For older adults, anemia's trademark loss of
oxygen-toting red blood cells has long been linked to
fatigue, muscle weakness and other physical ailments. Now
researchers at Johns Hopkins have found a relationship
between anemia and impaired thinking, too.
"Our work supports the notion that mild anemia may be
an independent risk factor for so-called executive-function
impairment in older adults," said Paulo Chaves, an
assistant professor at the School of Medicine and the lead
author of the study. "If further studies confirm that's
true, this could mean that correction of anemia in these
patients might offer a chance to prevent such a cognitive
decline."
Reporting on the research in the September issue of
The Journal of the American Geriatrics Society, the
Johns Hopkins investigators went looking for such an effect
because previous studies showed that age-related declines
in the brain's so-called executive function — problem
solving, planning, assessing dangers, following up on
important activities — lead to declines in
self-sufficiency.
"Executive function impairment, which happens often
before memory loss occurs, may happen early on in the
process of becoming unable to carry on with instrumental
day-to-day living activities, such as shopping, cooking,
taking medications, paying bills, walking, etc.," Chaves
said.
Chaves and his team gave three psychological tests
commonly used to evaluate executive function to 364 women
in Baltimore, all between 70 and 80 years old.
Approximately 10 percent had anemia, which was of mild
intensity.
Some 15 percent of those with the worst results on all
three of the tests were anemic, compared to only 3 percent
who scored best. Those with anemia were four to five times
more likely to perform worst on the executive function
tests, compared to those with normal blood hemoglobin,
after taking into account the effect of other factors that
affect cognition, such as age, education and existing
diseases.
"These preliminary results don't prove that anemia
causes impaired executive function, nor indicate that
treatment of anemia would necessarily lead to better
executive function," Chaves said. "However, they are
compelling enough to serve as a roadmap for continued
research."
How anemia could affect thinking remains to be
determined. It could be that it chronically diminishes the
supply of oxygen to the brain. Another view proposes that
the fatigue accompanying anemia leads to inactivity and the
loss of aerobic-fitness benefits to the prefrontal
cortex.
The study was funded by the National Institute on
Aging and grants from the Claude D. Pepper Older Americans
Independence Center at Johns Hopkins; General Clinical
Research Center, National Institutes of Health; and Ortho
Biotech Products, which produces a medication that
stimulates the production of red blood cells. Chaves has
served as a paid consultant for Ortho Biotech Products. The
terms of the latter arrangement were managed by The Johns
Hopkins University in accordance with its
conflict-of-interest policies.
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