Key Takeaways
- Wildfire smoke may be particularly hazardous to brain
health, according to a 10-year study of more than 1.2 million
southern Californians.
- Exposure to wildfire smoke increases the risk of being
diagnosed with dementia more than other forms of air
pollution.
- The risk of exposure to fine particulate matter
(PM2.5) air pollution is much more pronounced when the
source is wildfire smoke than when it comes from other sources,
such as motor vehicles and factories.
- To lower their risk, people should update their home air
filtration systems when possible, stay inside when the air quality
is unhealthy, and wear an N95 mask outside when the Air Quality
Index reaches 100.
PHILADELPHIA, July 29,
2024 /CNW/ -- Exposure to wildfire smoke
increases the risk of being diagnosed with dementia more than other
types of air pollution, according to a decade-long study of more
than 1.2 million people in southern California. The findings, reported today at
the Alzheimer's Association International Conference®
(AAIC®) 2024, in Philadelphia and online, suggest the brain
health threat posed by wildfire smoke is higher than other forms of
air pollution.
![#aaic24 (PRNewsfoto/Alzheimer's Association) #aaic24 (PRNewsfoto/Alzheimer's Association)](https://mma.prnewswire.com/media/2470275/AAIC24_rgb_Logo.jpg)
Wildfire smoke, motor vehicles and factories all emit a type of
air pollution called fine particulate matter (PM2.5).
This is a microscopic mixture of solid and liquid droplets in the
air that are 30 times smaller than the width of an average human
hair. Researchers found that the risk of dementia diagnosis due to
exposure to PM2.5 in wildfire smoke was notably stronger
— even with less exposure — than the risk due to the other sources
of PM2.5 air pollution. Exposure to non-wildfire
PM2.5 raised the risk of dementia diagnosis, but not as
much as wildfire smoke.
High levels of PM2.5 also have been shown to
raise the risk of heart disease, asthma and low birth weight.
"With the rising global incidence of wildfires, including in
California and the western U.S.,
exposure to this type of air pollution is an increasing threat to
brain health," said Claire Sexton,
DPhil, Alzheimer's Association senior director of scientific
programs and outreach. "These findings underscore the importance of
enacting policies to prevent wildfires and investigating better
methods to address them."
Researchers analyzed the health records of 1,227,241
socioeconomically diverse Kaiser Permanente southern California members who were 60 years or older
between 2009-2019, none of whom had been diagnosed with dementia at
the beginning of the study. Total PM2.5 was estimated
from various sources, including satellite-derived aerosol
properties and Environmental Protection Agency monitoring.
Researchers used air quality monitoring data, satellite imagery and
machine learning techniques to separate wildfire and non-wildfire
PM2.5. They determined each study participant's exposure
to both sources of PM2.5 according to where they lived.
They compared that information to subsequent diagnoses of dementia
in participants' health records.
Reported for the first time at AAIC 2024, the researchers
observed a 21% increase in the odds of dementia diagnosis for every
increase of 1 microgram per meter — or µg/m3, which is
the amount of particulate matter in a cubic meter of air — in the
three-year average wildfire PM2.5 exposure.
Comparatively, they determined study participants had a 3%
increased risk of dementia diagnosis for every increase of 3
µg/m3 in the three-year average of non-wildfire
PM2.5 exposure.
"Previous research has found that exposure to PM2.5
is associated with dementia, but in light of our large, long-term
study, it's apparent the risk from exposure due to wildfire smoke
is an even bigger concern," said Holly
Elser, M.D., Ph.D., the study's first author and a neurology
resident at the Hospital of the University of
Pennsylvania, Philadelphia.
"Air pollution produced by wildfires now accounts for more than 70%
of total PM2.5 exposure on poor air quality days in
California. This is a real
problem."
Dr. Elser noted several reasons why PM2.5 produced by
wildfires might be more hazardous to health: they are produced at
higher temperatures, contain a greater concentration of toxic
chemicals and, on average, are smaller in diameter than
PM2.5 from other sources. She said more research needs
to be done to determine the exact mechanisms.
"The findings appeared most pronounced among individuals from
racially and ethnically minoritized groups and in high poverty
areas," said Joan A. Casey, Ph.D.,
senior author of the study and assistant professor in the
Department of Environmental and Occupational Health Sciences at the
University of Washington, Seattle.
"These findings underscore that clinical and health policies
seeking to prevent dementia-associated disparities should include
efforts to reduce exposure to long-term wildfire and non-wildfire
PM2.5."
Drs. Elser and Casey recommend that people update their air
filtration systems and check the air quality on their weather app
if they use one. An Air Quality Index (AQI) number of 100 or higher
means the air is unhealthy to breathe. To reduce their risk when
the AQI is 100 or higher, people should stay inside when possible
and close the windows, and wear an N95 mask when they go
outside.
About the Alzheimer's Association International
Conference® (AAIC®)
The Alzheimer's
Association International Conference (AAIC) is the world's largest
gathering of researchers from around the world focused on
Alzheimer's and other dementias. As a part of the Alzheimer's
Association's research program, AAIC serves as a catalyst for
generating new knowledge about dementia and fostering a vital,
collegial research community.
AAIC 2024 home page: www.alz.org/aaic/
AAIC 2024 newsroom: www.alz.org/aaic/pressroom.asp
AAIC 2024 hashtag: #AAIC24
About the Alzheimer's Association®
The
Alzheimer's Association is a worldwide voluntary health
organization dedicated to Alzheimer's care, support and research.
Our mission is to lead the way to end Alzheimer's and all other
dementia — by accelerating global research, driving risk reduction
and early detection, and maximizing quality care and support. Our
vision is a world without Alzheimer's and all other
dementia®. Visit alz.org or call 800.272.3900.
- Holly C Elser, M.D., Ph.D., et al. Long-term wildfire
smoke exposure and incident dementia in a large California cohort. (Funding: the U.S. National
Institute on Aging R01-AG071024)
*** AAIC 2024 news releases may contain updated data that does
not match what is reported in the following abstract.
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SOURCE Alzheimer's Association