The U.S. has one of the largest income-based health disparities in the world, according to a new paper out in the journal Health Affairs. Among the poorest third of Americans studied, 38.2 percent report being in "fair or poor" health, compared with 12.3 percent of the richest third. Only Chile and Portugal have a larger income-based gap in the health status of their citizens.

Most of the 32 nations studied had income-based differences in how healthy their citizens are. Only in Japan and Switzerland were people about equally healthy regardless of their wealth. Poor people in the U.S. were also more likely than rich people to say they couldn't get access to care because of the cost, and more likely to report being dissatisfied with their last visit to the doctor. "The United States exhibited large disparities in most measures, making it unique among high income countries," the authors, Harvard health-policy researchers Joachim Hero, Alan Zaslavsky, and Robert Blendon write. The other countries with big gaps between rich and poor on all three measures were Bulgaria, Russia, Chile, and Portugal.