|
 Two
Studies of Older Adults Confirm Exercise Reduces Dementia Risk
Sept. 21, 2004 Two studies one of older men and
the other of older women confirm that exercise, even walking, can mean
a reduced risk of dementia.
The study of men focused specifically on walking.
It focused on 2,257 physically capable men between the ages of 71 and
93. There walking was monitored between 1991 and 1993. There were given
two dementia tests, first between 1994 and 1996, and then again between
1997 and 1999.
During the course of follow-up, 158 cases of
dementia were identified. After adjusting for age,
men who walked the least (.25 mile per day) experienced a
1.8-fold excess risk of dementia compared with those who walked
more than 2 miles per day. Compared with men who walked the most
(two miles per day), an excess risk of dementia was also
observed in those who walked 0.25 to 1 mile per day. These
associations persisted after accounting for other factors,
including the possibility that limited amounts of walking
could be the result of a decline in physical function due to
preclinical dementia.
The researchers concluded there findings suggest
that walking is associated with a reduced risk of dementia
and that promoting active lifestyles in physically capable
men could help late-life cognitive function.
In the study of women, they reported participation
in leisure-time physical activities on biennial mailed
questionnaires, beginning in 1986. The researchers assessed long-term
activity by averaging energy expenditures from questionnaires
in 1986 through participants' baseline cognitive assessments
(1995 to 2001).
Participants were 18,775 U.S. women aged 70 to 81
in the Nurses' Health Study.
They used scientific methods to estimate
adjusted mean differences in baseline cognitive performance
and cognitive decline over 2 years, across levels of physical
activity and walking. They used telephone calls for the assessments of
cognition one two occasions, approximately 2 years apart (1995
to 2001 and 1997 to 2003), including tests of general cognition,
verbal memory, category fluency, and attention.
They found higher levels of activity were
associated with better cognitive performance. On a global
score combining results of all 6 tests, women in the second
through fifth quintiles of energy expenditure scored an
average of 0.06, 0.06, 0.09, and 0.10 standard units higher
than women in the lowest quintile. Compared with women in the lowest
physical activity quintile, they found a 20% lower risk of
cognitive impairment for women in the highest quintile of
activity.
Among women performing the equivalent of
walking at an easy pace for at least 1.5 hours per week, mean
global scores were 0.06 to 0.07 units higher compared with
walking less than 40 minutes per week.
They also observed less cognitive
decline among women who were more active, especially those in
the 2 highest quintiles of energy expenditure. Women in the
fourth and fifth quintiles had mean changes in global scores
that were 0.04 and 0.06 standard units better than
those in the lowest quintile.
Their conclusion: Long-term regular physical
activity, including walking, is associated with significantly
better cognitive function and less cognitive decline in older
women.
The study of men was by Robert D. Abbott, PhD; Lon
R. White, MD; G. Webster Ross, MD; Kamal H. Masaki, MD; J. David Curb,
MD; Helen Petrovitch, MD
The study of women was by Jennifer Weuve, ScD; Jae
Hee Kang, ScD; JoAnn E. Manson, MD; Monique M. B. Breteler, MD; James H.
Ware, PhD; Francine Grodstein, ScD
Both studies are published in the Journal of the
American Medical Associations edition of Sept. 22, 2004.
Copyright: SeniorJournal.com |
