A risk factor is anything that increases your chances of getting sick or having a problem. Risk factors for Parkinson's disease are hard to identify, because the cause of the disease is unknown.
Advancing age is the only known risk factor for typical Parkinson's disease (not including early-onset Parkinson's). Most instances of Parkinson's occur after age 50. But the illness does occur in people between the ages of 30 and 50 or, in rare cases, at a younger age.
A very small number of people with Parkinson's have a close relative who also has the disease. But it doesn't appear that a family history of typical Parkinson's significantly increases your risk for the disease.
Having a family history of the disease is a more significant risk factor in cases of early-onset Parkinson's, but this form of the disease is not common.
Poisons in the environment
Some research suggests that long-term exposure to certain environmental risk factors such as pesticides, chemicals, or well water may increase a person's risk of developing Parkinson's disease.