Lingering pesticides linked to Parkinson's

[Roger]

Another reason to do provings of pesticides. + Roger
By Kathleen Fackelmann, USA TODAY
Past exposure to low levels of pesticides that linger in the environment
might accelerate the development of Parkinson's, which would put baby
boomers and millions of other aging Americans at risk of developing the
brain disease earlier in life.

At the American Chemical Society meeting in San Francisco last week,
researchers presented new findings that link Parkinson's to exposure to the
pesticides dieldrin and DDT. The federal government banned the toxins in the
1970s, but low levels still linger in the soil, says lead researcher Gary
Miller of Emory University in Atlanta. Miller's research focused on how
exposure to the pesticides from years ago affected the later development of
Parkinson's.

"If you're exposed to a pesticide like dieldrin, you might be diagnosed
(with Parkinson's) at age 70 instead of at 80," Miller says.

The preliminary report at the ACS meeting fits with evidence from a large
study published in July that suggests that exposure to pesticides might
increase the risk of developing the degenerative brain disease, which often
is diagnosed after age 60. That report didn't zero in on a specific
pesticide, but Miller and his colleague Kurt Pennell at the Georgia
Institute of Technology did.

The team examined brain tissue taken from 14 Parkinson's patients and 12
people who did not have the disease. They found that levels of dieldrin were
three times higher in the brain tissue taken from the Parkinson's patients.
That tissue also had the same high levels of a breakdown product of DDT.

A second report by the same team helps explain how pesticides might injure
the brain.

Miller and Pennell gave small doses of dieldrin to laboratory mice. After
only a month, the team found that the pesticide increased the amount of
brain damage done by free radicals, highly reactive molecules that are a
byproduct of metabolism.

The team found evidence that free radicals had damaged certain brain cells
that produce dopamine, a neurotransmitter that plays a key role in
Parkinson's disease. People who sustain damage to these same brain cells
start to develop the symptoms of Parkinson's, such as a shuffling walk,
Miller says.

He believes Parkinson's is kicked off by a combination of factors, including
genes, but then the disease speeds up as a result of exposure to pesticides
such as dieldrin.

The findings add to others that have linked pesticides to Parkinson's,
including a study of more than 143,000 people conducted by researcher
Alberto Ascherio of the Harvard School of Public Health and published in the
July issue of the Annals of Neurology. He found that people who had reported
exposure to pesticides had a 70% greater risk of Parkinson's.

Ascherio says pesticides still in use, such as those for a home garden, also
might pose some risk to these sensitive brain cells. To be safe, he says,
"people should limit their exposure."

Posted 9/17/2006 10:01 PM ET
http://www.usatoday.com/news/health/200 ... sons_x.htm
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