What Are 10 Possible Causes of Parkinson's Disease?

Medically Reviewed on 6/6/2022

What causes Parkinson's disease?

Parkinson's disease is a neurological condition that mainly affects your body's movement. The 10 possible causes of Parkinson's disease include genetics, chemical exposure, where you live, and other factors.
Parkinson's disease is a neurological condition that mainly affects your body's movement. The 10 possible causes of Parkinson's disease include genetics, chemical exposure, where you live, and other factors.

Parkinson's disease is a neurological condition that mainly affects your body's movement. The disease is progressive and has symptoms like tremors, slow movement, stiffness, and speech difficulty. Most people develop the disease around or after the age of 60. But 10% to 20% of people with Parkinson's develop it at age 50 or younger. Men are more likely to develop this condition than women.

Parkinson's symptoms are caused by a decrease in the cells in your brain that produce dopamine. It's the lower dopamine levels that cause the movement-based symptoms of this disease.

Experts are not 100% sure what exactly causes this disease. They believe most cases of Parkinson's don't have one single cause but may have multiple components interacting with each other.

Genetics. Between 10% and 15% of all Parkinson's cases are caused or influenced by at least 1 of 12 genetic mutations that can be passed down from a parent to a child.

Some of these gene mutations are more common in specific cultural groups. For example, Ashkenazi Jews and North African Berbers are more likely to have the G2019S mutation on the LRRK2 gene, which can cause Parkinson's. However, even having a genetic tendency for Parkinson's doesn't mean you will get it. Studies show that only between 25% and 35% of people with the G2019S mutation will get Parkinson's disease.

Pesticide and herbicide exposure. Some people believe that exposure to certain pesticides and herbicides, especially one called paraquat, may lead to Parkinson's disease. But studies about this are inconclusive.

Exposure to polychlorinated biphenyls (PCBs). Some people with Parkinson's have a higher-than-usual concentration of PCBs in their brains. These man-made chemicals were banned in the U.S. in 1979 due to the discovery of many harmful health effects. They may be found in vintage products from before that year, like plastics, flooring, and oil-based paints.

Long-term trichloroethylene (TCE) exposure. TCE is a solvent used in many paint removers and stain removers. It has mainly been found to be a risk factor for Parkinson's in people who worked in factories and were exposed to TCE over long periods of time.

Where you live. Some studies show that living in a rural area can make you more likely to develop Parkinson's disease. Experts believe this may be due to pesticides or other chemicals getting into the water supply.

Head injury. People who have had a traumatic brain injury have a higher risk of developing Parkinson's, but experts don't know exactly why.

Long-term lead exposure. Exposure to lead, especially long-term, can have many negative health effects. People who have long-term lead exposure may be as much as two to three times more likely to develop Parkinson's disease.

Amphetamine and methamphetamine abuse. Early research shows that people who have used amphetamines may have a higher risk of developing Parkinson's disease. Experts believe that these drugs can damage the parts of the brain that produce dopamine, leading to the disease. But your doctor may also prescribe amphetamines to help your Parkinson's symptoms once you're diagnosed.

Attention deficit hyperactivity disorder (ADHD). One study showed that people with ADHD are at least twice as likely to get Parkinson's disease and may be more likely to have an early onset of symptoms. ADHD symptoms are also caused by a lack of dopamine. The study also showed that people who were treated for ADHD with stimulant medications were six to eight times more likely to develop the condition. It may be important to note that amphetamines like Adderall are often the stimulants prescribed to treat ADHD.

Lewy bodies. Researchers have found that some people with Parkinson's disease have abnormal clumps of protein in the brain called Lewy bodies. But they're not sure if this is a cause or a symptom of the disease.

What is parkinsonism, and what causes it?

Some people may develop Parkinson's-like symptoms, including slow movement, muscle stiffness, or tremors, without having true Parkinson's disease. Causes of parkinsonism include:

Medication. Certain medications, mainly antipsychotic prescriptions, induce symptoms similar to Parkinson's disease. Luckily, the symptoms usually stop once you stop taking the medication.

Ministrokes. People with cerebrovascular disease may experience a series of ministrokes. The strokes cause multiple areas of the brain to become inactive, leading to the symptoms.

Progressive supranuclear palsy. Also called Steele-Richardson-Olszewski syndrome, this condition mainly causes balance and vision issues but also has other symptoms similar to Parkinson's.

Multiple system atrophy. This condition also has similar symptoms but also causes bladder issues and low blood pressure.

Corticobasal degeneration. This condition happens when a protein called tau doesn't break down properly in the brain. It builds up and causes damage and neurological degeneration.

Can you prevent Parkinson's disease?

Since the exact causes of Parkinson's are unclear, experts are not sure what you can do to prevent developing the condition.

Some research shows that regular exercise, especially aerobic exercise, has a protective effect against Parkinson's. Studies also show that people who get Parkinson's and have a history of regular exercise live longer and perform better on physical and cognitive tests. 

Other research suggests that drinking caffeine, especially green tea, can help prevent Parkinson's. However, more research is needed.

People who smoke cigarettes may have a much lower risk of developing Parkinson's. But researchers don't know if smoking has a protective effect against Parkinson's or if there's something about Parkinson's or its causes that makes people less likely to develop an addiction to smoking. If smoking does lower the risk of getting Parkinson's, researchers believe it is only the chemical nicotine that acts as a preventative. More research is needed, and health experts caution against smoking as a way to prevent Parkinson's because it can have a lot of other negative health effects, including lung disease, heart disease, and more.

One study showed that eating peppers and tomatoes may also prevent Parkinson's. Because general intake of vegetables did not lower Parkinson's risk, experts believe peppers and tomatoes might have a preventative effect because they have a small level of nicotine in them.

People who take the asthma drug salbutamol were found to be 30% less likely to develop Parkinson's disease. Researchers are using this information to develop more effective Parkinson's drugs.


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Medically Reviewed on 6/6/2022

American Parkinson Disease Association: "Holy Smoke! The connection between cigarettes and Parkinson's disease."

Arquivos de Neuro-Psiquitria: "Rural or urban living and Parkinson's disease."

EPA: "Learn about Polychlorinated Biphenyls (PCBs)."

Frontiers in Neurology: "Parkinson's Disease and the Environment."

Mayo Clinic: "Parkinson's disease," "Progressive supranuclear palsy."

Minnesota Department of Health: "Trichloroethylene (TCE) and Your Health."

National Health Service: "Causes: Parkinson's disease," "Multiple system atrophy," "Overview: Corticobasal degeneration."

Parkinson's Foundation: "Causes," "Environmental Factors."

The Michael J. Fox Foundation: "Could an Asthma Drug Be the Way to Prevent Parkinson's?" "Parkinson's Disease, Ashkenazi Jews and LRRK2: a consortium proposal," "Study: Pop a Pepper to Prevent Parkinson’s," "Young-Onset Parkinson's Disease."

University of Maryland Baltimore Washington Medical Center: "The Two Best Ways to Prevent Parkinsons Disease."

University of Utah Health: "ADHD May Increase the Risk of Parkinsons Disease and Similar Disorders."