Association Between Neighborhood Violence and Biological Stress in Children.

Importance: Exposure to violence continues to be a growing epidemic, particularly among children. An enhanced understanding of the biological effect of exposure to violence is critical. Objective: To examine the association between neighborhood violence and cellular and biological stress in children. Design, Setting, and Participants: A matched, cross-sectional study of 85 black children aged 5 to 16 years from 52 neighborhoods took place in the greater New Orleans, Louisiana, area between January 1, 2012, and July 31, 2013. Exposures: Density of businesses where individuals can purchase alcohol as measured by rates per capita of liquor or convenience stores, and violence as measured by reports of violent crime and reports of domestic violence, operationalized as reports per capita of crime and domestic violence. Rates of exposure within a 500-, 1000-, and 2000-m radius from the child's home were calculated. Main Outcomes and Measures: Primary biological outcomes were telomere length and cortisol functioning.
Results: Among the 85 children in the study, (mean [SD] age, 9.8 [3.1] years; 50 girls and 35 boys) significant variation in telomere length and cortisol functioning was observed at the neighborhood level, with intraclass correlation coefficients of 6% for telomere length, 3.4% for waking cortisol levels, and 5.5% for peak cortisol levels following a stressor. Density of liquor or convenience stores within a 500-m radius of a child's home was associated with a decrease in mean telomere length by 0.004 for each additional liquor store or convenience store (β [SE], -0.004 [0.002]; P = .02). The rate of domestic violence was significantly and inversely associated with a decrease in mean telomere length by 0.007 for each additional report of domestic violence in a 500-m radius of a child's home (β [SE], -0.007 [0.001]; P < .001). The rate of violent crime was significantly associated with a decrease in mean telomere length by 0.006 for each additional report of violent crime in a 500-m radius of a child's home (β [SE], -0.006 [0.002]; P < .001). Children exposed to more liquor and convenience stores within 500 m of their home were significantly less likely to reduce cortisol levels after a reactivity test (β, 0.029; P = .047), as were children exposed to high rates of domestic violence (β, 0.088; P = .12) and violent crime (β, 0.029; P = .006). Children exposed to more liquor and convenience stores within 500 m of their home had a steeper diurnal decline in cortisol levels during the day (β [SE], -0.002 [0.001]; P = .04), as did children exposed to more violent crime within 500 m of their home (β [SE] -0.032 [0.014]; P = .02). Conclusions and Relevance: Neighborhoods are important targets for interventions to reduce the effect of exposure to violence in the lives of children. These findings provide the first evidence that objective exposures to neighborhood-level violence influence both physiological and cellular markers of stress, even in children.