Ageing : Glossary of Terms
Ageing : A series of progressive and irreversible
biological changes that result in reduced ability to maintain homeostatis
in the face of threat and increased vulnerability. While many suggest
that this process starts in adolescence or early adulthood, the
pace of deterioration of different body systems varies considerably,
and is influenced by behavioural and socio-economic forces.
Ageism: prejudice based on age, associated with
the stereotyping of older people as being frail, mentally incompetent
and dependent; also includes the social pressures that reduce the
status and roles of older people.
Biological theories of ageing: these fall into the following
major categories: "damage" theories supported by observed declines
in DNA repair enzymes; genetic theories supported by heritability
studies, progeria syndromes, and animal studies; disposable soma
theory supported by variation in species specific life expectancies
which vary depending on the relative amounts of energy put into maintenance
of the body (soma) and into reproduction.
Chronological age: the use of
specific birth anniversaries to define old age; this is increasingly
regarded as inadequate for this purpose (e.g. this is illustrated
in the inconsistency that, until recently, the official retirement
age in Britain was lower for women (60) than men (65), whilst the
longevity of women is greater than that of men). (See old
age)
Compression of morbidity: the hypothesis that morbidity
in old age will be compressed into a shorter time span, perhaps
due to healthier lifestyles or medical advances. Alternative theories
of expansion of morbidity and of dynamic equilibrium have also been
proposed.
Dementia syndromes: progressive, global and irreversible
cognitive impairments caused most commonly by Alzheimer's Disease
(linked with apoE4 polymorphism), multiple cerebral infarcts, or
a combination of these.
Demographic transition: change in a society from a situation
of high mortality and fertility to one of low mortality and fertility,
resulting in a shift from a low to a high proportion of older people,
and an increase in total population size.
Demographic timebomb: the demands made by a growing
population of elderly people will outstrip health and social services
provision.
Dependency ratio: ratio of (potentially) economically
active population to the retired population and children under 16
years of age. Aged dependency ratio is the ratio of the economically
active to the retired population.
Disability free life expectancy: the number of years
of projected life expectancy that will be spent free of disability.
Usually defined from age 65 or as a percentage of total life expectancy.
See Health Expectancy.
Disengagement theory: an outdated theory, which, like activity
theory, emphasises the discontinuity between older age and earlier
stages of the life cycle. It postulates that withdrawal from interactions
and activities is an inevitable accompaniment of older age as people
become more self-preoccupied, and in order to minimise disruption
to society (e.g. when death takes place). There is little evidence
to support this theory and it legitimises the social redundancy of
older people.
Epidemiologic transition: in parallel with demographic
transition, patterns of mortality also shift from a high burden
from infectious diseases to an increase in chronic degenerative
diseases (cardiovascular diseases and cancers) and morbidity patterns
also show a similar increase in non-fatal but disabling conditions
(e.g. osteoarthritis).
'Fair innings' argument: it is argued, on the basis
of utilitarianism - that is, the greatest good of the greatest number
- that older people have had a 'fair innings' and should give up
their place in the health service queue; instead scarce medical resources
should be diverted towards the young , in order to give them a chance
of reaching older age.
Fitness gap: the difference between what an individual
is able to do (e.g. climb stairs) and needs to do to be able to
maintain independence, sometimes referred to as the disability gap
or ecological gap.
Fourth age: the period of increasing frailty before death.
Grey Panthers: old age activists in USA who have
successfully campaigned for better services for older people. Health expectancy: a generic
term for the wide range of indicators of life expectancy adjusted
for health status (e.g. dementia free life expectancy, disability
free life expectancy, healthy active life expectancy).
Healthy active life expectancy (HALE): the average
number of years that a fit person of a given age can be expected
to have before experiencing disability.
Life expectancy: is the average (median) number
of years that a person can expect to live but is usually based on
contemporary death rates which may be higher than those experienced
by future cohorts, so tends to underestimate life expectancy. May
be calculated from birth (in which case it is dominated by infant
mortality in poorer countries), or from other ages.
Life span: is the maximum number of years that a person has
been known to live, currently around 115 years. Frequently confused
with life expectancy.
Life table: a summary measure of the mortality and
survival of a population. Current life tables summarise mortality
experience by age of a population at a point in time. Cohort life
tables summarise the actual mortality experience of a cohort born
at about the same time and followed until all are dead. The e 0
x function derived from a life table is the average number
of years of life remaining to people who survive to age x.
Old age: this is usually defined
in relation to a specific birth anniversary, often coinciding with
an official age of retirement. (See chronological
age.) But like current retirement ages, this definitional age
cut off is arbitrary and increasingly blurred with the increase
in early retirement and unemployment among older workers. Terms
such as the "old old" and the "oldest old" have been used to refer
to those aged 75+ and 85+ respectively.
Rectangularisation of survival: the change in the shape of
the population survival curve in the 19 th century which featured
high infant mortality to the more rectangular shape associated with
very high survival prospects in early life.
Retirement age: inability or choice not to remain in paid
employment associated with reaching a certain age (varies between
50 and 70 years). Increasingly, retirement ages are more flexible.
Social construction of old age: the definition
of old age, and the experiences of older people, are a product of
the way society is organised and the structure of inequality within
it rather than a natural concomitant of the ageing process (e.g.
as in the traditional definition of old age which coincides with
official retirement age).
Successful, or positive, ageing: growth and development
in older age, and the successful adaptation to losses and challenges
associated with increasing age (e.g. using psychological strategies,
physical and social resources).
Third age: a continuation of life in which retirement enables
citizens to live at leisure and realise their purposes. This option
is not available for people on low incomes or in poor health.
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