More on air pollution and Alzheimer's disease

We've written before about research on a link between air pollution and Alzheimer's disease.  We know, for example, that people living near freeways are more likely to develop Alzheimer's disease.  An hypothesis about this has been that oxides of nitrogen enter the blood stream through the lungs and then find their way to the brain.  Meanwhile, fine particulates follow the path of the olfactory nerve from the nose to the brain.  And, apparently, changes in levels of air pollution can be correlated with changes in the incidence of dementia.  So there appears to be a cause and effect relationship.

Recent research at the University of Washington's Alzheimer's Disease Research Center has gone further in confirming the relationship.  The Winter/Spring issue of Dimensions; the magazine of the UW Alzheimer's Disease Research Center carried an interesting article on the research.  The research was published in the journal Environmental Health Perspectives in August 2021 as "Fine Particulate Matter and Dementia Incidence in the Adult Changes in Thought Study."  It drew on data from the ongoing and extensive study, "Adult Changes in Thought,"  (ACT) which began in Seattle in 1994.  Over the years, ACT has produced a huge trove of data that is being used by Alzheimer's researchers all over the world.  

In this case, researchers used measurements of levels of airborne pollutants in various neighborhoods around Seattle going back to the 1970s.  The study examined over 4,000 Seattle ACT participants, specifically focusing on about 1,000 who developed dementia during the course of the study.  They correlated the addresses of the participants with the levels of fine particulates measured in their neighborhoods.  While the instruments used to measure the particulates varied over the decades, the researchers used a new air pollution exposure model to estimate exposures from 1978 to 2018.  The study concluded "the evidence suggests that air pollution has neurodegenerative effects, and that reducing people's exposure to air pollution could help reduce the burden of dementia."

A finding was that a difference in air particulate levels of 1 microgram per cubic per cubic meter (that's not much) between neighborhoods could be associated with a 16% difference in incidence of dementia.  They article noted that this is about the difference in levels measured at Pike Street Market (origin of Starbuck's Pike Place coffee and near downtown) and those measured in residential areas around Discovery Park.  Discovery Park is near where one of our sons and his family live and is well away from the pollution-generating activities down town.