I suspect that the same people who make poor choices with respect to education, work ethic and other factors that impact income are the same people that make poor choices regarding diet, exercise and other behaviors that affect health.
Culture and environment play a part in it. Check the link in comment# 11. Enter race ethnicity chronic disease illness genetic predisposition into a search engine like Yahoo, Google, etc. and see what you find. Don't go to any hit, just the ones with credibility.
Cosmic blast may have killed off megafauna Scientists say early humans doomed, too
Lake Havasu teen becomes sixth 2007 victim of brain-eating amoeba (NOT a joke) IMHO, avoid such waters unless you must swim for your life.
FReepmail me if you want on or off my health and science ping list.
First, I must say that I'm more than a little uncomfortable that you equate items such as race and ethnicity with being poor. While I'm sure that a correlation exists, I'd prefer to look at poor Americans rather than race or ethnicity when evaluating this article. However, for the sake of simplicity, I will stipulate for the moment that race and ethnicity are appropriate proxies for low income.
The first quality hit (warning: .pdf) using the search terms you provided was from the Clinical Journal of the American Society of Nephrology (diseases of the kidney). The article indicates that black Americans survive chronic kidney disease longer than white Americans due to a "different genetic makeup". Therefore, a disproportionate number of Americans suffering from end stage renal disease are black Americans.
I'm sure drawing conclusions from the first Google hit is far from scientific. But it certainly casts doubt on your theory that blacks (a proxy for the poor) are genetically inferior to whites.