CCEB Seminar- Christopher Neil Morrison, PhD

"Using GPS to Assess Individuals' Exposure to Neighborhood Social and Physical Environments"Christopher Neil Morrison, PhDDepartment of Biostatistics, Epidemiology, and InformaticsUniversity of Pennsylvania The physical and social environmental conditions around individuals' places of residence affect their health outcomes. However, individuals move through space over time, and exposure measured at or around the home may not be a valid surrogate for absorbed exposure. Measurement error may bias estimated relationships. To improve upon residence-based measures of exposure to physical and social environmental conditions, previous studies have approximated individuals' movements at or near specific activity locations, defined as the places to which people travel as part of their routine activities. Global Positioning Systems (GPS)-enabled smartphones are a technological advance that allows researchers to more precisely measure exposures. The association between retail alcohol outlets and alcohol consumption is an ideal example with which to explore these measurement issues. Some previous studies find greater exposure to alcohol outlets within residential neighborhoods is associated with greater alcohol consumption, while other studies find no such association. The approaches taken to measuring exposure differ greatly between studies. Using data for 257 adolescents who were followed using GPS tracking and ecological momentary assessments over four weeks, this presentation will describe and compare residence-based, activity location-based, and GPS-based measures of exposure to retail alcohol outlets. The various exposure measures are then related to alcohol consumption during the four weeks. Results provide the basis for recommendations regarding optimal approaches to measuring individuals' exposure to retail alcohol outlets, and physical and environmental conditions more broadly.