Now, keep up to date
with daily feeds of newly posted stories
about America's Seniors...click on the box
to the left
Lower Biomarker Levels, Less Education
associated with Greater Cognitive Decline
Newswise, January 26, 2011 — Older adults without
dementia and with lower levels in plasma of
the biomarkers beta-amyloid 42/40 (protein
fragments) had an increased rate of
cognitive decline over a period of 9 years,
according to a study in the January 19 issue
of JAMA. The researchers also found that
this relationship was stronger among
individuals with less education and lower
levels of literacy.
An estimated 36 million people currently have dementia,
with the prevalence expected to double every
20 years, according to background
information in the article.
"Thus, biomarkers to identify elderly persons at risk of
developing dementia could be useful for
early prevention, if and when such
interventions are available, and treatment,"
the authors write.
"Lower plasma beta-amyloid 42 and 42/40 levels have been
associated with incident dementia, but
results are conflicting and few have
investigated cognitive decline among elders
without dementia."
Kristine Yaffe, M.D., of the University of California,
San Francisco, and San Francisco Veterans
Affairs Medical Center, and colleagues
conducted a study to investigate the
association between plasma beta-amyloid 42
and 42/40 levels and cognitive decline in a
large group of community-dwelling older
adults without dementia, and also examined
whether measures of cognitive reserve, as
indicated by levels of education and
literacy attained, modified the association
of plasma beta-amyloid level with cognitive
decline.
The analysis included 997 black and white
community-dwelling older adults who were
enrolled in the Health ABC Study, a
prospective observational study begun in
1997-1998 with 10-year follow-up in
2006-2007.
Participant average age was 74 years; 55.2 percent (n =
550) were female; and 54 percent (n = 538)
were black. Measures of beta-amyloid 42 and
42/40 and cognitive function (via Modified
Mini-Mental State Examination) were
obtained.
The researchers found that low beta-amyloid 42/40 level
was associated with greater cognitive
decline over 9 years.
After adjustment for several factors, the results
remained statistically significant. There
was also a significant association between
plasma beta-amyloid 42 levels and cognitive
decline.
There was no association between plasma beta-amyloid 40
levels and baseline cognitive function or
decline.
Also, cognitive reserve measures modified the association
between beta-amyloid 42/40 level and
cognitive decline. Older adults with low
reserve (as measured by less than a high
school diploma or sixth-grade or lower
literacy) had an even greater association
with beta-amyloid 42/40 level, whereas those
with high reserve had less association.
"These results are important, as the prevalence of
cognitive impairment is increasing
exponentially and prevention will be
crucial.
“To identify those at risk of dementia, biomarkers like
plasma beta-amyloid level that are
relatively easy to obtain and minimally
invasive could be useful.
“In addition, our finding of an interaction of cognitive
reserve with the association of plasma beta-amyloid
level and cognitive decline could have
public health importance because it may
suggest pathways for modifying beta-amyloid
effects on cognition," such as with
cognitive activity or ongoing education, the
authors write.
"Future studies should further explore the use of plasma
beta-amyloid as a biomarker, assess the
mechanisms by which cognitive reserve
modifies this association, and determine
whether increasing cognitive reserve through
interventions can reduce the risk of
Alzheimer disease."
