Diabetes in Midlife Linked to Later
Dementia
December 1, 2004
By Anthony J. Brown
Middle-aged people with diabetes are nearly three times
more likely to develop dementia in old age than people
without diabetes, according to a new study.
Studies looking at a cross-section of the population
have "tied diabetes to Alzheimer's disease or dementia,"
Dr. Michal Schnaider Beeri, from Mount Sinai School
of Medicine in New York, told Reuters Health. "Our
study is special because it shows a strong association
between these disorders over several decades."
The study involved 2600 subjects who participated in
the Israeli Ischemic Heart Disease study in the 1960s
and were still alive and available for follow-up in
1999. The subjects were between 40 and 65 years of age
when the study began.
The mental status of 1892 participants was determined,
and 652 were identified as possibly demented. This was
confirmed in 309 subjects (16.3 percent).
Those with diabetes during the study were 2.83-times
more likely to develop dementia than those without diabetes,
the investigators report in the medical journal Neurology.
As for how diabetes might promote dementia, Beeri offered
three possibilities.
First, excess glucose can create high levels of so-called
"advanced glycation end products," and these
have been linked to dementia and Alzheimer's disease
in several studies, she said.
"These end products seem to stick to beta-amyloid
and prevent its degradation," the researcher explained,
referring to the abnormal protein that accumulates in
the brain of people with Alzheimer's disease.
Beeri noted that if glycation end products are involved
this could be good news because recent reports suggest
that these levels can be modified by diet.
Another possible explanation is that insulin competes
for a degradation enzyme that also breaks down beta-amyloid,
Beeri said. Therefore, with high insulin levels (as
happens with type 2 diabetes), the enzyme is less able
to clear away beta-amyloid.
Or, it may be that diabetes' bad effect on the microcirculation
could lead to dementia by interfering with the brain's
blood supply, she added.
Source:http://abcnews.go.com
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