Even Short-Term Bursts of Air Pollution Impairs Older Folks’ Cognitive Functioning

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Fleeting rises in air pollution can damage the memory and thinking capacity of older men. A new study found the smallest amount of spikes in airborne toxins led to lower brain function scores among participants.

Coming only a few weeks after researchers found that being exposed to air pollution accelerated cognitive decline for people aged over 70, the new study published in Natural Ageing found a potential causal link from pollution to brain function, expanding existing scholarship that ties toxins affecting lungs to the toxins affecting the brain.

Short-Term Cognitive Function Impairment

The research team evaluated the brain functioning of some 1,000 men in the Greater Boston area in the US, with an average age of 70. The men’s performances were cross-mapped with local air quality data. As per the study’s findings, higher levels of particulate matter pollution were linked to low scores among participants, even if the level of toxins affecting lungs did not ever reach ‘dangerous’ levels as defined by the World Health Organization (WHO). The paper stated: 

“The effects of short-term PM exposures on cognitive ability and brain health may be in the same direction as those from long-term exposures […] additionally. Our results underscore that such short-term cognitive function impairment may happen under PM2 […]. Additionally, our results underscore that such short-term cognitive function impairment may happen under PM2.5/black carbon concentrations below the levels that regulators consider acceptable.”

According to experts, being exposed to toxins affecting the lungs can potentially lead to brain inflammation. Inflammation is the body’s natural, protective response to fight harmful contaminants; however, too much inflammation may lead to brain-related impairments and disease. Besides inflammation, accumulation of magnetite particles and amyloid plaques (an Alzheimer’s-associated protein) have been observed in the brains of humans and animals exposed to air pollution. Brain damage, whether in children or adults, can have a lifelong impact. 

Philippe Grandjean, professor of environmental medicine at the University of Southern Denmark and an adjunct professor of environmental health at the Harvard T.H. Chan School of Public Health, says: “You only have one chance to develop a brain — you can’t go back and do it over or get a transplant […] the main concern is really that even minor dysfunction of the brain can have dramatic consequences […] you can live a normal life with decreased liver function, and you can donate a kidney for transplantation, and it won’t affect your health. But for the brain, every IQ point is important.”

Brain-Related Health Risks

While IQ is not a comprehensive measure of the brain or social functioning, it has provided a good sense of whether contaminants may be damaging the brain, and losing IQ points can potentially impact one’s quality of life, education, and income. Grandjean says:

“In regard to the brain, we need to prevent even the smallest adverse effects […] “We’re not just trying to prevent brain disease, we’re trying to protect optimal brain development from supporting the highest possible functioning level and quality of life in the interest of the next generation and society.”

Toxins affecting lungs can emanate from a cocktail of things, from industrial emissions to heavy metals to pesticides to particulate matter and other airborne contaminants that can harm the human body, including, it seems more and more likely, the brain. Besides studying the brain-related health risks of individual contaminants in air pollution, scientists have studied how levels of particles that are 10 micrometers or smaller (PM10) and particles that are 2.5 micrometers or smaller (PM2.5) are associated with brain-related conditions.

Growing evidence suggests that toxins affecting lungs may more deeply affect long-term human health, behavior, and functioning than initially thought. Experts say this motivates the need for science-driven regulations and policies to minimize exposure.

Effect on the Ageing Brain

According to Andrea Baccarelli, a senior author of the study and professor of environmental health sciences at Columbia University in New York, the new research confirms the link between toxins affecting lungs and their effect on the ageing brain. Whereas the short-term effects could be reversed in situations where air pollution clears and the brain reboots and starts working back to its original level, multiple occurrences of these higher exposures cause permanent damage. He concluded: 

“Our findings do not suggest yet that all older people should be on anti-inflammatory drugs because these are medications with side-effects we cannot take lightly […] more holistically, reducing inflammation through a healthy diet, such as more fruit, vegetables, and fiber, or having regular physical exercise, can go a long way not only to make us generally healthier but also to make us more resilient against environmental threats such as air pollution.”