Air pollution may create ‘hot spots’ for Parkinson’s disease risk in the US

Written by Steven Reinberg

Health Day reporter

FRIDAY, Feb. 24, 2023 (HealthDay News) — People living in heavily polluted areas of the United States may be more susceptible to Parkinson’s disease, according to a new study.

Specifically, the culprit is a type of air pollution called fine particulate matter (PM2.5), which is less than 2.5 microns in diameter and comes from car exhaust, fuel burned in power plants and other industries, and forest and grass fires, according to researchers.

“We found an association between Parkinson’s disease and exposure to fine particles. Specifically, people with the highest exposure had a 25% higher risk of Parkinson’s disease than those with the lowest exposure,” said Brittany Krzyzanowski, who led the study. , of Barrow. Neurological Institute, Phoenix, Ariz.

“We also found that the strongest association between particulate matter and Parkinson’s disease was in the Mississippi-Ohio River Valley and the Rocky Mountain region,” he said.

“Our results suggest that regional differences in Parkinson’s disease may reflect that the composition of particles in some areas may be more toxic than others,” Krzyzanowski added. “We know that air pollution causes inflammation in the brain, which is linked to Parkinson’s disease.”

Krzyzanowski said that reducing air pollution levels could help reduce the risk of Parkinson’s disease, especially in areas with high levels of pollution.

“Despite 30 years of research to identify environmental risk factors for Parkinson’s disease, most efforts have focused on exposure to pesticides,” he said. “Our work suggests that air pollution may be a key factor in the development of Parkinson’s disease.”

For the study, Krzyzanowski and colleagues collected data from more than 22.5 million Medicare patients in 2009. Of these, nearly 84,000 had Parkinson’s disease. The research team mapped where the participants lived and calculated the rates of Parkinson’s disease in different regions. Average air pollution levels were also calculated.

The researchers found that 434 people out of 100,000 people exposed to the highest PM2.5 levels developed Parkinson’s disease, compared to 359 out of 100,000 in the areas with the lowest PM2.5 levels.

After controlling for other risk factors for Parkinson’s disease, such as age, smoking and use of medical care, the researchers found that people most exposed to air pollution had a 25% increased risk of Parkinson’s compared to those with the lowest exposure.

The strongest association was in the Rocky Mountain region, including Lake County, Colo., southwest of Denver, and surrounding counties. In these counties, the risk of Parkinson’s disease increased by 16% when moving from one level of exposure to fine particles to the next, according to the results.

Air pollution was associated with higher rates of Parkinson’s disease in the Mississippi-Ohio River Valley, which includes Tennessee and Kentucky, but the association was weaker: a 4% increased risk when exposure to fine particles was a level up. , the research group concluded.

The findings are scheduled to be presented April 22 at the American Academy of Neurology’s annual meeting in Boston. Results presented at a medical meeting should be considered preliminary until published in a peer-reviewed journal.

While the association found in the study does not prove causation, one expert says the link between air pollution and Parkinson’s risk should be seriously considered.

“The idea that a hotspot in the Mississippi-Ohio River Valley could potentially be associated with a 25% increase in the risk of Parkinson’s disease is staggering,” said Dr. Michael Okun, medical advisor to the Parkinson Foundation and director of the Norman Fixel Institute. for Neurological Diseases at the University of Florida Health Sciences in Gainesville.

“Identifying ‘hotspots’ in Parkinson’s disease that can help understand how the environment contributes to the development of neurodegenerative disease may provide another critical piece in the puzzle of environmental risk factors,” Okun said.

More information

To learn more about Parkinson’s, visit the Parkinson’s Foundation.

SOURCES: Brittany Krzyzanowski, PhD, Barrow Neurological Institute, Phoenix, Ariz.; Michael Okun, MD, medical advisor, Parkinson Foundation and director, Norman Fixel Institute for Neurological Diseases, University of Florida Health, Gainesville; April 22, 2023, presentation, American Academy of Neurology Annual Meeting, Boston