Study reveals link between air pollution and Parkinson’s disease

People living in regions with median levels of air pollution have a 56 per cent greater risk of developing Parkinson’s disease compared to those living in regions with the lowest level of air pollution, a new study has found.

The US research was conducted to identify national, geographic patterns of Parkinson’s disease and test for nationwide and region-specific associations with fine particulate matter.

Brittany Krzyzanowski, PhD, a researcher at Barrow Neurological Institute, who led the study, said:

“Previous studies have shown fine particulate matter to cause inflammation in the brain, a known mechanism by which Parkinson’s disease could develop.

“Using state-of-the-art geospatial analytical techniques, we were, for the first time, able to confirm a strong nationwide association between incident Parkinson’s disease and fine particulate matter in the US”

The research also found that the relationship between air pollution and Parkinson’s disease is not the same in every part of the country, and varies in strength by region.

The Mississippi-Ohio River Valley was identified as a Parkinson’s disease hotspot, along with central North Dakota, parts of Texas, Kansas, eastern Michigan and the tip of Florida.

People living in the western half of the US are at a reduced risk of developing Parkinson’s disease compared with the rest of the nation.

Krzyzanowski said:

“Regional differences in Parkinson’s disease might reflect regional differences in the composition of the particulate matter.

“Some areas may have particulate matter containing more toxic components compared to other areas.”

Although the researchers have not yet explored the different sources of air pollution, Krzyzanowski notes there is relatively high road network density in the Mississippi-Ohio River Valley and the rust belt makes up part of this region as well.

Krzyzanowski said: “This means that the pollution in these areas may contain more combustion particles from traffic and heavy metals from manufacturing which have been linked to cell death in the part of the brain involved in Parkinson’s disease.”

The population-based geographic study identified nearly 90,000 people with Parkinson’s disease from a Medicare dataset of nearly 22-million.

Those identified with having Parkinson’s disease were geocoded to the neighbourhood of residence, enabling researchers to calculate the rates of Parkinson’s disease within each region.

The average annual concentrations of fine particulate matter in these specific areas were also calculated.

After adjusting for other risk factors, including age, sex, race, smoking history and utilisation of medical care, Barrow researchers were then able to identify an association between a person’s previous exposure to fine particulate matter and their later risk of developing Parkinson’s disease.

Krzyzanowski said: “Population-based geographic studies like this have the potential to reveal important insight into the role of environmental toxins in the development and progression of Parkinson’s, and these same methods can be applied to explore other neurological health outcomes as well.”

The research teams hopes the data from this novel study will help enforce stricter policies that will lower air pollution levels and decrease the risk for Parkinson’s disease and other associated illnesses.

Krzyzanowski said: “Despite years of research trying to identify the environmental risk factors of Parkinson’s disease, most efforts have focused on exposure to pesticides.

“This study suggests that we should also be looking at air pollution as a contributor in the development of Parkinson’s disease.”