Redlining Linked to Asthma Racial Health Disparities, Inequities

The shadows of historic racist policies such as redlining continue to impact present-day health outcomes, leaving Black people to bear the burden of health inequities, according to a recent analysis by researchers from the University of Pittsburgh School of Public Health revealing asthma racial health disparities.

The NIH-funded study, published in the American Journal of Respiratory and Critical Care Medicine, examined how racism—rather than race—worsened asthma severity and perpetuated racial disparities for Black people. 

“We directly link racist loaning practices more than 80 years ago to the maintenance of poor environmental quality in the most redlined neighborhoods today,” lead author Alexander Schuyler, MD, PhD, a student in Pitt’s Medical Scientist Training Program, said in a public statement. “Our data, in turn, connects the higher pollution exposures to worsened asthma outcomes. In short, institutional racism – not race-based biology – is why many Black Pittsburghers experience severe asthma.” 

During the 1930s, the Home Owners' Loan Corporation (HOLC) created a four-tiered grading system for mortgage applications based on racial discrimination, also known as redlining, in over 200 cities, including Pittsburgh and Allegheny County.

Predominantly Black or immigrant neighborhoods were deemed “undesirable” for home loans and other financial investments in healthcare, business, and industry.

The corporation assigned an “A” score to neighborhoods it deemed “best” and a “D” score to neighborhoods it called “hazardous” for mortgage lending. “D” neighborhoods had the highest proportion of Black residents.

To conduct the study, researchers leveraged data from over 1,000 participants in the Asthma Institute’s Asthma Registry. They identified which neighborhoods were subjected to historical redlining, as defined by a 1930s HOLC map.

Researchers found that emissions of carbon monoxide, fine particulates, sulfur dioxide, and volatile organic compounds all increased across HOLC grades. However, “D” neighborhoods experienced the greatest environmental inequities as they had the highest pollution levels.

Similarly, people residing in “D” neighborhoods had the worst asthma-related outcomes.

“Air pollution induces structural changes in the lungs, causes inflammation, and damages cells lining the airway, all of which can exacerbate asthma,” said Sally Wenzel, MD, chair of Pitt Public Health’s Department of Environmental and Occupational Health.

“So, seeing worse asthma in people living in neighborhoods with more pollution isn’t surprising. What struck me was the enduring legacy of redlining,” continued Wenzel, who is also the director of Pitt’s Asthma and Environmental Lung Health Institute at UPMC. “We are still seeing the long-term effects of the loss of generational capital and neighborhoods labeled as ‘toxic.’ Institutional racism is something we, as clinicians, have to recognize as a real, continued threat to the health of our patients and one we must fight against.”

In addition, researchers found that participants living in “D” neighborhoods, especially those who identified as Black, received lower treatment quality. In comparison to participants residing in “A” neighborhoods, participants in “D” neighborhoods with worsening asthma were less likely to be prescribed stronger medications or be referred for advanced care.

“This is another example of ascribing an unsubstantiated biological value to race to explain Black people having worse health outcomes, rather than recognizing it as institutional racism, which is something that can be addressed,” Schuyler said. “I hope our work empowers patients and further directs clinicians to account for racism, not race, when caring for their patients and encourages all of us to support local and national policies that repair the multigenerational damage brought by institutional racism.”

The impacts of redlining have also been observed in maternal health disparities. A 2021 study discovered that poor maternal health outcomes were largely concentrated in areas that in the 1940s had been deemed “hazardous” for homeowner’s loans by HOLC.

In areas designated “Best” or “Still Desirable,” the researchers observed a 7.55 percent pre-term birth rate. However, in areas designated “Hazardous” in the 1940s, the researchers noticed a present-day pre-term birth rate of 12.38 percent.

The data showed similar trends with obstetric and medical complications; there were significantly higher rates of complications in places deemed “Hazardous” by HOLC in 1940 and lower rates in places deemed “Best” or “Still Desirable.”

“Potentially, the overarching influence of a system of profound structural inequity ripples forward in time with impacts that extend beyond measurable socioeconomic inequity,” the researchers stated.