New research has confirmed a troubling link between air pollution and dementia, raising fresh questions about the long-term health impact of city living and vehicle emissions.
While earlier research has suggested a link between air pollution and dementia, this new analysis — led by researchers at the University of Cambridge — is the most comprehensive to date, drawing on 51 studies and involving over 29 million people exposed to pollutants for at least a year.
The researchers found a positive and statistically significant association between three types of air pollution and dementia: particulate matter (PM2.5), nitrogen dioxide, and soot.
PM2.5 — fine particulate matter — comes from car exhaust, power plants, and wood-burning stoves. Nitrogen dioxide is another byproduct of fossil fuel combustion. Soot, often found in vehicle emissions, is also a form of particulate pollution.
All three pollutants can penetrate deep into the lungs and bloodstream, and have long been linked to respiratory and cardiovascular diseases.
For every 10 micrograms per cubic meter of PM2.5, a person’s relative risk of dementia increases by 17%. For soot, the risk rises by 13%.
The findings may fuel debate over environmental regulations, particularly in high-traffic urban areas like Dallas, where air quality concerns have recently drawn scrutiny.
Earlier this year, The Dallas Express reported that Americans face a significantly higher lifetime risk of dementia than previously believed — an estimated 42% risk after age 55, more than double prior estimates.
Senior author Dr. Haneen Khreis said the research provided “further evidence to support the observation that long-term exposure to outdoor air pollution is a risk factor for the onset of dementia in previously healthy adults,” according to The Guardian.
It is believed air pollution may contribute to dementia through chronic inflammation and oxidative stress — a process that damages cells, proteins, and DNA.
“Tackling air pollution can deliver long-term health, social, climate and economic benefits,” Khreis added. “It can reduce the immense burden on patients, families, and caregivers, while easing pressure on overstretched healthcare systems.”