In Europe, people over 65 years of age represented around 21.3% of the total population in 2023. In Latin America and the Caribbean, although this proportion is lower, ageing is also progressing rapidly: in 2022, 9.7% of its inhabitants had already turned 65.
This phenomenon poses significant challenges, particularly in terms of cognitive health. Recent research suggests that brain aging may progress chronologically, particularly in people exposed to high levels of environmental pollution. Air pollution – particularly fine particles measuring less than 2.5 microns (PM 2.5) – has been associated with accelerated cognitive decline in older adults, affecting key functions such as memory and thinking.
Attacking the barrier that protects the brain
Neuroscience has shown that these tiny particles have the ability to infiltrate the brain through the olfactory nerves. Another route of access involves areas where the brain’s protective barrier, called the blood-brain barrier, is weaker.
It has also been shown that constant exposure to air pollution can trigger chronic inflammation, which further deteriorates the effectiveness of the barrier. The risk is particularly high in the elderly: with age, this natural wall becomes more permeable, a porosity that facilitates the entry of nanoparticles into the brain and increases the risk of significant neurological damage.
The ravages of pollution
Population aging is leading to increasing rates of memory problems and dementia. Currently, it is estimated that around 55 million people worldwide suffer from dementia, and this number is expected to skyrocket to 152 million by 2050. It is arguably the most pressing public health issue of our time.
And while there is no cure, we can identify personal, social and contextual risk factors that impact age-related deterioration.
For example, a 2021 study showed a significant link between continued exposure to polluted air – particularly the aforementioned fine particles – and cognitive deterioration, in addition to an increased risk of developing dementia.
One of the key findings of this study is the relationship between living near highways or in urban areas with heavy vehicle traffic and accelerated mental decline. Residents of these environments are at significantly increased risk of developing cognitive problems and dementia, including Alzheimer’s disease.
The work also explored the impact on the brain through brain imaging, which revealed abnormalities in people exposed to high levels of pollution. These alterations include a reduction in the volume of white matter, which is essential for communication between different regions of the brain. These are losses that can result in slower processing of information and difficulties in functions such as memory and learning.
Finally, images have shown the presence of silent microinfarcts, small areas of brain damage caused by a lack of blood circulation. The experts who detected them suggest that exposure to air pollution seems to increase the incidence of these cardiovascular accidents, due to the chronic inflammation it causes in the cerebral vascular system.
Steps to breathe cleaner air
Various recommendations have been proposed to mitigate the effects of air pollution on brain health, particularly with regard to the risk of developing dementia. Addressing this challenge requires implementing public policies that improve air quality in cities.
One of the main proposals is the creation of green infrastructure, such as parks and wooded areas. These spaces not only improve air quality, but also promote mental health by providing spaces for physical and social activity and emotional well-being.
In addition, it is essential to strengthen regulations on industrial and road emissions, two major sources of pollution in urban areas.
There is therefore an urgent need to design and disseminate public awareness campaigns to inform the population and promote measures to reduce exposure. These measures are essential to protect the brain health of the most vulnerable populations, particularly the elderly.
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About the authors: Vanessa Perez is a professor in the Department of Psychobiology and Master in Clinical Neuropsychology, International University of Valencia | Maria J. Garcia-Rubio is a professor at the Faculty of Health Sciences of the International University of Valencia – Co-director of the VIU-NED Chair of Global Neuroscience and Social Change – Member of the Research Group in Psychology and Quality of Life (PsiCal), International University of Valencia
This article was originally published on The Conversation. Read the original.
