Twelve million people worldwide are living with Parkinson’s disease. That number has nearly doubled in six years.
Unlike many neurological conditions, researchers say Parkinson’s may largely be something we are doing to ourselves.
For most of history, Parkinson’s has been a very rare disease. Although records of possible Parkinson’s disease can be found in very early texts, the first clear medical documentation was written only two hundred years ago in 1817.
“The principal causes of the disease are not in our DNA but outside in our environment,” Dr. Ray Dorsey, a neurologist and co-author of “The Parkinson’s Plan,” told The Epoch Times. “Only 13 percent of Americans carry any known genetic cause or risk factor for the disease—the principal causes are chemicals in our food, water, and air.”
A Man-Made Disease?
Approximately 85 to 90 percent of Parkinson’s disease cases are linked to environmental factors or a combination of environmental exposure and genetic susceptibility, according to a 2025 study published in BMJ.
The researchers noted that only about 10 to 15 percent of cases are strictly caused by direct, inherited genetic mutations. For the vast majority of individuals, the condition is considered “idiopathic” (of unknown direct origin), meaning it is triggered by external elements acting on a person’s biological vulnerabilities.
Dorsey, who, along with the co-author of their book “The Parkinson’s Plan,” Dr. Michael S. Okun, has published more than 1,000 papers and personally cared for thousands of patients, said that the biggest surprise he discovered is that Parkinson’s may be preventable.
“Chemicals in our food, water, and air have created this largely man-made disease,” they wrote in their book. “These chemicals are all around us. And none are necessary.”
Dorsey and Okun don’t hesitate to describe the disease as a pandemic—not one caused by a virus, but by a new class of vectors, including pesticides, industrial solvents, and air pollution.
The Chemicals Under Suspicion
Multiple studies have identified specific environmental chemicals that may play a role in triggering or accelerating Parkinson’s. These include certain pesticides, the dry-cleaning and industrial solvents trichloroethylene (TCE) and perchloroethylene, and airborne pollutants.
These toxins are increasingly implicated because they are toxic to the very neurons whose destruction leads to Parkinson’s, Dr. Jeremy M. Liff, a neurologist at Northwell Lenox Hill and a senior member of the Society of Neurointerventional Surgery, told The Epoch Times.
A big one is paraquat, Liff said, an herbicide used in many large areas, especially in cities, and rotenone, which is used to kill fish. Trichloroethylene is not only used in dry cleaning but also in manufacturing, aerospace, and military applications, he said.
Trichloroethylene bothers Dr. John Gorecki the most—“precisely because it’s so ordinary.” Gorecki is a board-certified neurosurgeon and deep brain stimulation specialist at Northside Hospital in Atlanta, where the marine base water supply was heavily contaminated with TCE into the 1980s. “It was used for decades to degrease metal and dry-clean clothes, and it lingers in groundwater for a generation.”
The clearest signal that environmental changes may drive Parkinson’s came from Camp Lejeune, Gorecki said. A 2023 study found that veterans who served there had about 70 percent higher Parkinson’s risk than veterans who served elsewhere.
Another case occurred in Northern California, involving a group of young people who suddenly developed severe, irreversible Parkinsonism; they were rigid and frozen and barely able to move. All of them had used a bad batch of synthetic heroin that was contaminated with MPTP—a toxic chemical compound that causes permanent symptoms of Parkinson’s disease—and is similar to paraquat, a chemical that also has a strong association with Parkinson’s disease.
Outside of environmental factors, age is also a key driver of Parkinson’s disease.
Though the number of Parkinson’s cases is rapidly growing, whether it is driven by environmental toxins or other factors such as an aging population and better disease identification is not universally agreed upon, Dr. Rebecca Gilbert, neurologist at the American Parkinson Disease Association, told The Epoch Times.
The modeling study published in BMJ predicted that by 2050, global Parkinson’s cases could hit 25 million. The study attributed nearly 90 percent of this increase solely to the aging population. While age is a clear factor, early-onset Parkinson’s, which strikes people between the ages of 20 and 49, has also doubled globally, and these cases cannot be fully explained by aging.
” … demography and the by-products of industrialization have now created a Parkinson pandemic that will require heightened activism, focused planning, and novel approaches.” Dorsey wrote in a 2018 study.
Driven By Many Factors
Parkinson’s rarely develops from one villain, which makes proving the cause and mitigating its risks all the more difficult.
Gorecki points to a highly cited meta-analysis which found that paraquat exposure increases Parkinson’s disease risk by 1.6-fold, while the Agricultural Health Study, a large NIH-funded farming cohort, found no clear association at all.
While “strong, repeated associations” and plausible biological mechanistic models exist, Gorecki said that the field still lacks the clear causal proof that was eventually built for tobacco and lung cancer, the kind that satisfies all the criteria, including consistency across studies, a dose-response relationship, and a replicable biological mechanism.
“It’s the slow product of a whole life; the genes you started with colliding with the toxins, the head injuries, the infections, and the plain fact of aging, stacked up over decades,” Gorecki said. “Two farmers can work the same field and breathe the same air, and only one of them gets sick, because their biology met that exposure differently.”
Can the Rise Be Stopped?
From 1990 to 2015, the number of people with Parkinson disease doubled to more than 6 million, a number projected to double again to more than 12 million by 2040.
Dorsey and Okun have put forward a framework called PLAN—preventing the disease, learning why it starts, amplifying the voices of those affected, and navigating new treatments—with an ambitious goal of halting the global rise in new cases by 2035. Specific targets include a 0 percent increase in new cases globally and a tenfold increase in research funding with greater emphasis on prevention.
Dorsey pointed to countries that have already eliminated paraquat and trichloroethylene and reduced air pollution—England, Germany, and the Netherlands—where age-adjusted rates of new Parkinson’s cases are now stable or falling. “If the British, the Dutch, and the Germans can do this,” he said, “so too can Americans and the rest of the world.”
Some are skeptical of the zero-increase target.
“I admire the ambition, and I’d love to be wrong,” Gorecki said. “I don’t think zero is realistic, and I’d be careful about handing the public a number we can’t hit.”
Latency is also a problem. Much of what clinicians are diagnosing today, Gorecki said, traces back to exposures from 20, 30, or 40 years ago. Cleaning up the present matters, but it doesn’t erase what is already written into people’s neurology.
The chemicals believed to be responsible are so widespread, he said, that society has not yet grasped the scale of the problem, let alone built the political will to address it.
Alongside the environment, Parkinson’s is fundamentally a disease linked to aging, and the world is experiencing aging at an unprecedented rate in human history, Gorecki said.
“You can’t regulate your way out of a birthday.”
“There are factors in our environment that can increase a person’s risk of [Parkinson’s disease],” Gilbert said. “And there are things we can do to prevent that. We will never prevent every case of [the disease], but we must focus on preventing the preventable.”