Posted on Nov 22, 2016, 6 a.m.
Ambient fine particulate matter can damage the brain’s structure and impair cognitive function.
Air pollutants that originate from a variety of sources – such as power plants, factories, trucks and automobiles and the burning of wood – is characterized as having a particle size of a diameter of 2.5 millionth of a meter (referred to as PM2.5). Prolonged exposure to such ambient fine particulate matter has been shown by previous studies to travel deeply into the lungs and ma raise the risks of heart attacks and strokes. EH Wilker, from the Beth Israel Deaconess Medical Center (Massachusetts, USA), and colleagues analyzed data collected on over 900 men and women, ages 60 years and older and free of dementia and stroke, who were enrolled in the Framingham Offspring Study. The team evaluated how far participants lived from major roadways and used satellite imagery to assess prolonged exposure to PM2.5. The team measured total cerebral brain volume, a marker of age-associated brain atrophy; hippocampal volume, which reflect changes in the area of the brain that controls memory; white matter hyperintensity volume, which can be used as a measure of pathology and aging; and covert brain infarcts. Data analysis revealed that an increase of a mere 2 micrograms per cubic meter in PM2.5 associated with greater risk of covert brain infarcts and smaller cerebral brain volume, equivalent to approximately one year of brain aging. Observing that: “Exposure to elevated levels of [ambient fine particulate matter] was associated with smaller total cerebral brain volume, a marker of age-associated brain atrophy, and with higher odds of covert brain infarcts,” the study authors submit that: “These findings suggest that air pollution is associated with insidious effects on structural brain aging even in dementia- and stroke-free persons.”
Wilker EH, Preis SR, Beiser AS, Wolf PA, Au R, Kloog I, Li W, Schwartz J, Koutrakis P, DeCarli C, Seshadri S, Mittleman MA. “Long-Term Exposure to Fine Particulate Matter, Residential Proximity to Major Roads and Measures of Brain Structure.” Stroke. 2015 Apr 23.