Map of life expectancy at birth from Global Education Project.

Friday, November 20, 2009

Health Equity is Health, Period

I believe I may have mentioned here at one time or another that the amount of inequality in society is related to health status and longevity, regardless of the absolute level of material wealth. In other words, unequal societies are less healthy not only because they have more poor people, but just because they are unequal. Poor people in the United States have far more in the way of material resources than poor people in poor countries, but their health is still impaired.

Although I have long found the evidence for this conclusion convincing, it has remained controversial among those who are not such know-it-alls as I. But now some folks in Japan and Boston have pretty much nailed it down. (BMJ makes its peer reviewed research open access, but not the editorials, commentaries, and news reports which are usually more interesting to general readership. Annoying.)

The article is a bit technical, but in a nutshell, it's what's called a meta-analysis. That means they pooled data from many studies and analyzed it together. What they find is that an increase of .05 in an index called the Gini coefficient of income inequality is associated with an 8% increased mortality risk, but that there is a threshold -- the effect appears when the Gini coefficient is above .3.

The Gini coefficient is actually not very difficult to understand -- here's the Wikipedia article. Essentially, if income were exactly equal, then a graph plotting percent of national income against percent of population would be a perfectly straight, 45 degree line. With inequality, the line is curved, starting out nearly horizontal and becoming more vertical as you move right into the higher income part of the population. The Gini coefficient is simply the area between the curved line and the 45 degree straight line.

You won't be surprised, I'm sure, to learn that the United States has a fairly high Gini coefficient among the OECD countries. Half of them are under .3 and so have no excess deaths due to inequality per se, according to this analysis. (Examples include the Scandinavian countries Switzerland, Germany and France. You know, those socialist dungeons.) Canada, Ireland and Australia are barely above .3 and so their population attributable deaths are barely noticeable. The U.S., however, has a Gini coefficient of .357 and these authors attribute nearly 884,000 premature annual deaths in this country to inequality.

Here's a ranking of the planet's countries by Gini coefficient. It uses a different source, the UN, which gives our Gini as .4 (multiplied by 100 in this listing and reported as 40). That's more unequal than, for example, Trinidad and Tobago, Yemen, Uzbekistan, and Kazakhstan, not to mention Laos, Indonesia, and Guinea. It's identical to Ghana. And of course, it's getting worse.

Of course, we're still the greatest country on earth.

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