Pesticide linked to Parkinson's disease

From The University of Texas Southwestern Medical Center:

Pesticide levels in blood linked to Parkinson's disease, researchers find

DALLAS — People with Parkinson’s disease have significantly higher blood levels of a particular pesticide than healthy people or those with Alzheimer’s disease, researchers at UT Southwestern Medical Center have found.

In a study appearing in the July issue of Archives of Neurology, researchers found the pesticide beta-HCH (hexachlorocyclohexane) in 76 percent of people with Parkinson’s, compared with 40 percent of healthy controls and 30 percent of those with Alzheimer’s.

The finding might provide the basis for a beta-HCH blood test to identify individuals at risk for developing Parkinson’s disease. The results also point the way to more research on environmental causes of Parkinson’s.

“There’s been a link between pesticide use and Parkinson’s disease for a long time, but never a specific pesticide,” said Dr. Dwight German, professor of psychiatry at UT Southwestern and a senior author of the paper. “This is particularly important because the disease is not diagnosed until after significant nerve damage has occurred. A test for this risk factor might allow for early detection and protective treatment.”

About 1 million people in the U.S. have Parkinson’s, a number expected to rise as the population ages. The disease occurs when brain cells in particular regions die, causing tremors, cognitive problems and a host of other symptoms...

“Much higher levels of the beta-HCH were in the air, water and food chain when the Parkinson’s patients were in their 20s and 30s,” Dr. German said. “Also, the half-life of the pesticide is seven to eight years, so it stays in the body for a long time.”

Parkinson’s disease is more common among rural men than other demographic groups, but it is not a matter of a single factor causing the devastating disease, Dr. German said.

“Some people with Parkinson’s might have the disease because of exposure to environmental pesticides, but there are also genes known to play a role in the condition,” Dr. German said.

Although the current study points to an interesting link between the pesticide beta-HCH and Parkinson’s, there could be other pesticides involved with the disease, he said.

For example, the pesticide lindane often contains beta-HCH, but lindane breaks down faster. Beta-HCH might simply be a sign that someone was exposed to lindane, with lindane actually causing the damage to the brain, the researchers said...