Does living near highways increase dementia risk?
Living close to highways exposes people to traffic-related air pollution, which can raise the chances of developing dementia, especially when combined with other factors like past infections. A recent study looked at people aged 60 to 75 from the UK Biobank database. It defined high exposure as living 50 meters or less from a major road, like a highway. Those with a history of infections but no high exposure had a 54 percent higher risk of Alzheimer’s disease and other dementias compared to those without infections. High exposure alone did not clearly raise the risk on its own.https://www.frontiersin.org/journals/dementia/articles/10.3389/frdem.2025.1668381/full
The real concern came when both factors were present. People with infections and high exposure faced a 164 percent higher risk overall. This jumped to 349 percent higher in those without the APOE4 gene variant, a common genetic risk for Alzheimer’s. In people who carry APOE4, the added risk from pollution faded and was not significant. The study suggests that for non-carriers with infection history, staying away from high-traffic areas could lower dementia odds.https://www.frontiersin.org/journals/dementia/articles/10.3389/frdem.2025.1668381/full
Other research supports this link. One analysis found that higher air pollution and proximity to major roads matched up with greater dementia risk in neighborhoods. Greener spaces and walkable areas seemed to offer some protection.https://cottonwoodpsychology.com/news/study-links-neighborhood-green-space-and-air-pollution-to-dementia-risk/ Air pollution from highways includes tiny particles and gases from vehicle exhaust that may harm brain health over time by causing inflammation or damaging blood vessels.
County-level studies also point to differences in dementia rates tied to local risk factors, including pollution exposure, though they focus more on diagnosis patterns than direct highway links.https://pmc.ncbi.nlm.nih.gov/articles/PMC12709554/
Sources
https://www.frontiersin.org/journals/dementia/articles/10.3389/frdem.2025.1668381/full
https://cottonwoodpsychology.com/news/study-links-neighborhood-green-space-and-air-pollution-to-dementia-risk/
https://pmc.ncbi.nlm.nih.gov/articles/PMC12709554/
