Cognitive and physical activities in
midlife were linked independently with reduced risk of dementia and
dementia subtypes, a longitudinal study that spanned 44 years found.
Women who frequently engaged in cognitive activities -- including
artistic endeavors, reading, needlework, or social clubs -- when they
were ages 38 to 54 years were 46% less likely to develop Alzheimer's
disease in late life and 34% less likely to develop dementia, according
to Jenna Najar, MD, of the University of Gothenburg in Sweden, and
colleagues.
And
women who were physically active were 53% less likely to develop
dementia with cerebrovascular disease and 57% less likely to develop
mixed dementia, they reported in
Neurology.
"There have been a number of studies looking at the relationship
between activities and dementia risk, but the results have been a bit
conflicting," Najar said in an interview with
MedPage Today.
"One important thing our research contributes is our long observation
period. We have followed these women for more than 4 decades. This is
important because low activity levels could be an early symptom of
dementia processes."
While several longitudinal studies have reported that
mental and
physical activity
were tied to lower dementia risk, most have a high mean age at baseline
and a short follow-up period. Among studies that have followed
individuals for longer time spans, outcomes are mixed. Perhaps the most
striking long-term result came from another University of Gothenburg
study in 2018 that showed
highly fit women were nearly 90% less likely to have dementia decades later.
In this population-based study, Najar and colleagues evaluated 800
women from the Prospective Population Study of Women in Gothenburg,
following them from 1968 to 2012. At baseline, the women had a mean age
of 47 and were assessed in five cognitive activities -- intellectual,
artistic, manual, club, and religious -- with the frequency of each
activity rated as no/low (score 0), moderate (score 1), or high (score
2), using the following guidelines:
- Moderate intellectual activity was reading a book in the last 6 months; high was reading more frequently or writing
- Moderate
artistic activity was visiting a concert, theater, or art exhibition in
the last 6 months; high was attending more frequently, playing an
instrument, singing in a choir, or painting
- Moderate manual
activity was needlework in the last 6 months or gardening in the last
year; high involved several interests or frequent activities
- Moderate degree of club activity included having a membership; high meant having a board membership
- Moderate
degree of religious activity included church attendance at least a few
times in the last year; high included church attendance at least 12
times in the last year
The total possible score was 10. The researchers divided participants
into two cognitive activity groups: those with scores of 0 to 2 (44% of
participants) and those with scores of 3 to 10 (56% of participants).
They
also divided participants into two physical activity groups, active
(82% of participants) and inactive (17% of participants), based on
baseline assessments using the
Saltin-Grimby Physical Activity Level
scale. The active group engaged in activities that ranged from light
physical activity like walking, gardening, bowling, or biking a minimum
of 4 hours per week to regular intense exercise like running or swimming
several times a week or competitive sports. The inactive group was
sedentary, mostly watching television or movies.
At multiple points in the study, psychiatrists or psychiatric
research nurses performed neuropsychiatric examinations, using criteria
from the
Diagnostic and Statistical Manual of Mental Disorders, Third Edition Revised (
DSM-III-R).
Over the follow-up period, a subset of women were diagnosed with
dementia (n=194), including Alzheimer's disease (n=102), vascular
dementia (n=27), mixed dementia (n=41), and dementia with
cerebrovascular disease (n=81), based on established criteria and
information from neuropsychiatric examinations, informant interviews,
hospital records, and registry data. Mean age at dementia onset was
79.8. During follow-up, 596 women died; they had a mean age at death of
80.
Women with a high level of cognitive activities had reduced risk of
total dementia (HR 0.66, 95% CI 0.49-0.89) and Alzheimer's disease (HR
0.54, 95% CI 0.36-0.82) than women with a low level of cognitive
activities. Women who engaged frequently in physical activity in midlife
showed a reduced risk of mixed dementia (HR 0.43, 95% CI 0.22-0.86) and
dementia with cerebrovascular disease (HR 0.47, 95% CI 0.28-0.78) than
physically inactive women. There was no relationship between physical
activity and Alzheimer's disease.
After excluding women who developed dementia midway through the study
(to rule out the possibility that they had prodromal dementia at
baseline, with less participation in activities as an early symptom),
the researchers analyzed the data again and found similar results,
except the link between physical activity and dementia was stronger.
The authors noted several limitations to this analysis. They used
medical and hospital registry records to identify individuals lost to
cumulative attrition, but those sources underestimate the number of
dementia cases. Competing risk of death also may have affected results.
Cognitive and physical activities were self-reported and assessed only
once in the study, at baseline.
The study was
supported by the Swedish Research Council, the Swedish Research Council
for Health, Working Life and Welfare, the Swedish Alzheimer Foundation,
Swedish Brain Power, the Swedish Brain Fund, the Alzheimer's
Association, the Bank of Sweden Tercentenary Foundation, the
Söderström-Königska Hospital Foundation, the Gamla Tjänarinnor
Foundation, the Handlanden Hjalmar Svenssons Research Fund Foundation,
and IRIS Scholarship.
Najar and co-authors disclosed no relevant relationships with industry.
Older adults who either engage in
daily exercise or just do everyday tasks, such as housework, may
maintain more of their thinking skills and memory than their less active
counterparts.
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