The American Journal of Public Health (http://www.ajph.org) has published a study showing that age, sex, income, and other factors being equal, people living in areas of suburban sprawl will on average be six pounds heavier, and have 29% higher blood pressure, than those in the densest communities.

http://www.forbes.com/home_asia/2003/08/29/cx_da_0829topnews.html