Approximately 9% of U.S. middle and high school students reported using cannabis in e-cigarettes in 2016, according to research published in JAMA Pediatrics. This included one-third of students who reported e-cigarette use.

The results equate “to more than 2 million youth who have ever used cannabis in an e-cigarette, including nearly one in three high school e-cigarette users and nearly one in four middle school e-cigarette users,” Katrina E. Trivers, PhD, MSPH, lead epidemiologist in the CDC’s Office on Smoking and Health, told Infectious Diseases in Children.