A recent study published in The Lancet Planetary Health has found a significant link between long-term exposure to outdoor air pollution and the risk of dementia. The analysis of data from almost 30 million people revealed that particulate matter with a diameter of 2.5 microns or less (PM2.5), nitrogen dioxide (NO2), and soot are associated with an increased risk of dementia.
The study, which included data from 51 studies across high-income countries, found that exposure to PM2.5 increased the relative risk of dementia by 17% for every 10 micrograms per cubic meter (μg/m³) of pollutants in the air. The average roadside measurement for PM2.5 in Central London was 10 μg/m³.
Exposure to NO2 and soot also showed a positive association with dementia, with relative risks of 3% and 13%, respectively. The researchers noted that these findings provide further evidence to support the observation that long-term exposure to outdoor air pollution increases the risk of dementia in previously healthy adults.
The study’s senior author, Dr. Haneen Khreis, stated that tackling air pollution can deliver long-term health benefits, including reducing the burden on patients, families, and caregivers. The researchers emphasized the need for stricter limits on pollutants from transport and industry sectors, as well as regional and international policy interventions to combat air pollution equitably.
The study’s findings have significant implications for dementia prevention and highlight the importance of an interdisciplinary approach that incorporates urban planning, transport policy, and environmental regulation.
Source: https://medicalxpress.com/news/2025-07-term-exposure-outdoor-air-pollution.html