Perhaps one day there will be a stem-cell treatment that can double one’s life expectancy by slowing the aging process, making a centenarian as spry as a quinquagenarian. But if such a serum benefits only the few who can afford it, our national life expectancy will hardly budge — it’s an average, after all. In 19th-century Sweden, the figure was dragged down by infant mortality. Today in the United States, it grows slowly because of the premature deaths of the less fortunate. Thanks to this vast inequality, even a high-tech fountain of youth would hardly move the needle.
“Look at the countries with the highest average life expectancy,” says Denney, referring to places like Japan, Australia, Canada and, yes, Sweden — nations that distribute their health resources more evenly. “Ultimately,” he says, “life expectancy is a measure of quality of life.”