Young people who use e-cigarettes have a higher risk of also using marijuana.
That is according to a new study from Boston's Children's Hospital.
Researchers analyzed 21 studies involving more than 128-thousand young people ages 12 to 24.
Those who vaped were three and a half times more likely to have also used marijuana at some point.
That is compared to the teens who did not vape.
The association of e-cigarettes and marijuana use was higher in the younger teens.