Study: Teens Who Vape Or Use Hookah More Likely To Use Marijuana

(CNN) — Teens who used e-cigarettes and hookah were up to four times more likely to use marijuana later, according to a study published Monday in the journal Pediatrics.
Researchers from the University of Pennsylvania and the University of Southern California surveyed 2,668 students at 10 public high schools in Los Angeles beginning in fall 2013, when they were 14 years old and in ninth grade.
The students answered a paper-and-pencil, phone or internet survey that asked whether they had ev