‘Redlining’ linked to increased risk of heart disease

The most common type of heart disease in the United States is coronary artery disease (CAD), which can lead to a heart attack.

Discriminatory housing policies of the past can still impact heart disease risk factors and outcomes today.

According to a study recently published in the Journal of the American College of Cardiology. Health disparities have been linked to a number of socioeconomic, environmental and social variables. This research adds to the growing body of evidence demonstrating the long-term cardiovascular impacts that disparities can have on vulnerable groups.

The term “redlining” is used to refer to a variety of discriminatory housing practices. Its roots go back to a 1930s government program when the Home Owners’ Loan Corporation produced maps of over 200 US cities with rankings based on racial/ethnic mix, housing conditions and local environment.

Ranked locations were color coded as A (“best” or green), B (“still desirable” or blue), C (“definitely in decline” or yellow) and D (“dangerous” or red) according to potential risk loan. Areas with a D grade were called “underlined” areas. Despite the fact that these housing practices were outlawed in the 1960s, throughout the past century their consequences and other forms of discrimination have persisted in shaping social and environmental structures, deepening health inequities.

“We already know that historic redlining is linked to modern health inequalities in large urban areas, including asthma, certain types of cancer, premature birth, mental health and other chronic diseases,” said Sadeer Al -Kindi, MD, cardiologist. at University Hospitals Harrington Heart & Vascular Institute and assistant professor of medicine at Case Western Reserve University in Cleveland and lead author of the study. “Although ours is the first study to examine the national relationship between redlined neighborhoods and cardiovascular disease, it makes sense that many of the socioeconomic, environmental and social impacts of redlining on other domains of health outcomes residents are also seen in heart disease.”

A previous study demonstrated that black adults living in historically demarcated areas had a lower cardiovascular health score than black adults living in A-rated neighborhoods. The current study supports this finding and extends the demonstrated inequality in health nationwide, showing that redlining not only affects coronary heart disease, stroke, and chronic kidney disease, but is also associated with increased risk of comorbidities and lack of access to appropriate medical care.

The researchers used original graduated data from the Home Owners’ Loan Corporation (HOLC) and calculated the percentage intersection between each graduated neighborhood boundary and the 2020 U.S. Census tract boundaries. They excluded all tracts of census whose total area of ​​intersection was less than 20%. The researchers used the graded intersections to generate a scale using their corresponding HOLC numeric scores (1-4 corresponding to AD) and created a score that was transformed back into one of four categories: A (1), B ( 2), C (3) and D (4). The study defined neighborhoods underlined in red as D-ranked census tracts and neighborhoods not underlined in red as A-C-ranked census tracts.

The CDC PLACES Database, which reports prevalence estimates of census tract-level health indicators, as well as census tract-level exposure to particulate matter and diesel particulate matter from the 2021 Environmental Justice Tool of the Environmental Protection Agency, was used to calculate potential environmental confounders. Other outcome variables and assessments used included: markers of health care access, cardiometabolic risk factors, and cardiometabolic outcomes. The researchers then linked census tracts ranked by HOLC to the prevalence of cardiometabolic indicators and calculated the average of each indicator across census tracts in each HOLC grade.

Over 11,000 HOLC-classified census tracts were included, comprising over 38.5 million residents. A-ranked areas covered 7.1%, B-ranked areas covered 19.4%, C-ranked areas covered 42%, and D-ranked areas covered 31.5% of the census tracts. The percentage of black and Hispanic residents increased by HOLC grades (AD, respectively). In HOLC grades A through D, researchers found statistically significant increases in the prevalence of coronary heart disease, stroke, and chronic kidney disease.

“We found that neighborhoods with supposedly better HOLC scores had higher cholesterol screening and routine health visits than neighborhoods with lower HOLC scores. And the prevalence of adults ages 18 to 64 without health insurance nearly doubled, jumping from areas ranked A to D,” said Issam Motairek, MD, lead study author and clinical research associate at University Hospitals. Harrington Heart & Vascular Institute in Cleveland. . “Within each incremental increase on the HOLC grading spectrum, from A to D, we also observed an overall increase in rates of diabetes, obesity, hypertension, and smoking.”

According to the researchers, the association between redlining and the prevalence of cardiometabolic conditions further illustrates that historical practices of redlining can impact contemporary cardiovascular outcomes through traditional and non-traditional risk factors. Residents of gated neighborhoods, especially minorities, are known to have reduced access to public transportation, health insurance, and healthy food choices, increasing their risk of missed prevention and adverse health effects. health.

Disparities in environmental exposures and socioeconomic attributes may help explain poor health outcomes in red-lined neighborhoods, which are often located next to major sources of pollution and make residents more likely to experience the adverse health effects of disproportionately higher exposure to air pollution, less green space and other environmental toxins. Residents of gated neighborhoods also face financial hardship, broken communities, and racial discrimination, which can lead to increased stress and associated health issues.

Study limitations include self-reported health outcomes in the CDC PLACES database, which may be poorly characterized. The study was also unable to measure confounding factors such as behavioral and genetic factors. Nor has the definition of redlining census tract boundaries been standardized across studies.

Reference: “Historic Neighborhood Redlining and Contemporary Cardiometabolic Risk” by Issam Motairek, Eun Kyung Lee, Scott Janus, Michael Farkouh, Darcy Freedman, Jackson Wright, Khurram Nasir, Sanjay Rajagopalan and Sadeer Al-Kindi, July 4, 2022, Journal of the American College of Cardiology.
DOI: 10.1016/j.jacc.2022.05.010

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