Population aging is transforming the world in dramatic and
fundamental ways. The age distributions of
populations have changed and will continue to change radically,
due to long-term declines in fertility
rates and improvements in mortality rates (Table 70-1).
This transformation, known as the
Demographic Transition, is also accompanied by an
epidemiological transition, in which
noncommunicable chronic diseases are becoming the major causes
of death and contributors to the
expressing "dependency" of one form or another—the
ratio of adults in the workforce to those typically
out of the workforce, such as infants, children, retired
"young old" (those still active in many ways other
than paid work) and the oldest old. Global aging will affect
economic growth, migration, patterns of work
and retirement, family structures, pension and health systems,
and even trade and the relative standing
of nations. Both numbers (the size of an age group) and ratios
(the ratio of those in the labor force age
group to dependants such as the young or retired, or the ratio
of children to older people) are
important. The size of population age groups might affect the
number of hospital beds needed, while
the ratio of children to older people, the relative demand for
pediatricians and geriatricians.
aUN Population Division
defines Old Age Support Ratio as the number of persons aged 65 or older per
one hundred persons aged 15 to 64 years.
bThe UN includes all
European regions in its overall statistics; life expectancy at birth for males
ranges
from 63.8 years in Eastern Europe to 77.4 years in Western
Europe. For women it ranges from 74.8 to
83.1 years in Western Europe.
Source: United
Nations Population Division, World Population Ageing 2009.
While the increase in life expectancy, resulting from a series of
social, economic, public health, and
medical victories over disease, might very well be considered
the crowning achievement of the past
century and a half, the increased length of life coupled with
the shifts in the size of dependent groups
relative to the size of the labor force, present formidable
long-term challenges.
The pace of the change is accelerating. In countries where the
Demographic Transition began earlier,
the process was slower: it took France 115 years for the
proportion of the age group 65 and older to
increase from 7 to 14% of the total population, and the United
States will soon have completed this
same increase in 69 years. But in countries that started the
transition later, the process is occurring
much more rapidly: Japan took 26 years to go from 7 to 14% age
65 and older, while China and Brazil
are projected to require just 24 years.
Sometime around the year 2020, for the first time ever, the
number of people aged 65 and older in the
world is expected to exceed that of children under the age of 5.
Around the middle of the twentieth
century, the under-5 age group constituted almost 15% of the
total population and the over-65 age
group 5%. It took about 70 years for these two to reach equal
proportions. But population forecasts
predict it will take only another 30 years for the 65 and older
age group to equal about 15% and the
younger age group, 5%. By the middle of their careers, medical
students in most countries should
expect to be practicing in far older populations. Preparations
for these changes need to begin decades
in advance, and the costs and penalties of waiting can be very
high. While some governments have
started planning for the long term, many, if not
most, have yet to begin.
No comments:
Post a Comment