Aging and Health
MICHAL ENGELMAN
Department of Population and Family Health Sciences,
Johns Hopkins University, Bloomberg School
of Public Health, Baltimore, MD, USA
mengelma@jhsph.edu
Synonyms
Elderly and health; Health of the elderly; Older people
and health
Definitions
Population aging, the demographic process by which
older persons become a proportionally larger share of
the total population, is associated with changing patterns
of mortality, morbidity, and disability (UNPD
2002). In the older population different aspects of
health have to be considered. Gerontology, the scientific
study of the biological, psychological, and sociological
phenomena associated with old age and aging,
and geriatrics, the branch of medicine that focuses on
health promotion and the prevention and treatment of
disease and disability in later life, both deal with the
well-being of older people.
Basic Characteristics
A gradual demographic transition – from patterns of
high fertility and high mortality to patterns of lower fertility
and later mortality – has been underway across
the globe. Lower birth rates and growing longevity have
led to an overall increase in both the absolute number
and relative proportion of older people in the general
population. By 2002, the population of individuals 60
years and over reached 626 million, or 10 percent of
the total world population. Of these, nearly 70 million
are among the oldest-old, aged 80 or over. The older
population is projected to expand rapidly in the coming
decades, more than tripling its current size and reaching
2 billion by 2050. The oldest-old population is expected
to grow more than 5.5 times to reach 379 million by
2050. Decreasing fertility rates contribute to the prediction
that older individuals will at that time constitute 21
percent of the total world population, twice their current
proportion and equal to the number of predicted children.
The proportion of the oldest-old will quadruple
to 4 percent by the same year (UNPD 2003). Women
constitute the majority of older people in most countries
(Velkoff, Lawson 1998).
The demographic changes are linked with epidemiologic
transitions, in particular a shift in the leading
causes of death away from infectious, acute diseases
in early life towards chronic and degenerative illnesses in mid- and later life. Given the increase in total
life expectancy, a number of gerontological theories
addressing the implications of increased longevity for
population health have emerged, each proposing different
relationships between old-age mortality, morbidity,
and disability, or limitations in performing activities of
daily living. (For a review, see Agree, Freedman 1999)
The theories range from the most pessimistic – in which
delayed mortality is translated to increased years of life
with disease and disability – to the most optimistic, in
which morbidity and disability are compressed towards
the end of life, increasing the healthy proportion of
total life expectancy. More nuanced perspectives recognize
the complexity, mutability, and inter-connectedness
of the processes determining morbidity, disability,
and mortality, and suggests a continuous dynamic
relationship between them. International trends in mortality
and disability outcomes are mixed, supporting
a dynamic model of longevity and health in later life
that is influenced by a multitude of biomedical, environmental,
and social factors.
Population aging is an aggregate mark of human success
in reducing fertility, improving living conditions,
and curbing risks of death through innovations in public
health and medicine. However, insufficient preparedness
for the needs of an aging population on the part of
health and social service providers is a challenge confronting
societies at all levels of development.
Geriatric Health
Aging populations have higher rates of chronic disease
and disability, and the likelihood of having multiple
co-morbidities rises significantly with age. In high
and low-income countries alike, ischemic heart disease
and cerebrovascular diseases are the leading causes of
death. In more developed nations, cancers (lung, colon,
rectum, stomach, and breast), chronic obstructive pulmonary
diseases, diabetes mellitus, and Alzheimer’s
Disease and other dementias are also among the most
prevalent causes of death. A range of chronic and
adult-onset conditions including depression, hearing
loss, alcohol-use disorders, osteoarthritis, schizophrenia,
bipolar disorders, and chronic obstructive pulmonary
diseases are among the leading causes of global
disability (Murray et al. 2001). Chronic diseases may
contribute to the gradual loss of senses such as sight
and hearing, to impaired mobility, to increased risks of
falls and fractures, and to disability in the performance
of activities of daily living.
As senescence, or the slowing-down of physical systems
that takes place as the body ages, progresses,
a range of physical and mental capacities is weakened.
Age-related mental illness, especially dementia,
are particularly difficult to cope with for both patients
and caregivers alike. Dementia is a condition of irreversible
decline in cognition, functioning and behavior.
Alzheimer’s disease (AD) accounts for approximately
60–70% of dementia cases, with vascular dementia
accounting for the majority of the rest. The prevalence
of AD is estimated to be 8–15% in persons over 65. The
primary risk factor for dementia is age, with the prevalence
doubling for every 5-year age group after the age
of 65 and reaching as high as 39 percent after age 90
(Jorm, Jolley 1998).
