People do wonder whether low-density, un-walkable, cites are _bad_ for human health, and studies show that they typically are bad health. I recall some studies on urban form and it's relationship to life expectancy, crime, happiness at certain socioeconomic statuses. Poor people in much of Montreal are able to live in walkable cities with low housing cost and decent transit, and it turns out they live longer, are more economically mobile, and are happier than equivalent SES populations in large cities with car-centric design.