Researchers have found that individuals living in areas with median levels of air pollution are 56% more likely to develop Parkinson’s disease compared to those residing in regions with the lowest air pollution levels.
The study, soon to be published in Neurology, the medical journal of the American Academy of Neurology, aimed to uncover national and regional patterns of Parkinson’s disease and investigate connections with fine particulate matter.
“Previous research has shown that fine particulate matter can cause inflammation in the brain, a known mechanism for the development of Parkinson’s disease,” said Brittany Krzyzanowski, PhD, a researcher at the Barrow Neurological Institute and the study’s lead author. “Using advanced geospatial analytical techniques, we confirmed, for the first time, a strong nationwide association between incident Parkinson’s disease and fine particulate matter in the US.”
The study also revealed that the relationship between air pollution and Parkinson’s disease varies across the country, with certain regions more affected than others. The Mississippi-Ohio River Valley emerged as a hotspot, alongside central North Dakota, parts of Texas, Kansas, eastern Michigan, and the southern tip of Florida. Conversely, residents in the western half of the US face a lower risk of developing the disease.
“Regional differences in Parkinson’s disease may reflect variations in the composition of particulate matter. Some regions may have particulate matter with more toxic components,” Krzyzanowski explained.
While the study has not yet examined specific sources of air pollution, Krzyzanowski noted that the Mississippi-Ohio River Valley has a dense road network and industrial activity, potentially contributing to higher levels of combustion particles from traffic and heavy metals from manufacturing—factors linked to cell death in brain regions involved in Parkinson’s disease.
The study analyzed data from nearly 90,000 Parkinson’s disease patients identified within a Medicare dataset of approximately 22 million individuals. By geocoding the residences of these patients, researchers calculated Parkinson’s disease rates for specific regions and measured average annual concentrations of fine particulate matter in those areas.
After accounting for other risk factors, including age, sex, race, smoking history, and healthcare utilization, the researchers established a clear association between prior exposure to fine particulate matter and the later development of Parkinson’s disease.
“Population-based geographic studies like this can offer crucial insights into the role of environmental toxins in the onset and progression of Parkinson’s disease,” Krzyzanowski said. “These methods can also be applied to explore other neurological health outcomes.”
The researchers hope that the findings will prompt stricter policies to reduce air pollution levels, thereby lowering the risk of Parkinson’s disease and other related illnesses.
“While much of the research on environmental risk factors for Parkinson’s disease has focused on pesticides, our study highlights the need to consider air pollution as a significant contributor to the disease,” Krzyzanowski concluded.
(Ani)