Tracking teens with GPS-enabled cell phones to study contextual exposures and adolescent alcohol and risk behavior

Background: Teens' increased freedom to explore different environments potentially increases exposure to social disorganization, increasing risks for alcohol, tobacco, and other drug (ATOD) use and delinquency. Prior studies consider context as a static area around teens' homes (e.g., census tracts). A more salient approach may be to measure the “dynamic context,” places teens experience in daily activities, and determine its relation to ATOD/delinquency. Methods: In this pilot study, teens (N=17) aged 16-17 (52.9% female) carried GPS-enabled smartphones for one week during which their locations were tracked. Dynamic contexts were created for each participant by connecting GPS points in time order and adding a spatial buffer (100m) around their multiday route. Social disorganization data (measured by a census SES index and alcohol outlet data) were appended to routes. Teens completed online surveys and texts regarding their current behaviors. Results: Teens' dynamic contexts were land areas that intersected 49.5 census tracts on average and included minimal spatial intersection (4.6%) with their residential neighborhood (census tract). Dynamic contexts contained 9.4 times more alcohol outlets than present in their residential tract. However, there were no significant differences between these two areas in the SES index. In multivariable analyses, teens exposed to more alcohol outlets in their dynamic contexts were more likely to be lifetime drinkers. Linear regressions showed that the SES index in dynamic contexts was related to lifetime delinquency. Conclusions: Findings show the importance of considering dynamic contexts when examining high risk teen behaviors. This must be understood to inform prevention efforts.