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As a girl, Dr. Rita Hamad and her family fled Lebanon’s civil war and found a home in the United States. Three decades later, her research is offering a glimpse into the long-term health impacts of such a migration.

And while the research’s focus is on the 1980s and 1990s, it’s a period that echoes what is happening today: conflict driving people from their homes on a mass scale, and the countries where they are heading struggling with the economic, cultural, and political ramifications.


The study, published Wednesday in the Lancet Diabetes & Endocrinology, throws another question into that mix: How will the specific places the thousands of refugees settle affect their well-being years down the road? And it could influence broader conversations, including those in the United States, about how where we live shapes our future.

Hamad and her colleagues specifically looked at refugees who went to Sweden and found that they were more likely to develop type 2 diabetes if they landed in poorer neighborhoods.

“We did not intend for this to be informing the refugee crisis in Europe,” said Hamad, a family medicine doctor and PhD student at Stanford University. “But it does suggest that when people wind up in highly deprived neighborhoods straight off the bat … that we are going to see the effects of that years later.”


Experts have long observed that people who live in poor areas face higher risks of future health problems. But because researchers cannot go around randomly placing families in different neighborhoods and studying what happens, they have struggled to tease apart whether neighborhoods themselves play causative roles in future health problems, or if the factors that drive people to live in poor neighborhoods are the root of the health issues.

A policy in place in Sweden during the 1980s and 1990s created something of a natural, randomized experiment.

A similar natural experiment occurred when a US program offered some people in low-income public housing vouchers through a lottery to move to better neighborhoods. In that case, researchers found that people who received the vouchers had lower rates of obesity and diabetes down the road than those who stayed.

But one limitation was that families had to elect to enroll in the lottery. The refugees in Sweden — who were fleeing conflicts such as the Iran-Iraq War — did not choose to partake in the dispersal policy.

The Swedish government, concerned about the influx of people settling in Stockholm, Gothenburg, and other cities, divided the refugees throughout the country, based only on education, language, and family size.

For their analysis, Hamad’s team — led by her husband, health policy expert Justin White of the University of California, San Francisco, along with colleagues at Stanford and in Sweden — studied health data from more than 61,000 refugees who arrived in Sweden as adults between 1987 and 1991, when the dispersal policy was most strictly implemented. They chose to examine type 2 diabetes because of how where you live can contribute to it: Is healthy food available? Is the area walkable? Are good jobs available?

Poring over the data, the team discovered that people placed in the more deprived neighborhoods had a higher risk of developing type 2 diabetes than people placed in the more affluent neighborhoods. (The researchers divided neighborhoods into three levels of deprivation based on poverty and unemployment, education, and social welfare participation.)

In the worst neighborhoods, 7.9 percent of refugees had the disease, compared to 7.2 percent in the moderately deprived neighborhoods. In the best neighborhoods, only 5.8 percent of refugees had the disease — a rate on par with the national average. And where people were settled initially had an impact on their health even if they moved within a few years of arriving in Sweden, the researchers found.

“It helps build the story that there might actually be something about the composition of the neighborhood that does matter,” said Kathleen Cagney, a sociologist who directs the University of Chicago’s Population Research Center and who was not involved with the study.

The study’s results could also inform efforts to reduce the type 2 diabetes rates in the United States, said Briana Mezuk, an epidemiologist at Virginia Commonwealth University. If the government’s National Diabetes Prevention Program, for example, proves to be more effective in some areas than others, then specific neighborhood differences could be in part responsible.

“When we go to refine diabetes prevention programs, [the study is] going to be very important for us to look to,” Mezuk said.

The study’s findings come as the number of people displaced around the world reaches levels never before recorded. According to the United Nations, more than 1 million refugees and migrants headed to Europe by sea in 2015 alone.

Of course, the exact difference in risk experienced by the people included in the study might not apply to other settings. Sweden, for example, has a famously strong safety net that could have even improved the health of arriving refugees overall.

And it’s possible that the Swedish dispersal policy, which ended in the mid-1990s, actually lowered the overall prevalence of type 2 diabetes. If refugees had chosen where to settle, Hamad noted, they might have largely congregated in lower-income areas because of affordability and the presence of refugees there already.

The research team started work on the project two years ago, before the refugee crisis exploded across Europe and the world. That meant Hamad did not reflect on a personal connection to the research until more recently.

Her father had studied at the University of Texas at Austin, so her family headed to that city when they left the Middle East. But, she said, “if we had decided to go to Europe for some reason, we could have been subject to this type of policy.”