Air Pollution Linked too Increased Alzheimer’s Risk, Especially after Stroke
A new study published in PLOS Medicine suggests a direct link between air pollution and the advancement of Alzheimer’s disease. Researchers at Emory university, led by Yanling Deng, found that higher exposure to air pollution is associated with an increased risk of the disease, particularly in individuals with a history of stroke.
Alzheimer’s disease, the most common form of dementia, currently affects approximately 57 million people worldwide. While air pollution is a known risk factor for several chronic conditions – including hypertension, stroke, and depression – all of which are linked to Alzheimer’s – it was previously unclear whether pollution caused these conditions, which then increased Alzheimer’s risk, or if these conditions simply amplified the effects of pollution on brain health.
The Emory University team analyzed data from over 27.8 million Medicare beneficiaries aged 65 and older in the United States between 2000 and 2018. They correlated individual exposure levels to air pollution with the subsequent development of Alzheimer’s disease, while also accounting for the presence of other chronic health conditions.
The study revealed a important association between increased exposure to air pollution (specifically fine particulate matter) and a higher risk of Alzheimer’s.This association was notably stronger in individuals who had previously experienced a stroke. Hypertension and depression showed a minimal additional impact on the relationship.
These findings suggest that air pollution contributes to the onset of Alzheimer’s disease primarily through direct pathways, rather than indirectly through other chronic illnesses. Individuals with a history of stroke appear to be particularly vulnerable to the detrimental effects of air pollution on brain health.
“In this large, nationwide study, we found that long-term exposure to fine particulate matter air pollution was associated with an increased risk of Alzheimer’s disease, largely through direct effects on the brain, rather than through common chronic conditions like hypertension, stroke, or depression,” the authors conclude. “Our findings, indicating that people who have had a stroke may be particularly vulnerable to the harmful effects of smog on the brain, highlight an vital intersection between environmental and vascular risk factors.”
The researchers emphasize that improving air quality could be a crucial step in preventing dementia and protecting the health of older adults.
Sources:
* Deng, Y.,et al. (2023). Association of long-term exposure to fine particulate matter with Alzheimer’s disease and related dementias in the US Medicare population. PLOS Medicine. https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1004278
* Adnkronos. (2023, November 21). ‘PLOS Medicine’,l’inquinamento atmosferico potrebbe contribuire direttamente alla malattia di Alzheimer. https://www.adnkronos.com/salute/malattie/2023/11/21/plos-medicine-linquinamento-atmosferico-potrebbe-contribuire-direttamente-alla-malattia-di-alzheimer_766196.html
* Alzheimer’s Association. (n.d.). Alzheimer’s facts and figures. https://www.alz.org/alzheimers-dementia/facts-and-figures
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