If Alzheimer's disease runs in your family, you may be more likely to have
brain changes associated with the disorder even before symptoms such as memory
and thinking problems occur, according to new research.
An estimated 5.2 million Americans have Alzheimer's disease, a number
expected to increase dramatically as the baby boomer generation ages. The
Alzheimer's Association predicts that the number of people aged 65 and older
with the condition will reach 7.1 million by 2025.
How the research was done
To get a better handle on risk for Alzheimer's disease, researchers at Duke
University looked at brain scans of more than 250 adults aged 55 to 89. Some had
no signs of memory or thinking problems, while others did.
The researchers also analysed genes and other markers in spinal fluid that
are known to help predict Alzheimer's risk. A variation in the APOE gene was
seen among those participants who were at greater risk for earlier onset of
Individuals who had a parent or sibling with Alzheimer's disease showed
silent brain changes, the study found.
Specifically, close to 50% of healthy participants with a positive family
history would have met the criteria for early Alzheimer's disease based on
measurements of their cerebrospinal fluid, but just 20% of those without a
family history would have fulfilled such criteria.
"In early-onset Alzheimer's disease, the genetics are much more clear-cut and
we can test family members and know if they will develop Alzheimer's," said
senior author Dr P Murali Doraiswamy, a professor of psychiatry and medicine at
It is not as clear-cut, however, when it comes to later-onset Alzheimer's,
Doraiswamy said. "The genetics are much more complex, and although we know these
individuals are at a slightly greater risk, we don't know when they start
developing silent brain changes," he said.
"[The new study is] documenting very clearly that asymptomatic family members
have twice the rate of silent brain changes and that these changes happen in
certain pathways known to be related to Alzheimer's disease."
The findings may help advance research that seeks to prevent Alzheimer's
disease by using drugs, he said, and it's not a reason to panic and start to
think the worst if you have a family history of the disease. "The findings don't
suggest you should worry any more or any less," he said.
'Make brain-healthy choices'
Although the study found an association between having a family history of
Alzheimer's and showing brain changes related to the disease, it did not prove a
"Having a family history does not mean you will get Alzheimer's disease,"
said Dr Richard Isaacson, director of the Alzheimer's division at the University
of Miami Miller School of Medicine. You may be at a higher risk for developing
it, but it is not predestined, said Isaacson, who was not involved with the new
"Make brain-healthy choices now to help lower this risk," he suggested. "We
know that if it is good for the heart it is good for the brain." Such choices
include engaging in regular physical activity and eating a healthy low-fat
"It's also important to keep your brain fit by doing something you enjoy -
whether crossword puzzles or learning a foreign language - every day," Isaacson
"If you have a family history, get educated and informed about positive
lifestyle choices and consider taking part in an Alzheimer's prevention trial,"
"We can finally say 'Alzheimer's disease' and 'prevention' in the same
sentence, and that is a great thing."
Learn more about how Alzheimer's disease is diagnosed at the Alzheimer's