The world’s population is aging rapidly (United Nations, 2009 ). In 2009, one out of
nine persons in the world was older than 60. In 2050, one out of every fi ve persons
is expected to be 60 years or older (United Nations, 2009 ). In the world’s more
developed regions, estimates are that one out of three will be 60 years or over by
2050. These changes, which are coming rapidly, particularly in the developed world,
are attributable to three trends since the end of World War II. First, the baby boom
generation currently constitutes the largest birth cohort ever to approach retirement
age. Second, declining fertility rates in many countries lead to fewer younger people
relative to older adults. Women on average have fewer children, especially among
more developed regions (United Nations, 2009 ). Finally, life expectancies across
the world are increasing as people become healthier through greater access to
healthcare and improved societal infrastructure. The consequence of these trends is
an increase in the proportion of older people related to younger people, with Japan,
Italy, Germany and Sweden headlining these changes (United Nations, 2004 , 2009 )