Researchers have identified a key mechanism to better understand the association between exposure to fine particle pollution and cognitive decline: systemic inflammation.
- While the impact of air pollution on the lungs and cardiovascular system is well documented, studies have also established a link between exposure to fine particles and neurodegenerative diseases such as Alzheimer’s and Parkinson’s.
- According to new research, this influence on cognitive disorders is notably due to systemic inflammation caused by an increase in monocytes, a type of cell that plays a central role in the immune response.
- “This systemic inflammation could be the missing link linking PM2.5 to cognitive decline.” Indeed, this generalized inflammation could alter the immune functions of the brain, thus contributing to the deterioration of cognitive abilities.
Coming mainly from vehicle exhaust and industrial activities, fine particles (PM2.5, less than 2.5 microns) in the air are capable of penetrating deep into the lungs and even into the bloodstream, causing lots of damage. While their impact on the lungs and cardiovascular system is well documented, it is only recently that studies have established a link between exposure to fine particles and neurodegenerative diseases such as Alzheimer’s and Parkinson’s.
According to new research published in the journal Alzheimer’s & Dementiathis influence on cognitive disorders would be due in particular to systemic inflammation caused by an increase in monocytes, a type of cells that play a central role in the immune response.
An inflammatory response linked to exposure to air pollution
To reach this conclusion, researchers from the universities of Rostock, Bonn (Germany) and Luxembourg examined data from a Dutch cohort including more than 66,000 participants. By analyzing blood samples and cognitive test results over a ten-year period, they observed that prolonged exposure to PM2.5 air pollution was associated with slowed cognitive processing time, an indicator the speed of the brain’s response to stimuli. And this applies to both the elderly and young adults.
Interestingly, the researchers also found an increase in the number of white blood cells, particularly monocytes, suggesting an inflammatory response linked to pollution exposure. “While PM2.5 can directly affect the brain by crossing the blood-brain barrier and triggering local inflammation, these results highlight more generalized systemic inflammation upon exposure”according to a press release.
Reduce the cognitive risks associated with fine particles
“This systemic inflammation could be the missing link linking PM2.5 to cognitive decline”say the scientists. Indeed, this generalized inflammation could alter the immune functions of the brain, thus contributing to the deterioration of cognitive abilities. Note that this is the first large-scale study to directly link changes in white blood cell counts to the effects of fine particles on cognition.
As populations age and become increasingly urban, it becomes essential to better understand the impact of pollution on our brain health. “It is crucial to precisely identify the pollutants and cellular mechanisms involved in this process”underline the authors of the study. Such discoveries could indeed guide future public health policies, in order to reduce the cognitive risks linked to fine particles in the long term.