ban e-cigarettes in flavours other than tobacco in the US.
JUUL, the market leader, has voluntarily pulled some of its flavoured products from circulation.
