Chapter 2- Aldwin, Carolyn M. & Diane F. Gilmer. 2004. Health, Illness, and Optimal
Aging: Biological and Psychosocial Perspectives. Thousand Oaks, California: Sage
• There has been a dramatic change in population demographics in the last century
that continues to provide ongoing challenges for health care providers to provide
adequate services to the increasing number of older adults in the world. This
issue has become an important consideration in many countries where ethnic
diversity and increasing age will impact upon the type of treatment and services
• The worldwide demographic shift has enabled researchers to appreciate that aging
is not strictly genetically determined but is plastic or capable of being influenced
by external factors. However, the demographics of morbidity or mortality also
provides convincing truth that aging processes also exhibit cumulative affects
which can influence the acceleration or deceleration of the aging process.
• There are chronic diseases that are more prevalent among different population
groups. There are problems in estimating life expectancy by ethnicity as a result
of many errors that can occur. Ethnic differences in life expectancy are due to
genetic factors but they are also due to health behaviour habits and differential
• Population Aging in the United States
• In 1905, children and young people represented a large segment of the population
with only a small percentage of individuals of 65 years of age and older. In 1975,
this demographic profile had already changed and infants and children were no
longer the largest population group. The largest cohort consisted of the Baby
Boomers who at that time were between the ages of 10 and 30. The change had
also revealed that more people in their 60s and 70s were surviving into their 80s
• Many more individuals will survive into their 70s and 80s although there will still
be relatively few who are 85+. By 2030 the Baby Boomers will have become
older in age and it is estimated that 70 million people in the United States alone
will be 65 or older at that time. As a result of these shifts in the demographic
profile. Its initial shape as one that was pyramidal will become rectangular with
distributions that will have changed accordingly.
• In 1900, there were only approximately 100,000 people who were over the age of
85 in the United States. This age group currently represents 1.5% of the entire
population but its rate of growth has increased by 38% in the 1990s and is
expected to quadruple in the first half of this century. In 1980, it is estimated that
there were 14,000 centenarians living in the United States. This number has more
than tripled in the past 20 years, with 4 out of 5 being women, reflecting the
change in gender ratio that occurs with aging.
1 • The probability of reaching 100 years of age improved during the 20 century. In
1879, a person had a 1/400 chance of living to be 100 years old, but as of 1980,
there was a 1/87 chance to living to 100.
• There are concerns about the economic implications associated with caring for the
85 and older age group of individuals who will likely present with the greatest
health and social care needs. There will still be more younger and middle-aged
individuals than older people.
• Definition: Total Dependency Ratio (TDR) compares the number of
economically nonproductive citizens (below age 18 and age 65 and older) with
the number of working-aged adults. Although not entirely accurate some
individuals make considerable money in early or late life and some working-aged
adults are disabled, unemployed, or taking time out to raise children), the age
dependency ratio is a rough estimate of the number of people who need to be
supported by workers. The equation is: TRD = (a + c)/b
Where a = children < 18, b = adults 18-65, and c = adults 65 and older.
• There have been some concerns about the growing percentage of older adults that
will create a potential crisis in TDRs and will result in overwhelming pressure on
working aged adults. An increase in TDRs may also result in competition for
services between the old and young. TDRs do not translate directly to dollars
spent. Older adults are healthier than before which may lessen the expected
burden of health care costs.
• In countries such as the United States and Europe there are available resources
available to offer assistance for dependant members of their societies. However,
this is not necessarily the case in developing nations.
• Life Expectancy = average number of years that a person in a particular cohort
can expect to live. In 1900 life expectancy was approximately 47 years and in
1999 it was 79 years for a female and 74 years for a male. A child born in 2007
can expect to live at least 30 years longer than one born one century ago. In 1900
the leading causes of death in the United States were: infections diseases (such as
Tuberculosis), pneumonia, influenza and gastroenteritis. At that time very few
deaths were attributed to heart disease or lung cancer. As well at that time, death
was distributed throughout the life span and people of all ages died of Small Pox
• Childbirth was associated with high mortality rates and infant mortality rates were
also high. At that time, there was difficulty in providing adequate treatment for
viral infections. There were often ineffective treatments for bacterial infections
and vaccines were unavailable as yet to counteract the spread of viral diseases.
The development of public health measures in the last century to control the
spread of communicable diseases and the development of vaccinations and
treatments offered greater hope. Since the 1930s the primary causes of death th
were chronic illnesses rather than infectious diseases. By the end of the 20
century, the leading causes of death among those 65 and older were: cancer,
stroke, chronic pulmonary, pneumonia, influenza, with variations that were
influenced by ethnicity.
2 • In the past 100 years, age specific life expectancy has also changed. These
changes reflect a decrease in infant and maternal mortality rates, improved
sanitation practices, better medical care and overall better nutrition. Age specific
life expectancy for