The article, "Is Sprawl Unhealthy", appears in the current issue of Journal of Planning Education and Research (not online).
Dr. Peter Gordon discusses the findings reported in the article in his blog, and includes excerpts from the authors:
"Measures of sprawl have no significant relationship to frequency of walking, body mass index, or diagnosis of various chronic diseases. However, among those with chronic conditions, including hypertension, diabetes, and lung disease, those who live in areas with more highly connected street networks have higher rated health."
Thanks to Chris Steins