Kelly-Schwartz 2004 - "Is Sprawl Unhealthy?"

Kelly-Schwartz, Alexia; Stockard, Jean, et al
"Is Sprawl Unhealthy? A Multilevel Analysis of the Relationship of Metropolitan Sprawl to the Health of Individuals"
Journal of Planning Education and Research
December 2004; v.24, n2; pp.184-196
On the Web
Relevance: high

The authors replicated and extended Ewing et al's work on the effect of sprawl on health. They compared self- and physican-rated health as well as a variety of chronic conditions across metropolitan areas while controlling for income, education, sex, etc. They found that sprawl does affect health somewhat, but in a complex way that is difficult to track.  It appears that a highly gridded street network is associated with better health while more density is associated with poorer health.  While sprawl was not significantly associated with a higher prevalence of chronic conditions, among those with those conditions, the gridded street network was associated with better health.

The authors say that better self- and physician health ratings are associated with a more gridded street network, less density, more walking, and lower BMI.

They seemed to find that compactness directly increases walking by only a small amount, but gridded streets and less density improve health regardless of BMI or walking status. (Check the original study; I'm not familiar with the methods of analysis used.)

Caveats:

• Their walking measure is having walked at least a mile without stopping, so daily trips to a store, park, or transit center closer than a mile to homes/employment are not counted. This may be the extra physical activity that is mysteriously improving health.
• The authors focus on PMSAs which are larger than counties, Ewing's units of analysis, making the analysis more aggregate and possibly less accurate.