Alzheimer's, Dementia & Mental Health
Blinding Age-Related Macular Degeneration May Be
Associated With Cognitive Impairment
AMD - leading cause of blindness in senior citizens
- has long been thought to share a common pathway with Alzheimer's
disease
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Exam for AMD |
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May 11, 2009 - Older adults who score poorly on
tests of cognitive function, including thinking, learning and memory,
appear more likely to have the early stages of the eye disease
age-related macular degeneration, according to a report in the May issue
of Archives of Ophthalmology, one of the JAMA/Archives journals.
Age-related macular degeneration (AMD) - the
leading cause of visual impairment in industrialized nations - has long
been thought to share a common pathway with Alzheimer's disease,
according to background information in the article.
First, both conditions involve similar changes in
the brain and eye, including the buildup of protein fragments known as
beta-amyloid.
"Second, clinical studies suggest that AMD and
Alzheimer's disease share similar vascular risk factors, such as
hypertension (high blood pressure) and cigarette smoking," the authors
write.
"Both AMD and Alzheimer's disease have been linked
to an increased risk of stroke."
Michelle L. Baker, M.D., of the University of
Melbourne, Victoria, Australia, and colleagues assessed 2,088
individuals age 69 to 97. Participants underwent cognitive testing,
retinal photography for the detection of AMD and an extensive assessment
of artery disease and its risk factors (including blood pressure,
smoking status and body mass index).
After controlling for age, sex, race and the center
at which they participated in the study, the one-fourth of individuals
with the lowest scores on one cognitive test were twice as likely to
have early-stage AMD as were individuals with higher scores. However,
there was no association between AMD and scores on a second cognitive
test, dementia or Alzheimer's disease.
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Center vision lost to AMD |
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"In conclusion, we found an association between low
cognitive function and early AMD in this older population," the authors
write. "These data, along with others, provide further support that AMD
and cognitive impairment may share similar complex pathogenesis
[development] and risk factors."
Editor's Note: The research reported in this
article was supported by contracts from the National Heart, Lung and
Blood Institute, with additional contributions from the National
Institute of Neurological Disorders and Stroke. Additional support was
provided by a grant from the National Heart, Lung and Blood Institute
and by the National Heart Foundation.
