Home' Trinidad and Tobago Guardian : July 2nd 2015 Contents B26
body & soul
Guardian www.guardian.co.tt Thursday, July 2, 2015
Nearly two-thirds of Americans with Alzheimer s
disease are women, and now some scientists are
questioning the long-held assumption that it s just
because they tend to live longer than men.
What else may put woman at extra risk? Could
it be genetics? Biological differences in how women
age? Maybe even lifestyle factors? Finding out might
affect treatments or preventive care.
Research shows a notorious Alzheimer s-related
gene has a bigger impact on women than men.
"There are enough biological questions pointing
to increased risk in women that we need to delve
into that and find out why," said Maria Carrillo, chief
science officer for the Alzheimer s Association.
Last month, the association brought 15 leading
scientists together to ask what s known about women s
risk. Later this summer, Carrillo said it plans to begin
funding research to address some of the gaps.
A recent Alzheimer s Association report estimates
that at age 65, women have about a one in six chance
of developing Alzheimer s during the rest of their
lives, compared with a one in 11 chance for men.
The tricky part is determining how much of the dis-
parity is due to women s longevity or other factors.
"It is true that age is the greatest risk factor for
developing Alzheimer s disease," said University of
Southern California professor Roberta Diaz Brinton,
who presented data on gender differences at a meeting
of the National Institutes of Health this year.
But, she said, "on average, women live four or five
years longer than men, and we know that Alzheimer s
is a disease that starts 20 years before the diagnosis."
That s how early cellular damage can quietly begin.
Brinton is researching if menopause can be a tipping
point that leaves certain women vulnerable.
However it starts brewing, there s some evidence
that once Alzheimer s is diagnosed, women may
worsen faster; scans show more rapid shrinkage of
certain brain areas.
But gene research offers the most startling evidence
of a sex difference. Stanford University researchers
analysed records of more than 8,000 people for a
form of a gene named ApoE-4, long known to increase
Alzheimer s risk. Women who carry a copy of that
gene variant were about twice as likely to eventually
develop Alzheimer s as women without the gene,
while men s risk was only slightly increased, Stanford s
Dr Michael Greicius reported last year.
It s not clear why. It may be in how the gene inter-
acts with estrogen, Brinton said.
Amy Shives, 57, of Spokane, Washington, recalls
when her mother began showing symptoms of
Alzheimer s. But it wasn t until after her own diagnosis
a few years ago that Shives looked up the gender
"That was alarming," said Shives, who is in the
early stages of Alzheimer s, which struck at a younger-
than-usual age and forced her retirement as a college
counselor. "The impact on our lives and that of our
families is extraordinary."
She points to another disproportionate burden:
about 60 per cent of US caregivers for Alzheimer s
patients are women.
"My daughters are in their 20s and I m already
ill," Shives worries. "It s very stressful for them to
think about when their mother s going to need their
help." What drives the difference in Alzheimer s cases
isn t clear, said Dr Susan Resnick of the National
Institutes of Health, pointing to conflicting research.
What about hormones? That s been hard to pin
down. Years ago, a major study found that estrogen
therapy after 65 might increase risk of dementia,
although later research showed hormone replacement
around the onset of menopause wasn t a problem.
Roberta Brinton studies how menopause changes
the brain. Estrogen helps regulate the brain s metab-
olism, how it produces the energy for proper cognitive
function, and it must switch to a less efficient backup
method as estrogen plummets, she explained.
"It s like the brain is a little bit diabetic," said Brin-
ton, who is studying whether that may relate to
menopausal symptoms in women who later experience
Carrillo notes that 40 years ago, heart disease was
studied mainly in men, with little understanding of
how women s heart risks can differ.
"How do we make sure we re not making that
mistake when it comes to Alzheimer s?" she asked.
Scientists to study why most
Alzheimer's patients are women
Nearly two-thirds of
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