The brain function of Americans 70 and older appears to be
improving,
according to a study that found a smaller percentage of seniors
with
serious memory and language problems in 2002 than in 1993.
The finding, which researchers say is still preliminary,
parallels an
improvement in physical functioning among older Americans that is
well
documented.
"If this study is indeed confirmed and replicated, then it says
that
cognitive decline associated with aging is malleable," said
Richard
Suzman, director for behavioral and social research at the National
Institute on Aging, which helped fund the study. "There may be
interventions that can be brought to bear to accelerate the trend.
It's
potentially very good news."
Although the study does not mean that every individual will live
healthier
into old age, it does suggest that as a whole, people are
functioning at a
higher level for longer periods. That could mean that more people
will be
able to live independently later in life, said Suzman.
Researchers, however, cautioned that the aging of the baby
boomers and the
nationwide epidemic of obesity and diabetes will still bring a
significant
jump in the number of people with Alzheimer's disease over the next
few
decades. Both diabetes and obesity are risk factors for
cardiovascular
problems that can damage the brain.
Scientists are uncertain exactly what accounted for the improved
cognitive
health of the 2002 participants, but the study found that, on
average,
they had about one more year of formal education (12 vs. 11) than
those in
1993, and had about $100,000 more in net worth. Using statistical
analyses,
the study found that those two factors could explain 43 percent of
the
difference in mental function. Education might help by enabling
individuals
to take on more mentally challenging jobs and leisure activities,
thereby
expanding brain capacity, while wealth might allow people to get
better
care for cardiovascular ailments.
The study, published online Wednesday in the journal Alzheimer's
&
Dementia, compared results of mental function tests of more than
7,000
people over age 69 in 1993 with about the same number in 2002. More
than 12
percent of test subjects in 1993 showed evidence of mental problems
consistent with mild to severe dementia, compared with 8.7 percent
in
2002. The researchers did not have access to clinical data that
would have
allowed them to test for dementia directly.
Extrapolated to the entire population, that would mean about
900,000
fewer people over 69 showed significant cognitive problems in 2002
than
would have been expected based on the 1993 patterns, said Dr.
Kenneth M.
Langa, an associate professor of medicine at the University of
Michigan,
who was the study's lead author.
"We think that the brain health of ((older)) people in 2002 is
better than
the brain health in 1993," said Langa.
At least one local geriatrician is seeing that change in her
patients.
"When they say 90 is the new 80, it's true," said Dr. Suzanne
Salamon,
associate chief of clinical geriatrics at Beth Israel Deaconess
Medical
Center. "I see 90-year-olds who are very active, going to
lectures,
enjoying life. We're seeing this a lot more."
However, there appears to be a downside to the trend. In the
study, people
who showed moderate to severe cognitive impairment in 2002 were
more likely
to die within two years than those with impairments in 1993, and
this was
especially true of those with more education. Langa and his
colleagues
suggest that education helps the brain function better despite
accumulating
damage, so the problems aren't evident until they are much more
severe. As
a result the decline to death appears more rapid. This supports
findings in
other studies of a protective "cognitive reserve" in some people.
Other scientists cautioned about generalizing too much from one
study's
results, until they are confirmed by other researchers. In
addition, some
questioned details of the methodology, particularly whether the
study
properly took into consideration age differences in the two
populations and
whether it is appropriate to predict a trend from testing at just
two time
periods.
"The data are highly limited for reaching the conclusion they
have," said
Dr. Denis Evans, a professor of medicine at Rush University Medical
Center
in Chicago who studies cognitive decline in old age. "I would
hedge it."
Langa said the trend became even stronger when the research team
controlled
for the fact that the study population in 2002 was older than that
in 1993.
And, he said, a preliminary look at test results from seniors in
2004 and
2006 suggests the trend is continuing.
"We think the change is strong enough to hold even if there are
some
problems" with technical details of the study, Langa said.
The conclusions are also consistent with the findings of two
previous
studies, but contradict a third study that found no change using
similar
data.
The research builds on studies that found chronic physical
disability had
declined among people 65 and older - from more than 26 percent of
the
population in 1982, to 19 percent in 2004, Suzman said. Those
studies
measured seniors' ability to perform basic activities such as using
the
toilet, as well as activities with a mental component, such as
talking on
the telephone.
"That finding changed the view of ((physical)) aging to one
over which
society has some modest degree of control," said Suzman. He
suggested that
the current study, if confirmed and if the trend continues, might
lead to a
similar change in thinking about mental aging.
The researchers suggest that better management of heart disease
risks,
such as high blood pressure and high cholesterol, might help most
people
maintain brain function, but the study did not measure that. Other
researchers have suggested that exercising, eating healthy food,
and
socializing may help keep the mind sharp.
"I can't make a specific medical recommendation from this
study," Langa
said, "but continuing to use your brain and staying connected to
the world
. seems to be important for maintaining your brain health." .
Alice Dembner can be reached at dembner@globe.com.
c.2007 The Boston Globe