People with Parkinson's disease have significantly higher blood levels of a particular pesticide than healthy people or those with Alzheimer's disease, say researchers.
The researchers at UT Southwestern Medical Center 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.
According to researchers, the finding may 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. 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," said Dr. Dwight German, professor of psychiatry at UT Southwestern and a senior author of the paper.
The study involved 113 participants, ages 50 to 89. Fifty had Parkinson's, 43 were healthy and 20 had Alzheimer's. The researchers tested the subjects' blood for 15 pesticides known as organochlorines.
These pesticides, which include the well-known DDT, were widely used in the U.S. from the 1950s to the 1970s but are more tightly regulated now. They persist in the environment for years without breaking down.
In the body, they dissolve in fats and are known to attack the type of brain nerves that die in Parkinson's disease, the researchers said.
The study appears in the July issue of Archives of Neurology.