Scientists are working to better understand the broad range of environmental exposures linked to Parkinson’s disease. While the exact cause of Parkinson’s disease is unknown, most experts agree that the condition is caused by a combination of genetic and environmental factors (chemicals from occupational exposure or rural living, head trauma, etc.). Some experts explain it this way: genes load the gun and environment pulls the trigger.
We know that exposure to certain environmental factors increases an individual’s risk of developing Parkinson’s disease, but exposure to any one of these factors doesn’t mean a person will actually develop the disease. In most people with Parkinson’s, it’s a collection of factors acting synergistically that ultimately leads to symptoms and a diagnosis.
Non-genetic risk factors for Parkinson’s disease
While age is the biggest risk factor for Parkinson's, many chemicals used in various professions – such as welding, farming, military activities and industrial processes – have been associated with the disease. Some specific chemicals and other factors are listed below:
- Insecticides: permethrin and beta-hexachlorocyclohexane (beta-HCH)
- Herbicides: paraquat and 2,4-dichlorophenoxyacetic acid
- Fungicide: maneb
- Agent Orange used in the Vietnam War
- MPTP, a synthetic neurotoxin (can cause Parkinsonism)
- Head injuries