Parkinson’s Disease in the U.S.: From National Surge to Regional Hot Spots

​How Parkinson’s Incidence Is Changing
 
Parkinson’s disease has become one of the fastest-growing neurological conditions in the world. It is no longer accurate to say the increase comes only from an aging population. According to Global Burden of Disease estimates, the number of annual new diagnoses increased from approximately 400,000 in 1990 to more than 1.3 million by 2021. Even when age is factored in, the rate of new cases has climbed steadily, from about 13 per 100,000 people in the 1990s to around 15 to 16 per 100,000 by 2021. Men are more likely than women to develop Parkinson’s, and the risk rises sharply after age 60.
 
This is not just a global phenomenon. The United States now reports some of the highest incidence rates in the world, around 26 per 100,000 when adjusted for age. Incidence has grown faster here than in most regions, which means America’s health system faces not just more elderly patients but also more new cases per capita than in previous generations.
 
Evidence From Cohort Studies
 
Large-scale studies in North America have confirmed the trend. Among adults 65 and older, Parkinson’s incidence is estimated at between 108 and 212 per 100,000 person-years, depending on the cohort. For those aged 45 and older, the incidence ranges from 47 to 77 per 100,000. These differences reflect the methodology, as some studies rely on Medicare claims. In contrast, others use neurologist-confirmed diagnoses, but the common conclusion is unmistakable: the incidence is rising, and the growth is not uniform across the map.
 
The Parkinson’s Belt
 
Geography is central to the story. In the early 2000s, researchers mapping Medicare data identified a swath of counties with consistently higher prevalence of Parkinson’s disease. This region, spanning much of the Midwest and into parts of the South, became known as the Parkinson’s Belt. Later studies refined the picture, showing high incidence not only in the Midwest–South corridor but also in Southern California, Southeast Texas, Central Pennsylvania, and Florida.
 
The clustering remains even after adjusting for age and sex. In other words, it is not simply that retirees are moving to these places; there appear to be local environmental and occupational exposures at play. The belt is not as famous as the “stroke belt” of the Southeast, but its implications are just as profound.
 
What Drives the Increase
 
Several forces are pushing incidence upward:

• Age: The strongest driver remains simple demographics. Parkinson’s risk multiplies after age 60, and the world is growing older.
• Sex: Men develop Parkinson’s more often than women, and that gap has not closed.
• Better Detection: Neurologists now diagnose earlier, and coding has improved, which raises the incidence in the data.
• Environment: The most contentious but essential factor. Pesticides such as paraquat, solvents like trichloroethylene, and airborne metals have all been linked to elevated risk. Industrial and agricultural regions overlap suspiciously well with the Parkinson’s Belt.

 
Incidence vs. Prevalence
 
Incidence tracks new diagnoses each year, while prevalence measures the total number of people living with the disease. Prevalence has more than doubled since 1990, reaching nearly 12 million worldwide by 2021. People live longer with Parkinson’s than they once did, which means more patients require long-term care. Rising incidence feeds into rising prevalence, making Parkinson’s both a personal and a health system challenge.
 
The Equity Dimension
 
The Parkinson’s Belt also intersects with questions of equity. Regions with higher incidence often have fewer neurologists per capita, meaning patients may go undiagnosed longer or lack access to advanced care. Many belt counties also have industrial legacies, including pesticide-intensive farming, chemical plants, and mining. These factors combine to create higher local risks in the very places where care is most scarce.
 
What It Means
 
The data leads to several conclusions:

1. Parkinson’s disease is rising globally and fastest in high-income countries, especially the U.S.
2. Geographic clustering is real. The Parkinson’s Belt and its satellite hotspots show that incidence is not evenly distributed.
3. Environmental exposures, alongside aging, are shaping the epidemic.
4. The public health response must go beyond treating patients—it must reduce exposures, expand access to care, and track cases with the same rigor as cancer registries.

 
Closing Perspective
 
The Parkinson’s Belt is not just a curiosity on a map. It serves as a reminder that disease is never distributed randomly. Where people live, work, and age shapes their risks in ways as profound as their biology. As incidence rises, policymakers will need to treat Parkinson’s like the modern epidemic it has become, not a rare disease of the elderly.