Exposure to specific types of air pollution has been linked to a higher risk of developing dementia, according to the most comprehensive research of its kind. Dementia currently affects an estimated 57 million people worldwide, with figures expected to rise to at least 150 million by 2050. This new study, led by researchers at the Medical Research Council’s Epidemiology Unit at the University of Cambridge, systematically reviewed 51 studies involving over 29 million participants exposed to air pollutants for a minimum of one year.
++ Martine McCutcheon declared bankrupt following marriage breakdown
The research identified a significant positive association between three common air pollutants—PM2.5 (tiny particles from vehicle emissions, power plants, and wood-burning stoves), nitrogen dioxide (from burning fossil fuels), and soot (from vehicle exhausts and wood fires)—and the incidence of dementia. For every 10 micrograms per cubic metre increase in PM2.5, the relative risk of dementia rose by 17%, while soot exposure was associated with a 13% increase. These pollutant levels were found to meet or exceed these thresholds in central London, Birmingham, and Glasgow in 2023.
Dementia’s most common form, Alzheimer’s disease, affects approximately 982,000 people in the UK, with symptoms including memory loss, difficulty concentrating, and mood changes. Dr Haneen Khreis, senior author of the study, emphasised that the findings strengthen the evidence that long-term outdoor air pollution exposure contributes to dementia onset. She highlighted the broader benefits of tackling air pollution, including health, social, economic, and climate advantages, as well as easing pressure on healthcare services.
++ Toddler suffers severe burns after contact with Britain’s most dangerous plant
While the study provides robust evidence, researchers noted limitations such as a predominance of white participants from high-income countries. Future research should involve more diverse populations. Dr Isolde Radford from Alzheimer’s Research UK stressed the need for government leadership to address air pollution as a major modifiable risk factor for dementia. She called for a coordinated, cross-government strategy that extends beyond health departments to include environmental agencies, urging urgent action to combat this invisible threat.
