The driving force behind the changing age structure, apart from reduction in fertility, is
the “longevity transition” that continues to raise life expectancy, with most increases in
survival now accruing late in the lifespan (Eggleston and Fuchs 2012). In fact, “mortality
is declining as rapidly in those countries like Japan and Sweden where it is already lowest,
as it is in lagging countries like the US, suggesting that life expectancy is not yet
approaching a biological limit” (Lee 2011, p.571). Moreover, life expectancy could
further dramatically increase if individuals and societies adopted even part of the
currently known life-extending behaviors and policies—eliminating obesity, tobacco use
and alcohol abuse; increasing physical activity, healthy diets, and safe driving; and so on
(Oeppen and Vaupel 2002).