Air pollution linked to an increased risk of Alzheimer’s disease

A largest-of-its-kind study published in Environmental Health Perspectives found that exposure to traffic-related air pollution is associated with an increased risk of developing Alzheimer’s disease later in life.

In short:

• Individuals who were otherwise cognitively healthy but had greater exposure to air pollution were more likely to have indicators of Alzheimer’s disease in their cerebrospinal fluid.
• These indicators point to an accumulation of amyloid plaques in the brain, which can lead to an increased likelihood of developing Alzheimer’s in the future.
• Air pollution particles have the ability to enter the brain directly through olfactory nerves, causing stress, inflammation and potential damage.

Key quotes:

“Our results add to the growing body of evidence that suggests that air pollution directly contributes to neurodegeneration.”

Why this matters:

Air pollution is one of the leading risk factors for human health globally, responsible for an estimated 6.6 million deaths in 2019 alone. While many of the negative effects of air pollution are well established, the results of this study suggest that air pollution has a much more extensive impact on health than previously understood, even at levels of exposure within the current health standards set by the EPA. The authors of this study highlight the need for further research to better grasp and prevent the full range of harmful outcomes associated with exposure.

Related EHN coverage:

• Air pollution linked to Parkinson's disease in two new studies
• Eliminating fossil fuels would save millions of lives, study finds

More resources:

• Health and Environment Alliance (HEAL): Resources on Air Quality.
• US Environmental Protection Agency (EPA): Air Topics (including air quality data from where you live)

Casey, Emma et al. for Environmental Health Perspectives vol. 132, 4. Apr. 3, 2024