WEDNESDAY, Sept. 28 (HealthDay News) — The drinking habits of the friends of a teenager's boyfriend or girlfriend may have more influence on the youngster's drinking than the habits of the teen's own friends or romantic partner.

That's the finding of U.S. researchers who analyzed national data collected from 449 heterosexual couples who were in grades 7 to 12 in the mid-1990s.

The study appears in the October issue of the journal American Sociological Review.

"Dating someone whose friends are big drinkers is more likely to cause an adolescent to engage in dangerous drinking behaviors than are the drinking habits of the adolescent's own friends or romantic partner," lead author Derek Kreager, an associate professor of crime, law, and justice at Pennsylvania State University, said in a journal news release. "This applies to both binge drinking and drinking frequency."

For example, the researchers found that teens whose romantic partner's friends were heavy drinkers were more than twice as likely to binge drink than adolescents with friends or romantic partners who were heavy drinkers.

"The friends of a partner are likely to be very different from the adolescent and his or her friends and they might also be, at least a little, different from the partner," Kreager said. "Adolescents are motivated to be more like their partner's friends in an effort to strengthen their relationship with their partner."

But he noted that the influence of a romantic partner's friends isn't always negative.

"If an adolescent is a drinker and he or she starts going out with someone whose friends predominantly don't drink, you would find the same effect but in the opposite direction," Kreager explained.

When educators address drinking behaviors and attitudes, they should give more thought to dating and related influences, Kreager said.