Chronic diseases exact a heavy burden on older adults
due to associated long-term illness, diminished quality
of life, and increased health care costs. Although
the risk of disease and disability clearly increases with
advancing age, poor health is not an inevitable consequence
of aging. A healthy lifestyle (including regular
physical activity, a nutritious diet, and avoidance
of tobacco) is the recommended course for prevention.
Screening for early detection is also recommended for
those illnesses (e. g. some cancers, diabetes and its complications,
etc.) for which a course of treatment is available.
Aging and Pharmacotherapy
Older people are particularly susceptible to the risks of
medication use. Age-related loss of physiologic reserve
leads to pharmacokinetic changes and increases interindividual
variability. The loss of renal function, for
example, decreases the clearance of common drugs in
older people, while the loss of lean body mass and fat
mass leads to an altered volume of drug distribution.
Polypharmacy – the use of multiple (usually 5 or more)
medications – is a common issue since geriatric patients
frequently have multiple co-morbidities each treated
with one or more medication. Furthermore, some medications
bring about side effects that then lead to
the prescription of additional drugs to treat the added
symptoms. Polypharmacy increases the potential of
drug interactions, adverse drug reactions, and the use
of inappropriate medications, or drugs that should be avoided in certain doses, disease states, or in combination
with other drugs (Hanlon et al. 2001).
Care-Giving
Historically, older people in need of assistance received
care from younger family members. However, previously
high levels of mortality and fertility meant that
the proportion of individuals reaching older ages was
relatively small while a larger pool of children and relatives
was available to share care-giving responsibilities.
More recently, the proportion of the population
at older ages has been expanding as the numbers of
younger family members available to provide care has
been shrinking.
Women – wives, daughters, daughters-in-law, nieces
and granddaughters – have traditionally provided the
bulk of family care-giving and continue to do so despite
rising levels of labor force participation. Older people
are as likely to provide care as they are to receive it,
and in developing and developed countries alike, spouses
are the main caregivers for both men and women.
Because of the sex differential in longevity, however,
women are more likely than men to find themselves
without a spouse and to be living alone when they need
care (Velkoff, Lawson 1998).
A relatively small proportion of older people – between
1 and 10 percent – reside in institutions in developed
nations (Velkoff, Lawson 1998). There has been growing
concern – though not much documentation – that as
networks of family caregivers shrink the rate of institutionalization
among older people may rise. Additional
concerns about the quality and cost of institutional care
are garnering attention in many countries.
Aging in Developing Nations
In developing nations a rapid demographic transition
has outpaced economic development. Since 1980,
developing countries have been home to a larger proportion
of the world’s population of persons aged 60
and above than their industrialized counterparts (Lloyd-
Sherlock 2000). By 2000, 249 million people, or 59%
of the world’s 65 years of age and over population lived
in developing countries (US Census Bureau 2001).
According to demographic projections, by 2050, more
than three-quarters of the world’s older people will
be living in developing countries. By 2050 developing
countries will posses a similar age structure to
today’s more industrialized nations. Older people will
then comprise over 30% of the population in East Asia,
more than 20% of the population in Southern Asia and
Latin America, and approximately 10% of the population
in Africa (UNPD2003).
Though they are among the most disadvantaged populations
in developing nations, older people have not
been prioritized by international aid agencies. Eighty
percent of older people in developing countries have no
regular incomes, and approximately 100 million older
persons live on less than a dollar a day. Older people
in developing regions are often excluded from economic
development, healthcare and education programs
due to age limits and discrimination and humanitarian
agencies often fail to identify older people as a target
in the planning and delivery of services in conflict
areas (Help – Age International 2002). While incidence
of chronic and age-related disease has been rising
rapidly in developing nations, there is a lack of professionals
in geriatric medicine, preventing older adults
from receiving the health care they need (Keller et al.
2002).
Though norms of filial piety are still strong in many
developing countries, changes in family structures and
co-residence patterns are rendering traditional support
networks more vulnerable. Recognizing the need for
increased awareness and action on issues related to
global aging, the Second World Assembly on Aging
adopted the Madrid International Plan of Action in
2002. The Plan calls on governments, non-governmental
organizations, and the international community to
adopt the concept of “a society for all ages,” to end
age-based discrimination and abuse, and incorporate
the concerns of older people into national and international
economic and social development policies (United
Nations Programme on Ageing, 2002). The formation
of implementation andmonitoring strategies for the
Plan is now in progress.
Cross-References
Age-Dependency Ratio
Demographic Transition
Disability
Epidemiologic Transition
Geriatrics
Gerontology
Life Expectancy
Population Aging
Senescence
References
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