While googling for studies done on new year's resolutions, I stumbled across a blog written by Dr. Greg Mankiw, an economics professor at Harvard who teaches Ec10 (http://gregmankiw.blogspot.com/). Dr. Mankiw's blog, in turn, led me to a fascinating New York Times article written today on the link between education and health.
It would seem that the most important indicator for health is the level of education attained by the patient. This correlation seems to be omnipresent and one of the most powerful indicators of lifespan, more than race or income. In fact, the more years that a child has spent in school, the more years that that child actually lives: "Three economists noted the correlation between education and health and gave some advice: If you want to improve health, you will get more return by investing in education than by investing in medical care."
The article digresses into the problems inherent in separating correlation from causation, but the idea of investing money into education for the sake of health struck me as particularly clever because it was like killing two birds with one stone (by birds...I mean education and public health, and by stone...I mean money).
NYT article: Kolata, Gina. "A Surprising Secret to a Long Life: Stay in School." New York Times, Jan. 3, 2007. http://www.nytimes.com/2007/01/03/health/03aging.html?pagewanted=2&_r=1 and http://www.nytimes.com/aging.