A new big-data analysis of the U.S. pinpoints how urban design aids the health of city residents - especially when cities provide walking opportunities, greenery, and mixed-use streets with a blend of commercial and residential activity.
The study examines tens of thousands of urban census-bureau tracts in the U.S., seeing how city features correlate with population health measures, while accounting for socioeconomic considerations as well.
"We found that on a very large scale, urban planning and design, such as the availability of different amenities and their spatial arrangement, plays a critical role in population health outomes," says Winston Yap, a visiting scholar at the MIT Senseable City Lab, a postdoc at Cornell University, and co-author of a new paper outlining the study's findings.
While there is not one design template for all locations, short and well-connected blocks with a variety of amenities, as well as the strategic placement of parks, all help well-being - physiologically and psychologically.
"We usually think about physical health first, but we also found a high correlation between good design and mental health," says Fabio Duarte, an MIT researcher and co-author of the paper. "If you are walking more, it is not only a matter of physical fitness, but gives people a chance to avoid isolation, have serendipitous meetings with people, and at least see there are others around."
The paper, " Urban motifs associated with population health ," appears today in Nature Health. The authors are Yap; Duarte, who is associate director and a principal research scientist at MIT Senseable City Lab; postdocs Yu Zheng, Kee Moon Zhang, and Peng Luo, who is also an incoming assistant professor at the University of Iowa; Paolo Vineis, a professor at Imperial College, London; Carlo Ratti, director of the MIT Senseable City Lab; and Filip Biljecki, an associate professor at the National University of Singapore.
Only connect
The researchers say they conducted the analysis not just due to an interest in cities, but out of recognition that health care systems are often swamped, and preventative health measures are ever-more important.
"We wanted to do this study because health care systems around the world are overloaded," Yan says. "There's a lot of burden on health care systems, and there is a need not just for treatment but for prevention as well, for obesity, high cholesterol, depression and other mental health issues, and more."
To conduct the study, the researchers analyzed 28,323 census tracts, using data from the U.S. Census Bureau along with health data from the U.S. Center for Disease Control and Prevention (CDC). They then used geospatial data, including more than 8 million street view images, to see how urban form related to the health status of residents in those areas. The study accounts for socioeconomic factors and other variables in building an assessment of the relationship between design and health. The study confimed that by themselves, socioeconomic factors are associated with urban health disparities; it then examined the relative impact of differences in urban design in those different settings.
"By bringing together open demographic, health, and environmental data, the study highlights the importance of open data accessibility for planning healthy cities," says Ratti.
The scholars also applied a graph deep-learning model to the data, an emerging machine-learning technique they used to help understand which key factors in urban design are most connected to health outcomes.
The research reveals that in some cases, rectangularity in city blocks, and "building spread," meaning structures that cover the full size of their lots, can enhance wellness. Examples of this include Manhattan or Boston's Back Bay neighborhood, where mixed-use buildings on relatively short blocks create many amenities and a variety of walking routes. That said, circular and curving street forms can also work, as long as they feature a lot of interconnectedness as well.
Urban greenery is almost always a significant factor in urban wellness, with parks scoring high as a facet of city design that helps resident health. Beyond that, expanding the tree canopy can also help urban health outcomes.
The presence of cultural institutions and restaurants are also linked to general health, while access to health care amenities are understandably connected to physical health improvements. In general, access to points of interest, broadly defined, whether cultural or commercial, is a significant factor in abetting better health, in cities across the country.
"One of the major contributions of the study is that we look at not only one or two cities, but the entire United States," Yap says. "In a large-scale study, we were trying to find patterns that were consistent across different urban contexts, as well as populations with different characteristics. Just using this data, we can predict very confidently the population health outcomes for a neighborhood."
Knowing where to intervene
The research also provides a kind of road map for urban planners and city officials when it comes to policy decisions and local improvements. Among other things, the study suggests where cities might see the greatest return on investment in urban improvements, in health terms. Improvements in lower-income neighborhoods, on aggregate, may generate about four times the added health benefits than the same level of investment in better-off areas that already realize the benefits of good urban amenities.
"It's important to know where to intervene," Yan says.
"I think for me it shows how intertwined different policies are," Duarte adds. "Some funding for urban development could have a direct influence on health, and could be more inexpensive than [direct spending on health]."
The researchers regard the study as just one empirical step in this domain. As they note, additional studies could observe changes over time, to further enhance our picture of the connection between urban design and health. Still, as the authors write in the paper, "we believe that our broad picture provides an overarching scaffolding for the understanding of the social and material determinants of health and can guide [further] analytical studies."
The research received support from the Campus for Research Excellence and Technological Enterprise (CREATE) program of the National Research Foundation Singapore; the Singapore-MIT Alliance for Research and Technology (SMART); and the MIT Senseable City Lab consortium. It is part of the Largescale 3D Geospatial Data for Urban Analytics project, supported by the National University of Singapore.
