Journal of Rehabilitation Medicine: Special Issue 50-4bokBW | Page 9

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Rehabilitation: the health strategy of the 21 st century
IMPACT OF THESE TRENDS ON
FUNCTIONING AND DISABILITY
The impact of the combination of population
ageing and the shift in prevalence to non-com-
municable health problems will be that a higher
proportion of the world’s population will be living
with one or more limitations in functioning, and
so will be likely to experience disability. Limi-
tations in functioning associated with chronic
NCDs and ageing include long-term sensory, cog-
nitive, mobility and other impairments as well as
restrictions in activities, simple or complex. The
burden of disease for NCDs in the older popula-
tion is strongly determined by disability, rather
than premature death. In short, although people
worldwide are living longer, generally speaking,
they are also living with more disability (13).
It is true that in high-income countries there is
some evidence of a trend towards a reduction in
the time lived with disability. An analysis carried
out by the World Health Organization (WHO) in
2014 of large longitudinal studies conducted in
high-income countries suggested that the preva-
lence of disability of such a level of severity as
to require assistance from another person to carry
out basic activities, such as eating and washing,
may be declining slightly (3). However, that study
also showed that there has been no significant
change in less severe disability over the past 30
years, and that the evidence we have from low-
and medium-income countries, although of lower
quality, suggests the opposite trend; that is, an
increase in the level of disability with age, linked
to an increase in the number of underlying health
conditions (multimorbidity).
It is important to bear in mind that, quite
independently of the diseases and injuries we ex-
perience as we age, at the biological level, ageing
is simply the gradual process of molecular and
cellular deterioration that inevitably results in pro-
gressive impairments across all body functions,
accompanied by a broad range of psychosocial
changes. Muscle mass declines with age, articular
cartilage loses strength and flexibility, and vision,
hearing, and cognitive functions, including me-
mory, tend to decline with age.
In other words, according to the WHO’s Inter-
national Classification of Functioning, Disability
and Health (ICF) (14), ageing is the inevitable
process of capacity decline, a process which,
depending on a person’s access to environmental
Switzerland
Denmark
Netherlands
Sweden
Czech Republic
Italy
France
Austria
Slovenia
Germany
Spain
Estonia
Belgium
China
Hungary
Portugal
Poland
Mexico
Russian Federation
South Africa
Ghana
India
lack of exercise, which will further increase the
prevalence of chronic health problems (8).
0
10
SHARE
SAGE
20
30
40 50 60
Percentage
65–74 years
65–74 years
70
80
90
≥75 years
≥75 years
Note: The five basic ADL items included i n the analysis were eating, bathing,
dressing, getting in and out of bed, and using the toilet.
Fig. 2. Percentage of population aged 65–74, and
75 years or older, with a limitation in 1 or more of 5
basic activities of daily living (ADL), by country. World
Health Organization. World Report on Ageing and
Health. Geneva: WHO; 2015. http://apps.who.int/
iris/bitstream/10665/186463/1/9789240694811_eng.
pdf?ua=1. SAGE: Study on global AGEing and adult
health; SHARE: Survey of Health, Ageing and Retirement
in Europe.
facilitators or the presence of barriers, may also
result in a permanent decrement or progressive
decline in the performance of activities, simple
or complex. In short, ageing is the process of
declining health, usually linked to an increase in
the experience of disability or the likelihood of
experiencing disability (Fig. 2) (1).
Another significant feature of the ageing process
is the phenomenon of multimorbidity. The issue
here is not so much that of people developing
several serious diseases or injuries at once, alt-
hough that is not uncommon. It is rather the more
subtle phenomenon of accumulating several dif-
ferent chronic conditions at the same time, each
of which might be of low or moderate severity,
but together will produce a more severe level of
decline in capacity (15). Disease combinations
may worsen the impact on capacity associated with
each disease on its own, and overall the impact of
multimorbidity in older age may be far greater than
the sum of the individual impacts expected from
each health problem alone. Multimorbidity com-
plicates treatment planning and has well-known
J Rehabil Med 50, 2018