A Surprising Secret to a Long Life: Stay in School

The New York Times reports:

James Smith, a health economist at the RAND Corporation, has heard a variety of hypotheses about what it takes to live a long life — money, lack of stress, a loving family, lots of friends. But he has been a skeptic.

Yes, he says, it is clear that on average some groups in every society live longer than others. The rich live longer than the poor, whites live longer than blacks in the United States. Longevity, in general, is not evenly distributed in the population. But what, he asks, is cause and what is effect? And how can they be disentangled?

He is venturing, of course, into one of the prevailing mysteries of aging, the persistent differences seen in the life spans of large groups. In every country, there is an average life span for the nation as a whole and there are average life spans for different subsets, based on race, geography, education and even churchgoing.

Education.