Three-quarters of U.S. teens who use e-cigarettes are vaping addictive or mind-altering substances -- more than once suspected, according to a new study.
The findings add to growing concerns about teen vaping.
"We found that youth were more likely to report vaping nicotine and marijuana than 'just flavoring' only, and that cigarette smoking intensity was associated with an increasing proportion of students reporting vaping nicotine only," said co-investigator Hongying Dai, an associate professor in the College of Public Health at the University of Nebraska Medical Center in Omaha.
Her team analyzed data from more than 14,500 teens who were part of a 2017 nationwide survey. Twelve percent said they had vaped within the past month, with 7.4% using nicotine and 3.6% using marijuana.
One-quarter said they had vaped flavoring only. The rest had vaped nicotine, marijuana or multiple substances, the study found.
Current levels of cigarette smoking were associated with an increased risk of vaping all three substances.
Tenth- and 12th-graders were more likely than eighth-graders to vape nicotine, marijuana and flavoring. And boys were more likely to do so than girls. Blacks were less likely than whites to vape nicotine and flavoring, and Hispanics were less likely to vape nicotine.
Dai called the findings a "more nuanced view" of youth's e-cigarette use than previous studies.
The new research was published Dec. 16 in the American Journal of Preventive Medicine.
"Continuous surveillance of youth behaviors and strategies and interventions to reduce youth e-cigarette use are needed. The truth is that no form of tobacco is safe," study co-investigator Mohammad Siahpush said in a journal news release. Siahpush is associate dean for research at the university.
Teen vaping rose sharply between 2017 and this year, and the U.S. surgeon general issued an advisory about it in 2018.
A recent string of vaping-related lung injuries has spurred calls for restrictions on flavored vaping products and e-cigarettes.
The U.S. Centers for Disease Control and Prevention has more on e-cigarettes and children, teens and young adults.