The rise in human life expectancy over the past two centuries is a remarkable accomplishment of modern civilization (1, 2). This progress was achieved during the demographic transition of societies from regimes of high mortality and fertility to regimes of low mortality and fertility (3, 4). At present, among the world’s nations, Japanese women have the highest life expectancy at birth, above 87 y.
In 1840, the record was held by Swedish women, with an average life span of 46 y (5). This advance has been accompanied by an increase in life span equality: In low mortality populations today, most individuals survive to similar ages