While there’s no single cause of Parkinson’s disease, the degenerative brain condition may be linked to your genes. But is that the only factor? Are there environmental causes of Parkinson’s disease that you should be avoiding?

“Parkinson’s disease is rarely caused just from genetic or environmental factors,” says researcher Ignacio Fernandez Mata, PhD. “In most cases, the interaction between both factors into your predisposition for Parkinson’s disease.”

Environmental toxins have been strongly linked to Parkinson’s disease, but it’s still hard to prove that they directly cause it. Toxins that play a role include:

• Air pollution, especially in larger, urban areas
• Certain pesticides and herbicides, such as paraquat and 2,4-dichlorophenoxyacetic acid (also known as 2,4-D)
• MPTP, a synthetic neurotoxin often found in illicit drugs
• Agent Orange, a chemical primarily used during the Vietnam War
• Certain metals, like manganese (sometimes used in batteries) and lead
• Certain solvents and cleaning chemicals,like TCE, found in paint removers, household cleaners and products used in dry cleaning and manufacturing

These environmental toxins can be risk factors — meaning they can increase your chances of developing Parkinson’s disease.

“Not everybody who is exposed to these toxins gets Parkinson’s disease,” clarifies Dr. Mata. “They don’t cause Parkinson’s disease, but they increase the risk of developing it.”

And it’s important to note that the amount of exposure to these environmental toxins plays a role, too.

“It’s not like you’re exposed to something one day, and then you automatically get Parkinson’s disease — the same way that somebody who smokes a cigarette one day, doesn’t automatically get lung cancer,” he illustrates. “It’s really about chronic exposure.”

And “chronic exposure” can mean different things for different people.

“It’s very hard to put a threshold or a limit on how much exposure you’d need to have, but the more exposure you get — and the more years of exposure you have — then the higher your chances are that you’re going to develop a neurological disorder,” he adds.

Challenges in researching the risk of environmental toxins

Dr. Mata says there’s more research on genetic factors and Parkinson’s disease than on how environmental factors may play a role. So, why is this?

When it comes to genetics, researchers can use a blood sample to look at your DNA. But with environmental factors, it’s harder to measure how much exposure somebody has had over their lifetime.

“We think that Parkinson’s disease might start 20 or 30 years before you see symptoms,” explains Dr. Mata. “So, that means for somebody who’s in their 60s, you would have to figure out what they did in their 30s and 40s to see if that had an impact.”

Healthcare providers may use questionnaires to make some of those environmental connections by looking at people’s history, he notes. They may ask questions about living in a rural area, job history (for example, welders may be exposed to manganese and other heavy metals) and even if you drink well water. The problem? Those questionnaires aren’t always accurate.

And that makes it difficult for researchers to draw any broad conclusions.

“It’s very easy for us to collect information from thousands of people and look at their genetics,” says Dr. Mata. “But extracting environmental information is extremely hard and not always correct.”

What you can do to reduce your exposure to environmental toxins

While the risk of chronic exposure to many of these toxins is low for most of us, there are still a few things you can do to further decrease your risk:

• Wear protective gear when necessary. If you have a job where you handle or are in contact with chemicals or pesticides, Dr. Mata says you should wear the appropriate equipment, such as a mask and gloves, to limit your exposure.
• Consider your family history. If someone in your family has Parkinson’s disease, you may want to avoid certain environmental toxins as much as possible, he says. “If you already have a genetic predisposition for developing Parkinson’s disease, exposure to certain toxins is just adding to your risk.”
• Rethink how you drink water. Certain water supplies may contain high amounts of chemicals, like lead, that may not be good for you. If you’re concerned, consider installing a water filter to your home’s faucets or drinking from bottled water.
• Raise awareness. Support measures to limit or ban certain chemicals or support initiatives to restrict use. This is one way to reduce everybody’s risk of developing Parkinson’s disease or other diseases, says Dr. Mata.

More research is needed

It can be hard to pinpoint what may lead to a Parkinson’s disease diagnosis — it’s likely due to a combination of factors like your genetics and environmental factors.

“The best thing that we can do is continue to research any connection and try to find out what all these chemicals are and how they may contribute to the disease,” concludes Dr. Mata.