Browsing by Author "Morrison, Christopher N."

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    Assessing Individuals’ Exposure to Environmental Conditions Using Residence-Based Measures, Activity Location-Based Measures, and Activity Path-Based Measures
    (Wolters Kluwer, 2019-03) Morrison, Christopher N.; Byrnes, Hilary F.; Miller, Brenda A.; Kaner, Emily; Wiehe, Sarah E.; Ponicki, William R.; Wiebe, Douglas J.; Pediatrics, School of Medicine
    Background: Many approaches are available to researchers who wish to measure individuals' exposure to environmental conditions. Different approaches may yield different estimates of associations with health outcomes. Taking adolescents' exposure to alcohol outlets as an example, we aimed to (1) compare exposure measures and (2) assess whether exposure measures were differentially associated with alcohol consumption. Methods: We tracked 231 adolescents 14-16 years of age from the San Francisco Bay Area for 4 weeks in 2015/2016 using global positioning systems (GPS). Participants were texted ecologic momentary assessment surveys six times per week, including assessment of alcohol consumption. We used GPS data to calculate exposure to alcohol outlets using three approach types: residence-based (e.g., within the home census tract), activity location-based (e.g., within buffer distances of frequently attended places), and activity path-based (e.g., average outlets per hour within buffer distances of GPS route lines). Spearman correlations compared exposure measures, and separate Tobit models assessed associations with the proportion of ecologic momentary assessment responses positive for alcohol consumption. Results: Measures were mostly strongly correlated within approach types (ρ ≥ 0.7), but weakly (ρ < 0.3) to moderately (0.3 ≤ ρ < 0.7) correlated between approach types. Associations with alcohol consumption were mostly inconsistent within and between approach types. Some of the residence-based measures (e.g., census tract: β = 8.3, 95% CI = 2.8, 13.8), none of the activity location-based approaches, and most of the activity path-based approaches (e.g., outlet-hours per hour, 100 m buffer: β = 8.3, 95% CI = 3.3, 13.3) were associated with alcohol consumption. Conclusions: Methodologic decisions regarding measurement of exposure to environmental conditions may affect study results.
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    Association of environmental indicators with teen alcohol use and problem behavior: Teens' observations vs. objectively-measured indicators
    (Elsevier, 2017-01) Byrnes, Hilary F.; Miller, Brenda A.; Morrison, Christopher N.; Wiebe, Douglas J.; Woychik, Marcie; Wiehe, Sarah E.; Medicine, School of Medicine
    Most prior studies use objectively measured data (e.g., census-based indicators) to assess contextual risks. However, teens' observations might be more important for their risk behavior. OBJECTIVES: 1) determine relationships between observed and objective indicators of contextual risks 2) determine relations of observed and objective indicators with teen alcohol use and problem behavior. Teens aged 14-16 (N=170) carried GPS-enabled smartphones for one month, with locations documented. Ecological momentary assessment (EMA) measured teens' observations via texts regarding risk behaviors and environmental observations. Objective indicators of alcohol outlets and disorganization were spatially joined to EMAs based on teens' location at the time of the texts. Observed and objective disorganization, and objective indicators of alcohol outlets were related to alcohol use. Observed disorganization was related to problem behavior, while objective indicators were unrelated. Findings suggest the importance of considering teens' observations of contextual risk for understanding influences on risk behavior and suggest future directions for research and prevention strategies.
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    Brief report: Using global positioning system (GPS) enabled cell phones to examine adolescent travel patterns and time in proximity to alcohol outlets
    (Elsevier, 2016-07) Byrnes, Hilary F.; Miller, Brenda A.; Morrison, Christopher N.; Wiebe, Douglas J.; Remer, Lillian G.; Wiehe, Sarah E.; Department of Pediatrics, IU School of Medicine
    As adolescents gain freedom to explore new environments unsupervised, more time in proximity to alcohol outlets may increase risks for alcohol and marijuana use. This pilot study: 1) Describes variations in adolescents' proximity to outlets by time of day and day of the week, 2) Examines variations in outlet proximity by drinking and marijuana use status, and 3) Tests feasibility of obtaining real-time data to study adolescent proximity to outlets. U.S. adolescents (N = 18) aged 16–17 (50% female) carried GPS-enabled smartphones for one week with their locations tracked. The geographic areas where adolescents spend time, activity spaces, were created by connecting GPS points sequentially and adding spatial buffers around routes. Proximity to outlets was greater during after school and evening hours. Drinkers and marijuana users were in proximity to outlets 1½ to 2 times more than non-users. Findings provide information about where adolescents spend time and times of greatest risk, informing prevention efforts.
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    Exposure to alcohol outlets, alcohol access, and alcohol consumption among adolescents
    (Elsevier, 2019-12-01) Morrison, Christopher N.; Byrnes, Hilary F.; Miller, Brenda A.; Wiehe, Sarah E.; Ponicki, William R.; Wiebe, Douglas J.; Pediatrics, School of Medicine
    Background: Adolescents who live near more alcohol outlets tend to consume more alcohol, despite laws prohibiting alcohol purchases for people aged <21 years. We examined relationships between adolescents' exposure to alcohol outlets, the sources through which they access alcohol, and their alcohol consumption. Methods: Participants for this longitudinal study (n = 168) were aged 15-18 years and were from 10 cities in the San Francisco Bay Area. We collected survey data to measure participant characteristics, followed by 1 month of GPS tracking to measure exposure to alcohol outlets (separated into exposures near home and away from home for bars, restaurants, and off-premise outlets). A follow-up survey approximately 1 year later measured alcohol access (through outlets, family members, peers aged <21 years, peers aged ≥21 years) and alcohol consumption (e.g. count of drinking days in last 30). Generalized structural equation models related exposure to alcohol outlets, alcohol access, and alcohol consumption. Results: Exposure to bars and off-premise outlets near home was positively associated with accessing alcohol from peers aged <21, and in turn, accessing alcohol from peers aged <21 was positively associated with alcohol consumption. There was no direct association between exposure to alcohol outlets near home or away from home and alcohol consumption. Conclusions: Interventions that reduce adolescents' access through peers aged <21 may reduce adolescents' alcohol consumption.