The effect of neighborhood context on the relationship between substance misuse and weapons aggression in urban adolescents seeking ed care

Background: Frameworks for studying the ecology of human behavior suggest that multiple levels of the environment influence behavior and that these levels interact. Applied to studies of weapons aggression, this suggests proximal risk factor (e.g., substance use) effects may differ across neighborhoods. Objectives: To estimate how the association between weapons aggression and substance use varies as a function of several community-level variables. Methods: Individual-level measures (demographics, behavioral measures) were obtained from a survey of youth aged 14-24 years old seeking care at a Level-1 ED in Flint, Michigan. Community-level variables were obtained from public sources. Logistic generalized additive models were used to test whether community-level variables (crime rates, alcohol outlets, demographics) modify the link between individual-level substance use variables and the primary outcome measure: self-reported past 6-month weapon (firearm/knife) related aggression. Results: The effect of marijuana misuse on weapons aggression varied significantly as a function of five community-level variables: racial composition, vacant housing rates, female headed household rates, density of package alcohol outlets, and nearby drug crime rates the effect of high-risk alcohol use did not depend on any of the eight community variables tested. Conclusions: The relationship between marijuana misuse and weapons aggression differed across neighborhoods with generally less association in more disadvantaged neighborhoods, while high-risk alcohol use showed a consistently high association with weapons aggression that did not vary across neighborhoods the results aid in understanding the contributions of alcohol and marijuana use to the etiology of weapon-related aggression among urban youth, but further study in the general population is required.