Introduction
‘Why
do people with serious and persistent disabilities report that they
experience a good or excellent quality of life when to most external
observers these people seem to live an undesirable daily existence?’.
This phenomenon was first described by
Albrecht and Devlieger (1999)
and was referred to as the “disability paradox” (DP). About three
percent of people aged 55 years and older and almost sixty percent of
people older than 85 years have severe functional limitations (
van Groenou & Deeg, 2006).
Functional limitations are defined as the extent to which a person
experiences limitations in carrying out the activities of daily living
such as climbing up and down a staircase, dressing and undressing or
walking. Given the aging population, increasing numbers of people live
with some kind of functional disability. Moreover, while it may
intuitively make sense to expect that maintaining subjective wellbeing
(SWB) becomes increasingly difficult when facing age-related losses, the
DP suggests otherwise (
Kunzmann et al., 2000;
Whitbourne & Sneed, 2002). Therefore it is important to consider the DP in the context of aging.
Different
theories have been postulated that might explain this paradox. For
example, the ‘discounting theory’ suggests that future-oriented coping
might play a role. Older adults may actively construct representations
of the future that are consistent with normative age-related declines
and losses. Once these declines and losses actually occur, these
expectations may reduce their potentially negative psychological effects
(
Cheng et al., 2009).
This theory fits within the broader framework of selection,
optimization, and compensation (SOC). SOC posits that aging is
associated with proactive structuring of people’s lives to maximize
fulfillment of fewer, yet more subjectively important goals (
Freund & Baltes, 1998).
Also in line with this framework is the social production function
theory of successful aging (SPF). This theory specifies three key goals
that determine overall wellbeing and tend to change in importance as
people age (
Steverink et al., 1998). First,
status,
or what someone “has”, is gained by attaining a higher position in
social hierarchies, such as educational and occupational hierarchies.
Second,
behavioral confirmation stems from what someone “does”, and is mainly gained through social activities. Third,
affection is the feeling that others care about you (
Steverink et al., 1998).
With aging, status tends to decline first, for example as a result of
retirement. The relevance of these theories to the DP is that decline of
physical functioning often accompanies declines in status and,
subsequently, behavioral confirmation. However, in response, older
adults can increasingly shift their attention and efforts towards
affection, for example through intensifying emotionally rewarding social
contacts. As such, they balance gains and losses and maintain wellbeing
despite functional decline.
Nevertheless, the existence of the DP in old age has been put into question (
Cabrita et al., 2017;
Gana et al., 2015;
Jonker et al., 2008).
Specifically, it has been argued that the presence of the DP depends
on: (a) the SWB dimension under investigation, (b) the research design,
and (c) individuals’ demographic psychosocial characteristics. We
elaborate on these three issues.
First,
concerning the issue of dimensionality, subjective well-being (SWB) is a
broad concept comprising both a cognitive component (life satisfaction;
LS), and an affective component, which is usually further subdivided
into positive affect (PA; e.g., happiness, engagement, and joy) and
negative affect (NA; e.g., worry, fear, uneasiness). NA is sometimes
referred to as ‘depressed affect’, when it is operationalized using
subscales from depressive symptomatology questionnaires (
Hertzog et al., 1990).
This conceptualization of SWB by Diener was recently supported by a
meta-analysis that demonstrated that PA, NA and LS were unique
dimensions with substantial loadings on a latent SWB factor (
Busseri, 2018). These factor loadings did not vary significantly as a function of sample characteristics.
However,
the intensity and speed of change over time may differ between SWB
indicators. Originally, it was argued that the cognitive component (LS)
is more stable than the affective component (NA and PA;
Gana et al., 2015;
Puvill et al., 2016). Indeed, various studies show that life satisfaction is remarkably stable over time (e.g.,
Fujita & Diener, 2005;
Gana et al., 2012), and other studies demonstrate that PA tends to decrease and NA tends to increase with advancing age (e.g.,
Griffin et al., 2006).
Kunzmann and colleagues (2008)
focused only on the affective components of SWB, and found that NA was
more stable over time than PA. Reasons why the cognitive component would
be more stable than the affective component mainly include
methodological ones: LS is often asked with a single question about a
very broad circumstance (satisfaction with life
in general),
whereas questionnaires on PA and NA consider a shorter time frame and
appear to be more sensitive to daily hassles and events (
Gana et al., 2015;
Hansen & Slagsvold, 2012).
