If an expert were to point to a down-at-heels neighborhood and declare that people who live there have worse health than people who live in a more prosperous neighborhood nearby, few of us would be surprised. But does the neighborhood introduce health risks, or does it simply group together people who have health problems correlated with poverty?
Health and policy experts have struggled to answer that question reliably.
In a paper published today in JAMA Network Open, Justin White, PhD, assistant professor of epidemiology and biostatistics, and Rita Hamad, MD, PhD, associate professor of family and community medicine, show that living in a disadvantaged neighborhood actually causes poor outcomes in cardiovascular health. Cardiovascular health is a key contributor to overall mortality.
Working with Danish researchers, the two took advantage of a natural experiment that occurred in Denmark in the 1980s to 1990s. Experiencing an influx of refugees from the Middle East, former Yugoslavia, and sub-Saharan Africa during that period, Denmark adopted a policy by which refugees were assigned nearly randomly to settle in neighborhoods across the country. This offered a rare circumstance in which people’s circumstances and preferences did not determine where they lived.
And because Scandinavian countries maintain famously thorough administrative records on residents, the researchers could track refugees’ health over a 30-year period.
“A lot of epidemiological studies have shown a strong association between neighborhood characteristics and people’s health,” White said. “We wanted to go a step further to get at the causal relationship.”
White and Hamad used Danish data about the neighborhoods – including median income, income inequality, crime rate, welfare participation and education – to rank them on a spectrum of high to low disadvantage. With 30 years of health records, they saw that refugees assigned to more disadvantaged neighborhoods developed more cardiovascular risk factors – including high cholesterol, high blood pressure and type 2 diabetes – and were more likely to have heart attacks than those assigned to less disadvantaged neighborhoods.
“We should be investing in our communities, because this study suggests there’s a link between neighborhood and long-term health outcomes,” White said. “In the U.S. in particular, we should also be thinking about how we treat refugees and the conditions where they are placed.”
Hamad’s prior work with Kirsten Bibbins-Domingo, MD, PhD, has also suggested that healthcare providers need to inquire about and address social and economic factors to provide the best care for their patients. In many European countries, neighborhood disadvantage is already used to identify patients at high risk during cardiovascular screening, Hamad said.
Of course, the next question is how one’s neighborhood affects one’s health. In the Scandinavian context, it’s not lack of access to affordable health care. Is it the lack of green space that affects cardiovascular health? Is it the stress of living in areas with high crime rates? Does lack of public transit take a toll on residents’ health by limiting where they can seek employment, healthy food and health care? To what extent does seeing our neighbors struggle impact our own health?
White and Hamad have recently received NIH funding to look more closely at the mechanisms through which a neighborhood affects residents’ health, so these answers are forthcoming.
For now, it’s safe to conclude that no man or woman is an island. “People surrounding you have an influence on your health. The social and built environments are really important,” White concluded.