Homophily and peer influence effects for spreading adolescent smoking and vaping norms, and other smoking outcomes, in schools: The MECHANISMS study

Jennifer M. Murray*, Sharon C. Sánchez-Franco, Olga L. Sarmiento, Erik O. Kimbrough, Christopher Tate, Shannon C. Montgomery, Joaquín Jaramillo, Rajnish Kumar, Laura Dunne, Abhijit Ramalingam, Erin L. Krupka, Felipe Montes, Huiyu Zhou, Laurence Moore, Linda Bauld, Blanca Llorente, Frank Kee, Ruth F. Hunter

*Corresponding author for this work

Research output: Contribution to journalMeeting abstractpeer-review


Background/purpose: The MECHANISMS study targets smoking prevention for 12-13 year olds in Northern Ireland and Bogotá, and investigates the mechanisms through which social norms for smoking and vaping are transmitted through school social networks. We aimed to provide a broad overview of homophily and peer influence effects for norms and other smoking outcomes. Methods: Pre- and post- intervention, participants completed online behavioral economics experiments eliciting social norms for smoking and vaping. Pupils also completed self-report surveys capturing their friendship networks, self-report smoking norms, self-report smoking behavior, intentions, knowledge, attitudes, and psycho-social antecedents. Homophily was examined using logistic regressions with dummy variables indicating friend nominations as outcome variables, and absolute differences between focal participants and potential friends on smoking outcomes as predictors. Peer influence from friends, school classes, and school year groups, was examined using ordinary least square regressions with focal participants' follow-up scores as outcome variables, and average peer scores as predictors. Results: Twelve schools participated (1344 pupils). Our results provide evidence demonstrating homophily and peer influence effects from average peer responses for the experimental norms (homophily: odds ratios [ORs]=0.94-0.98; peer influence: standardized regression coefficients [βs]=0.08-0.19), self-report norms (homophily: ORs=0.95-0.99; peer influence: βs=0.07-0.19), other self-report smoking outcomes (homophily: ORs=0,95-0.99; peer influence: βs=0.07-0.23), and objectively measured smoking behavior (homophily: ORs=0.87-0.90; peer influence: βs=0.26-0.55; p≤0.01). Conclusions/implications: These findings support using social norms strategies in adolescent smoking prevention interventions. Future research should consider homophily and social influence processes jointly, and investigate whether these findings translate to other settings with varying culture and norms.
Original languageEnglish
Pages (from-to)S11
Number of pages1
JournalInternational Journal of Behavioral Medicine
Issue numberSuppl 1
Publication statusPublished - 05 Jun 2021
Event6th International Congress of Behavioural Medicine 2021 - Glasgow, United Kingdom
Duration: 07 Jun 202111 Jun 2021


Dive into the research topics of 'Homophily and peer influence effects for spreading adolescent smoking and vaping norms, and other smoking outcomes, in schools: The MECHANISMS study'. Together they form a unique fingerprint.

Cite this