Popular kids in US and Mexico more likely to smoke,

New research from the University of Southern California (USC) and University of Texas finds that popular students in seven Southern California high schools are more likely to smoke cigarettes than their less popular counterparts.

The study, which appears online this week in the Journal of Adolescent Health, confirms trends observed in previous USC-led studies of students in the sixth through 12th grades across the United States and in Mexico.

"That we're still seeing this association more than 10 years later, despite marginal declines in smoking, suggests that popularity is a strong predictor of smoking behavior," said Thomas W. Valente, Ph.D., professor of preventive medicine at the Keck School of Medicine of USC and lead author of three prior studies on the subject.

In the newest study, Valente and colleagues asked 1,950 students in the ninth and 10th grades in October 2006 and 2007 whether they had ever tried smoking, how frequently they had smoked in the past 30 days, how many students their age they thought smoked cigarettes, how they perceived their close friends felt about smoking, and who their five best friends were at school. Popularity was measured by the frequency that other respondents named a student as a friend.

The researchers found that those who believed their close friends smoked were more likely to also smoke, even if their perception was incorrect. Popular students became smokers earlier than the less popular. And students who became smokers between the ninth and 10th grade were more likely to form friendships with other smokers.

Surprisingly, student perception of the norm (i.e., out of 100 students your age, how many do you think smoke cigarettes once a month or more?) was less likely to influence smoking than the perceived behavior of their close friends.

In a 2012 study that appeared in Salud Pública de México, the bi-monthly journal published by the Instituto Nacional de Salud Pública (National Institute of Public Health), Valente and colleagues at the Mexican Social Security Institute surveyed 399 teenagers at a high school in Jalisco. Two other studies — one in 2005 that polled 1,486 students in the sixth and seventh grades across Southern California and another in 2001 that polled 2,525 high-school students across the United States — also appeared in the Journal of Adolescent Health.

"Adolescence is a time when students turn to others to figure out what is important. These are four different samples, now, coming from different places — and the finding is consistent," Valente said.