That’s been pretty well established. But what about promoting better health in poor nations? Does that spur wealth? Greg Mankiw points to this study:
there is no evidence that the large exogenous increase in life expectancy led to a significant increase in per capita economic growth. These results confirm that global efforts to combat poor health conditions in less developed countries can be highly effective, but also shed doubt on claims that unfavorable health conditions are the root cause of the poverty of some nations.
Mankiw’s bottom line:
Even if reformers (such as Jeff Sachs and Bill Gates) succeed in their admirable goal of promoting better health in poor countries, we should not expect that success to fix the problem of persistent poverty.
Mankiw has also woven together some different takes on income inequality. (See also this link.) Related: When Inequality Matters