Racially divided neighborhoods linked to higher cardiovascular disease risk for Black Americans, major study suggests

Death rates from cardiovascular disease (CVD) have declined substantially for all racial and ethnic groups in the United States in recent decades, but disparities in CVD mortality among the races have grown. While Black and white Americans died from CVD at the same rate in 1950, for example, Black Americans today are 30 percent more likely to die from CVD than their white counterparts.

“This is true even after accounting for age, gender and socioeconomic status and for individual risk factors such as diabetes, smoking and hypertension,” said Kristi Allgood, PhD, a social epidemiologist with the Texas A&M University School of Public Health. “We wanted to find out about any connection between segregation and cardiovascular health.”

For their study, published in Race and Social Problems, Allgood and colleagues from the University of Michigan and the Charles R. Drew University of Medicine and Science evaluated the association between the Framingham 30-year cardiovascular disease risk score and three U.S. Census Bureau measures of residential segregation: evenness (the extent to which the  distribution of different races is equal in a geographical area),exposure (the degree of potential interaction with same group members in a geographical area) and concentration (the over-concentration of one group compared to another in a geographic area).

Specifically, the researchers used the Longitudinal Study of Adolescent to Adult Health to determine the extent to which evenness, exposure and concentration found in Wave I residential segregation (when school-aged respondents were in 7th through 12th grade) and 30-year CVD risk in Wave IV (when respondents were young adults between 24 and 32 years old) would be modified by race and ethnicity.

Extensive studies show that racial segregation from U.S. federal housing policies has long-term impacts on health and other areas for racial minorities. Based on this, the researchers hypothesized that among Black respondents, residing in highly segregated neighborhoods would be associated with an increased 30-year CVD risk score. In contrast, they expected that for white respondents, higher levels of segregation would be associated with a decreased 30-year CVD risk score.

The study was a population-based, multi-level, prospective design using nationally representative Add Health data, a school-based study of adolescents that examines behavioral, emotional, social, educational and contextual factors as respondents transition from adolescence to adulthood.

Wave I data was from 1995 and included 20,745 non-Hispanic Black and non-Hispanic white adolescents representative of American adolescents with respect to region, urbanicity, school features, race and ethnicity. Those who completed Wave I were interviewed in their homes about demographics, socioeconomic status, physical health and risk behaviors. Height and weight measurements were taken at all waves, with blood pressure as a measurement of cardiovascular risk factors starting in Wave IV. The final sample was 8,744 due to missing or incomplete data.

Statistical analyses found lingering high levels of segregation by race—the concentration measurement—consistent with previous studies. While concentration was not associated with 30-year CVD risk overall, the relationship between concentration and 30-year CVD risk was found to be dependent on race in a way that was harmful to Black respondents but produced a lower CVD risk for white respondents.

Contrary to expectations, the evenness and exposure measures were not associated with 30-year CVD risk, although Black respondents had higher CVD risk than white respondents.

“This study fills a void by focusing on 30-year CVD risk at a point in time for the respondents where an intervention could make a difference in the development of CVD,” Allgood said. “Disparities in cardiovascular disease by race cannot be eliminated until we understand the role of residential segregation on the risk factors that place racial and ethnic minoritized individuals at a disadvantage.”