A new study conducted by scientists from Emory University in the USA analyzed data from over 27 million people aged 65 and older from 2000 to 2018; approximately three million of them were diagnosed with Alzheimer's disease. Simultaneously, the researchers examined the prevalence of comorbidities such as hypertension, stroke, and depression to determine how they might influence the development of Alzheimer's.
The link between air pollution levels, measured by the concentration of fine particles (PM₂.₅), and the risk of developing the disease was established based on the participants' place of residence. Fine particulate matter, which can penetrate the lungs and enter the bloodstream, primarily originates from vehicle emissions, power plants, wildfires, and household fuel burning.
The authors of the study noted that the results indicate that polluted air has a direct negative impact on the brain, rather than through the mediation of chronic diseases. This connection is particularly pronounced in individuals who have experienced a stroke. The researchers stated, "Our data suggest that stroke patients may be more vulnerable to the negative effects of polluted air on brain health, highlighting the importance of the interplay between environmental and vascular risk factors." It was also found that prolonged exposure to particulate matter is associated with an increased likelihood of developing cardiovascular diseases and mental health disorders.
However, the study has its limitations: pollution levels were assessed based on postal codes rather than specific addresses, and only outdoor air was considered, without accounting for indoor pollution factors such as cooking or heating.
Mark Dallas from the University of Reading, who was not involved in the study, noted: "Although the work is based on averaged pollution data and medical records, the results align with previously accumulated data that air pollution is a modifiable risk factor for dementia." He added that this study confirms a simple truth: the air people breathe over many years affects the aging of their brains.
