Parkinson’s disease happens when nerve cells, or neurons, in the area of the brain that controls movement, begin to weaken or die. This means they are unable to produce dopamine, which contributes to a person’s ability to move. This progressive neurological disorder can cause a person to experience uncontrollable movements such as shaking or trembling, slow or interrupted movements, and problems with coordination and balance.

While experts are still uncovering the exact cause of Parkinson’s disease, several known risk factors increase the likelihood someone might develop this disorder, such as:

Age

Age is a significant factor contributing to Parkinson’s disease. Although age doesn’t directly cause a person to develop the condition, being older is the greatest risk factor for Parkinson’s disease. This is because brain cells shrink and become more prone to injury as you age. Additionally, genes can morph over time, which can trigger changes in cellular activity that ultimately lead to Parkinson’s.

Typically, people receive a diagnosis of Parkinson’s disease when they are in their 60s. However, the disorder isn’t solely reserved for seniors. Early-onset Parkinson’s disease, or young-onset Parkinson’s disease (YOPD), is when the disorder occurs before the age of 50. YOPD accounts for 5 to 10% of Parkinson’s disease cases.

Genetics

An individual’s genetic makeup and family history play a role in their likelihood of developing Parkinson’s disease. Up to 15% of people with Parkinson’s disease have a close relative who also has the condition. Evidence suggests about 5 to 10% of Parkinson’s cases are genetic. Researchers are still working to learn more about the role of genetics and Parkinson’s disease.

Although several genes have been found to be linked with Parkinson’s disease, more diverse research is required to understand the full scope. If you and your loved one have a family history of Parkinson’s disease, consider genetic testing.

Environmental Triggers

Exposure to toxins in the environment can increase your risk of developing Parkinson’s disease. Toxins can include:

• Pesticides and herbicides: Exposure to pesticides and herbicides used in farming has been linked to Parkinson’s disease.
• Trichloroethylene (TCE): This chemical is used in dry cleaning, industrial degreasing, and some household cleaners. Researchers have linked exposure to TCE with an increased risk of Parkinson’s disease.
• Air pollution: The combination of hazardous substances from natural and human sources can increase your chances of getting Parkinson’s disease.

Even long-term exposure to a toxin on its own is unlikely to cause Parkinson’s disease. Instead, more than likely, it comes down to a combination of other risk factors alongside exposure to environmental toxins.

The interactions between genes and the environment can be quite complex, with a lot of unknowns. Researchers are still trying to understand why environmental factors contribute to the development of Parkinson’s disease.

Head Trauma

Traumatic brain injury (TBI) can significantly increase your chances of developing Parkinson’s disease later in life. The head injury that occurs with TBI triggers a reaction that involves some of the processes implicated in the development of Parkinson’s, such as inflammation and protein aggregation.

Environments or activities where you’re likely to develop a head injury theoretically put you at a higher risk of Parkinson’s disease. For example, football players and boxers who’ve sustained multiple concussions are at an increased risk.

Medications

Certain medications have been linked to an increased risk of developing Parkinson’s disease symptoms. The term for this is drug-induced parkinsonism. Symptoms usually subside when you stop taking the medication. While medications can’t cause Parkinson’s disease itself, the accompanying effects can mimic the experiences of those with the disease.

Drugs that can cause symptoms associated with Parkinson’s disease include:

• Antipsychotics: These medications are used to treat symptoms of psychosis, such as hallucinations and delusions. They can also be used to treat other mental health conditions, including bipolar disorder, depression, and anxiety. 
• Anti-nausea medications: These medications help with nausea and vomiting.
• Drugs that treat hyperkinetic movement disorders: These medications treat abnormal involuntary movement, which can include regular and rhythmic movements.