Association of Neighborhood Characteristics and Travel Patterns With Fatal Drug Overdoses

Fatal drug overdoses increased in US cities from 1999 through 2017.¹ Low-resource urban areas—popularly characterized as places where overdoses and drug trade thrive—are often considered self-contained, with residents considered the primary consumers of local drug markets.² There has been less discussion regarding inbound travel to such drug markets from nonresidents and which neighborhood characteristics may correspond with travel decisions. Targeting residents of overdose hot spots for intervention may reinforce stereotypes while excluding nonresident people who use drugs from treatment screening and delivery. We examined travel patterns between locations where fatal drug overdoses occurred and the home residences of the people who died plus the neighborhood-level characteristics that may have differed across these locations. We also compared travel patterns specifically for overdoses involving fentanyl and heroin.

The Columbia University Medical Center institutional review board waived study review and also waived the need for patient informed consent because this research did not involve human subjects research. We followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline. For this cross-sectional study, all fatal drug overdose records from the Cook County, Illinois, medical examiner were obtained for the period August 1, 2014, through December 31, 2018. The records included full toxicology reports; Global Positioning System (GPS) coordinates for overdose location; zip codes of home residence; and age, sex, and race/ethnicity (eMethods in the Supplement). Public transit data included Chicago Transit Authority L and Metra commuter rail stations because transit hubs provide access to drug markets for nonresidents.³

We assessed neighborhood disadvantage using the formula {[(c/10 + d/10) − (a/10 + b/10)]/4} with 5-year US Census percentages, where a represents adults 25 years or older with a college degree, b represents owner-occupied housing, c represents households with incomes below the federal poverty threshold, and d represents female-headed households with children. Neighborhood disadvantage scores ranged from −5 (very low or little disadvantage) to +5 (very severe disadvantage).⁴ We assessed segregation using the Index of Concentration at the Extremes⁵ by subtracting the number of non-Latino Black residents from the number of non-Latino White residents in a zip code and dividing by the zip code population (segregation ranges, −1 indicates 100% Black population; 0 indicates 50% Black, 50% White; and 1 indicates 100% White].

We calculated the euclidean distance from the home zip code centroid to GPS coordinates of the overdose location (eFigure in the Supplement). Because urban zip codes are compact and divided along lines that do not necessarily correspond with residents’ versions of their neighborhood,⁶ we designated overdoses that occurred in the same or contiguous zip codes as home zip code nontraveling and overdoses that occurred 2 or more zip codes away as “far” traveling (eFigure in the Supplement). We used logistic regression to assess individual- and neighborhood-level correlates of travel. Two-sided P < .05 was considered statistically significant. R software, version 3.4.1 (R Foundational for Statistical Computing) was used for statistical analysis.

Of 3927 fatal overdoses, the mean (SD) age across all overdoses was 44.1 (12.6) years, 2972 (75.7%) were men, 1832 (46.7%) were non-Latino White, and 1596 (40.6%) were non-Latino Black. A total of 1171 individuals (30%) had traveled 2 or more zip codes beyond their home zip code (mean [SD] distance, 49.4 [262.4] km). Men (923 of 1171 individuals [78.8%]; P = .003) and younger individuals (mean [SD] age, 41.9 [12.2] vs 44.8 [12.6] years; P < .001) were significantly more likely to travel, and there were no differences by racial/ethnic subcategories. Decedents were more likely to travel far from zip codes with low to high neighborhood deprivation (adjusted odds ratio [AOR], 1.43; 95% CI, 1.27-1.60) and from zip codes that were predominantly non-Latino White to predominantly non-Latino Black (AOR, 2.13; 95% CI, 1.61-2.83) (Table 1). Travel was significantly associated with fentanyl-involved overdoses (AOR, 1.40; 95% CI, 1.20-1.63), but not with heroin-involved overdoses (AOR, 1.12; 95% CI, 0.96-1.29) after controlling for race/ethnicity, sex, neighborhood deprivation score, and transit hub in home zip code (Table 2).

Thirty percent of decedents traveled far from their home to the location of the fatal overdose. Decedents tended to travel to more resource-deprived and segregated neighborhoods compared with their home neighborhood. Those who traveled were more likely to have fentanyl in their system at the time of death. This cross-sectional study was limited to fatal overdoses in 1 US mixed urban-suburban county. We did not have access to narratives for how or why people traveled to their overdose location. Additional narrative information is needed to provide context into how place and travel contribute to overdose.

People who use drugs to fatal ends may reside far distances from where they consume drugs. Nonresidents of overdose hot spots should be a focus of treatment screening and delivery.

Accepted for Publication: June 22, 2020.

Published Online: November 23, 2020. doi:10.1001/jamainternmed.2020.3823

Corresponding Author: Elizabeth D. Nesoff, PhD, MPH, Department of Epidemiology, Columbia University Mailman School of Public Health, 722 W 168th St, Fifth Floor, New York, NY 10032 (en2408@columbia.edu).

Author Contributions: Dr Nesoff had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: All authors.

Acquisition, analysis, or interpretation of data: Nesoff.

Drafting of the manuscript: Nesoff.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Nesoff.

Obtained funding: Nesoff, Martins.

Administrative, technical, or material support: Branas.

Supervision: Branas, Martins.

Conflict of Interest Disclosures: None reported.

Funding/Support: This work was supported by grant T32DA031099 from the National Institute on Drug Abuse.

Role of the Funder/Sponsor: The National Institute on Drug Abuse had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.