22-Feb-2016
Neurology
MINNEAPOLIS
People who
keep mentally and physically healthy in middle age may help stave off the
symptoms of Alzheimer’s disease, but the activity does not affect the
underlying disease changes in the brain for most people, according to a study
published in the February 24 online edition of Neurology®, the medical journal
of the American Academy of Neurology.
The findings differed for people
who are carriers of a gene linked to Alzheimer’s, called APOE4, which affects
about 20 percent of the population. Those with the gene who had at least 14
years of education and kept mentally active in middle age had lower levels of
proteins, called amyloid plaques, that can build up in brain tissue and lead to
Alzheimer’s disease than those with the gene and a high level of education but
who did not keep mentally active in middle age. Among the APOE4 high education
individuals, the predicted amyloid levels in a 79-year-old who kept mentally
active (67th percentile) would be the same as the predicted amyloid levels in a
74 year-old who did not (33rd percentile).
“Recent studies have shown
conflicting results about the value of physical and mental activity related to
the risk of developing Alzheimer’s disease, and we noticed that levels of
education differed in those studies,” said study author Prashanthi Vemuri, PhD,
of the Mayo Clinic in Rochester, Minn. “When we looked specifically at the
level of lifetime learning, we found that carriers of the APOE4 gene who had
higher education and continued to learn through middle age had fewer amyloid
deposition on imaging when compared to those who did not continue with
intellectual activity in middle age.”
Vemuri said the overall findings
for people who do not carry the gene should not discourage people from
exercising and taking part in activities such as reading books and magazines,
playing games and using computers. “There is substantial evidence that these
activities help to delay the onset of memory and thinking problems,” Vemuri
said. “What we don’t know is how this process works.”
For the study, researchers
evaluated 393 people without dementia who were part of the Mayo Clinic Study of
Aging. Of those, 53 had mild cognitive impairment. All were 70 years of age or
older. They were divided into two groups, those with more than 14 years of
education and those with less.
Researchers then used MRI and PET
scans to look for biomarkers of Alzheimer’s disease and questionnaires to
evaluate weekly intellectual and physical activity in middle age.
For the group as a whole, education,
occupation and mental and physical activity in middle age appeared to have
little to no effect on the rates of worsening amyloid plaques, brain glucose
metabolism and brain volume. But for APOE4 carriers with high education and
continued lifetime learning, there was less amyloid deposition in the brain
than those with high education who did not continue to learn.
“It is possible those who did not
continue intellectual activity in middle age did so because they had higher
levels of amyloid plaques,” said Vemuri. “While there are many limitations with
this study, our findings show further study is needed and suggest that
differing education levels in other recent studies may explain the conflicting
results seen in the research literature.”
The study was supported by the
National Institutes of Health.
The American Academy of
Neurology, an association of 30,000 neurologists and neuroscience
professionals, is dedicated to promoting the highest quality patient-centered
neurologic care. A neurologist is a doctor with specialized training in
diagnosing, treating and managing disorders of the brain and nervous system
such as Alzheimer’s disease, stroke, migraine, multiple sclerosis, brain
injury, Parkinson’s disease and epilepsy.
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