Nevertheless, one of the few studies that could directly compare
longitudinal changes across both cognitive and affective dimensions
found PA to be the most stable, while LS decreased and NA increased (
Hansen & Slagsvold, 2012). The authors of that study argue that the stability of PA could be due to improving emotion regulation skills with age (
Carstensen et al., 1999).
Given the conflicting evidence on the stability of SWB components and
the implications of this for the DP, the current study includes
longitudinal trajectories of LS, NA and PA.
Second,
concerning issues of study design, most studies describing the DP have
treated their sample as a single homogeneous group rather than
considering whether differential trajectories of decline in functioning
and/or well-being are present. This can be problematic, because in the
general older population, substantial groups do not display functional
decline until high ages. For example,
Kok and colleagues (2017)
observed different types of trajectories of functional limitations in
older men and women, and found that 68% of men and 54% of women aged 55
and older showed no functional decline across 16 years of time. We argue
that such groups should be excluded before examining the DP, because it
can by definition not be observed in older adults without functional
decline. Therefore, in the present study we use data-driven methods to
distinguish a group of older adults with substantial functional decline
over a 16-year period.
Furthermore, given that there is substantial heterogeneity between older adults in their trajectories of SWB (
Fujita & Diener, 2005;
Gana et al., 2012;
Griffin et al., 2006;
Hansen & Slagsvold, 2012),
it may be too simplistic to draw conclusions about the DP based on the
average (change in) SWB. Furthermore, focusing on trajectories rather
than cross-sectional observations of functional limitations and SWB is
important because a recent review by
Cabrita and colleagues (2017)
demonstrated that only the longitudinal studies included (n = 4,
spanning 4 months and 2, 4, and 6 years respectively) provided
consistent evidence that higher SWB was associated with fewer functional
limitations. Therefore, besides focusing on older adults with
substantial functional decline, within this group we identify subgroups
with distinct types of SWB trajectories.
Functional decline trajectories and SWB trajectories may also differ by gender. For example,
Doblhammer and Hoffmann (2009) find that women live longer with functional limitations. In line with this, in the same dataset as used in the present study (
Kok et al., 2017),
we previously found that men more often had a stable high physical
functioning trajectory than women (68 versus 54%), and that 5.5% of
women had a stable low functioning trajectory whereas none of the men
had this type of trajectory. Concerning SWB, the same study found that
only in women (9%) a distinct subgroup with stable high depressive
symptoms could be identified, although percentages with stable high LS
were about equal (89% in men versus 83% in women;
Kok et al., 2017).
To allow for observing potential gender differences in the DP, we
therefore analyze functional and SWB trajectories separately for men and
women.
Third, the extent to which the
disability paradox is evident may vary according to psychosocial and
demographic factors. For example, higher socio-economic status, being
married, and psychological characteristics such as high perceived
control and self-esteem have been shown to help maintain SWB despite
functional decline (
Fellinghauer et al., 2012;
Jonker et al., 2008).
Personality traits are thought to affect well-being by influencing
emotional reactivity and by facilitating adaptation following
challenging life events, such as the onset of impairments (
Lucas & Diener, 2015).
In addition, older individuals with high levels of self-efficacy (i.e.,
the belief of a person in his or her ability to organize and execute
behaviors necessary to produce desired attainments) are less likely to
perceive limitations in daily activities and more likely to report
higher levels of SWB (
Seeman et al., 1999).
Because such constructs fit well within the SOC, SPF and discounting
theories, in the present study we also investigate whether various
demographic and psychosocial characteristics are associated with the DP.
Building
on these conceptual and methodological considerations, and expanding
the available literature, the current study examines the prevalence and
associated psychosocial factors of the DP in people aged 55 years and
older who experienced substantial functional decline over a 16-year
period. We take into account the multidimensionality of SWB by examining
trajectories separately for PA, NA and LS, and separately for men and
women. Given that physical functioning and SWB are not strongly
correlated and that some studies demonstrate declines of SWB components
with ageing, we hypothesize that within the population of older adults
with functional decline several subgroups exist; groups who maintain
stable levels of well-being, supporting the DP, and groups who decline
in well-being over time, contradicting the DP. Regarding the different
components of SWB, because most empirical evidence suggests life
satisfaction has the strongest stability over time, we hypothesize that
the DP is more clearly present for the cognitive component of SWB (LS)
than for the affective components of SWB (PA and NA).
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