Housing and public health advocates have long wanted to establish an empirical connection between the built environment and people’s health. Ideally such evidence would confirm what we already suspect; that denser more compact communities facilitate improved health. And indeed, housing has often been linked to improved health but there haven’t been any sustained studies that firmly link certain kinds of housing to specific improved health outcomes.
Additionally, most work in housing has concentrated on affordability issues while work in health has focused on the health effects of social and economic disparities.
A recent study has tried to bridge this gap in data by comparing two trusted longitudinal surveys that have been consistently collecting data for 30 years, the American Housing Survey (AHS) and the National Health and Nutrition Examination Survey (NHANES).
Generally speaking both housing and health have improved over the last thirty years although not uniformly. The study of the survey data found some interesting connections, through time, between some key aspects of housing and health.
There were two that caught my eye. The first is lead exposure. The study found that the most compelling shift in health related benefits has come from the rehabilitation or demolition of increasingly old housing that had high levels of lead. As policies to remove lead from paint and other materials used to build housing were enacted, and as these old buildings were fixed or nixed, the measured amount of lead in people’s bodies has decreased significantly.
Second, the study found improved outcomes in measured blood pressure that corresponded to the “presence of commercial buildings in residential areas.” In other words, people that lived in compact, dense neighborhoods had lower blood pressure than people that lived in neighborhoods without a mix of housing and retail. There were some negative implications connected to urban areas as well, but those decreased over time because, the researchers suggest, of an increase in zoning in industrial areas.
Zoning was created originally just for this purpose: to segregate uses to protect people’s health, to prevent, as the old phrase goes, “a pig in the parlor.” The study seems to show that zoning has worked to improve peoples health over time by protecting them from heavy industrial uses.
The first seems to push against those who argue that replacing older public and private housing with new construction is a net negative for low income people. Opponents of legislation earlier this year to increase density around transit stations often make this argument suggesting that newer development will make things worse for low income people living in older housing. Along with energy savings this study shows that new and improved housing also can reduce exposure to environmental hazards that contribute to illness and disease.
The second finding hints at the relationship between density and health. It isn’t a knockout punch but it certainly points the way toward doing more studies on health outcomes and density. What makes blood pressure go down? Proximity to amenities? More walking and less driving?
We know about the benefits of compact communities when it comes to water quality and greenhouse gas emissions but including health benefits in the mix would help make the case.
Finally, adding reduced health and transportation costs might also further improve our definition of what affordable housing means. Today affordability is almost always defined as monthly housing costs that do not exceed 30 percent of monthly income. If good housing choices make us healthier (and therefore cut other costs like doctor’s bills and maybe even medication), then those savings could be included in a definition of affordability that is a more sensitive measure than 30 percent of monthly income.