A new study by researchers at the Feinberg School of Medicine at Northwestern University in Chicago finds that Black residents living in highly segregated neighborhoods have significantly shortened life expectancies. Compared to residents living in less segregated predominantly White neighborhoods, life expectancies of people in highly segregated areas are four years shorter on average, the study found.
Not only were lives shorter, the study also found residents in more segregated areas were more likely to lack college education, live below the federal poverty line, and be unemployed. These traits in part represent the social determinants of health.
A common phrase is ‘your zip code is more important than your genetic code,’” said lead author Sadiya Khan, associate professor of cardiology and epidemiology at Northwestern University Feinberg School of Medicine. “At a broader level, we’ve learned much about the health consequences of adverse social determinants of health, but we were trying to better understand on a local level what the implications of racial segregation are on life expectancy.”
The study examined 63,694 census tracts (small, relatively permanent geographic entities within counties) across the U.S. and found the national average life expectancy was 78 years old. In predominantly Black neighborhoods with high racial segregation, the average life expectancy was 75 years old, which is significantly lower than the average life expectancy (79 years old) in neighborhoods with low racial segregation. In high-versus low-segregated neighborhoods, a higher percent of residents lacked a college education (81 percent vs. 69 percent, respectively), were living below the federal poverty line (24 percent vs. 11 percent, respectively) and were unemployed (16 percent vs. 8 percent, respectively), the study found.
Dr. Kahn added that “while the mechanisms by which neighborhood segregation may contribute to differences in life expectancy are many, we sought to focus on key socioeconomic factors that are likely attributable to redlining and downstream differences by neighborhood in economic investment and resources in communities, which all have downstream consequences on health. These factors explained more than half of the differences in life expectancy across neighborhoods in our analysis.”
The full study, “Associations Between Neighborhood-Level Racial Residential Segregation, Socioeconomic Factors, and Life Expectancy in the US,” was published on the JAMA Health Forum. It can be accessed here.