Parkinson's
Found More Often In Men Than In Women
Studies Confirm
Men At Higher Risk
A review of multiple
studies appears to confirm that men face a much higher chance
of developing Parkinson's disease compared to women, according
to a new report in the Journal of Neurology, Neurosurgery
and Psychiatry.
"This has been something
that everyone has assumed for a while, but whenever you stand
up and say it someone will say, 'There's no proof of that,"
says Dr. Fred Wooten, chairman of the neurology department at
the University of Virginia School of Medicine in Charlottesville.
"'Well, now we've
got the closest thing there is to proof," he says.
According to Dr. Wooten,
the most likely culprit for a 'gender gap' for Parkinson's may
be the heightened vulnerability of male offspring to a genetic
mutation passed down by their mothers.
Parkinson's
Symptoms Are Progressive
Parkinson's disease
involves the steady loss of brain cells that produce dopamine,
a chemical messenger essential to proper motor function.
As the levels of dopamine
decrease, chemical messages between brain cells "misfire," triggering
symptoms such as tremors, loss of balance, rigidity, and other
abnormalities.
Parkinson's is progressive
and has no cure, although the use of certain drugs can ease
its symptoms. The National Parkinson's Foundation
estimates that 1.5 million US adults are affected
with the disease.
Dr. Wooten says the
observation that Parkinson's affects more men than women has
a long history.
"In the original description
in 1807 by James Parkinson, he describes five men [and no women],"
Dr. Wooten points out. "So from the absolute beginning of the
descriptions there's always been the sense that there are more
men than women affected."
Still, no one had
pulled together the data to prove this gender bias until now.
Experts
Continue To Look For Reasons
In their study, Dr.
Wooten's team examined data from seven population-based studies
conducted in the US, China, and four European countries since
1980.
They report that,
worldwide, males face a 50 percent higher risk of developing
Parkinson's than do females.
Uncovering the reasons
behind this trend may be a tougher problem, however. There is
"weak" evidence that something about the male lifestyle - increased
exposure to pesticides, for example, or a higher incidence of
head injury - might account for men's higher incidence of Parkinson's
disease, Dr. Wooten says.
A second theory holds
that estrogen might help protect women against neurological
illnesses such as Parkinson's.
"There's a great deal
of evidence, both from test-tube studies as well as some animal
studies, that estrogen has a neuroprotective role and that higher
levels of estrogen in women might somehow protect them from
this particular neurodegenerative disease," Dr. Wooten explains.
But more intriguing
theories focus on the genetics of men - and their mothers.
Genetic mutations
specific to Parkinson's have recently been located on the X
chromosome.
"Genetic abnormalities
on the X chromosome tend to affect men more than women," Dr.
Wooten says, "because men have only one X chromosome and
women have two," leaving men less leeway whenever X-chromosome
genes are expressed.
Men might also be
more vulnerable to a Parkinson's-linked mutation of a gene found
in what is known as mitochondrial DNA. Mitochondrial DNA
is a relatively tiny reservoir of DNA found outside the nucleus,
and it is only passed via the mother to her offspring.
For reasons that remain
unclear, the sons of women who carry this mitochondrial abnormality
could be at especially high risk of developing the disease.
"We are about to publish
another large, more definitive [study], showing that there's
an unexpected excess of maternal transmission in Parkinson's
disease," Dr. Wooten explains.
"If you look at a
group of patients affected with Parkinson's disease, and you
ask how many of them have an affected mother and how many of
them have an affected father, the incidence of affected mothers
is higher," he says.
Parkinson's is not
the only brain disease more likely to hit men than women.
"Diseases like amyotrophic
lateral sclerosis - ALS, or Lou Gehrig's disease - are more
common in men," says Dr. Jay Van Gerpen, director of the Movement
Disorder Clinic, part of the Ochsner Clinic in New Orleans.
Dr. Van Gerpen also
notes tremor-type illnesses similar to Parkinson's appear to
affect more men than women.
Can anything reduce the
risk for Parkinson's? Dr. Van Gerpen says one lifestyle factors
known to decrease disease risk at this point in time is
coffee-drinking.
A cup or two
of coffee per day might be beneficial, Dr. Van Gerpen says.
"There have been a
number of studies that have shown this - that patients who consume
coffee are less likely to get Parkinson's disease. As a coffee
drinker myself, that's good news."
Always consult your
physician for more information. |
May 2004
Parkinson's
Found More Often In Men Than In Women
Parkinson's
Symptoms Are Progressive
Experts
Continue To Look For Reasons
Parkinson's
Disease FAQ
Online
Resources
Parkinson's
Disease FAQ
According to the Parkinson's
Disease Foundation, as many as 1 million Americans
suffer from Parkinson's disease. While about 15 percent of
Parkinson's patients are diagnosed before the age of 40, incidence
increases with age.
The cause is unknown,
and although there is presently no cure, there are many treatment
options such as medication and surgery to manage the symptoms.
Parkinson's disease
belongs to a group of conditions called movement disorders.
It is both chronic, meaning it persists over a long period of
time, and progressive, meaning its symptoms grow worse over
time.
The Parkinson's
Disease Foundation states that the disease occurs
when a group of brain cells, responsible for the production
of a chemical called dopamine, begin to malfunction and eventually
die.
Dopamine is a neurotransmitter,
or chemical messenger, that transports signals to the parts
of the brain that control movement initiation and coordination.
When Parkinson's disease
occurs, for unexplained reasons, these cells begin to die at
a faster rate and the amount of dopamine produced in the brain
decreases.
The four primary symptoms
are:
-
tremor of the hands, arms,
legs, jaw, and face
-
rigidity or stiffness of
the limbs and trunk
-
bradykinesia or slowness
of movement
-
postural instability or impaired
balance and coordination
The following is a
list of secondary symptoms of Parkinson's disease:
-
-
loss of facial expression
-
micrographia (small, cramped
handwriting)
-
-
-
-
-
-
-
-
-
-
memory difficulties and slowed
thinking
-
-
-
-
Always consult your
physician for more information.
Online
Resources
(Our Organization
is not responsible for the content of Internet sites.)
Centers
for Disease Control and Prevention (CDC)
Healthfinder,
US Department of Health and Human Services (HHS)
National
Institute of Neurological Disorders and Stroke
National
Institutes of Health (NIH)
National
Library of Medicine
National
Parkinson's Foundation
|
