ADL disability is an age-related condition that leads to poor quality of life, increased
health-related care costs, and increased mortality. The proportion of older adults are
increasing worldwide, and it is therefore important both for society and the individual
that research provide us with information about the process leading to ADL disability
and how to identify persons at risk. The most effective design for following the aging
process is found in population-based studies that include all older persons, both those
living at home and those in residential care. This thesis uses data from three populationbased
studies: the Kungsholmen Project (KP), the Nordanstig Project (NP) and the
SNAC-N study. The aims of the thesis was to examine temporal changes in physical
functioning in older adults, to identify underlying development of new disability and
functional decline, as well as to explore geographical variation in physical functioning
between urban and rural elderly habitats. We also wanted to describe the amount of
informal and formal care in relation to levels of ADL disability. The ultimate aim was
to identify factors suitable for prevention.
Study I: We I compared two populations of older adults, 75 years and older (the KP
and the NP) from different living areas (urban and rural) and found differences in ADL
disability, morbidity and disease patterns. The most common health problem in both
areas was cardiovascular diseases (39.9% in the urban area and 45.2% in the rural
area). There were great differences, urban vs rural, in the prevalence of stroke (7.4% vs
14.0%), diabetes mellitus (6.3% vs 16.1%), and Parkinson’s disease (1.0% vs 3.7%).
Having two or more diseases vs. no disease was more common in the rural area than in
the urban area, odds ratio (OR) = 1.9, 95% confidence interval (CI) = 1.4-2.4. Living
area differences (urban vs rural) were found in population attributable risk (PAR) for
disability due to stroke (5.6 vs 32.2), diabetes mellitus (1.2 vs 6.1), fractures (1.4 vs
10.7), and hearing impairment (8.7 vs 22.0).
Study II: Data were gathered from a population-based study of adults 60 years and
older, the SNAC-Nordanstig (SNAC-N), and the study explored the association
between ADL disability, muscle strength, disease severity and mortality. Upper and
lower muscle strength decreased with increasing age, with a tendency for lower
performance in women than in men. A significant association was found between ADL
disability and having reduced lower muscle strength. Having an increased number of
diseases increased the risk of being ADL disabled. Diseases with the greatest impact on
ADL disability were musculoskeletal diseases, hypertension and dementia. ADL
disability and being unable to perform the gait speed test were factors that increased the
risk of death. Inability to perform the chair stand test or weaker grip strength increased
the risk of death for men.
Study III: Data from two populations, 78 years and older, the NP (1995-1998) and the
SNAC-N study (2001-2003), were used to study time trends in the prevalence of ADL
disability and survival, comparing two cohorts. The prevalence of ADL disability was
stable from 1995-1998 to 2001-2002 for men, while women became more disabled in
ADL over the time period, (OR 2.36; CI 1.12-4.94). No significant difference was
found in survival time between the cohorts in either ADL-disabled or non-disabled
persons. There was a tendency for increased survival for non-disabled persons in the
SNAC-N study compared with the NP, although it was not significant; this was
particularly true for women. In general, women survived longer than men did
regardless of whether they were ADL disabled or not.
Study IV: The aims were to examine the incidence of ADL disability, to explore
whether being physically active earlier in life is a significant predictor of being
disability free at follow-up, and to describe the amount of informal and formal care
received in relation to ADL disability. Data were gathered from persons 78 years and
older in the SNAC-N study. The incidence rates for men were almost the same in the
age group 78-81 compared with the age group 84 years and older, 42.3 vs. 42.5/1000
person-years. For women the incidence rate for ADL disability increased significantly
from the age group 78-81 to the age group 84 years and older, 20.8 vs. 118.3/1000
person-years. In the age group 78-81 years, being physically active earlier (aOR 6.2)
and during the past 12 months before the baseline examination (aOR 2.9) were both
significant preventive factors for ADL disability. The amount of both informal and
formal care increased with the number of ADL activities the persons were dependent
on and the amount of informal care was greater than the amount of formal care.
Conclusions: This thesis shows an increase in ADL disability due to increased age, and
that women are more ADL disabled than men, but also shows how diseases affect ADL
disability. The diseases that negatively affect ADL are often due to unhealthy lifestyle,
e.g. physical inactivity, obesity and smoking, etc. The results show the importance of
prevention of the factors that cause ADL disability, preferably already in midlife. The
amount of both informal and formal care increased significantly with the number of
ADL activities the persons required help with. Regarding prevention of becoming ADL
disabled, it is of importance to find ways to postpone the onset of ADL disability so
that we can live longer without disability