Environmental Toxins Linked to Steep Rise in Parkinson’s Disease

Parkinson’s is now the second-most common neurodegenerative disease after Alzheimer’s disease and the fastest-growing degenerative neurological disorder, according to the Parkinson’s Foundation. 

“The world’s fastest-growing brain disease is largely manmade,” Dr. E. Ray Dorsey, the David M. Levy professor of neurology at the University of Rochester Medical Center, said in a statement. “The principal causes are toxic exposures to chemicals synthesized in the labs of chemical companies worldwide.”

According to the Parkinson’s Foundation, Americans are facing a steep increase in Parkinson’s disease which could see nearly 1.5 million people living with the disease by 2030, and there’s evidence that exposure to environmental toxins is a strong factor in this rise.

Americans Are a ‘Living, Breathing Repository’ for Chemicals

We’re exposed to 80,000 or more toxic chemicals as we work, play, and even sleep, according to a Senate hearing transcript. This is so many that it’s nearly impossible to determine how each affects our health, or how these chemicals interact and what potential neurological impacts they could have during our lives.

“We can trace this problem back to current law that covers the safety of chemicals. That law, the Toxic Substances Control Act, or TSCA as it is known, fails to give EPA the tools it needs to protect against unsafe chemicals,” said the Environmental Protection Agency (EPA) during the Senate hearing.

“When we use these products, the chemicals in them can end up in our bodies. So in essence, the American public has become a living, breathing repository for chemical substances,” the EPA warned.

Not much is known regarding the potential impact of these chemicals on brain and nervous system health, but there’s a growing consensus that aging and genetics don’t fully account for the steep rise in Parkinson’s.

Pesticides and Herbicides Increase Parkinson’s Risk

Research published in the International Journal of Environmental Research and Public Health concluded that occupational exposure to pesticides brings about at least a 50 percent increased risk of developing neurodegenerative disease.

Certain herbicides are also linked to Parkinson’s.

There is evidence supporting the development of the disease after exposure to glyphosate-based herbicides, such as Roundup, due to neuron death in the brain’s substantia nigra, which is associated with the development of Parkinson’s.

Paraquat is another type of herbicide, which—besides being extremely poisonous to humans—is also linked to increased Parkinson’s risk.

“There is a class action lawsuit regarding the use of paraquat and Parkinson’s disease,” Dr. Mary Kay Ross, a fellow of the American College of Emergency Physicians and founder of the Brain Health & Research Institute, told The Epoch Times.

2011 study by the National Institutes of Health (NIH) and the Parkinson’s Institute collected federal survey data from farm families in Iowa and North Carolina to conclude that these people were 2.5 times more likely to develop the disease if they’d used the herbicide paraquat or the pesticide rotenone.

“Rotenone directly inhibits the function of the mitochondria, the structure responsible for making energy in the cell,” study coauthor Freya Kamel, who has a doctorate in biological sciences, said in a statement. “Paraquat increases production of certain oxygen derivatives that may harm cellular structures.”

She went on to say that “people who used these pesticides or others with a similar mechanism of action were more likely to develop Parkinson’s disease.”

Other Chemicals: Dry Cleaning Chemical, PCBs

A hypothesis paper in the Journal of Parkinson’s Disease suggests a strong link between exposure to trichloroethylene (TCE), a common solvent also used in dry cleaning clothes, and the increasing incidence of Parkinson’s.

“TCE has many known adverse health effects, and several studies have suggested TCE exposure is a risk factor for Parkinson’s disease even from exposures decades before disease onset,” said Ross.

Another chemical, widely used for nearly 60 years, is also linked to developing the degenerative neurological disorder.

Polychlorinated biphenyls (PCBs) are highly carcinogenic chemical compounds used in industrial and consumer products, including older appliances, fluorescent light fixtures, and electronic components. These compounds were used from the late 1920s until they were banned in 1979.

Before the ban, PCBs entered the air, water, and soil during their manufacture as wastes containing the compound were often disposed of in dump sites and landfills, according to the National Oceanic and Atmospheric Administration (NOAA).

Prior to knowledge of the consequences of widespread use, the chemical was even sprayed on dirt roads to keep down dust, according to NOAA. Unfortunately, PCB regulations allow inadvertently generated PCBs (iPCBs) at “defined concentrations, under certain conditions, and with requirements to report to EPA and maintain certain records,” the EPA website states.

PCBs can also be released into the environment from pre-ban sources such as:

  • Poorly maintained hazardous waste sites containing PCBs.
  • Illegal or improper dumping of PCB wastes.
  • Leaks or releases from electrical transformers containing PCBs.

Ross said PCBs have been found in “relatively high concentrations” in the post-mortem brains of people who had Parkinson’s. However, the risk from exposure isn’t equal in the population.

“Occupational exposure to PCBs has been associated with greater risk of Parkinson’s in women, but not in men despite the fact that [Parkinson’s] is more common in men,” noted Ross. She warned that TCE exposure is a risk factor for Parkinson’s disease even from exposures decades before disease onset.

Exposure to manganese and lead has also been associated with increased risk.

High-dose manganese exposure linked to occupations like welding is known to cause a form of Parkinson’s called manganism. Recent research finds long-term exposure to lead is also associated with increased Parkinson’s risk.

Association Between Exposure to Toxins and Parkinson’s Is ‘Complex’

Markus Riessland, who holds a doctorate in human genetics and is an assistant professor at the Department of Neurobiology and Behavior at Stony Brook University, said there’s definitely an association between environmental toxins and Parkinson’s disease, “but it’s a little bit more complex.”

“Not only the exposure causes the disease, but you may have to have sort of a genetic predisposition to be more at risk or to actually then develop symptoms,” he explained.

Riessland pointed out that it’s never really a one-to-one ratio of exposure to developing the disease.

A study published in the journal Brain Science found exposure to certain toxins can increase Parkinson’s risk by stimulating epigenetic changes that activate genes associated with the disorder.

“There are many people who are exposed to environmental toxins that never develop Parkinson’s and vice versa,” he said. “But there is an increased risk, there is definitely an association.”

Riessland cautioned that the risk of pesticide and herbicide chemicals is present for those in rural areas, even if they don’t use these chemicals themselves. There is still an increased risk, although it’s dependent on the individual.

“So some people have long exposure and develop Parkinson’s,” he said. “Others have long exposure and never develop it.”

George Citroner reports on health and medicine, covering topics that include cancer, infectious diseases, and neurodegenerative conditions. He was awarded the Media Orthopaedic Reporting Excellence (MORE) award in 2020 for a story on osteoporosis risk in men.
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