Peer beliefs and smoking in adolescence: a longitudinal social network analysis.

Background: Peer smoking is one of the strongest predictors of adolescent cigarette use, but less is known about whether other peer characteristics also contribute to this behavior.

Objectives: This study examined the links between adolescent cigarette use and peer beliefs about smoking. It tested whether peer beliefs about smoking are associated with changes in cigarette use, whether this association is a result of changes in individual beliefs about smoking, and how beliefs inform friendship choices.

Methods: Analyses drew on data collected from 29 school-based networks, each measured at five occasions as students moved from 6th through 9th grade, as part of the study of the PROSPER partnership model. Longitudinal social network models provided estimates of friendship selection and behavior for an average of 6,200 students at each measurement point and more than 9,000 students overall.

Results: Peer beliefs about smoking influenced cigarette use both directly and through their impact on individual beliefs. Respondents tended to name friends whose beliefs about smoking were similar to their own, and the likelihood of being named as a friend was higher for those who reported more positive beliefs about smoking.

Conclusion: The results from this study suggest that peer beliefs about smoking, in addition to peer cigarette use itself, are associated with adolescent smoking through several mechanisms. Because beliefs favorable to cigarette use are present before adolescents actually smoke, these results underscore the importance of implementing smoking prevention programs in early adolescence.