A recent study published in the Euronews journal revealed that increased exposure to polluted air may raise the likelihood of developing Alzheimer's disease.
Polluted air has long been considered a potential risk factor for Alzheimer's disease, as well as for various chronic conditions such as hypertension, depression, and stroke. However, it has not been clear whether dementia arises directly from exposure to pollutants or if chronic diseases exacerbate the impact of pollution on the brain.
Researchers from Emory University in the USA analyzed data from over 27 million individuals aged 65 and older, collected from 2000 to 2018. About three million participants were diagnosed with Alzheimer's disease during this period.
The study also examined the prevalence of three major comorbidities—stroke, hypertension, and depression—to determine how they might influence the development of dementia.
The level of air pollution from fine particulate matter (PM₂.₅) was compared with health data from participants based on their place of residence. These particles are dangerous as they can penetrate the lungs and enter the bloodstream. Major sources of pollution include exhaust fumes, emissions from power plants and industrial facilities, wildfires, as well as the burning of wood and fossil fuels in homes.
The authors of the study concluded that polluted air has a direct impact on the brain, bypassing the effects of chronic diseases. They noted that the link between air pollution and Alzheimer's disease is particularly pronounced in individuals who have suffered a stroke.
"Our data show that stroke patients may be more susceptible to the harmful effects of polluted air on brain health, highlighting the importance of the relationship between environmental and vascular risk factors," the researchers stated.
Furthermore, prolonged exposure to fine particulate matter is associated with an increased risk of chronic diseases, including cardiovascular ailments, hypertension, and mental disorders.
It is important to mention some limitations of this study. The level of pollution was determined based on postal codes, which does not account for individual addresses. Additionally, the study focused solely on outdoor air quality, without considering factors such as cooking and heating, which may also contribute to indoor pollution levels.
Mark Dallas from the University of Reading, who was not involved in the study, noted that despite the limitations, the findings support existing data that air pollution is a modifiable risk factor for dementia. He added that overall, the work emphasizes the importance of clean air for brain health throughout life.
