Redlined Massachusetts Tracts Saw 86% Higher Overdose Death Rates

Massachusetts census tracts assigned the worst grade on 1930s federal redlining maps recorded opioid-related overdose death rates 86% higher than tracts assigned the best grade, according to a study from Boston Medical Center researchers published in the Journal of Health Care for the Poor and Underserved. The analysis covered 326 census tracts where 1,829 adults died of opioid-related overdoses between 2015 and 2019.

The gap did not stop at the two extremes. Compared with tracts graded "best," overdose death rates were 53% higher in tracts graded "still desirable" and 61% higher in those graded "declining," a pattern that tracked the historical lending grades step by step. The differences stayed statistically significant after the researchers adjusted for race and ethnicity, the age composition of each neighborhood, and a social vulnerability index.

How the study was built

The Home Owners' Loan Corporation, a federal agency created during the Great Depression, drew maps in the 1930s that graded neighborhoods from "best" to "hazardous" for mortgage lending. The lower grades were applied disproportionately to Black and immigrant communities and were followed by decades of disinvestment.

The Boston Medical Center team converted those grades into a historical redlining score for each Massachusetts census tract, then matched the scores to state overdose death records for 2015 through 2019. The study's first author is Rebecca Smeltzer, a doctoral student at the University of Southern California; Avik Chatterjee, an addiction specialist at Boston Medical Center, is senior author.

Why place matters to an overdose

"Addressing the opioid overdose crisis requires understanding the broader social and structural factors that shape health outcomes," Chatterjee said. "Where people live, the resources available to their communities, and the lasting effects of historical disinvestment all matter."

That framing moves the question away from individual risk factors alone. A neighborhood graded "hazardous" in 1937 was one where mortgages were difficult to obtain, where homeownership and the wealth it builds were harder to hold, and where commercial investment followed the lending map. Ninety years later, the study found, the same tracts carry a measurably higher rate of fatal overdose.

"Our findings suggest that overdose risk is influenced not only by individual factors, but also by long-standing structural inequities tied to place and community investment," Smeltzer said.

The researchers argue the finding has a policy consequence: investment in housing, economic opportunity, health care access and community resources in these neighborhoods may reduce overdose deaths.

A statewide decline that is not shared evenly

The study lands at an awkward moment for Massachusetts, which has reported substantial progress. According to the state Department of Public Health, opioid-related overdose deaths fell nearly 60% between 2022 and 2025, dropping below 1,000 for the first time in more than a decade.

A falling statewide total and a persistent neighborhood gradient can both be true at once. If declines concentrate in better-resourced communities, the average improves while the tracts with the highest historical burden keep the highest rates — a dynamic that matters for where treatment capacity and medication for opioid use disorder get placed.

The Massachusetts findings also fit a wider body of research on geography and overdose. Studies of the current wave have repeatedly found that fatal overdoses cluster in neighborhoods with less access to care, thinner pharmacy networks and more housing instability. Linking that to lending maps drawn before most of the people in the study were born is the study's contribution.

The limits of a 1930s map

The authors are explicit that the analysis identifies an association, not causation. Historical redlining grades were assigned to neighborhoods that already differed in income, housing stock and population, and the study cannot separate the effect of the grade from everything else that followed it.

The analysis was also restricted to census tracts with sufficient historical mapping coverage and excluded nonurban communities that never received a redlining grade — which means rural Massachusetts, where overdose rates have also run high, is largely outside the frame. Rural parts of the country have their own access problems that a lending map cannot describe.

What remains is a usable measurement: a stable, publicly drawn classification from the 1930s that predicts where overdose deaths concentrated in the 2010s, after adjustment for the obvious confounders. For state and county health departments deciding where to put the next mobile unit or the next bridge clinic, that is a map they can act on — and a reminder that the national decline in overdose deaths is an average that hides places where the toll never fell.