The Longitudinal Aging Study Amsterdam (LASA)
Motivation
Changes in bodily functions and in various aspects of life are important
characteristics of aging. Many such changes will affect the autonomy and
well-being of older persons. At the start of LASA in 1991, in the Netherlands
almost all research among older persons had been cross-sectional. This
precludes the possibility to study the effects of changing circumstances on the
autonomy and well-being of older persons. Moreover, processes of change in
older persons are essentially multifactorial. To obtain proper insight into
processes of change in older persons, multi- or preferably interdisciplinary
research is a prerequisite. In the Netherlands, with some isolated exceptions,
there is no tradition of such research.
Objectives
LASA is designed to be an interdisciplinary, longitudinal study. Although
basically scientific in nature, the study should provide a basis for developing
and evaluating (central and local government) policy in the field of aging. The
global objective of current policy in the field of aging can be formulated as
enhancing the autonomy and quality of life of older persons. It is expected
that by using longitudinal data, policy relevant aspects of aging can be
identified and new policy aims can be developed. Moreover, assumptions from
which policy measures are developed can be tested, and effects of policy
changes can be assessed prospectively. LASA is primarily an observational
study; the database will allow testing of various specific hypotheses. Full
intervention studies will not be included in LASA.
Central questions
LASA's main topics of concern are autonomy and quality of life of older
persons. Autonomy is operationally defined as functioning, i.e. observable
behavior; quality of life is defined as the evaluation by older persons of
their functioning. Four components of functioning are distinguished: physical,
cognitive, emotional and social. The four components will have different
contributions to autonomy and quality of life. This distinction, however, does
not intend to deny any interrelation between these components. The study
focuses primarily on predictors of change in these components of functioning,
on trajectories of functioning, and on consequences of change in functioning.
The following central questions have been formulated:
1. Among older persons, what changes over time take place in the physical,
cognitive, emotional and social components of functioning?
2. What are the predictors of change for each of the four components of
functioning?
3. How are changes in the four components of functioning interrelated?
4. What are the consequences of changes in functioning in terms of older
persons' contributions to society, their adjustment and their need for care?
More detailed research questions are formulated, some of which make use of
additional data collected in specific subsamples. The most important of these
side studies are on the course of depression, and on predictors of falls and
fractures.
Elaboration
The measurement
instruments selected largely correspond to those which are being used in
potentially comparable research elsewhere in the Netherlands. Thus, a condition
for wider use of the data is created, e.g. by pooling of data. Furthermore, a
number of measurement instruments is selected for reasons of international
comparability. This enables research on the effect of different socio-cultural
developments and care systems on autonomy and well-being of older persons.
Changes in functioning are established during the study period, based on
successive study cycles. In addition to interview questions, objective
measurements provide indicators sensitive to change.
Physical
functioning is measured by self-reports on functional limitations, and by
objective measures of endurance, strength, mobility, coordination, balance, and
vision. Cognitive
functioning is measured by a brief screening test of dementia, and by tests
of intelligence, learning capacity, memory, and information processing speed. Emotional
functioning is measured by widely used depression and anxiety scales. Social functioning
is measured by composition of the social network, frequency of contacts,
exchange of support, and by social participation.
In addition to the behavioral aspect of functioning, the respondent's
evaluation of their functioning is recorded, including self-perceptions of
health, memory complaints, and loneliness.
Characteristics that are expected to predict changes in one of more of the
components of functioning (the independent
variables) are related both to the environment and to the individual:
chronic conditions, use of medications, objective clinical assessments, use of
services, life style, personality, personal biography, housing and living
arrangements, socio-economic status, and "life events" prior to and
during the study period.
Personal standards or aspiration levels and coping, expect to influence
trajectories as mediating
variables, are operationally defined as norms about aging, priorities in
life, perceived self-efficacy, mastery, humor as a coping strategy, metamemory,
and standards of affiliation.
The consequences
of improvements and declines in functioning and the resulting (in)dependence
are quantified in terms of the need for health and social services. Time,
circumstances and causes of death are studied in connection with type of
functional decline in the last phase of life.
The conceptual model described is summarized in the figure below.
Acknowledgement
The Longitudinal Aging Study Amsterdam is facilitated primarily by the
Department of Policies for the Ageing, Ministry
of Health, Welfare, and Sports, and by the Vrije
Universiteit. Other grants are provided by the Prevention Fund / Health
Research and Development Council (ZON), the University Stimulating Fund of the
Vrije Universiteit, the National Research Program on the Chronically ill, and
the Netherlands Organization for Scientific Research (NWO). The Vrije
Universiteit supports the study by supplying several research staff, housing,
and facilities.
Institutional affiliations within the Vrije Universiteit
LASA is carried out primarily at the Department of Psychiatry (Faculty of
Medicine; Institute for Research in Extramural
Medicine, EMGO), and at the Department of
Sociology (Faculty of Social Sciences).
Since 1995, also the Department of Endocrinology (VU Medical Center, as far as
it resorts under EMGO), is responsible for the execution of LASA. Furthermore,
collaboration has been effectuated with the Departments of General Practice,
Nursing Home and Social Medicine (VU Medical Center, as far as it resorts under
EMGO), the Department of Education Sciences (Faculty of Human Movement
Sciences), the Department of Social Psychiatry (Faculty of Psychology and
Education), and the Department of Econometrics (Faculty of Economics).
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Updated 16-4-2008
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