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“Geography of risk” impacts analysis of racial inequities in COVID-19 deaths


April 22, 2021

April 5, 2021

COVID-19 has placed a disproportionate burden on communities of color, reflected in the higher rates of positive cases, long-term health effects and deaths. While public health leaders analyze and quantify these inequities, a group of UNC epidemiologists is concerned that surveillance methods do not fully consider structural racism’s impact on the geographic distribution of cases.

In a new commentary, they call for a different approach to monitoring COVID-19 data – one that compares risks across racial and ethnic demographics, which can help lawmakers, researchers and health professionals create a more equitable response to the pandemic.

Lauren Zalla

Lauren Zalla

The commentary, published in the American Journal of Epidemiology, examines why the Centers for Disease Control and Prevention’s (CDC) method of analyzing mortality data doesn’t provide a full picture of racial inequity in the risk of contracting and dying from COVID-19. The commentary is a collaboration between doctoral student Lauren Zalla and assistant professors Chantel Martin, PhD, and Jess Edwards, PhD, from the UNC Gillings School of Global Public Health, along with Danielle Gartner, PhD, from Michigan State University and Grace Noppert, PhD, from the University of Michigan. Martin is also a Faculty Fellow at the Carolina Population Center; Noppert is a former postdoctoral student.

Dr. Chantel Martin

Dr. Chantel Martin

Dr. Jess Edwards

Dr. Jess Edwards

Historical policies in the United States have entrenched structural racism into the country’s geography. Redlining, a policy of racially segregating communities that was legally abolished in 1968, has had lasting social and health ramifications for communities of color. Its effects, to this day, have created inequities in access to quality education, employment and health care.

“One of the most powerful mechanisms through which racism operates is the structuring of physical space,” the team stated in the commentary. “Policies that instituted reservations and sanctioned redlining, that concentrated the agricultural industry in certain towns and not others, that funded water and sanitation projects in some counties and not others, that ‘revitalized’ some neighborhoods and not others, have created a geography of risk, effectively drawing the map for the spread of COVID-19.”

When the CDC began releasing data on disparities in COVID-19 deaths, they cautioned not to compare the racial and ethnic distribution of these deaths to the racial and ethnic distribution of the entire U.S. population. This is because COVID-19 deaths are concentrated in areas where the racial and ethnic population distribution differs from the U.S. overall. The CDC advised that the racial distribution of COVID-19 deaths should instead be compared to an adjusted population distribution that they constructed using a statistical technique called weighting to more closely resemble the places hardest hit by the pandemic.

“This adjustment makes disparities appear to vanish,” Zalla explained. “In the first nine months of 2020, 42% of people who died from COVID-19 were Black or Latinx. These groups represent 31% of the U.S. population but are overrepresented in places like New York, Los Angeles and Chicago, so they represent 47.6% of the weighted population constructed by the CDC.”

In other words, weighting makes it seem like Black and Latinx people are underrepresented among COVID-19 deaths when, in fact, they are overrepresented.

“The CDC’s statistical adjustment for geography ignores the fact that structural racism has played an important role in determining how different racial and ethnic groups are distributed throughout the U.S.,” Zalla said. “The fact that communities of color are more likely to live in places like New York, Los Angeles and Chicago is itself an important component of disparities in COVID-19 exposure. Statistically erasing the relationship between race and place ignores the history of structural racism that has so powerfully shaped where people live and work and, consequently, what health risks they are exposed to.”

Employment opportunities for Black, Latinx and other underrepresented populations are often concentrated in lower-paying industries that are less likely to provide health insurance but are more likely to create risks for exposure to infectious diseases like the coronavirus. They may live farther from a COVID-19 testing center, may not have easy access to nutritious food or a health care facility, and may experience poorer air quality that can impact susceptibility and transmission of COVID-19. Black and Latinx communities also experience higher rates of comorbidities, such as diabetes and hypertension, that can put them at risk for the worst outcomes.

To more comprehensively measure the inequities in COVID-19 deaths, the team proposed an approach that directly estimates and compares the risk of death across racial and ethnic groups.

For example, the risk of dying from COVID-19 in the first 9 months of 2020 was one in 1,020 for Black people, as compared to one in 2,000 for white people. The 9-month risk of death was also higher among Latinx and Indigenous people compared to white people. An approach that communicates risk in this manner also communicates how great the burden of disease is in these populations.

“It’s not enough to know, at the national level, whether certain groups bear a disproportionately high or low burden of COVID-19,” said Zalla. “We need to know how to target resources to reach those most at risk. To do that, we need estimates of the risk of death in specific population groups and in specific places. We write in our commentary, for instance, that one in 313 residents of the Navajo Nation died from COVID-19 by September 2020. By the end of March 2021, that number was one in 139. We should be using group-specific estimates to identify and concentrate resources in the places and populations that have suffered the worst of the pandemic.”

Understanding the geography of risk and how racial health inequities are produced helps to shape better methods of analysis, which are a critical part of public health’s mission to promote equity.

“Without this context,” the group stated in the commentary, “the field of public health risks becoming complicit in the perpetuation of systems that reinforce structural racism.”