The Relationship of Historical Redlining with Present-Day Neighborhood Environmental and Health Outcomes: A Scoping Review and Conceptual Model

Abstract

Following the Great Depression and related home foreclosures, the federal government established new agencies to facilitate access to affordable home mortgages, including the Home Owners’ Loan Corporation (HOLC) and Federal Housing Administration (FHA). HOLC and FHA directed widespread neighborhood appraisals to determine investment risk, referred to as “redlining,” which took into account residents’ race. Redlining thereby contributed to segregation, disinvestment, and racial inequities in opportunities for homeownership and wealth accumulation. Recent research examines associations between historical redlining and subsequent environmental determinants of health and health-related outcomes. In this scoping review, we assess the extent of the current body of evidence, the range of outcomes studied, and key study characteristics, examining the direction and strength of the relationship between redlining, neighborhood environments, and health as well as different methodological approaches. Overall, studies nearly universally report evidence of an association between redlining and health-relevant outcomes, although heterogeneity in study design precludes direct comparison of results. We critically consider evidence regarding HOLC’s causality and offer a conceptual framework for the relationship between redlining and present-day health. Finally, we point to key directions for future research to improve and broaden understanding of redlining’s enduring impact and translate findings into public health and planning practice.

Linking environmental injustices in Detroit, MI to institutional racial segregation through historical federal redlining

“…Rather, they are reflections on how the federal government reinforced racial and ethnic segregation and the use of race as a significant determinant of property value [7]. HOLC's 1930s formalization of "redlining" was how the federal government supported a diverse set of actors' discriminatory beliefs on race and place which perpetuated racial and ethnic segregation across the US [8]. This provides evidence against de facto residential segregation, and shifts the ensuing impacts (e.g., environmental) onto the institutions themselves (i.e., de jure residential segregation) [5,6].…”

“…Within the context of historical redlining, recent studies have shown associations between redlining and heat stress and higher intra-urban heat [12], less greenspace [13,14], higher incidence of brownfield sites [14], oil and gas well siting [15], and air pollution [8,16]. Poor health is a well-understood consequence of environmental exposures; redlining has also been associated with higher cardiovascular disease risk [17], asthma risk [18], preterm birth [19,20], breast cancer mortality [21], and generally poorer mental and physical health [22][23][24].…”

Redlining has led to increasing rates of nephrolithiasis in minoritized populations: a hypothesis

“…Although these grades were assigned nearly 100 years ago, they have a remarkably persistent association with present day environmental conditions [31]. When surveyed in 2020, the grades assigned in the 1930s were associated with significant differences in ambient temperature [32].…”

“…When controlling for median household income and proportion of Black residents in Baltimore, MD neighborhoods, Grade D areas are associated with 5.2 years reduction in life expectancy and C-graded areas with 4.9 year reduction [43]. Overall, a recent scoping review found that studies nearly universally reported evidence of an association between redlining and health-relevant outcomes [31].…”

Long-term Effects of Redlining on Environmental Risk Exposure

“…Urban design, in turn, can further amplify these background climate stressors through the well-known urban heat island and rainfall effects, which are largely controlled by the local dominance of impervious land covers, surface roughness, and lack of mature tree canopy. While the extent to which present-day exposures and outcomes related to these climate-exacerbated environmental risks in urban areas can be linked to historical policies has received recent attention (Mujahid et al 2021;Lane et al 2022;Swope et al 2022), causal inference within observed correlative associations has yet to be established. Here, we use a boundary design to estimate the persistent, causal effects of redlining on present-day exposure to climate change-exacerbated environmental risks in six large U.S. cities.…”