Studies Link Paraquat, Other Pesticides To Parkinson’s Disease


Two years ago, UCLA researchers announced a link between Parkinson’s disease and two common pesticides revealed in a study, not of field workers, but of people living near farms sprayed with the pesticides maneb and paraquat. The study revealed that people living near fields in which the pesticides were sprayed suffered from a 75%-increased risk for Parkinson’s disease.

A follow-up to the April 2009 study has revealed that a third pesticide, ziram, has been implicated in the pathology of Parkinson’s disease, said UCLA. In this more recent study, the team looked at where people worked. For instance, teachers, firefighters, and clerks, who did not work in, but who worked near, fields sprayed with pesticides.

The combination of exposures, including ziram, maneb, and paraquat, near any workplace increased the risk of Parkinson’s disease three-fold, said the UCLA researchers; combined exposure to ziram and paraquat was linked to an 80%-increased risk, said the UCLA team. The study appeared over the summer in the European Journal of Epidemiology.

The study was the first its kind providing compelling human evidence that the three-chemical combination creates a more significant risk for Parkinson’s than exposure to any of the chemicals alone, said UCLA. Each pesticide affects different mechanisms meant to cause cell death. Because of this, when used collaboratively, they may create an increased Parkinson’s disease risk, said UCLA..

Meanwhile, research conducted by researchers at the National Institute of Environmental Health Sciences (NIEHS), an arm of the National Institutes of Health (NIH), in collaboration with the Parkinson’s Institute and Clinical Center in Sunnyvale, California, revealed a link to Parkinson’s disease and the pesticides rotenone and paraquat, said Science Daily. That team found that people using either chemical experienced a 2.5-fold increased risk for developing the disease.

“Rotenone directly inhibits the function of the mitochondria, the structure responsible for making energy in the cell,” said Freya Kamel, Ph.D., a researcher in the intramural program at NIEHS and study co-author; the study appeared online in the journal Environmental Health Perspectives, said Science Daily. “Paraquat increases production of certain oxygen derivatives that may harm cellular structures. People who used these pesticides or others with a similar mechanism of action were more likely to develop Parkinson’s disease,” Kamel added.