Link Between Air Pollution and Dementia Risk
Recent research has shown that exposure to certain types of air pollution may increase the likelihood of developing dementia, according to a thorough study. It’s estimated that around 57 million people are living with dementia globally, and projections suggest this number could rise to at least 150 million by 2050.
This report was compiled by researchers from the Medical Research Council’s epidemiology unit at the University of Cambridge, incorporating a systematic review of 51 studies. They analyzed data from over 29 million individuals who had been exposed to air pollutants for a minimum of one year.
While air pollution has long been recognized as a contributing factor to dementia, this particular research, being the most exhaustive of its kind, identified a significant correlation between three specific air pollutants and dementia risk. The pollutants of focus included PM2.5—derived from sources like vehicle emissions and burning wood—nitrogen dioxide from fossil fuel combustion, and soot originating from exhaust and wood fires.
These pollutants, when inhaled, can penetrate deeply into the lungs, leading to various respiratory issues and raising the risk of heart complications. The findings indicated that an increase of 10 micrograms per cubic meter of PM2.5 could raise the relative risk of dementia by 17%. Meanwhile, an equivalent rise in soot levels would contribute to a 13% increased risk.
In 2023, levels of soot and PM2.5 nearly approached or even surpassed concerning thresholds at roadside locations in places like central London, Birmingham, and Glasgow.
Alzheimer’s disease is the most prevalent form of dementia, affecting about 982,000 individuals in the UK. Common symptoms include memory impairment, concentration difficulties, and emotional changes.
Dr. Haneen Khreis, the lead author of the study, remarked that this research provides further validation for the idea that long-term exposure to outdoor air pollution is a risk factor for dementia in previously healthy adults. She emphasized that addressing air pollution could yield extensive long-term health, social, and economic benefits, helping to alleviate the burden on patients and healthcare systems.
It is thought that air pollution could trigger dementia by causing inflammation in the brain and oxidative stress, a chemical reaction in the body that can harm cells and genetic material.
The researchers noted limitations in their study, as most of the data collected came from predominantly white participants living in wealthier nations. They suggested that future studies should aim to include a more diverse range of participants.
Dr. Isolde Radford, a senior policy manager at Alzheimer’s Research UK, stated that this comprehensive review adds to the growing evidence linking air pollution—from vehicle emissions to wood-burners—with increased dementia risk. She stressed that while air pollution is a key modifiable risk factor, solving it requires significant government intervention.
Radford called for a robust, cross-departmental approach to health prevention, involving not just health agencies but also other sectors like environmental protection, to effectively combat the underlying causes of dementia risk.
The findings of this report were published in The Lancet Planetary Health.
