Study Links Living in Racially Segregated Neighborhoods to Higher Blood Pressure

According to a new study published in JAMA Internal Medicine, black individuals living in more racially segregated neighborhoods tended to have higher blood pressure, while those who moved to less segregated areas saw their blood pressure decrease.

The researchers conducted their analysis using over 25 years of data from the prospective Coronary Artery Risk Development in Young Adults (CARDIA) study, which measures risk factors for cardiovascular disease as participants grow from young adulthood to middle age. They selected 2280 black participants with available blood pressure readings and baseline data to comprise the sample for the current study. Segregation levels in the subjects’ neighborhoods were categorized as being high, medium, or low based on measures of racial composition.

Of course, most participants moved during the 25-year study period, so the researchers created models to measure changes in exposure to segregation over this time. They also adjusted their analyses to account for several factors that could potentially impact blood pressure or its relationship with neighborhood segregation, such as age, sex, cigarette smoking, exercise habits, body mass index, educational attainment, and neighborhood poverty rates.

The analyses indicated that each increase of 1 standard deviation in neighborhood segregation score was associated with a 0.16 mmHg increase in participants’ systolic blood pressure. This association remained significant after adjusting for the blood pressure risk factors, income, and blood pressure medication use.

Among the participants who lived in a high-segregation neighborhood at the beginning of the study, systolic blood pressure decreased by 1.33 mmHg when moving to a medium-segregation area and 1.19 mmHg when in a low-segregation area, compared with baseline blood pressure levels in high-segregation neighborhoods.

When only including participants in this subset who never moved back to high-segregation neighborhoods, the researchers witnessed decreases in systolic blood pressure of 5.71 mmHg and 3.94 mmHg after moving to low-segregation and medium-segregation neighborhoods, respectively. Neither neighborhood segregation score nor changes in segregation category were associated with changes in diastolic blood pressure.

To explain their findings, the study authors hypothesized that exposure to racial segregation could contribute to higher levels of stress, which could then impact blood pressure. They also said that neighborhood segregation “affects the quality of schools, the value of housing, and the physical access to health-promoting resources (eg, pharmacies, full-service grocers, and gyms)” that can help residents manage their blood pressure.

According to the researchers, these findings highlight the importance of interventions targeting this vulnerable population and the considerable potential for improvement. They cited prior research that found a cardiovascular risk intervention among black individuals could avert 10 coronary heart disease and stroke events and 20 heart failure events per 100,000 person-years for each 1 mmHg reduction in systolic blood pressure. Ultimately, the study authors wrote, interventions aimed at reducing blood pressure could help reduce the disparities in health outcomes between different racial and ethnic groups and across neighborhoods in the United States.

“Findings from our observational study suggest that social policies that minimize segregation, such as the opening of housing markets, may have meaningful health benefits, including the reduction of blood pressure,” they concluded.