*The following is excerpted from an online article posted on HealthDay.
The e-cigarette may not be just a "healthier alternative" to smoking for teens. New research shows that teens who vape may be more apt to use tobacco cigarettes later on.
When teens smoked an e-cigarette during one month, they were up to seven times more likely to smoke tobacco in the future, researchers found.
"Youth using e-cigarettes were consistently more likely to smoke," said study author Krysten Bold, an associate research scientist at Yale School of Medicine's department of psychiatry.
But, she also noted, "We cannot determine cause and effect from these kinds of reports. There can be many reasons kids decide to smoke."
Approximately 3 million U.S. teens currently use e-cigarettes, the researchers said.
"E-cigarettes are commonly used by youth, and have many features that are appealing to kids," Bold explained.
The study included more than 800 high schoolers from three public schools in Connecticut. The students completed surveys at three different times: 2013, 2014 and 2015.
The average age of the teens at the beginning of the study was 15. There were 428 girls and the group was nearly 90 percent white.
The researchers also looked at the reverse relationship -- whether kids who smoked tobacco cigarettes were more likely to try e-cigarettes in the future. But they found no statistically significant relationship.
The findings "highlight that we really need to talk to kids about e-cigarettes and their potential consequences," Bold said. She added that more research is needed into possible long-term effects.
The new study was published online Dec. 4 in the journal Pediatrics.