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Recent research from University College London (UCL) indicates that prolonged exposure to elevated levels of air pollution can adversely affect the cognitive health of older adults in England.
Published in The Journals of Gerontology: Series A, the study identifies a connection between nitrogen dioxide (NOâ‚‚) and fine particulate matter (PM2.5) exposure and declines in cognitive abilities, most notably in language proficiency.
NOâ‚‚ is predominantly released into the atmosphere through the combustion of fossil fuels, particularly from vehicles such as cars and trucks, along with emissions from power plants and off-road machinery. PM2.5 mainly arises from burning petrol, diesel, oil, or wood, and consists of microscopic particles that can penetrate deep into the respiratory system.
The research team evaluated data from 1,127 participants aged 65 and above, who took part in the ELSA Harmonised Cognitive Assessment Protocol (ELSA-HCAP) in 2018.
The team assessed participants’ exposure to air pollution over a span of eight to ten years (from 2008 to 2017) and examined their cognitive functions, including memory, executive functions (such as planning and problem-solving), language skills, and overall cognitive capacity.
Participants underwent various established neurocognitive evaluations, including the “East Boston Memory Test” and the “Wechsler Memory Scale,” alongside tasks for immediate and delayed recall, reverse counting, and shape drawing.
The results revealed that those living in regions with higher concentrations of NOâ‚‚ and PM2.5 demonstrated significantly poorer performance in cognitive assessments compared to those in areas with moderate pollution levels. Notably, the link between high pollution exposure and language skills was particularly pronounced, with individuals in the most polluted neighborhoods often ranking in the lowest third of cognitive test results.
Furthermore, the study explored the varying effects of different pollution sources on cognitive health. It found strong associations between industrial emissions, home heating, and fuel combustion (including coal and oil) with diminished language performance, specifically relating to speed and fluency in word access and production.
While the researchers did not delve into the underlying mechanisms of their findings, they suggested that the impairment might be linked to the temporal lobe function. This area of the brain plays a crucial role in language and semantic processing. More comprehensive studies are warranted to further investigate these connections.
Dr. Giorgio Di Gessa, the lead author, stated, “This research demonstrates that air pollution poses risks not only to respiratory and cardiovascular health but also to cognitive function, especially among individuals exposed to high pollution levels for extended periods.” He added, “The most consistent links we observed were associated with language abilities, which might imply that certain pollutants uniquely affect specific cognitive processes.”
In light of these findings, the researchers advocate for enhanced air quality regulations, particularly in regions where pollution levels remain elevated, to safeguard the cognitive health of an aging population.
Professor Paola Zaninotto, deputy director of the ELSA study, remarked, “Our use of high-quality data to track pollution over a decade provides solid evidence that sustained exposure to pollutants is detrimental to cognitive health.”
Funding for the ELSA study comes from the National Institute on Aging as well as various UK government departments, coordinated by the National Institute for Health and Care Research (NIHR).
Study limitations
It is important to note that the air pollution data utilized in this study spans only ten years, which may not adequately capture lifelong exposure patterns. Additionally, the reliance on annual average pollution levels may overlook the effects of short-term peaks in pollution. The study’s sample size and its focus on England also limit the generalizability of the findings to wider populations.
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