Jiu-Chiuan Chen, M.D., Sc.D.
University of Southern California
Women in their 70s and 80s who were exposed to higher levels of air pollution were more likely to experience greater memory decline and more Alzheimer’s-like brain atrophy than women in the same age group exposed to cleaner air, according to an NIEHS-funded study.
Researchers used data from 998 women, aged 73 to 87 years, who had up to two brain scans five years apart and took part in an annual episodic memory assessment between 1999 and 2010 as part of the landmark Women’s Health Initiative. The Women’s Health Initiative was launched in 1993 by the National Institutes of Health and enrolled more than 160,000 women. The brain scans were scored on the basis of their similarity to Alzheimer’s disease patterns by a machine learning tool that was trained with brain scans of people with Alzheimer’s disease. The researchers also collected information about where the women lived and environmental data from those locations to estimate their exposure to fine particle air pollution.
The researchers found that long-term fine particle air pollution was associated with accelerated decline of episodic memory based on memory assessments and predominately affected immediate recall and new learning. They also found that higher Alzheimer’s risk scores, which indicate more Alzheimer’s-like brain atrophy, were also associated with higher air pollution and partially explained the association between air pollution and memory decline.
According to the authors, the study provides new information about how fine particulate air pollution may alter brain structure and contribute to Alzheimer’s disease by identifying some of the brain changes linking air pollution and memory decline.
Citation: Younan D, Petkus AJ, Widaman KF, Wang X, Casanova R, Espeland MA, Gatz M, Henderson VW, Manson JE, Rapp SR, Sachs BC, Serre ML, Gaussoin SA, Barnard R, Saldana S, Vizuete W, Beavers DP, Salinas JA, Chui HC, Resnick SM, Shumaker SA, Chen JC. 2019. Particulate matter and episodic memory decline mediated by early neuroanatomic biomarkers of Alzheimer's disease. Brain 143(1):289-302.